I spoke with an Outback Power Systems engineer recently. I had some specific questions about one of their inverters. He answered them quite clearly. I've always thought their products to be top line, if not the best. Anyhow he confirmed my main concern about the inverter I had a chance to buy on a deal. He also clarified one point that I was also wondering about.
The question relates to inverter/chargers, like Outback, Magnum Energy, Trace/Xantrex. Plain vanilla inverters, like most square wave inverters, are just inverters. They do not have battery charging circuitry incorporated within them. You need a separate charger to recharge the batteries from a generator or other AC power source when you have an economy inverter. Inverter/chargers have a battery charger incorporated into the unit. In the case of my Outback VFX3524M the charger has a maximum charge rate of 85 amps at 24 VDC.
These inverter/chargers all are setup so when the connected generator is fired up, the AC power to the inverter causes the inverter section to switch out. The AC power to the cabin then is coming from the generator. The generator power is also powering the battery charger section. I have wondered why this was? Why was the generator power not just used to power the battery charger section, while any AC loads would still be supplied by the inverter section? ???
Since I have a small generator this was of concern. By past experience I know that when my 2800 watt generator (derated by altitude to about 2300 watts) is working hard enough to power the old 75 amp Iota charger, it is not a good move to use the microwave at the same time. There's just not enough power available from the generator. Buying a larger generator would be a solution, but that's not a part of this scenario. Ideally I would like to be able to use the generator power to charge the batteries and leave the inverter to supply any cabin electrical needs.
Outbacks engineer supplied the answer. Keep in mind I have a planned 24 VDC system. The Outback 3524 inverter is designed to operate with an input voltage maximum of 32 volts. There are similar limits with other brands. Some are even less, like 30 volts maximum.
Batteries should be subjected to an 'equalization charge' about once a month to assist in achieving maximum battery life. An equalization charge is a higher than usual voltage, low current, charge rate. An equalization charge is done at 2.57 to 2.68 volts per cell (in a wet lead acid cell battery). In a 24 VDC system that is 31 to 32 volts.
Do you see the issue? The voltages are getting too close for the comfort of an engineer. In a real world situation it might happen that the charging voltage could spike higher than 32 and thus it might cause damage to the inverter/charger. Hence, the inverter manufacturer usually elects to program the inverter to drop out when the AC power in, is active.
I am not certain, but I do believe I killed my Exeltech 1100 watt inverter when I was equalizing the batteries. The Exeltech does not have a charger built in. I left it connected to the batteries. At the same time I bumped my stand alone charger into high voltage mode. It might have exceeded the design input voltage for the inverter. Poooof! Or maybe it was 'just one of those things'. ??? ???
Anyhow, I thought it was interesting.
I think this would be a good place to talk about good things, bad things, odd things, that we have encountered in alternative power systems.
My Trace inverters go off at about 21 volts low or 30 volts max. I have two 4024 Trace sine wave inverters stacked to make 240v. They are also over-current protected internally so that any short will trip them out and a manual reset is required if a short happens.
I know as I sometimes equalize and bulk charge with my DC welder. I doubt I am treating my batteries as well as possible but when doing it I monitor them pretty closely. I generally charge at between 60 to 100 amps but the welder does not taper off on charge as the batteries get full therefore monitoring is necessary. This is across 12 375ah batteries or 1125ah at 24v.
Excellent information guys and maybe Glenn, you could start up a separate section on off grid power? I love this idea.
Just some FYI, I had some free time between Christmas and New Years and decided to take a little road trip, just drive alone for hours and see some country to try to get rid of all the crap in my brain from the past year. Anyway, as I traveled west on old Route 66 as I was coming into Tucumcari, NM, I saw this huge wind turbin and as I got closer I could see that I could get right up to the base so I did. This thing was huge, I'm guessing 20' or more at the base and at least 150' tall with blades that had to be 100' long.
I took a bunch of pics if anyone is interested. On my way home a few days later, I was a billboard on I-40 eastbound that said it was the largest wind turbin in the world!!! Suspect that maybe it was when installed but, maybe not anymore. It is 1.6Megawatts!
I had heard that these big turbins were quite noisy and that is way some people object to them. Well, let me tell you this monster was so quiet I couldn't hear it running at all.
I was also amazed at the 100's of wind turbins I saw in Oklahoma, Tx, NM and even AZ. Someone sure believes in them!
PS: I went all the way to the Grand Canyon. Highly recommend the trip on the old Mother Road.
Okie Bob
Lets just go ahead and add our thought's , pix and everything to this thread, BoB. :) It will be easy to find here and this thread can expand endlessly on off grid power.
Getting ready to change my solar tracker cylinder to a larger one so I have to rotate the panels to the sun in the morning after which it tracks all day.
Readings .... set 1 in light but 160 degrees away from the sun at 8 AM(back of tracker toward the sun) - 1 amp immediately change to 16 amps when toward the sun.
set 2 .5 amps away 10 amps when toward the sun.
So happy to see this thread start up.
My planned solar PV installation is probably fairly unique. I say that because the favored cabin spot is not at all close to the favored PV panel spot. Three hundred and twenty five feet separate the two. :o
Running low voltages like 12 or even 24 volts over a distance like that would suffer huge power losses to electrical resistance unless the cables were huge. Huge copper cable costs a huge amount of money. What to do? Run the panels in series to up the voltage and keep the amps low. The problem with this is that many charge controllers cannot handle high input voltages. Some of the popular charge controllers only accept up to 24 VDC, some 48 VDC. The three panels I'm buying put out about 86 VDC maximum power voltage when connected in series. With the 7.3 amp maximum power output I can get away with using 4 gauge copper wire from the panels to the cabin and charge controller and have less than 2% voltage drop. That's pretty good.
The catch is most charge controllers can not handle that voltage. The Outback MX-60 or the newer replacement FlexMAX 60 can handle it. So even though the FlexMAX60 will cost about $500, I'll save a bundle on wire costs.
Some of you may have noted I seem to be big on Outback. I don't work for them and none of my relatives do. They make an excellent product, that's all.
The Outback charge controller can also be programmed for just about any voltage combination you could come up with for both input and output (battery bank) voltages.
More trouble for monitoring etc, but you could build a battery house at the panels and just send 120 or 240 underground to the cabin, but I'm sure you considered that already. Thought I'd bring it up for pro and con discussion.
Some other things to be aware of when choosing PV panels and charge controllers....
PV panels get hot with the sun shining on them and they are producing power.
PV panel output voltage drops as the panel heats up. A panel laid flat or nearly flat on a roof will run at a higher temperature than a panel mounted so air can freely move around it, like on a pole top mount.
Conversely, as a panel is cooled, as on a -20 degree day, it's output voltage rises. Cold weather performance is enhanced. This is good as cold weather usually means shorter days, fewer hours of sunshine. That won;t make up for the greater number of hours os summer sunshine, but it helps.
However, along with cold weather and the higher output voltages comes a danger. All electronics have a design range for input voltages; a lower limit and a higher limit. Drop below the lower limit and the unit may just stop functioning until the voltage rises. Exceed the upper limit and the unit may stop functioning permanently. Toast.
What this means is that on a frosty January morning as the temperature hits its low point and the sun peeks over the hill and strikes the PV panels, the voltage may spike well over the normal operating range. With panels in series this could easily overrun the maximum voltage of the charge controller. Therefore this low temperature voltage condition must be taken into account when designing a system where low temperatures may be encountered.
There is a specification called 'open circuit voltage' or Voc listed for all PV panels. This is supposed to be the maximum output voltage but cold temperatures can cause this to be exceeded. A general rule of thumb is to take that figure and multiply it by 1.3 to obtain the maximum likely voltage output and select the charge controller, or the PV panel strings with that figure in mind. Destruction of the charge controller is possible, maybe even likely if that voltage maximum is exceeded for even a split second.
My location in the Jemez has reached a lowest temperature of -32 degrees in the past ten years according to the hour by hour weather records I researched. Running the numbers on my prospective setup indicates I should not have any cold weather over voltage problems. Hurray!
There is a 'tool' on the Outback website that can assist in checking whether or not a particular arrangement of panels can be safely used with Outback charge controllers. Go to http://outbackpower.com/resources/string_sizing_tool/ (http://outbackpower.com/resources/string_sizing_tool/). The tool allows you to choose your panels from a list or to enter custom data in case you panel is not listed. You select battery bank voltage and the maximum and minimum temperatures for the location. The graph chart then indicates whats okay and what is not.
Quote from: glenn kangiser on January 14, 2009, 01:51:12 AM
More trouble for monitoring etc, but you could build a battery house at the panels and just send 120 or 240 underground to the cabin, but I'm sure you considered that already. Thought I'd bring it up for pro and con discussion.
Excellent point. :)
I ran the numbers for 120 VAC. I didn't run 240 VAC because my installation does not need 240 VAC (and two inverters stacked).
I found there was little difference. By inverting the DC panel power to 120 VAC at the panels I could have changed the wire size to 6 AWG, instead of 4 AWG.
However, that would have meant locating the batteries down at the panels, or very near them. Somehow I prefer to have the batteries up at the cabin. It would have also entailed running some cat5 cable from the batteries to the cabin, where the remote control panel would be, to allow remote control of the inverter; on-off functions and programming of the charge controller from the Outback Mate2.
It didn't seem to be a great net gain to me, in this particular situation. However, this is something that should be considered for any installation where the PV panels are not located right nearby the point of use.
Another factor in deciding against placing the batteries and inverter down at the batteries, and running 120 VAC up to the cabin, was the placement of the generator. The generator would be used about once a month to equalize the batteries. If the batteries and inverter were down the hill at the solar PV and battery location it would make sense to place the generator down there as well. If I didn't do that I'd be faced with running 325 feet of proper sized wire from cabin to panel/inverter/battery location. I didn't really want the genset down the hill. I'd rather have it up near the shed or cabin. Maybe that's just my personal quirks showing. :-\
So there's another chapter in the mysterious workings of my brain. ::)
I like the stuff nearby also. You just don't know what those little machines are up to when they are down there by themselves.
I wanted this information on my solar tracker on the Underground Cabin Update but I will link it here for those who don't get over there. http://countryplans.com/smf/index.php?topic=151.msg78994#msg78994 Info and pix on the previous page also. Will update pix soon. I hope... [waiting]
Plus like right now, according to my spies in them thar mountains ;D there's three feet of snow. :o :o
With my planned installation of the batteries and related peripherals at the cabin it is much handier. More so since it didn't really make all that much difference on wire size.
The cost of the larger wire would likely have been exceeded by the building materials for a secure battery house.
Quote from: MountainDon on January 14, 2009, 01:57:57 AM
Conversely, as a panel is cooled, as on a -20 degree day, it's output voltage rises. Cold weather performance is enhanced. This is good as cold weather usually means shorter days, fewer hours of sunshine. That won;t make up for the greater number of hours os summer sunshine, but it helps.
However, along with cold weather and the higher output voltages comes a danger. All electronics have a design range for input voltages; a lower limit and a higher limit. Drop below the lower limit and the unit may just stop functioning until the voltage rises. Exceed the upper limit and the unit may stop functioning permanently. Toast.
1.3 should be plenty of safety factor. Totally unloaded, I think that the theoretical maximum for a PV cell is .7V and it goes down from there with temperature. The other good thing is that as soon as you apply any load to the cell, the voltage drops dramatically. That's why you need a much higher PV voltage to charge batteries... 18 to 28V for a 12V battery.
Don, I'd be surprised if the nice inverters don't have overvoltage input protection, and overcurrent output protection. Anyway... 1.3xpanel voltage seems like a good rule of thumb.
-f-
First, I must correct an error. I realized as my brain woke up this morning, that I posted some slightly incorrect info in the post regarding where to place the inverter in my situation and the wire sizes.
I had stated that for running AC from the panel/batteries/inverter location down the hill the wire size would have been 6 AWG. That is wrong. 6 AWG is the maximum size wire the VFX3524 inverter will accept on the AC connections.
When I originally ran the numbers the wire size fir the DC or AC run up the hill turned out to be the same; 4 AWG. However that was with a smaller output inverter. With the VFX3524 capable of putting out 3500 watts the actual computed wire size would be 3 AWG, which is a bit larger. That's calculated at full capacity which it is true, would likely never be reached. ???
My apologies for any confusion.
You are right on Frank, with a couple of footnotes.
It depends in part how close to the input limit your setup is running during normal operation. Many installations would never have a problem. In my case I'm getting close to pushing the limits with the panels I want, but according to Outback still within bounds.
During those periods of early morning very cold weather times there may not be enough of a load to help bring the voltage spike down. The charge controllers do not act instantly when they receive the wakeup call from the power coming from the PV panels. That is, they receive the power, wakeup, scan the batteries to see what they need, then turn the input into output. Enough of a delay to potentially cause problems. The 'nice' ones go to sleep during the hours of darkness. That could allow plenty of time for a spike to zap something. At least that's what the Outback tech guys have told me.
Although I don't have any figures on this, altitude can play a factor in the output power of a PV panel. At higher altitudes there is less air between the panel and the sun. This could have a small effect on over volting. ???
There is a device available that can help with cold morning start up over volt protection for panels connected in series. The Apollo Low Temperature Overvoltage Bypass (http://apollo%20low%20temperature%20overvoltage%20bypass) will cut one panel in the string out of the circuit at either 32 or 50 degrees F (panel temperature). It automatically reconnects when the temperature rises. More $$ to spend though.
This topic is not meant to be an organized coherent lecture series; it's just like any other topic here. Everyone can pitch in, query and discuss. Much of what may be presented may be slightly opinionated, but I try to keep it factual. I will be trying to keep anything I present within NEC guidelines. If you are off in the boonies or simply don't feel the need to "toe the line" by all means follow your own drummer.
Wiring, that is wiring in the DC areas of an alternative power system, is an area where many folks make errors. One of the first and most common errors is in the colors of wires selected for the DC side. The confusion, or errors, come from our familiarity with DC automotive wiring. When looking at the automobile battery the positive or hot lead is usually red and the negative, or ground lead is black. Using red and black like this would cause your system to fail an electrical inspection.
The NEC makes no distinction between AC and DC wiring as far as color codes are concerned. The neutral or negative wire is permitted to be white or grey. That's all. No black neutrals or negatives. Black is reserved for a hot or positive wire. Red may also be a hot or positive wire.
Also automotive battery cables do not have the necessary UL approval and are not approved by the NEC for any wiring, including battery hookups. Ditto for welding cables;not approved. This may only be important to you if your installation has to be inspected by an inspector who follows the book.
More on wires for specific tasks will come later in another post.
Fuses and Circuit Breakers and Switches may be listed for only AC use, some can be used with both. This is because AC power and DC power react differently. The AC power we use changes direction 60 times per second (60 Hz). This change of state makes it easier to break the circuit cleanly. One thing that distinguishes a DC switch are the much heavier contacts. Using an ordinary home wall switch (AC only) to operate a DC powered device will lead to switch failure. The contacts may weld themselves shut in a worst case scenario.
For DC circuit protection there are acceptable fuses and breakers. Square D makes a line of household circuit breakers that are approved for use in circuits up to 24 VDC. The actual breaker info says it can handle up to 48 VDC, but the NEC limits it to 24 VDC as under some conditions a 48 VDC system may go over the 48 volt limit. So the Square D QO series panels and breakers are ideal for many DC circuits that may be used in cabin off grid systems. Don't try to mix AC and DC in the same panels though.
Inverters should be wired with a disconnect and a fuse or circuit breaker in the DC supply line. The wiring and fuse or breaker must be sized according to the inverter requirements. If you use a circuit breaker as protection they will usually be accepted as a suitable disconnect as well. I have found solarseller.com (http://solarseller.com/) to be a good source for many off grid power items, including high amp capacity breakers.
Proper boxes and panels for enclosing these breakers may need some fabrication. Whether or not they meet NEC approval is another matter. ??? UL approved enclosures are expensive. Let your conscience and the inspector be your guide.
Gotta go for now
Okie Bob,
We also rode a bit of Route 66 last Feb. My first drive out in that area. My first look at American windfarms. Quite impressive ... as was the whole 9k mile driving vacation.
I wonder how many windfarms that we saw were owned/intangled by Enron? I know they owned a number of them.
I had a question under my cabin topic (http://countryplans.com/smf/index.php?topic=2335.msg79344#msg79344) that I thought I would answer here.
I had heard that you wanted to keep an even number of panels. Is that incorrect?
Yes, I am using an odd number of panels. Panels are used in even numbers quite often. There is no real reason to do that though. Panel mounts do very often come in 2x2 or 2x3 configurations. That could be one reason. The number of panels should be driven by the total number of watts that are required from the panels.
In my case I decided that I wanted about 500 watts total. More would be alright too. In a location where the cabin and panels are close together there are many configurations that could supply that easily. My 325 foot distance renders some solutions less practical.
For example many panels are basically putting out 12 VDC. Many folks here with small systems have based their systems on such panels and use 12 VDC battery banks. They may have several batteries in parallel connections to maintain that basic 12 VDC configuration. Right now I won't bother with getting into the pros and cons. Rather I want to explain the reasoning behind my choice of three panels, an odd number.
Panels come in many different base voltages; 12 VDC, 16 VDC, 20 VDC, 24 VDC and even higher like 50 VDC. Some panel combinations would have required both series and parallel connecting. Some of those would have resulted in 48 VDC at 12 amps or more. Raising the amps transmitted to to that level resulted in wires that would have to be larger.
The three Sharp 208 watt panels in series have a Vmp (maximum power voltage) of 85.5 volts. Each panel puts out an Imp (maximum power amperage) of 7.63 amps. Connected in series the amperage (Imp) stays at 7.63. Keeping the amps low and bringing the volts high results in being able to use a smaller wire.
Using as small a wire gauge as I could was important to my situation where the panels and batteries are separated by 325 feet. At maximum output I will have less than a 2% voltage drop which is what I was aiming for. If I parallel connected the panels the wire would need to be much larger to avoid excessive power loss. It would have been very expensive as well.. As it is I have $450 worth of wire and I got a good price on it.
Series stringing like that is only possible with a charge controller like the Outback MX or FlexMATE 60 or 80. They allow virtually infinite voltages up to their maximum of 145/150 and also work with virtually any battery bank voltage. They are extremely versatile. There are some other charge controllers that could be used with higher voltage arrays. One other reason I'm going with Outback equipment is all their components can be interconnected to one central indoor remote control for programming and monitoring.
I hope that is clear.
Great post Mtn.Don! One I will be sure to refer to many times in my quest for solar power. Has anyone mentioned Home Power magazine? I recently subscribed to it, and it seems to fit the bill for the DIY'er, with lots of buyers guides.
I can't help but feel overwhelmed by the calculations that go into solar. I work with Ohms law now and then at work, but solar gets me worried every time. Is there any books or links you would suggest to combat fear with education? Thanks
Most of what I've learned about solar PV has been gleaned from a variety of sources. That and simple application of what electrical/electronic knowledge I already had.
The following websites do have information, sometimes you have to search and read through the entire site. They also sell a variety of solar equipment.
I have purchased from the first four businesses listed and have no fault with any of them.
Affordable Solar, Albuquerque, NM (http://www.affordable-solar.com/)
TheSolar.Biz, in SW NM (http://thesolar.biz/default.htm)
solarseller.com Long Beach, CA (http://solarseller.com/)
Northern Arizona Wind & Sun (http://store.solar-electric.com/)
Northern AZ also has a pretty good info section (http://www.solar-electric.com/).
Backwoods Solar (http://backwoodssolar.com/) I've not bought from them, but there's useful information.
Don,
Thanks for the links. What have you read about using microwaves and other such appliances with such a heavy draw at start up? Is there anything special that need to be taken into consideration in your opinion.
Thanks,
Craig
Depends on the size of your inverter and additional loads, soomb.
I can run my 5 horsepower rock crusher motor on mine but it likely is only drawing about 2 or 3 horsepower most of the time actual load. Forgot --- I'm actually running it on 240v or two 4000 watt inverters. d*
Mine and others have no problem. I don't know that microwaves have such a surge as just plain heavy current draw, but since it is usually for a short time, they can work out fine. I'd say a 2000 watt inverter with some surge capability would handle it though.
Glenn,
Thanks for the input. I need to sit down and get to reading. I want to be able to prove to my wife that when we build a cabin she will not be sitting in a cold corner reading by oil lamp light (I like the rustic idea, but I like having my wife around more).
Thanks again.
Craig,
The inverter has to be sized to be able to operate the microwave. The advertised rating you see, say 600 watts, is the cooking power. A 600 watt cooking power microwave will probably draw about 1100 watts from the inverter. Sometimes you can only find that info on the microwave itself, not in the info or on the box.
The inverter should be a pure sine wave inverter. Personal experience has shown that some microwaves don't work on (cheap) square wave inverters. That may vary. ??? Even if the microwave works on square wave it will be noisier and fan may run slower. The unit will run hotter; not cooking hotter, but the electronics will waste energy and run hotter with a square wave.
The battery bank and cabling has to be able to supply the current draw. That's one reason why I prefer in 24 VDC systems over 12 VDC battery systems.
FWIW, I don't even consider modified sine wave for anything but misc. use - say plugged into the truck cigarette lighter or something to charge Ryobi batteries - phone etc.
For anything serious relating to living, only pure sine wave.
Since the subject has come up, I'll get into some pure sine wave vs square wave inverters. I call them square wave, not modified square wave like all the ad talk does. That's because modified or not, if the word square is in there there are disadvantages. Pure sine wave is the only way to go if you are running anything but simple lights.
Advantages of Pure Sine Wave Inverters.
Never any doubt anything you plug in will work if the inverter can supply enough watts.
Items that can have issues are...
Microwvaes as noted above.
Inductive loads like motors (and the microwave) run quieter, cooler and faster. Running cooler means they last longer. This applies to a lot of tools.
Some devices like FL lights, radios, TV's, answering machines, etc might have a hum. Some do and some don't. Some are worse than others. We have a TV that is fine and a couple CFL's that have a slight, usually inaudible, hum.
Laser printer and photocopiers may have problems with output on square wave.
My wife's electronic sewing machine does not work on square wave.
Some variable speed plug in power tools will burn out.
Some microprocessor controlled furnace and pellet stoves may not operate correctly.
Battery chargers that have the little cube that plugs into the outlet may not work or may get very hot and burn out. This may also apply to things like flashlights that you plug directly into an outlet. Not all of them, but I did a number on an AC adapter for a portable radio. Very smelly event. However, most battery chargers that have a regular AC cord and plug that connects a charger to the wall outlet should work fine.
Digital clocks in radios may not work.
As you can see there are a lot of 'may not work'. Electrical devices are not all created equal. In some cases the item works but draws more current putting more load on the batteries. Those items will be running hotter as well and as mentioned above may not last as long due to the heating.
Advantages of Square Wave Inverters, AKA Disadvantages of Pure Sine Wave Inverters.
Pure sine wave are more expensive, much more expensive.
Some things will burn out -- such as my $600 Bosch rotohammer w/soft start drilling -- Square wave took the speed control out of it.
My water pump only pumped about 1/2 as much water on the same power on square wave. I understand there is something else you can add to make it run better but why bother -- get a sine wave and save money elsewhere.
As stated, motors run hotter, slower and run longer (not longer in lasting longer, but runs longer as in more time per day). Sort of counter productive making a refrigerator motor run hotter with it located right under the cold box of most refrigerators. And since they are one of the biggest power users that will but much more load on the batteries.
Don and Glenn, I am really enjoying this topic and would like to see it moved up to the top as one of the regular what ever you call it prime topics. I still believe that the more time goes by the more people are going to be getting off grid. Obviously, not those in town but, those outside the city limits and the further outside the city limits the more people are going to be getting off grid.
Don, you have certainly added some useful notes that I would never have considered had you not posted them and for that I think you.
I may be the only one that is interested in wind power too but, maybe that will change with time? I'd sure like to see more on wind and know Glenn has a wind turbin or two? And I'd really like to hear this same sort of exchange where I can learn from your mistakes!
Okie Bob
I don't make mistakes, BoB. [crz]
It is called planned obsolescence. Some sooner than others. [waiting]
For those who don't care to go through the whole Underground Cabin Update looking, here's a link to the start of my Solar Tracker Project, which I might add is a huge success. :)
http://countryplans.com/smf/index.php?topic=151.msg77051#msg77051
A pix of the tracker and Wind Generator together.
![](https://i35.photobucket.com/albums/d184/glennkangiser/trackerandwindgenerator.jpg)
I'll sticky it for a bit and well see how long interest continues. :)
Hmmmm... I wonder if you were to use a big isolation transformer on the output of a modified-square wave inverter. Seems like that should result in a sine at the output of the secondary....
-f-
You think it would knock the corners off the squares, Frank?
Don, or anybody else, I have some copper plate - maybe about .065 or so. Stole it from my son, but when I mentioned that fact he gave it to me -- didn't want me to look bad I guess...
I haven't found much on plate or strip - maybe 1 inch or so wide, ampacity. There must be something on it. hmm
Goto Storm Copper (http://stormcopper.com/design/Buss-Bar-Ampacities.htm) click on ampacity tables.
I'm pondering using copper straps in place of regular battery cables. ???
1/16 x 1 would just about cover my needs... 175 amps max more or less.
That's what I was thinking about. I think these were parts of metal roofing or for a copper range hood he made for a customer - probably the range hood now that I think about it. He put a copper roof on in Santa Monica I think it was.
I also want to build my own knife switches so I don't have to leave an Ax nearby to cut the cables in case of emergency. Shouldn't be any worse than welding though, eh? 'cept for that hydrogen... [crz]
Thanks for the link.
Ax = the ultimate knife switch rofl rofl
Storm Copper offers loads of copper goods. They claim they have 1,000,000 pounds of copper stock in inventory. :o
FYI, they also sell copper nails and silicon bronze nuts and bolts.
Cool -- I just picked up my milkbox full of silicon bronze scrap from the valley house. I think it must have been 150 to 200 lbs. I use it for casting replica parts though I haven't done it in years.
Interesting discussion on DC vs AC buss bars.
" 50556
Copper Size for DC low-voltage high-amperage
November 18, 2008
Hello all,
I'm a new plating learner.
Now I have a rectifier which the rating the output rating is 12VDC,4000A. The current size of copper busbar which link from rectifier to chrome tank is 12mm x 100mm. To me, I think it is under size since the the current ampacity of it should be around 2600A (in AC, DC should be less). My question are:
1) What is the actual size of busbar i have to used in this case?
2) How to calculate for DC busbar?
3) Is that the size will be different for DC and AC 50 Hz? In same current, copper which apply to DC circuit should be more larger than AC 50Hz circuit?
Thanks
Khor Patrick
Plating Learner - Malaysia
contact button
November 24, 2008
This link should give you all the info you need.
http://www.stormcopper.com/design/Buss-Bar-Ampacities.htm
Kurt Sammons
- Inman, SC
November 24, 2008
Thanks, Kurt. I think that page should be fine for AC current calculations.
For DC bussing for a rectifier, however, I think the standard number used for decades, 1000 amps/square inch, is an easier and safer approach.
Khor, for an electroplating bussing installation I would consider the ampacity of a 12 mm x 100 mm busbar (slightly under 1/2" x slightly under 4") to be about 1860 Amps, but we could call it 2000 Amps. You need two, not one, 12 mm x 100 mm busbars, although most experienced installers would probably use four 6 mm x 100 mm bars instead. Isn't that what is coming out of the rectifier?
Regards,
Ted Mooney, P.E.
finishing.com
Brick, New Jersey
December 5, 2008
Ted
I have never claimed to be an electrical engineer, but have run alot of wire in my day. I never considered that there would be a difference in ampacity for AC vs DC. I reached out to the folks at Storm Copper for validation. My question was very simple:
Is there a significant difference between AC ampacity and DC ampacity?
There response was:
Yes. DC causes greater heating of the bus. I believe de-rate AC values around 30%.
A quick study of their ampacity tables complicates the issue even more. a 1/2"x2" buss is listed at 1000 amps. Fits your number perfectly. A 1/4"x4" buss however is at 1250 amps. Maybe more heat transfer area to keep it cool.
However, Storm is suggesting to derate the AC by 30% for DC current meaning those two bars would be 700 and 875 amps.
Kurt Sammons
- Inman, SC
December 15, 2008
Thanks again, Kurt. I've been sizing bus bar the same way for 40 years and would dearly love to get out of that rut and hear a newer and better way. And I understand that a 1/4 x 4 bar has greater surface area and cooling, and consequently higher current carrying capacity, than a 1/2 by 2 bar.
But the fact is, 1000 Amps/sq. in has proven itself for decades. If these charts indicated higher ampacity than the simple old-fashioned method, I would want to go along with them. But when they suggest that copper can only carry 70 to 87 percent of what we know it has safely and reliably carried in tens of thousands of plating and anodizing installations over 5 or more decades, I think it is they who need to go back to the drawing board :-)
Their figures may be for bus bars enclosed in power distribution boxes or ducts rather than out in the open air though.
Regards,
Ted Mooney, P.E.
finishing.com
Brick, New Jersey"
http://www.finishing.com/505/56.shtml
I put my new bank of batteries in last night using copper buss bars. Boy is that easier than cables. I cut my bars off sheet copper with a power hacksaw (band saw) as it was raining and I did not want to start my shear - had to move a welder/generator - two trucks and a trailer for power.
I drilled holes low near the ends so they would fit the terminal bolts easily. I would have spent hours making cables. The buss bars took less than an hour for all 8 of them and are much neater in appearance. I may split hose to slip over them for insulation - lots of bare copper there. I'd hate to drop a wrench across them. d*
Reading the charts over I decided that 1/6 x 1" was big enough but I went about 1 1/4" on the buss tying the two banks together and attaching to the inverters. I drilled 2 extra holes in the center of that buss for future connections. Possibly I'll get a pix today.
Please post the pics when you get them. I am still learning and I think I have a visual on what you are discussing but the photos will be of great help.
Thanks
Like these. These are lead coated or silver plated copper.
thank you sir.
Based on the discussion of using hose to jacket them, do they get all that hot?
No. But sheathing them will give more protection against accidental short circuiting.
Those are the commercial version of what I did - I wonder if they will go sideways like mine as there is only about 5/16 clearance from the bolt to the lead of the terminal. I guess a tin snips could take care of that though.
Here's mine - love that old wiring on the original set. :)
![](https://i35.photobucket.com/albums/d184/glennkangiser/batterybank.jpg)
I wonder if the lead or tin coat makes a significant difference? There is something called skin effect - seems more to do with a/c but it is effected by the coating such as copper over steel works pretty good.
Quote from: soomb on January 24, 2009, 12:46:18 PM
thank you sir.
Based on the discussion of using hose to jacket them, do they get all that hot?
soomb, there is no heating involved especially with the amount of batteries I have using several different supply paths. I sized the strips I cut assuming maybe near 200 amps max current so the 187 was close enough for me for the 1/16 x 1" copper and like the old engoineers comments above - I am not worried about derating it. I will never reach near that load.
Assuming 4000 watts per inverter - I have 2, so 4000 watts / 24 volts = 166 amps - round up to 180 amps for inefficiencies - so running 240 volts with both inverters I could pull max 360 amps or so. 180 amps each - the bars I used would do that at 30 degrees C according to the chart or 86f temp. rise. I would not hit that often as my biggest load is the pump at 10 amps per inverter - or possibly some of my machines may be more. Also though - that would be on 2 banks of batteries only - I now have 5 banks of 4 batteries so each would only get about 70 amps at maximum current draw of both inverters.
Even the 1/16 x 1/2 is good for 103 amps under the following conditions.
"* Applicable to typical in-service conditions (indoors, 40C ambient temperature), horizontal run on edge, and free from external magnetic influences." So I have used twice as big a buss as necessary for my purposes. I myself would not like to see the temperature rise they allow as that is just power being wasted to create heat -- so I went for the larger buss bars.
I do find heating under heavy charge or heavy use if a terminal is corroded increasing it's resistance. When heavy charging with the welder I often take the non-contact thermometer and take temp readings at all of the terminal connections cleaning any that get a temperature rise.
Quote from: glenn kangiser on January 24, 2009, 01:56:26 PM
I wonder if the lead or tin coat makes a significant difference? There is something called skin effect - seems more to do with a/c but it is effected by the coating such as copper over steel works pretty good.
Something to do with removing the oxidation of Cu from the battery bank I would imagine; though that is conjecture. From the Storm Copper website on battery interconnects...
Generally, Battery Connectors are plated in Tin for sealed battery applications and Lead or a Tin/Lead Alloy for Flooded Battery Connector applications.I figure one could cheat and simply apply solder to the ends of the straps once the holes are drilled/punched.
Glenn, I got to tell you I would not have believed those were your batteries with the nice neat battery strap connectors if I had not seen the familiar rats nest wiring job behind it. ;D ;D I am impressed to no end. :D
My GC2's have vertical threaded stud mounts so I could run the straps flat. I think that is what I will do between batteries.
[rofl2] I couldn't even believe the difference. :)
I think I will coat the ends with protectant of some sort - petroleum jelly ? Grease - guess I'll google it. The NAPA battery protector stuff doesn't seem to last.
I see from the quote above they are rated standing on edge, but with the smaller batteries cooling should not be a problem.
Note that the cables coming off of the new batteries are something like 000 aluminum service entrance cable with the ends protected with the special dissimilar metal grease and then a copper pipe sleeve smashed flat over them and drilled. No corrosion of any kind on them noted in a couple years.
The batteries with the straps invite maintenance :D, whereas with the rat's nest it's difficult to see the cell caps let alone get at them at times. ;D ;D I use cables in the 4 GC2's in the RV and I'm afraid it looks a little scary too. I was going to do cables (home made) but I believe the straps are now a no brainer.
I use a gallon water jug with a hose in the cap to get through the mess but it's still not fun. I like the straps.
Hey Glenn, I'm not sure if it is appropriate for this application, but you could mask off the ends of your straps and dip them in that plastic dip coating they make for tool handles.
-- Pritch
That is a good idea, Pritch. Plastic is plastic I think. Good idea.
As an alternative rather than that I could likely also get away with the 2" wide 10 or 20 mill tape they make I think - that would be easy. Not as heavy but likely sufficient.
To DC or to AC the small off grid cabin?
With apologies to William Shakespeare.
When I began to design my cabin I knew it would be off the electrical grid; the connection would cost more than the land and the cabin. Way more. I first thought I would build a power system that used a lot of the DC power directly to power DC lighting. The first advantage to going in the direction of a DC power based cabin that I thought of was the apparent simplicity. No inverter losses involved to run simple things like lights, I thought. I was willing to include a medium size inverter of 1100 to 1500 watts to enable the use of a microwave, perhaps a vacuum cleaner or the occasional use of a toaster.
I discovered the availability of DC voltage CFL lighting;12, 24 or 48 VDC. Good I thought. Yes they cost more than the 120 VAC CFL I could buy in bulk at Costco, Sam's or even Lowe's. Yeah, and I'd have to order them and pay for shipping. Fair enough.
So I drew plans. I had a DC panel. I had an AC panel. Even though I was building off the beaten track, under the radar I wanted to keep the building and it's components within the scope of the building codes and the NEC. Pretty much. Therefore I would need to keep the DC separate from the AC. I soon discovered that automotive type fuses and switches would be problematic. But then I got lucky and discovered that the Square D line of circuit breakers were UL approved for up to 48 VDC! On-off switches remained a problem. Let it be noted that virtually all on-off household switches are not DC rated. They will burn out quickly when used on DC circuits. Automobile switches are not UL listed. I did find some DC rated switches, UL listed for about $12 apiece.
My wife wanted to use some table lamps in the cabin. Alright no problem, I can use some of those DC CFL's in them. Ooops, the socket switches would not survive the DC experience for long. Well, OK, I'd figure something out on that.
The next thought was how to ensure keeping the DC separate from the AC, for it was a 'given' that there must be outlets for the microwave, toaster, possibly a vacuum cleaner, and now outlets for the DC lamps. Not a big deal I said. ::) I knew that the NEC allowed the use of 240 VAC receptacles and plugs for DC use as long as there was no 240 VAC power systems in the cabin. Home free, I thought.
For the AC power I figured I'd use either a modified square wave inverter or possibly a pure sine wave inverter such as the Exeltech 1100 watt unit in the RV. (Note: I refer to a modified square wave inverter. I refuse to call them a modified sine wave inverter as that is a marketing lie. Square wave is square wave, modified or not. Some devices work fine on square wave; incandescent lamps for example. Some devices work, but under duress; like motors. Motors run slower and hotter. They waste power. In some cases they burn out prematurely. Some devices simply won't work at all. The microwave in our RV is an example. It makes all the proper noises, the turntable turns, and after nuking a cup of water for 2 minutes it emerges as cold as it was when it was placed in the microwave. Some devices like a small battery charger for NiCad cells destroy themselves when powered by square wave power. I had a very odoriferous event on a camping trip in UT when I attempted to recharge some flashlight batteries. I was very leery of allowing my wife to use her computerized sewing machine off a square wave inverter.
Ok, I said. I'll move the Exeltech pure sine wave 1100 watt inverter from the RV to the cabin. Perfect! NO, wait a sec. Not so perfect. d* How many times has my dear wonderful, beautiful, warm, loving, adorable, accepting of all my foibles and idiosyncrasies, wife started the microwave (it needs 1000 watts to run) and then simultaneously attempted to use some other AC operated appliance. This won't fly, I realized. Add to that the different outlets, some for DC, some for AC; this was becoming complicated. Momentarily I considered no electricity at all; Aladdin oil lamps for lights and the rest be dammed. :o No.
FYI, Exeltech makes some very fine pure sine wave inverters that are stand alone, no battery charger included and priced fairly. They also have a stackable series.
OK. I know there are many folks out there who have a DC based power system; some are members of this forum. What they have set up works for them according to what I see. That's great! More power to them! ;D My point in this is that you should take the time to run through your expectations of your off grid power system before deciding on the final plan.
My hybrid AC/DC system had me using more wire. DC systems usually require larger gauge wires because of the higher amperage the wires are asked to carry. There is the problem of DC listed switches. Then there's the fact that DC powered CFL's cost more than the commonly available SC versions. FYI, the only difference between an AC fluorescent lamp and a DC powered one is the ballast. The tubes are the same. It had two service panels instead of one, and more wire of a heavier gauge.
After the considerable amount of time devoted to considering all the above I decided that for this particular cabin of ours it did not make sense to do a DC based system. The PV panels have remained more or less constant. Ditto the charge controller and batteries.
However the big change comes with the wiring. Our cabin is basically wired like the typical home. AC circuits for virtually everything; 14-2 wire; the AC power coming from a pure sine wave inverter capable of supplying 3500 watts continuously (30 amps). I have fudged a little; I have three 12 VDC lights that will operate directly off DC , just in case the inverter craps out at some point. I also have a 24 VDC ceiling fan because it's efficiency is so vastly superior to the best of the 120 VAC units. Everything else is just like at home on the grid. No strange light bulbs, no strange receptacles, no wondering if I can use the microwave and the toaster at the same time.
Anyhow, my purpose here was to incite thought. I'm sure there are folks who will have no issues with a DC based system To them, I say, good show! You have simplified beyondd where I draw the line. I'm just not quite ready to venture there. Think it through before you finalize your off grid plans.
I hope all that makes some sense. Any comments will be appreciated.
I agree with you, Don.
With the efficiencies of modern Sine Wave inverters, and the lower cost of standard A/C equipment plus the availability of the normal A/C items, it only makes sense to me to run standard A/C for anything other than a small system. Even the small system is likely easier to do with A/C in my opinion.
My brain cells got prompted to recall this by a comment in another topic.
In our cabin wiring I have wired several outlet halves to be switched (on-off) by a wall switch. Some of these are designated for items like the microwave, the TV and the stereo. All these have phantom loads; the clock in the microwave and the remote control circuitry in the TV and stereo. For those who are not aware, anything that has a cordless remote control is using a small amount of power even when turned off. While it sits there waiting for the wake up signal it uses a timy bit of power.
Same thing applies to the cordless phone base station, and many other items in any home. Around home I don't worry about it. Right now I know there are a couple battery chargers in the garage that are sitting there wasting a little power. Plus there's the garage door opener waiting for the signal to open the door. And the sensor activated lighting around the building exterior. And the sensor activated light that turns the front entry light on when one comes through the front door; handy when carrying stuff. Also guaranteed to surprise anyone breaking through the door.
Back to the topic of switched outlets for off grid power. I also used a switch with a pilot light. The light is low power neon and only comes on when the switch is in the ON position, no light when turned off. I've also used those for the exterior lights. A glance at the switches by the door will let you know you forgot to turn off the lights outside.
Similar to this one (mine are the standard toggle type)...
![](http://assets.twacomm.com/assets/2055108707/product_images/17895.jpg)
Also available in a three way type. If you go for these beware that some pilot eqipped switches have the pilot illuminated when the switch is off; handy for finding in the dark, but not what we want for this purpose.
topic on battery cable connections (http://countryplans.com/smf/index.php?topic=6181.msg80649#msg80649)
Off Grid Power System Calculators.
Here are several sites I've had bookmarked for some time. I like some more than others. Some have online forms that can be filled in. You click a button and it does the math. Others have print out forms and you do the math yourself. They may not be perfect in that the resulting recommended configuration is not necessarily the only way or the best way. However, they are a reasonable place to start. Remember, as always, garbage in = garbage out. You must enter realistic power usage, not want to wish for, but what you will use. Then add a little extra as insurance.
I think this one is my favorite
http://www.wagonmaker.com/script_calculator.html (http://www.wagonmaker.com/script_calculator.html)
Not bad either
http://store.altenergystore.com/calculators/off_grid_calculator/#load-calc (http://store.altenergystore.com/calculators/off_grid_calculator/#load-calc)
http://www.me.utexas.edu/~me374s/javatop.html (http://www.me.utexas.edu/~me374s/javatop.html)
http://www.evsolar.com/worksheet.html (http://www.evsolar.com/worksheet.html)
And a few more...
http://www.bigfrogmountain.com/calculators.cfm (http://www.bigfrogmountain.com/calculators.cfm)
http://www.solar4power.com/solar-power-sizing.html#battery (http://www.solar4power.com/solar-power-sizing.html#battery)
http://www.green-trust.org/2003/pvsizing/default.htm (http://www.green-trust.org/2003/pvsizing/default.htm)
http://www.solar-power-answers.co.uk/design.php (http://www.solar-power-answers.co.uk/design.php)
PLUS, the following is a good one that is meant for determining how many panels of your choosing can be safely used with your Outback Charge Controller. It was mentioned previously.
http://outbackpower.com/resources/string_sizing_tool/ (http://outbackpower.com/resources/string_sizing_tool/)
Batteries, Series VS Parallel
Most of us will likely end up with batteries in some sort of a series - parallel system, partly because golf cart and L16 style batteries are reasonably priced and because our system may need to be enlarged at some point. I figure that eight 6 volt golf cart batteries will fill our needs; two strings of four in series connected in parallel. If I need to increase capacity I'll add another string of four in series to be paralleled with the others. I'll know about that soon after getting it going. My battery box is going to be sized to accept up to twelve batteries of the L16 size just in case.
There are advantages and disadvantages to this. On the advantage side we just added batteries, didn't have to ditch the ones we had and buy larger ones. We can add four of the same capacity and increase our reserve power. One disadvantage to this series / parallel system is the large number of cells to maintain. Another is the increased number of cable or buss connections.
Another disadvantage to paralleling may be viewed as a positive to some. That is that a failed cell will not drop the design voltage as there are the parallel ones to make up the difference. It may not be obvious that there is a problem, until you notice that cell requiring more watering. So while the battery bank will maintain design voltage and still have pretty good capacity it will self discharge at a higher rate. A parallel bank with a bad cell will sap energy as the other cells try to charge it (this occurs continuously, even with no system load, which adds up in sapping energy).
This does not occur in a series only string. A bad cell in series will drag the voltage of the system down, but it will not absorb power from the other cells. The power passes through the bad cell. The failed cell may add some resistance (which does sap energy, but only when a load is applied) and, since it does not contribute any voltage, it will show as a reduced battery bank voltage. The lowered voltage makes it easier to spot a bad cell.
Bigger cells in series also mean fewer cells to maintain. Of course bigger cells also mean heavier more bulky cells, a downside in many remote locations.
My dream battery bank for our cabin would be:
- Twelve 2 volt 845 amp/hr HUP-One cells in series for a 24 VDC system; approx $7000+. There are some others by Rolls or Surette, but they are in the same price range. These are expected to last 15 - 20 years. Many have been in service longer.
So while the ideal may be a series only string, you need deep pockets to start with that.
Further to the above. A series /parallel also have the advantage of redundancy. A bad cell or battery in one series string could be temporarily dealt with by removing that string from the parallel array, until the cell/battery is replaced.
However to counter that a properly maintained battery bank consisting of HUP's or Rolls/Surettes is not very likely to give problems for many many years.
I knew you'd have some good points on this.
Now how to handle this problem of a cell dropping in a series of a parallel set. I found that equalizing as you and a dealer mentioned to me seems to help greatly -- head for 32 volts for a few hours. This is a hard one. Many chargers or inverter chargers don't want to go there.
I find that a charger working on just 2 of the 6 volt batteries - since I have a 12 volt charger can remove power from the group and charge certain parts of the series group without pulling the group down much -- recycling - pull it out of all and put it into 2 of them only, bringing them back up to meet the rest. The most effective is using the welder to get the equalization charge for me.
Soon I hope to be able to report on a new charger - MikeyB is checking on it tomorrow.
Locating the bad cells is easy - I pull all of the caps off of one series group and check every cell with the Hydrometer.
when done with that group I do the next one. Record the readings or mark the low cells for future monitoring after charging or equalizing. Specific Gravity of all should be in the good range. If one cell is significantly lower than the rest, then it needs attention or the whole pack will suffer. Distilled water only as necessary then equalize them.
Quote from: glenn kangiser on January 26, 2009, 11:49:59 PM
-- head for 32 volts for a few hours. This is a hard one. Many chargers or inverter chargers don't want to go there.
That is yet another wonderful thing about the Outback equipment. :D The charge rates are all user programmable. On a 24 VDC system the EQ charge can be set all the way up to 34 volts. :o
The Trace 4024 kicks out at 30.4 or maybe .2 I think as far as when inverting and equalizing with an outside source. Once it hits that voltage the system shuts down untill the voltage drops back to within he normal range. I have not checked for programmable settings as I don't use it for equalization. I should check it to see -- it is not fun to get lost in the programming menus on the Trace. Lots of owner manual study might help.
I did not notice sulfation releasing and battery improvement until equalization voltage got to 31.2 then the voltage would drop back to 30.8 as internal resistance dropped and additional charge was allowed in by the battery. SG (specific Gravity) improved in my worst cells also. I had at least 3 that were below to well below normal. All it takes is 1 below the rest in the string to kill a string of batteries.
Here are the Trojans that were given to me - they were a bit over 3 years old.
![](https://i35.photobucket.com/albums/d184/glennkangiser/L16s.jpg)
An inadequately sized system and overuse along with insufficient equalization and lack of sufficient maintenance has caused sulfation to the point that the owners couldn't get them to keep enough charge to keep their house running.
Somehow they had changed them out and just wanted them removed from their crawlspace. I thought this would be a great opportunity for me to play with desulfation. Here is one of the cells that is in worse shape. I marked it and took a pix so I could keep track of progress. I filled adjacent cells with rain water as one was dry on top and put the small desulfator on the two worst batteries until I get a bigger desulfator through Mike.
![](https://i35.photobucket.com/albums/d184/glennkangiser/sulfationTrojan-A-.jpg)
As you can see, the plates are nearly not visible through the sulfate crystallization in the above pix. I was able to get the 2 volt and 4 volt batter to take a charge with my 10 amp NAPA PWM charger. Some of the new NAPA chargers use pulse technology and are superior to the old chargers using much less power to make a better charge. I heard about it but they don't give any info in their catalog. I went to the Shumaker website to verify what the charger did. They manufacture it.
I have found this battery listed from $389 to $559 each on the net depending on the quality of dealer - some seem a bit unscrupulous.
I can still buy them in other brands for around $250 or maybe a bit less wholesale - just a guide price so you don't get taken advantage of.
The moral to all of this. I guess it would be, take good care of your Trojans and they will take care of you. [waiting]
Here is a link to another picture of the Two batteries I currently have the desulfator on showing what you should be able to see if the batteries were not sulfated as well as some more commentary on my tracker.
Trojans being repaired at the Underground Cabin! (http://countryplans.com/smf/index.php?topic=151.msg80770#msg80770)
Tesa, I split your questions off to "tesa's Off Grid System"
http://countryplans.com/smf/index.php?topic=6230.msg81195#msg81195 (http://countryplans.com/smf/index.php?topic=6230.msg81195#msg81195)
Don,
I may have missed it, but if you don't mind, have you had a hard time keeping your system charged from the panels alone down there? I helped a friend install his genset on his system in Fort Davis a month ago, and he is having a problem getting a good charge during the day. We sized the system properly, but he bought the pv panels on his own. Another outfit installed his controller, batteries and inverter. He's been telling me even during the sunny days, at night the genset kicks on twice for about a half hour. His genset is used soley for charging the batteries right now. Panels are in an open area at the highest point on his property. I am going off by assumption and the last time I was over your way, but I remember Jemez mountains being simiar to the fort davis area. Any pointers are greatly appreciated, as I am lost on the solar side of things.
If he has clear skies and no shadows over his panels then there is something wrong - maybe not enough panels or wired wrong.
Cold does not matter. Cloudy skies will drop panel output to maybe 1%to 5% in my experience.
Too much voltage loss on the wire - Long wire run? Small wire?
My panels put out great when the sun is out in the winter.
Lots of possible reasons this is happening...
The first thing I would do is to check the specific gravity of the battery electrolyte in each cell. Does the hydrometer reading indicate full charge after the charge controller indicates it's full? Is there one or more low cells? Some charge controllers are programmable; perhaps it is not allowing the batteries to actually reach full charge.
Check all the DC connections for corrosion and tightness. Using a non contact infrared thermometer on all connections with a good load applied can help find a connection with high resistance.
If the batteries check out fully charged on all cells after solar charging, then it would seem he's using, or losing, more power than anticipated. Or the battery bank is simply too small for what it's being asked to do.
The set points for the auto start generator may be set incorrectly. It seems to me if the generator is coming on for only a half hour something is wrong there. ??? I'd tell him to go and take a reading on the cells with the hydrometer when the generator kicks in. See what the state of charge really is; if charging is really needed at that point.
Does the generator only kick in during or immediately after a heavy load like running a big microwave for a while? That could be indicating battery capacity is insufficient to prevent rapid draw down of the battery voltage, which would cause the generator to kick in.
Anyhow that's where I would start.
How cold do the batteries get? Capacity of the batteries fall with cold. 32 degrees F = approx 20% less
Correct the sp gr for temp.
If the batteries are AGM's forget all the above about checking sp gr. That's the only thing I don't like about AGM's.
Update on the tracker and how to tell the level of propane in the pressure tubes.
http://countryplans.com/smf/index.php?topic=151.msg81271#msg81271
His panels are in the sun almost all day.
Don,
I appreciate your help. I have forwarded your response to him and am going to let him look at it and confront the people who installed/programmed his inverter. I just dropped it off of the back of the truck, hooked up the two wire-start, hooked up the l.p.. and test ran it. The brief tour I took of the setup looked professionally done. Thanks for the help and maybe I can help him out.
This a great topic
I plan to be off grid later this year (I hope)
I am trying to decide what batteries to buy
Someone here mentioned "HUP" -- not sure what these are
I have some experience with Trojan 'cart batteries' and they seem ok but for a serious system I think I need a serious battery bank
I have 6 AirX 48 volt wind generators (from Ebay at a very good price)
the plans call for 1500 watts of PV planels too
I am having difficulty calculating the size of the battery bank
On another note ...
I just bought a 8000 watt inverter from ebay -- made in Taiwan
I looked great and was priced right at $2700 --free shipping
now for the rest of the story
Yesterday I hooked it up to some four 12volt batts in series
the output is 218 VAC across the 'N" and "L" lines but
ground an "L" reads 125 VAC
and ground and "N" reads only 85 VAC :(
email to KIPOINT in TAiwan says they will get back to me after "new moon holiday" Feb 2
anyway back to the batteries
I am almost decided to go with the 12V L-16 Trojans
but maybe Concord or Surrette would be worth the money :-\
HUP One, or Solar One batteries info...
http://www.hupsolarone.com/benefits.htm (http://www.hupsolarone.com/benefits.htm)
http://thesolar.biz/hup_solar_one_batteries.htm (http://thesolar.biz/hup_solar_one_batteries.htm)
They warrant their batteries to have 2100 cycles at 80% Depth Of Discharge.: 4000 cycles at 5%, I think.
------------------
sizing tool
http://www.wagonmaker.com/script_calculator.html (http://www.wagonmaker.com/script_calculator.html)
Thanks Don
I hadn't come across that brand before
now I just need to take out a second mortgage ....... ;D
$$$ That's one of the big reasons L-16's enjoy great popularity.
Batteries are the heart of off grid power systems. I have loads of notes collected over time. I plan on sorting, condensing and adding to previous posts here.
FIRST... BATTERY ACID is HAZARDOUS. At the very least eye goggles should be worn. Having a bottle of sterile eye wash at hand is also a very good idea. Having it "at hand" so you can grasp it readily when you have your eyes screwed shut because they have acid in them is very important. It does little good if it's in the shed "someplace".
Get a plastic bottle and fill it with baking soda and water solution. Keep it by the batteries or with you tool kit. Use it to neutralize accidental splash or spills and to clean normal acid spatter from battery tops. Don't ever wear your favorite blue jeans! You won't know if you ruined them till you wash them next time.
Let's have a look at determining
State of Charge on wet cell batteries. That includes standard and low maintenance. The key thing is the ability to remove the cap from the cell and measure specific gravity and/or add water as needed. These are sometimes referred to as Flooded cell batteries.
There are a variety of devices to measure specific gravity. Some use floating colored balls or disks. Do NOT bother with these. Others use a swinging "scale" that "floats" as the electrolyte is sucked into its chamber. Do NOT buy one of those either. Purchase a good old fashioned graduated float style, preferably one with a built in thermometer. NAPA auto parts sell one like that.
![](http://partimages2.genpt.com/partimages/215521.jpg)
http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=BK&PartNumber=7001145&Description=Battery+Tester+%2f+Hand+Held (http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=BK&PartNumber=7001145&Description=Battery+Tester+%2f+Hand+Held)
You want the thermometer as lead-acid batteries are rated at a temperature of 25 degrees Celsius (77 F). Battery capacity, how much power can be pulled from a wet cell battery, falls as the temperature falls. Conversely battery capacity increases as the temperature rises. Battery life is increased at lower temperatures and reduced at elevated temperatures.
Hydrometer readings should not vary more than .05 difference between cells.
A voltmeter may also be used to determine the state of charge. However, the battery must have been sitting with no charge or load having been applied to it for a period of three hours minimum. The reason for this is the battery will hold onto a "surface charge voltage" for some time after being charged. It takes several hours to dissipate. For those in a hurry a load of approx 20 amps for ten minutes will remove the surface charge, more or less and will MTL give a usable reading.
Here's a chart showing specific gravities for several different States of Charge for wet cell batteries, at temperatures from zero to 120 degrees F. Also included are open circuit voltage readings, based on a 12 VDC battery. Halve the voltage readings for a 6 VDC battery.
The chart uses rounded off figures so in it we refer to the standard temperature as 80 degrees F (26.7 C)
![](https://i133.photobucket.com/albums/q75/djmillerbucket/electrical/StateofCharge-wet.jpg)
Lastly, for now, only add water to a charged cell. The electrolyte expands as it goes from less charged to fully charged. The exception to this rule would be if the electrolyte is below the top of the plates; then add just enough to cover the plates.
WHY a MPPT CHARGE CONTROLLER is BEST
(Maximum Power Point Tracking)
Because PV cells and batteries are both not very smart; in fact panels are dumb and batteries plain stupid.
Many PV panels are built to put out a nominal 12 volts. The catch is "nominal". In actual fact, almost all "12 volt" solar panels are designed to put out from 16 to 18 volts. The problem is that a nominal 12 volt battery is pretty close to an actual 12 volts - 10.5 to 12.7 volts, depending on state of charge. Under charge, most batteries want from around 13.2 to 14.4 volts to fully charge - quite a bit different than what most panels are designed to put out.
OK, so let's use the popular Kyocera 130 watt solar panel as an example. Catch #1 is that it is rated at 130 watts at a particular voltage and current. The Kyocera KC-130 is rated at 7.39 amps at 17.6 volts. (7.39 amps times 17.6 volts = 130 watts).
So what happens when you hook up this 130 watt panel to your battery through a regular charge controller?
Your panel puts out 7.4 amps. Your battery is sitting at 12 volts under charge: 7.4 amps times 12 volts = 88.8 watts. You lost over 41 watts. That 41 watts is not going anywhere, it just is not being produced because there is a poor match between the panel and the battery. With a very low battery, say 10.5 volts, it's even worse - you could be losing as much as 35% (11 volts x 7.4 amps = 81.4 watts. You lost about 48 watts.
One solution you might think of; why not just make panels so that they put out 14 volts or so to match the battery?
Catch #22a is that the panel is rated at 130 watts at full sunlight at a particular temperature (STC - or standard test conditions). If temperature of the solar panel is high, you don't get 17.4 volts. At the temperatures seen in many hot climate areas, you might get under 16 volts. If you started with a 15 volt panel (like some of the so-called "self regulating" panels), you are in trouble, as you won't have enough voltage to put a charge into the battery. Solar panels have to have enough leeway built in to perform under the worst of conditions. The panel will just sit there looking dumb, and your batteries will get even stupider than usual.
How Maximum Power Point Tracking helps.
This is not tracking like Glenn has his panels tracking the sun. This is digital tracking of the power output of the PV panels and the needs of the batteries, then using high frequency DC to DC converters. They take the DC input from the solar panels, change it to high frequency AC, and convert it back down to a different DC voltage and current to exactly match the panels to the batteries. Digital MPPT controllers are microprocessor controlled. They know when to adjust the output that it is being sent to the battery, and they actually shut down for a few microseconds and "look" at the solar panel and battery and make any needed adjustments.
Assume your battery is low, at 12 volts. A MPPT takes that 17.6 volts at 7.4 amps and converts it down, so that what the battery gets is now 10.8 amps at 12 volts. Now you still have almost 130 watts, and everyone is happy.
Ideally, for 100% power conversion you would get around 11.3 amps at 11.5 volts, but you have to feed the battery a higher voltage to force the amps in. And this is a simplified explanation - in actual fact the output of the MPPT charge controller might vary continually to adjust for getting the maximum amps into the battery.
A MPPT tracks the maximum power point, which is going to be different from the STC (Standard Test Conditions) rating under almost all situations. Under very cold conditions a 120 watt panel is actually capable of putting over 130+ watts because the power output goes up as panel temperature goes down - but if you don't have some way of tracking that power point, you are going to lose it. On the other hand under very hot conditions, the power drops - you lose power as the temperature goes up. That is why you get less gain in summer.
MPPT's are most effective under these conditions:
**Cloudy or hazy days - when the extra power is needed the most.
**Cold weather - solar panels work better at cold temperatures, but without a MPPT you are losing most of that. Cold weather is most likely in winter - the time when sun hours are low and you need the power to recharge batteries the most.
**Low battery charge - the lower the state of charge in your battery, the more current a MPPT puts into them - another time when the extra power is needed the most. You can have both cold weather and low battery at the same time.
**Long wire runs - If you are charging a 12 volt battery, and your panels are 100 feet away, the voltage drop and power loss can be considerable unless you use very large wire. That can be very expensive. But if you have four 12 volt panels wired in series for 48 volts, the power loss is much less, and the controller will convert that high voltage to 12 volts at the battery. That also means that if you have a high voltage panel setup feeding the controller, you can use much smaller wire. That's my situation, except my cable run is more like 325 feet.
The L16's are 6 volts at 375ah each plus or minus a bit depending on brand and model. You can series or parallel them for whatever voltage and amps you need.
For a start, running a pretty full house with quite a bit of power probably 2 sets of 4 (or 8 batteries total) for a decent 24 volt system or all 8 in series for a decent 48 volt system will get you going. That is in lieu of proper figurinng and calculating - Ideally I would like to see 16 of them for a decent 48v system or - 2 groups of 8 batteries paralleled.
I find that a voltmeter can be misleading in that it could show a full voltage, but not the state of the electrolyte like the Hydrometer will.
The Hydrometer is the most important low cost tool for the state of the individual cells, and in a group of batteries one low cell can cut the capacity of the entire group. Getting over 31. 2 volts on up toward 32 volts seems to be a critical point of equalization although I have heard as high as 34 volts in several places. When hitting that point I noted a drop in voltage then increasing acceptance of charge. That seems to be the point that the low cell starts coming back with the rest and it may take several hours to do it - ideally once a month. If on a good maintenance schedule , it may not take that long.... I wouldn't know about that.... [waiting]
Quote from: glenn kangiser on February 01, 2009, 09:30:57 PM
I find that a voltmeter can be misleading in that it could show a full voltage, but not the state of the electrolyte like the Hydrometer will.
That's the only bad thing about AGM batteries, which I plan on getting into later. They have no available liquid electrolyte. So you need to use volts. The difficult part to me, is having the time for the batteries to sit there with no charge going in, no loads coming out for a long enough time. I've heard three hours is the minimum time. Better is at least 8 to 10 hours. I guess that means shutting down for the night and pulling the PV input breaker/disconnect so the morning sun doesn't start the next charge cycle. ???
The voltmeter won't find which cell is dead, only narrow down to the battery. But in a multiple cell battery I guess that doesn't matter much.
A good carbon pile load checker could do that but the cost of a good one is up there. Mike is supposed to get us a good deal on some of the new testers that are electronic pretty soon I think I may spring for one of them to see how well they work. Bad thing about the load testers like this is they do pull a lot of current from the battery.
Sealed cell AGM BATTERIES (AGM = Absorbed Glass Mats)
I've used AGM batteries for years, actually over a decade, in my modified Jeeps. I used them because they are extremely resistant to vibration and shock. As well they are a true maintenance free battery and long lived. I've got 5 years of service and most have been still strong at that point. I've changed them out of concerns for reliability when off in the boonies. A side benefit for off road use is their sealed nature; no dripping acid if you find yourself dirty side up. n*
For an off grid power storage battery system AGM batteries have some advantages as well. AGM's are not gel cell batteries, they are better. The electrolyte in an AGM is not gelled; the electrolyte is still liquid. It is held within a very fine fiber Boron-Silicate glass mat. If the case of an AGM battery is cracked the liquid will still not leak out. The AGM take more abuse than a gel cell. Let it be noted that gel cells do not take kindly to deep discharges or to overcharging. As well gel cells can not be fast charged; they require special chargers. Most good inverter-chargers can be programmed to the required charge rates though.
AGM's can be mounted sideways or upside down. (Handy for a second battery in the Jeep.) AGM's are cheaper to ship as there is no Hazmat fee. Nearly all AGM batteries are "recombinant"; that means the Oxygen and Hydrogen recombine INSIDE the battery. These use gas phase transfer of oxygen to the negative plates to recombine them back into water while charging and prevent the loss of water through electrolysis. The recombining is typically 99+% efficient, so almost no water is lost.
The charging voltages are the same as for any standard battery. The internal resistance is extremely low; there is almost no heating of the battery even under heavy charge and discharge currents.
AGM's have a very low self-discharge - from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than standard batteries. Less to worry about in a three season off grid cabin for example.
AGM's emit no hydrogen under normal charge rates and under heavy charge rates the hydrogen emissions are so low there is virtually no danger of explosion. They can be safely stored indoors in a non vented enclosure.
Wow, what a super battery! :D Is there any downside? Not many; with one being there are not a very large number of choices for 6 volt versions with high capacities for off grid storage systems. As mentioned before the sealed nature means you can not check their charge level with a hydrometer. However, that is more than counterbalanced by their ability to absorb overcharges and to not deteriorate as quickly with high discharges, and being sealed against water loss.
The biggest downside is their cost. An AGM will cost at least 2 to 3 times as much as a conventional wet cell battery of comparable capacity. :o
Concorde Sunextender does make a 6 volt 220 amp hour battery, comparable to a golf cart battery, as well as a 305 amp hour battery. The 305 cost about $400+ and the 220 about $275-350. Concorde also has a 2 volt 915 amp hour battery I've seen on sale at $200; regular up to $450.
As you can see the advantages do cost. I would use them if the cost was less.
The standard lead acid batteries with the new desulfators we are working on getting set up with may last as long as 15 years they claim.
I am anxiously awaiting getting the unit from Mike to see what it will do to reclaim the used L16's I have. That would mean a very substantial savings in battery costs.
That could make them more cost effective than the AGM's I think and no mystery regarding what the cells are up to.
Are you using those low cost desulphators you mentioned some time back?
I currently have the low cost one on two of the batteries - I accidently wet one of them washing the batts with the hose so now have only one. I sealed it with silicone rubber. Improvement is slow - not much improvement in SG yet but it seems there is some. I put the desulfator on full time and charger on every other day or so as I get excess power to play with it.
The one we are supposed to get set up as dealers on is around 20 amps of desulfating and charging power built specifically for recovering batteries. Most battery companies are not interested in selling these desulfator/chargers because they would rather sell batteries.
Mike has used their small 2.5 amp one and recovered a big Caterpillar battery - 8D that had been sitting for about 6 years. I am not sure of the quality of the recovery yet as I don't have hydrometer readings - I keep forgetting to ask him to check. He just has the one for experimenting now - I have already ordered the bigger one.
On my tracker - as the sun continues to come up, a few minor adjustments in the tracker wake-up trough arm geometry and timing (by moving the center attachment point forward - back - up or down on the angle iron frame) has it waking up around 7:40 with most movement complete around 7:46 - pressure rises on the west side during the rapid movement toward the east so movement slows but it is getting sun to all panels by that time and by 8 AM I am getting about 19 amps at 25 volts.
I haven't added the rest of the panels to the tracker yet. 6 more 100 watt or so panels to go on there.
:o That's going to be some array!!!
I picked up my top of pole mount from the Uni-Rac warehouse today. Can't wait for the snow to melt.
It is pushing the envelope a bit. I worked out the maximum expected wind force and think it will take it - but I'm not an engineer. I do want to truss the bottom and center frames. I added 3 pipe braces to the top of the post - a 2 inch and 2 one inch pipe ones to the I beam and purlins below.
I will friction mount the top two so they will blow down decreasing resistance in high wind. d* I think.... :) The green house should deflect the wind over it on the front - the mountain should along with turbulence from the trees on the back. I am going to set my thin film panels up on the green house as a 3' high wind deflecting fence also. They will be permanent mounted as they take too large an area to track cost effectively - only 40 watts per panel in about the same area as the others.
I have thought of using the big one as a master and making slaves though.
Could be a Rube Goldberg, eh?
Quote from: MountainDon on February 01, 2009, 11:45:42 PM
Sealed cell AGM BATTERIES (AGM = Absorbed Glass Mats)
Concorde also has a 2 volt 915 amp hour battery I've seen on sale at $200.
Velly interesting! I assume each battery is a single cell ... allowing significant single-cell testing at the terminals. 60 batteries in series ... 120 volts ... $12,000 ... and approx 28 kilowatt-hours (at a 50% discharge ... if I did the math correctly). That's a lot of stored energy for the bucks!
In my neck of the woods, stored energy in a pumped storage (kinda) makes sense ... that battery array would equate to 100k gallons of water dropping 100 ft ... ain't bad!
Quote from: JRR on February 05, 2009, 09:04:18 AM
I assume each battery is a single cell ... allowing significant single-cell testing at the terminals.
Absolutely correct! Big cells. :)
![](http://www.trojanbattery.com/Products/images/J185H-AC.jpg)
Has anyone got any experieince with these
I can get them locally for about $330
12 V 225 AH @ 20hr
they are actually for floor buffing machines
the the guy at Batteries Plus said he had sold several to solar system users with good luck (but then he
is a salesman)
Since I have decided on a 48 V sytem it would cut the number to 8 or 12 for my wind solar system
about 30 % of a HUP or Concorde or Surrette cost
For my off grid system I plan to use
Six AirX (48 V) These should give about 180 KW-Hr per month plus 1500 watts of solar panels (haven't got these yet) but these are looking good cost wise
http://cgi.ebay.com/Pallet-of-SIX-200-Watt-Solar-Panels-NEW-2-60-Per-Watt_W0QQitemZ220356552797QQcmdZViewItemQQptZElectrical_Solar_US?hash=item220356552797&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1309%7C301%3A1%7C293%3A1%7C294%3A50 (http://cgi.ebay.com/Pallet-of-SIX-200-Watt-Solar-Panels-NEW-2-60-Per-Watt_W0QQitemZ220356552797QQcmdZViewItemQQptZElectrical_Solar_US?hash=item220356552797&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1309%7C301%3A1%7C293%3A1%7C294%3A50)
For the battery bank I am thinking
12 X 225 AH = 2700
50 % charge = 1350 AH
or about 67 KwHrs
Any Ideas --- this is in south west Wisconsin so only averages about 4.2 hours of effective sunshine according to this site
http://www.wholesalesolar.com/StartHere/OFFGRID/OFFGRIDCalculator.html
I know I should wait until the last minute to buy the batts but I am worried the price is going to skyrocket (along with everything else in hyperinflation) I plan to get this wind/PV system up by fall 2009
I may be in the market for a heavy duty inverter (if the Taiwan unit doesn't work out ) at least 4000 watts to kick the deep well pump over
Outback or ???
You have confused me; sometimes that is easy to do ??? You stated...
12 x 225 = 2700 amp-hr and you also stated you were going to use a 48 volt system.
That 2700 amp-hr is true if those 12 volt batteries were all connected in parallel in a 12 volt system. That would be 2700 amp-hrs rated at 12 volts, not 48 volts.
With four 12 volt batteries in series to supply the 48 volt basis for the system, one string of four would have a capacity of 225 amp-hrs. Two series strings in parallel would have a capacity of 450 amp-hrs and a battery bank of three series strings in parallel would be equal to 675 amp-hrs. All at 48 volts.
I guess it depends on whether or not you are taking 48 volts as the system basis into account when calculating loads and reserves.
Regarding those J185H-AC batteries, I'm not familiar with them. How do those prices work out compared to L-16's. They are rated as deep cycle. It would be interesting to know if the plates are the same thickness as in an L-16 or if they are thinner like the T-105's. That could make a difference to their life.
Quote from: Windpower on February 05, 2009, 05:26:14 PM
![](http://www.trojanbattery.com/Products/images/J185H-AC.jpg)
For the battery bank I am thinking
12 X 225 AH = 2700 the math is correct, its the absense of terms that get us in trouble: 12v x 225 AH = 2700watt-hr.
50 % charge = 1350 AH 50% discharge = 1350 watt-hr, or 1.35 kw-hr.
or about 67 KwHrs ??
1.35 kw-hr for $330 is close to, but not quite as good a purchase as .915 kw-hr for $200. (This assumes "everything else" is equal.)
Before buying those J185H-AC batteries I'd really want to know about the plate thickness. Going by the weight I would believe that one of those 12 volt batteries is about as good as two 6 volt T-105 GC batteries in series. The T-105 weighs in at 62 lbs. each. The J185H-AC weighs in at 128 lbs. Both are rated at 225 amp-hrs.
Info taken from Trojan's website (http://www.trojanbattery.com/Index.aspx)
Windpower, does your system have to be inspected and up to NEC code??
...from the website link to the PV panels "SUN MODULES ARE NOT UL CERTIFIED"
Good price otherwise
The formula is (amp-hours * voltage) / 1000 = kilowatthours
225 amphours x 12 volts = 2700 / 1000 = 2.7 KwH per battery
50% of 2.7 = 1.35 KwH per battery
1.35 KwH x 12 batteries = 16.2 KwH
Windpower references a 67 KwH figure...
I still think he believes that battery array is more powerful than it really is, by a factor of approximately 4.
67 / 16.2 = 4.13
??? ???
Thanks Don for catching the math error
I thought that seemed too high for KwHr(that will teach me to do the arithmetic in my head NOT)
duh
d*
:-[
let's try this again
4 batteries in series times 3 parallel equals 675 AH at 48 V
675 AH X 50 % = 330 (Recommended useful discharge capacity)
330 AH X 48 V = (about) 16 Kw Hrs
anyway, now that we're on the same page (planet ?) mathematically
What do you think Don, enough battery capacity at 16 KW Hr
I think we will, on average, use up about 6 to 10 KW Hr per day between business and shop use
I forgot to mention we do have a diesel back up generator running on biodiesel (just in case)
The nice thing about the farm is that it is quite windy and the wind usually is there when it is not sunny
but my gut feel here is that I need more battery capacity ---maybe 32 KW Hr
whoa the mind boggles -- that seems like a big battery bank
This is a great forum
Thanks guys
What do the power company bills / records indicate your use to be. Ours has about 4 years worth available online. We run 14 to 28 per day depending on time of year. (summer A/C)
Big battery banks are sometimes needed and that's where those big 2 volt cells come in handy. And they come in expensive. :(
You could also add one string if it proved necessary. Is most of your use going to be during daytime or nightime?
How about grid tie, using the grid as the "battery"?
Depending on the local power company it can work advantageously. Of course I'm seeing that from a NM point of view where the power company (has to) pays us more (13 cents) than what the user pays them for purchased power (9 to 10 cents).
The "People's Republic of Wisconsin" is fraught with regulations
I really want to get off grid at (almost) all costs
I think the future is not good and the best thing is to get away from the 'system' as far as possible even if it costs more short term capital
WI has tax credits too -- but I don't even want to take those -- fine print and all that
I can really see the advantage of 2 V cell especially if one fails --- a 'cheap' replacement
I see most of our power draw during the day -- night: heating and monitoring ---relatively low and steady power draw
I am starting to think of 2 battery banks -- one solar and one wind tied to one inverter HHHmmmmm
:-\
I was wondering about day use vs night use, as solar will be replenishing the batteries as you use it, during sunny periods. That helps "extend" the battery capacity. Of course the same thing for wind whenever the wind blows. So 16 KwH may be okay.
Of course a bigger battery bank would have the advantage of not drawing the batteries down so far and they will last longer because of that.
I wouldn't sell the tax credits short... the federal ones are very simple. Keep the receipts just in case you are asked to prove you bought solar equipment. Here in NM there is no sales tax on solar equipment (panels, inverters like the Outback, Magnum, etc. , charge controllers, panel mounts...) that is bought and used in state. Another reason I like dealing with the locals.
Thanks again Don
There are tax credits for wind in WI too but you have to jump through lots of hoops
I wish I thought there was more time to jump through them but sadly I think we are set for "the second very great depression" economically
good website here run by George Ure:
http://www.urbansurvival.com
George is into PV, goats and economics
For me I feel that there is little time to get up there and get it runnin' (less han a year)
I admire those of you that have seen the avalanche comming and taken action
I am now in the catch up mode (maybe the story of my life LOL)
over and out for tonite
cheers
bill
I think you have the idea, bill.
I didn't want the credits as I would be on their list and taxed every year on the equipment. I don't want anything from them and don't want them taking anymore from me. They have to take about twice as much as they give back. Gotta cover overhead.
I'd put all of the power in to one bank I think - they compliment each other and wind and solar may or may not be available at the same time - you can still have multiple parallel strings of batteries in series -- hmm?
Note - I'm on the road for a day or two starting tomorrow morning.
my latest plan is 3 battery banks of 48 V DC
I think each bank should be about 16 KW-Hr
Theoretically I can switch the charge in and output between solar and wind
need to find some big friggin DC switches (relays ?)
but then this is little more than a seat of the pants estimate or a SWAG (Scientific Wild Ass Guess )
there are precious few hard models out there on the net that I have seen for sizing battery banks
maybe we are all SWAGing it
maybe some big relays switched by voltage in the banks -- starting to sound complicated
We have 5 banks of 375ah @ 24 volts so 375x24=9000 x 5= 45000 so similar to what you are talking I think. About half of that would be usable for best battery life.
Is that right, Don? hmm
I don't see a need to switch them. DC big stuff gets expensive due to possible long arcs.
I am just going to make big copper pipe or bar? knife switches eventually to isolate banks for equalization, safety and repair purposes.
Quote from: glenn kangiser on February 10, 2009, 09:01:55 PM
Is that right, Don? hmm
Ideally, one would normally use only 25% of the battery rated capacity. However, in reality most users probably draw down to 50% fairly regularly.
DC switches are much larger with much heavier contacts than AC devices. The alternating nature of AC power greatly assists the breaking of an AC circuit under load. That's one reason hi amp DC breakers and switches cost so much. Another contributing factor to price would be low market volume, compared to AC.
There are some deals available on high amp DC rated breakers at
solarseller.com (http://solarseller.com/dc_circuit_breakers__dc_circuit_breaker_ul_listed_to_125_volts_dc.htm) , if that would help in any planning.
DC breakers are supposed to be mounted vertically, although not everyone does that. n* ... something to do with arc flame travel.
Thanks Don -
A side note - being a welder, long DC arcs don't scare me as long as they are not setting my house on fire at the time. d*
Around 24 volts at 100 to 250 amps is a very common DC welding volt and amperage. :)
I just made a big mistake
I bought an inverter from a Taiwancompany on Ebay
Advertised as a "pure sine wave inverter"
see here
http://cgi.ebay.com/8000W-Solar-Pure-Sine-Wave-Inverter-48V-220V-240V_W0QQitemZ180302969213QQcmdZViewItemQQptZCar_Electronics_Parts_Accessories?hash=item180302969213&_trksid=p3286.c0.m14&_trkparms=72%3A1234%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50
BUT
when I hooked it up to a 48 volt battery bankand measure the voltage
I get grd to "L" of 135 VAC and
Ground to "N" of only 84 VAC
N to L is 218 VAC
I do notsee how I can use this with the low voltage side
the company says I cannot return it for a refund becase I did not specify the voltages needed
I specified in an email that irequired U. S. standard 220 VAC
I believe US voltage is plus or minus 10 % from 115 VAC which is what we specify on hte lab instruments my company sells
anybody know where I can find hte spec ?
I am really pissed off >:(
any ideas ....
can you involve EBay by reporting the seller and requesting mediation? I would think it is better to make you happy than to be taken off of EBay and risk losing the income from selling to others less informed.
ouch! daniel and i were just last night, speaking about searching on ebay for some things
i told him i'd rather not, not that i'm knockin' ebay, and i've bought a few things in my day,
but it would be just my luck i'd get involved in something like that, and our budget being
what it is, i can't afford any "losses"
i know there are great folks on ebay, trust worthy folks, but for some things, for me anyway
i'd rather not
but you've also gotta balance that with a great deal, and when you do find a great deal from
a reputable source on ebay, jump on it!
good luck
tesa
regarding the tax breaks. i was sort of skeptical too, as i like flyin' under the government radar, for
lack of a better term, but i think i'm still gonna go for it, and claim it on this years taxes
being homeschoolers, the homeschooling community, for years, has tried to get people to
come together, and lobby washington for tax breaks, since most of us still pay school
taxes, even tho we don't send our kids to school
however, most of the homeschoolers i know don't want to jump thru washingtons hoops is
we were to get a tax break, all the strings and such
so most of us smile, and pay our school taxes, and leave it be
a tax break would be nice, but i'm not willing to give them (the government) anymore controll
than they already have
tesa
Windpower, FWIW, most of the name inverter mfgs label their units for use in the U.S. as 240v ac, not 220. Regardless, 84 volts on one leg is way too low and would indicate a defective inverter, IMO. They should at least replace it, and Soomb is likely right, pressure them through Ebay. Also, if you paid through PayPal, I think you can stop payment to the vendor through them, or even get their account frozen, if there's an unresolved dispute about the merchandise. PayPal (owned for some time by Ebay) puts the burden on the seller, which is where it sounds like it should be in this case. G/L!
G/L on the dispute with eBay / PayPal.
QuoteI believe US voltage is plus or minus 10 % from 115 VAC which is what we specify on hte lab instruments my company sells
Standard voltages in the USA and Canada have evolved/changed over the years. It was 110 years back, then 115-117, and for some time has been 120. Most electrical devices have no problem adjusting to anything in that range.
For the curious...
Voltages and Plug Styles Around the World (http://www.kropla.com/electric2.htm)
Did they send a 50 Hz or a 60 Hz, or is that user adjustable?
It does seem that the one leg is way too high and the other way too low. I wouldn't call that to be operating properly; what does the vendor have to say about that?
Quote from: tesa on February 12, 2009, 08:50:42 AM
regarding the tax breaks. i was sort of skeptical too, as i like flyin' under the government radar, for
lack of a better term, but i think i'm still gonna go for it, and claim it on this years taxes....
....being homeschoolers, the homeschooling community, for years, has tried to get people to
come together, and lobby washington for tax breaks, since most of us still pay school
taxes, even tho we don't send our kids to school
Re: energy tax credit. A 30% credit on my federal taxes for 2009 (and available for several years into the future), is well worth the slight effort required to fill in one line, IMO. I doubt the acceptance of that credit will directly result in the raising of taxable property value. For one thing, there is no assignation of the credit to any particular parcel or property on the federal form. If and when the property is reassessed the actual tax dollar increase is a small fraction of what I'll receive in that tax credit.
We don't home school, but I have a thought or two on the related tax issues.... Everybody pays school taxes. At the local level it's most visible on the property tax bill. Of course a portion of all general taxes collected by the state and federal governments go towards schools as well. Since even people who do not ever have children are also paying taxes that go to schools and education, why should a person who elects to go to a private school, or to homeschool, be exempt from, or credited, those taxes? That would only be fair is the single childless person could get a rebate/credit/exemption as well.
At the same time that I say that I believe there is a lot of wasted money being spent on public schools. They do not do a great job on the whole. So, I can understand why some homeschool, some use private schools. School taxes and education is a difficult question, perhaps deserving of it's own topic, if anyone is so inclined.
Thanks for the input Soomb Don Harry tesa
The specs on their ads look great
but they sent me an email saying that I didn't specify the voltages I needed, so it is not defective and no one else is complaining yada yada yada
I did send an email to ebay reporting the item and ebay has responded
I figure few even check the voltage but being a Field engineer and seeing my share of expensive instruments fried up by bad power ....
A little about me-- I install and repair Chromatography and Mass spectrometer laboratory instrument --for the last 30 years or so -- I am not a novice at this -- if you watch CSI you can see some our instruments
what is scary is that with this imbalance in the legs there is going to be a lot of equipment fried up -- and most won't even know why -- hopefully it won't cause any fires
really sucks
Thanks again for the input
In the mean time DON"T BUY ONE OF THESE POS
I'll keep you posted
regarding the tax break, so i should keep all my paperwork from thing i buy as documentation, right?
we're getting everything from parts on sale, so i'll just keep that paperwork, and the batteires were
buying, we'll be sure and save that receipt as well
i also downloaded the tax form, i think its form 5695, or something like that so i'll have it come
tax time
i think its good they (the man) offers it, i think it might help give people incentive to use renewable
sources, for us, it didn't matter, we were gonna do it no matter what, but a wee break is nice
we're looking at maby 4K for our whole system, (oh, speaking of that, should i try and claim the
generator too?? i mean, it is part of our system) a big house, could be in the tens of thousands
for a system, which would be a bigger break, bigger write off
tesa
I would say so - it is a required part of the system.
Yes, save the receipts.
I could be wrong, but I think you are jumping the gun on taking the tax credit on the year 2008. :-\ :-\
You haven't bought the items yet so I don't see those purchases being eligible for filing on the 2008 tax year. ???
At least that was my interpretation for the items I've bought this spring; 2009.
So, if that's why you are seemingly in a hurry on the solar power thing, you might want to verify what tax year you can claim on.
As far as the generator goes; I'm not certain about it being eligible. That could be open to interpretation, as a generator is not necessary for grid tied system, for example. ??? ???
Good question, though. I've not thought of that as I've owned the generator for years already and it didn't make sense to me to reach way back and claim it now.
??? ??? ??? ???
I finally got the various Pulse Chargers and Tester in for my testing so I can see if I want to sell these things or not. If they work as we hope I could save myself and my customers hundreds to thousands of dollars per year or two.
I had decent sun today so started testing them. I have the unusable L-16s that sulfated up on a friend and she gave them to me. I also have my own older battery packs which are low with some problems as well as my Jeep battery which I have recovered some with my original small desulfator.
As I gather some data I will likely break this testing off into another thread and we can follow it from there. The recovery charger while expensive is one of the most interesting to me. We will see if it can bring some of these back from the dead.
The following question was asked on another topic. I thought it would be relevant to post my reply here.
QuoteDo you plan on taking down your solar panels when you leave for the season or will you leave the system operational? If the latter, what special considerations will need to be given for the batteries during the winter?
When our cabin's solar PV system is completed this year, my plan for subsequent winters follows.
1. Make certain the batteries are fully charged.
2. Run an equalization charge if it has not been performed in the last 30 days.
3. Add water to the cells if they need any to be at their maximum fluid level.
If you do that there should be no problem with leaving the system to take care of itself. All system loads will be disconnected by pulling the cabin breaker panel disconnects.
To clarify my previous post:
I will actually be throwing the breaker on the + cable between the batteries and the inverter, rather than the main breaker at the service panel. That will ensure that the inverter is not making any ghost demands. I have an Airpax 250 amp 160 VDC circuit breaker to act as a disconnect as well as a safety electrical interrupter.
Furthermore, the PV panels will be left up and connected to the charge controller. This part of the system will be left active and will allow the batteries to maintain full charge even if there is some slight self discharge.
For the winter period of absence I may drop one panel from the normal series array of three to avoid any complications that could arise if the weather would turn to a near impossible low temp some evening in the coldest part of a winter storm. That would be one of those 100 or maybe even 500 year events, but why tempt fate?
What does dropping one panel do?
The panels I have, the Sharp ND-208, are rated at a maximum open circuit output of 36.1 volts. Three in series = a maximum theoretical voltage of 108.3 volts. The Outback charge controller has a maximum start up of 145 volts and 150 volts absolute peak. As the sun first strikes the panels in the morning the voltage will likely hit the peak or near to the peak voltage, and then settle downwards to around the rated operating voltage of 28.5 (X3 = 85.5 volts @ 77 degrees).
PV panels outputs are rated at an ambient temperature of 77 degrees F (25 C). As the air temperature drops the output voltage of the three panel PV series array rises.
At 77 degrees we have a temp corrected maximum voltage of 108
At 50 degrees we have a temp corrected maximum voltage of 115
At 32 degrees we have a temp corrected maximum voltage of 119
At 0 degrees we have a temp corrected maximum voltage of 126
At -10 degrees we have a temp corrected maximum voltage of 128
At -20 degrees we have a temp corrected maximum voltage of 131
At -30 degrees we have a temp corrected maximum voltage of 133
At -40 degrees we have a temp corrected maximum voltage of 135
So, in theory, my setup should be within the design (and warranty) parameters set by Outback. However, PV panel output voltage can surge when sunlight first hits them. If this happens on a real frosty morning it is possible, maybe not likely but still possible, that the voltage could spike higher than the design limits of the charge controller. That could result in a unit with a problem.
Therefore, even though it is a very longshot that it would get cold enough and that the morning would be clear enough to conspire to spike the voltage high enough to cause a problem, the safe solution is to remove one panel from the series array. That reduces those voltages by 1/3. The disconnected panel will not be damaged. The two panels left connected in series will be able to supply more than enough power to maintain the battery charge.
thank you for the excellent explanation.
I really like the Backwoods Solar catalog. It's practically an instruction book for getting set up.
They do have good information in it and on their website. I do find their prices just a little higher than some other places like Affordable Solar or TheSolar.biz
MountainDon,
How frequently do you equalize your batteries?
The goal is to equalize every 30 days. In reality that may turn out to be 45-60 days or so. d* Keeping a log book, rather then relying on a faulty memory is a good idea. Also logging the specific gravity of each cell may be helpful in tracking changes in performance. (Remember to apply temperature corrections if the temperature of the batteries varies seasonally.)
That's for flooded wet cell batteries. AGM types can be equalized three to four times a year.
Is it possible to over equalize? What I mean is, can you damage the batteries by equalizing twice per month?
You will just use more water and have to replenish more often. That's for wet cell.
That's what I was thinking, but someone told me they thought it would damage the plates and equalizing should be done four times per year. I've only had my system since October 2008 so I'm still learning, but it seems that I get a little better performance if I equalize monthly.
Quote from: pagancelt on March 19, 2009, 10:39:15 AM
... it seems that I get a little better performance if I equalize monthly.
You're onto something... :D :D
I believe the only way to damage the batteries by equalizing is to initiate the process and then forget about it and run the water down below plate tops. You can do that by overcharging too, or with total neglect.
I believe total neglect is how Glenn got the L16's he's playing with.
I think they failed to equalize often enough and allowed the system to run low for way too long in the winter before kicking the generator in. Low charge for long periods is conducive to bad sulfation.
I did some serious equalizing yesterday. I am capable of cooking batteries when I equalize, however most will not be able too and in fact ill have a hard time getting the voltage high enough to do a good job of equalizing. I believe Don mentioned getting to 32 to 34 volts on a 24v system and many systems cannot get that high.
I use a DC welder on constant current - Variable voltage. I unhooked the batteries from the system yesterday on the above mentioned set of Trojans I am playing with. The Xtreme recovery charger is doing the job over a week or two but I think it is better to use for the serious polishing off after a good equalization gives it something to work with.
I first hooked up all eight batts in parallel - 2 sets of 24 volts and I saw that the better set was equalizing but the worse set was not so that told me each string has to be equalized individually. I hooked the bad set alone and put about 100 to 150 amps to it - slowly raising the voltage for the first half hour or so then raising it to around 32.5 and maintaining that. As sulfation breaks away from the plates, internal resistance drops and voltage drops across the set. I monitored it on the voltmeter. I find that it always seems to drop to around 31.8 or so then slows -likely building a charge in the new found area. At that point I again up the amps to get the voltage around 32.5. It is necessary to watch terminal temps doing this also - I overheated one yesterday - didn't destroy it though.
I watched the acid in the cells. I capped the boiling ones and uncapped the rather dead looking ones. As each of them started to boil I capped them and continued until all 12 were pretty much boiling acid. This seems to be an indication of the sulfation being removed. The acid also turns dark as the sulfation is removed. It did not seem to be over heating the batteries but they did heat up. This was done over a period of a couple of hours. I assume the last ones to boil are not as clean as the first ones and intend to do more after the batteries cool if the Xtreme Recovery charger does not bring them back. I will monitor acid SG as that seems to be the best indicator of state of charge and condition.
The Xtreme Tester - don't know the real name now - but same company gives a great indication of health also but they must be offline.
As to over equalizing - I think more research is in order. I have seen old batteries with the plates eaten up - I don't know what the definite cause was.
I can get 31 volts from my panels and I think this is what the charge controller is actually set at, I've thought about opening it up and changing it to 32 volts. I can hear the batteries bubbling so I know they're getting over charged. Do you think this is necessary or is 31 volts enough to break up the deposits? When I charge with the generator I get the full 32 volts.
The strange thing is, and maybe Glenn or Don can fill me in a bit, I have an Outback Inverter with the Mate and my charge controller is a Xantrex. The Xantrex will show battery voltage at 31 while the Outback Mate gives me a voltage of 31.6. Which is more accurate? Does it even matter? I've been considering getting a good battery monitor this summer but then I wonder how necessary that is as well.
Thanks for the information.
I think the higher voltages should only be used for equalizing. I think that may eat the plates if done all of the time. I think about 28.5 is about all you want for normal charge. Don may pop in with that info - I'm about out of time but more research is in order I think. My cheaper MPPT (BK?) only goes to about 29.5 which I set it at because the batts only get to about 28 something normally. I don't want it kicking out too soon.
Could be a discrepancy in calibration or a loose connection giving higher resistance raising the reading.
It seems that over the 31.8 is what does the desulfation but that high all of the time could shorten battery life I think. I think it removes a bit of the surface of one plate.
It only goes to 31 volts during equalization and in normal charge mode it goes to the bulk charge rate of 29 volts and then drops down to the float stage of 27 volts.
Sounds good.
The solar dealer in Arizona - 9Lake Powell? - Page? It was over the phone) told me that over 32 volts was necessary to do good on equalizing - My testing seems to confirm that.
How far over 32 volts? Also is the MPPT worth the money?
Just got off the phone with the battery place
http://www.staabbattery.com/
Trojan L16 PA C 420 AH for $303
seems like a fair price -- includes delivery locally
so I'll need 8 in series for about 11 KW Hr of storage (at 50% discharge)
I'll need at least 2 banks one for the wind generators and one bank for the solar panels (-- I think I will need about 1500 watts of SP) according to this calculator
http://www.wholesalesolar.com/StartHere/OFFGRID/OFFGRIDCalculator.html
unfortunately this is about $5000 in batteries -- ouch
Forget the Rolls -- it would be $10,000 and change, (but they do carry a 10 year warranty)
I think this will be close to optimum -- about 330 KW Hrs per month from both wind and solar
Leaning towards the Xantrex XW4548 inverter
http://www.wholesalesolar.com/products.folder/inverter-folder/xantrexxw4548.html
but I have heard good things about the Outbacks too
I need the high surge to kick start the 3/4 Hp well pump (460 feet deep -- some of the coldest best tasting water ever)
I am thinking that the batteries should get bumped up on priorities -- went to price them at several solar/wind net suppliers and saw a lot of "out of stock" on batteries
Any recomendations on Charge controllers ?
Dave, the battery guy said that the charge controller is critical to battery life in solar applications and is a big reason why many battery manufacturers only give a 1 year warranty on solar apps
An MPPT charge controller is a must, not a luxury, in my opinion. Use of an MPPT controller will allow every last watt of power to be wrung from your panels. This becomes even more important the further north you go. No I'll rephrase that; if you are not in AZ or NM you are not making proper use of the power the panels put out if you do not have an MPPT controller. My opinion, but also that of a lot of other folks.
I favor the Outback Flexmate 60 or 80 for a great MPPT charge controller. Someplace else in this thread I believe I addressed my reasons. They are well engineered and solidly built. I believe they are the most programmable of all the units out there.
The Flexmate controllers also connect to the Mate, the Outback remote control panel and programming device. The Mate is also used with the Outback Inverters, so to me it makes a lot of sense to go all Outback. Xantrex probably makes fine equipment too.
Re: the above post. I am enamored with Outback. I'll admit it. Don't let that deter from choosing something else. As I stated someplace previously my criteria for charge controller included the long distance between panels and batteries. Running the panels in series for 72 VDC nominal reduced the cable size saving a bundle of money. That necessitated a charge controller like the Outback. After that choosing an Outback Inverter seemed best because of the ability to use one Mate control panel for both.
The charging and equalization info I go by...
one cell 12 VDC 24 VDC 48 VDC
Equalization 2.58 -2.67 (max) 15.5-16.0 31.0-32.0 61.9-64.1
Absorption/Bulk 2.37-2.45 (max) 14.2-14.7 28.4-29.4 56.9-58.8
Float 2.20-2.23 (max) 13.2-13.4 26.4-26.8 52.8-53.5
The ideal float voltage is the lowest voltage setting that will maintain the battery at full charge. The higher the voltage the more water the cell will consume. The minimum equalization voltage is highly recommended unless it is suspected a sulphation problem exists.
Equalization is required when the cell specific gravities vary from highest to lowest by +/- 0.015 (1.245 - 1.260 at full charge)
The point is to bring the batteries up to the equalization voltage and continue charging for 1-2 hours at a low current, without excessive heat. The final or finishing charging current should be 3-7% (we recommend 5%) of the 20 hr capacity in amps.
If battery temperature exceeds 125ºF the battery should be taken off of charge and allowed to cool before equalization is continued. When two consistent specific gravity readings are taken a half hour apart the battery is equalized. It is recommended to water the battery cells before or half way through the equalization. This is to assure the water is completely mixed into the electrolyte.
Quote from: pagancelt on March 19, 2009, 01:08:20 PM
How far over 32 volts? Also is the MPPT worth the money?
Looks like Don got some of this same info but I have other stuff too so I will repeat it :)
I just go between 32 and 33 - maybe 32.5 but I use the welder
Some info from Sens charger site
"Q: What does "equalize" charging do, and why is it needed?
A: All batteries, even those assembled into unitized blocks, are all built of individual battery cells connected in series to obtain the required DC voltage. Like all manufactured products, there is variation between the capacities of each cell in the battery. As the battery ages this variation increases. Since the battery is a chain of cells that is only as strong as the weakest link some scheme is required to ensure that all cells stay at peak capacity.
A scheme called "equalizing" is commonly used in both lead-acid and nickel cadmium batteries. Equalizing temporarily elevates the charging voltage of the entire battery string above the normal "float" voltage. The elevated charging voltage allows all cells, including the weak ones, to accept more current from the charger than they would at float voltage. A consequence of the elevated equalize voltage is that all cells in the battery are overcharged. This is acceptable for short periods provided the battery has sufficient electrolyte.
Overcharging greatly increases the rate at which the water in battery electrolyte is electrolyzed into oxygen and hydrogen gas. Since low electrolyte level will permanently damage the battery it is important to limit when, and for how long, the battery is charged at the equalize voltage."
This article says 31 to 32 max. for a 24 V system. Their info seems good and to be safe I would recommend following it. I have bought from them before - good people.
http://www.thesolar.biz/Battery_charging_article.htm
I do go over the 32 but it drops to the 31.8 pretty fast . It seems that this is where the action of removing the sulfation takes place. They say not to overheat the batteries above 125f and to add water as needed - I read that letting them dry out below the plates when equalizing is real bad and will destroy them.
I tested the batteries I equalized this morning with the Xtreme tester and all batteries got a passing grade with some showing good and charge. Now that they are getting back usable I will spend a bit more time with the equalizing. I noted that the Sens charger uses Constant voltage DC - that is also a capability of my welder so I may play with that a bit also. -- that will provide a tapering charge as the batteries come up.
Don and Glenn,
Thanks for all of the information. It looks like I'm right in line with everything you've both recommended, which is nice. I'm happy with the Outback inverter, and the Xantrex charge controller works fine, I'm just thinking an Outback MPPT would give me some extra charging in November and December, which were my worst months so far. Our loads are so minimal, a few hundred watts per day, that I wonder if it's worth the money. A personal choice, I suppose.
Also your houses are very nice, at some point I'm going to start a thread and explain what I'm considering building.
Our pleasure.
I would think it would take a bigger load to make it pay but if you like quality and tweaking it for the most it may be worth it for the satisfaction.
The panels on it should be matched for best effect but it will also give the best available with what you have if mixed too.
I have one that I checked is BZ controller but no features - just bulk and float - no equalize. It does maximize the panel output well though. I like to equalize manually anyway.
pagancelt, I'm thinking that if during Nov and Dec you were not getting enough power from the PV array, necessitating running the generator for general charging, then an MPPT controller could be a big help. I think you stated someplace you got it operational in October? You might want to hold off until you see what happens over the summer. If you're in VT, like I seem to recall, summer should be much better.
The solution could also be more PV panels. Hard to say for sure. ???
It also depends on the weather. If there are lots of storms and little direct sun then you may need the generator no matter what. Dark cloudy days may only produce a 10th or less power than a sunny day.
Central Vermont and it's cloudy through November and December, plus the shortening days. We averaged about 8 to 9 amps per day through those months and now we're averaging 20 to 50 amps per day, depending on state of charge. We're getting to the float stage 4 or 5 times per week so we're easily replacing what we use and this is also showing as fewer amps per day because once we get to float the controller shuts down. We hit float last Saturday by 11 AM so the total for that day was only 18 amps even though it was sunny the whole day. During November and December we never drained the batteries to 50%, I think we drew them down to 80% or so. We ran the generator three times, twice because we were leaving and wanted the batteries at full charge because our place is wood heat and we couldn't find anybody to house sit, and once we did an equalization charge. We'd had the system running for almost 4 months when we equalized and saw an immediate result.
I figure I'll give it another winter before I decide if I want to go with an MPPT or add more panels. Ultimately I want to get to a point where I don't need to use the generator, which might be difficult given my location.
I have to use the generator every so often in long storms in winter so it is a bit of a problem unless you are way overbuilt.
Our wind generator really helped during this storm - it took over so no need to run the generator.
That's the balance. If you can generate enough power through the winter you're probably way overbuilt for summer, but then you run the generator which you want to avoid.
At some point I would like to have some wind generation, but right now I think it would be cheaper to just hook up another four panels to the array. My wife thinks I should stop thinking about it so much and look at the fact that we ran the generator for about ten hours all winter, and around four hours of that was necessary to charge and then equalize the batteries.
Maybe she has a point.
If that's all the genny had to run, and if things are working well you're probably okay. Your wife may be right; time to leave well enough alone.
Yeah, you're both probably right, Don.
Recovering the batteries.... not a fast process but it is working. I find that the fastest improvement is gained from the controlled equalizing and again the critical point seems to be about 31.8 on 24v or 15.9 on the 12v system. That seems to be where we come back to after going to around 32v or 16v for equalizing voltage.
Per a tip on a charger site I have gone to equalizing with the constant voltage (wire feed) function of my DC generator welder.
The rewards? These are 3 year old Trojan L16's valued at around $3000 and once they are fully recovered I think they will be usable for another 10 years if I keep the desulfators running on the system and charge health sufficient most of the time and good. Stuff does happen though - extended storms - pumping during cloudy days - things that need watching but don't always get it.
Changing to a Grundfos SQFlex pump could help a lot also.
Xtreme says even average batteries have enough material in them to go 10 years. Keeping enough water in them is key to good life also - as they get older they need more - as they equalize monitor them and don't allow water to go below the top of plates.
The Xtreme recovery charger (list around $800) seems to be helping also but the equalization with the welder was necessary to help it along on these big batteries. Not allowing overheating is necessary. The voltage rise to 16 or 32 with plenty of water over the plates is necessary for a speedier recovery. Sulfation is almost not seen on the plates now but I don't want to overdo the recovery with the welder. I monitor with a voltmeter as I do the equalization.
Glenn,
Is the cost of all this battery rehab going to be offset by their added life?
--Pritch
The recovery charger I got at wholesale as my friend is a regional distributor and I am set up at dealer rates. I was going to get it anyway when I found out what it would do as I have a lot of machinery that is randomly abused in a sort of nonsensical rotation--- producing lots of damaged batteries. d* ...so I would not include the total cost in there for it. Say $200 of it.
The equalization is something which could have prevented the problem in advance but needs to be done on a continuing basis, so lets say an added cost of $100 for extra welder fuel.
Somewhere between the time I get paid for and the time I don't get paid for is the reality of what it costs me to gain something I wouldn't have otherwise. I try to work on this as I work on in shop projects so I can monitor it while I work. All in all I say yes- I should come out at least $2000 ahead at today's prices.
Note that I don't devote a lot of time to improving the condition of the batteries and that they are currently in use along with my 20 other L16's. That is why this is taking a long time. I leave the desulfator recovery charger running and switch it around to different pairs of batteries every few days. I have improved them enough to have put them online and they prevent having to turn on the generator in all but the longest storms ar cloudy periods. We have used maybe 5 to 10 gallons of generator gas in about the last 2 months.
The trick seems to be to get the specific gravity SG of all cells up to good - not having one cell with low SG in a group. A hydrometer will monitor it on Lead Acid batteries - not so on AGMs, Gel or others so it is my opinion that Lead Acid are easier to and have a greater chance of recovery from abuse. It is common to accidently abuse your batteries - especially if you are not aware of the problems... and even if you are. That is where the proper knowledge to do this comes in handy. Also - what if there is ever a problem getting them - due to the economic downturn and destruction of US industry or energy sources?
Badly abused batteries can take several months to improve as is mentioned in the book by another free battery proponent, Poor Man's Guide to Wind Power - or close to that. He tells how to build your own desulfator. It was not for sale on line the last time I checked, an e-book--- but I bought it when it was.
Thanks Glenn. Do you have any experience with the automatic battery waterers that are out there?
-- Pritch
Haven't come across them, Pritch. Years ago when I worked at Dodge, I believe, we had a battery filler that was spring loaded on the spout, as I recall - you would push it down and it would stop when the battery was properly filled.
I currently have a plastic gallon milk jug with a snap on top and a stiff hose pushed through that. It works well to fill them. I fill it with rainwater from a 50 gallon drum and use that to fill the batteries. Probably time to check the drum for mosquito larvae.
I still have one of those Glenn. They work well.
I don't know anyone who uses the auto waterers
I've touted the advantages of a MPPT [Maximum Power Point Tracking] Charge Controller in many places on the forum without saying anymore than they are more efficient. Just what does more efficient mean and how is it accomplished?
I'll begin with a description of how a conventional charge controller, that is any non-MPPT type, works.
In use a conventional charge controller basically connects the output from the PV panels to the batteries. This forces the PV panels to operate at the battery voltage. Battery voltage is not the ideal operating point at which modules produce their rated maximum power.
For an example, let's look at a system one of my neighbors use, since I already have the numbers. He uses six BP 80 watt panels. They are nominally rated as 12 Volts; 17.6 Volts at maximum power rating (Vmp), maximum current output of 4.5 amps (Imp). 17.6 x 4.5 = 79.2 watts. Close enough to be sold as 80 watts. He uses four 12 volt batteries to store the power. The panels are connected in parallel. For the purpose of comparison I'm going to simplify the system down to a single panel.
Situation #1.
The panel puts out a maximum of 4.5 amps. The batteries are sitting at 12 volts. That drags the panel voltage down to 12; 12 x 4.5 = 54 watts. We've just lost 26 watts worth of power; 32% of what was purchased. Those 26 watts are not going anywhere, they are not being produced because the panels don't match the batteries.
The panels need to have a higher voltage rating than the batteries though to make up for cloudy days when their output falls. Panel output also falls under high temperature conditions.
Situation #2.
The same 4.5 amp panels, but the batteries have been discharged to where their voltage is down to 11 volts. That drags the voltage of the panels down and we end up with 11 x 4.5 = 49.5 watts, a loss of 30.5 watts; 38% of the rated power.
With MPPT the charge controller momentarily disconnects the panels from the batteries. It then looks at the output of the PV panels and the voltage of the batteries. It then calculates the best combination of volts and amps to charge the batteries with the maximum amount of power. In other words the MPPT controller can reduce the voltage to match the battery and increase the amps. A conventional controller can not increase the amps.
Inside the MPPT controller is a high efficiency DC to DC converter controlled by a computer chip. It samples the PV panel output and battery voltage continuously; this only takes micro seconds. The DC to DC converter can increase the amperage output to the batteries.
MPPT controllers are best at increasing power output in cold weather and conditions of low battery state of charge. Since cold weather usually means winter that also usually equates to fewer hours of useful sunshine for generating power.
Typical cold weather increases can range from 20 to 40% more power with a MPPT controller. Warm weather increases will be less, maybe only 10 – 20% depending on battery use.
The MPPT controller also excels at making best use of the PV panel power over long runs of wire. The PV panels can be connected in series for lower losses in transmission and then brought down to the 12 volts needed for the batteries. There are limits to the upper voltage range for every controller, so that must not be exceeded.
The DC to DC converter actually takes the input DC and changes it to a high frequency AC. Then it converts that AC down to a voltage better suited to the battery condition. They are extremely efficient and small in size.
Further note to the above:
The gain in current of a MPPT controller is roughly the same proportion as the percentage difference between the panel voltage and the battery voltage. If the panel is 17 volts and the battery 12 V the gain is 17/12 = 1.41 or 40%. This is under ideal conditions and never happens in real life.
The above equation assumes that the current at 17 volts and 12 V is identical. In real life it is not. The nameplate panel ratings are at bright sun and 25 deg panels. If you have bright sun, it heats your panels and you no longer have 25 deg panels. A good rule of thumb is take the nameplate MPP rating and multiply by 0.9 - 0.95.
Heat affects the equation by decreasing the 17 V MPPT and of course lowering the gain. As the battery fills, the 12 is increasing to say 13 or 14, hence the proportion increase in charge current decreases. Note however that the highest increase occurs where you need it the most - into discharged batteries.
Thanks Don
I am convinced I need the mppt type
I have almost talked myself into the Xantrex XW 60
the outback has some very nice features but the Xantrex line of inverters and controlers look very compatible with my plans -- they have a single status panel and a remote output that can be programed to start the genny if needed
( a great feature if I go away for a couple days and my DW has to deal with a low power situtation)
and the Xantrex is on sale at the Solar Biz for $470
basically I will have the 2460 watts of solar panels
6 Air X 400 watt wind generators
and a back up diesel (or propane or gas) genny
conservatively I should get about 300 KW Hrs a month from the panels and about 180 from the air 400's per month
16 KW hrs per day should be more than enough without the genny unless I really start running the power tools in the shop
Quote from: Windpower on April 29, 2009, 02:41:26 PM
the outback has some very nice ..... the Xantrex line of inverters and controlers .....they have a single status panel and a remote output that can be programed to start the genny if needed
( a great feature if I go away for a couple days and my DW has to deal with a low power situtation)
Outbacks can do all that too. Either should get the job done though.
Battery Wall Chart.
http://nofrillstech.info/Wallchart.pdf
Battery Info
http://www.theresourcestore.ca/toolbox-batteries.php
Don - how's the reliability on these things? Any more/less than a typical controller.
Good reliability from what different vendors have said and from the few people I know with them.
The biggest problem source would be from voltage spikes. Use proper lightning arrestors and size the PV string to prevent cold weather wake up shock.
I have been looking at the Outback system.
Can you explain to me how the MATE and FLEXNET works?
I'm not rapping my head around this at all. so if you can just explain what they do would be great.
I think the Flexnet shows you the info about how your system is operating, but where does the MATE come into play?
as I said totally lost here and might have confused my self.
Also you guys talk about tools in your shop, could you give me a rough idea if I have a hobby wood working shop, for making small things like cutting boards how much extra capacity I'm looking at needing in a battery system? I'm not worried about extra panels as I would only be in the shop maybe one day out of two weeks, so the battery system should be all topped up by then. I just need a rough bases here as to what kind of load someone might use playing with a drill press and a plainer, maybe half a days worth of playing around in the shop might not need more battery capacity? after counting in the added margin in the system anyway?
Thanks
I think the whole system would have to take into consideration the size of the tools you may want to use in the shop.
I think if you are capable of powering your washing machine you could be capable of powering some of the small shop tools. Many of these tools are used only for a small amount of time and likely if you are not using them a the same time as the washing machine is running then you would be OK. I have two 4024's making 240 volts or 120 and find that I can do most anything in the shop with about 2500 watts of panels and a 1000 watt wind generator. For heavy use I can charge or power with the welder generator. I seldom do though. I would recommend at least 8 to 12 L16 batteries for shop use. I also power a wire feed welder sometimes for several hours of off and on welding without the generator.
Even one 4000 watt inverter will handle a lot of shop tools. A 2 horse motor only takes about 1500 watts under full load but requires extra starting capacity. I commonly use that and more on my 120v inverter.
Thanks that was my thoughts too, but wanted to make sure I wasn't missing anything, a small bench top drill press probly uses about the same power as a stand up vacuum.
another question, am I going to find that the majority of common well pumps are going to be wanting 240V?
I would rather not have to deal with 240V if I don't have too, but at the same time my goal is to have as common of a house as a grid tied one (I know that means big bucks in a solar system)
Grundfos SQ Flex takes care of that problem- nearly any way you want to power it.
In brief, Outbacks FlexNet is a fancy monitoring system. It acts like a "fuel gauge" style status bar, current state-of-charge and whether you are currently charging or discharging your batteries. It also shows the amount of power your system is currently producing and consuming as well as the amount of power going IN and OUT of your battery bank. Another thing it will do is monitor the cumulative energy your system has produced and consumed as well as the total amount of energy that has gone to charging your batteries. It's 'bells and whisltes'; nice but not necessary, even to a number guy like myself. ;D
The Mate on the other hand is a remote programming management tool. One Mate can service several inverters and charge controllers. It's very good to have. The Hub will allow the connection of many items to one mate.
Grounding the PV system.
By that I mean the DC side of the system. And by system I mean a stand alone off grid system. The AC side of the system should be treated as any normal grid tied AC system. That means the AC side should have the neutral AC wire bonded (connected) to the grounding electrode conductor (a.k.a. the bare ground wire) at one point, usually within the service panel and then connected to the grounding electrode (the 8 ft copper plated rod in the ground, metal water pipe, etc.)
The DC side is similar but has special requirements. For example, there are special ground requirements and ground fault devices required for any roof top PV panel installations. I'm not going to touch on roof top installations. The following information is intended for ground level or pole mounted panel installations. Let it be noted that references to the NEC rules are made because many of us will have to have our PV installations inspected and approved. I'm not passing judgment of the validity of the NEC rulings, I'm just relaying information as I understand it. If we do not expect to be inspected... well, take this all into consideration.
Let's start with the PV panels themselves. All panel module frames must be connected to a ground. The modules must be bonded to the supporting framework and any other metal parts such as poles, combiner boxes and power centers. The NEC does not consider a connection bolted through an aluminum module frame to a support as a viable ground connection. That is because of the normal oxidation or the anodizing of aluminum. Current rules require special tin plated connectors that are secured to the aluminum with stainless steel 10-32 machine screws and nuts. Recent PV modules are manufactured with marked ground points and a pre-punched hole for the 10-32 fasteners. Self tapping, or self threading screws used to be allowed for ground lug connections. That has been disallowed because of the rule that requires all threaded electrical connections to be able to withstand at least 10 tightening and loosening cycles. Self-threaders fail that test on aluminum.
Here's a more or less typical NEC drive-you-crazy ruling... Those marked ground points are the only ones recognized for use. The only thing that sets these apart from any other hole is that they are punch marked with a ground symbol and that is the point where the connection was made during testing. So any other hole could work, it's simply not approved. d* Ooops, I was editorializing.
The special approved ground lugs are expensive; (TheSolar.Biz has the best price I've seen, about half what most others charge.) An alternate that may be approved by some inspectors, is a stainless steel machine screw and nut with two stainless steel washers. The copper grounding wire would be wound once around the bolt between the two washers and then the bolt tightened.
The module grounding rule goes on to state that removing a panel for maintenance shall not interrupt the grounding of any other module. This also applies to any grounded equipment; removal of any piece of grounded equipment must not interrupt the grounding path of any other equipment. The special ground lugs make this easy as they use a "lay-in" method with set screw for securing the wire to the lug. So the best practice would be to use one of these lugs on each module and on any of the aluminum support arms. Connect all together using bare copper wire of the same size, or larger, as the wire used for the positive and negative module connections, usually 10 AWG. Connecting the ground to a steel component (pole) can be done with more traditional methods (screws, bolts) as long as they are approved for outdoor use. Those little green grounding screws on outlets and what not are not outside approved; they will rust. Use stainless steel and it should be okay.
It should also be noted that grounding lugs must be secured with sole purpose fasteners. That is to say the bolt used for the grounding lug must not also be used to hold other components together. So, no doubling up a ground connector to a bolt that is securing a panel to a mount arm.
In short, the panels, all metal frames and parts should be connected with a bare copper grounding wire; everything from the modules to the combiner box. From the combiner box copper wires will more than likely be connected to a larger diameter wire to transmit the power to the charge controller.
Where oversized wires are used to minimize voltage drop the equipment grounding connector must be of at least the same size as the over sized wires, according to the NEC. That means the third wire must be the same size as the positive and the negative wires. This is commonly overlooked or not understood. This could be expensive on a long panel to controller run, but there is an out. If the distance between the modules and the charge controller and batteries is greater than 30 feet (the NEC is vague on this), the third wire may be dispensed with. This will be referred to as a remote array. As well as the distance requirement, the second condition that must be met is the absence of any other conductive path from A to B. That is, no metal fences, water pipes, metal conduit, communication cables, etc.
There are two ways to ground such a remote array:
1) Bond the negative conductor to the grounding system at both the array and at the inverter/battery/power center location. Do not run any equipment grounding conductors between the two locations. (Run only the positive and negative wires.) Use ground rods at both locations. Do not bond the ground rods together. If the two conditions (distance and no conductive path) cannot be met, then the following method must be used:
2) Do not bond the negative to the grounding system at the array. Bond the negative only at the inverter/battery/power center. Run an equipment grounding conductor between the two locations. Use ground rods at both locations.
In a 12 volt DC system it is not necessary to bond either of the power carrying wires to the grounding electrode. Normally, we will ground the negative wire; most inverters and other equipment is made to operate with the negative grounded. Most 24 volt DC and all higher voltage systems are required to have a single point where one of the power carrying wires, normally the negative wire, is bonded to the ground wire and the grounding electrode, the same as in an AC system. The rule is actually written around the 50 volt DC figure; below 50 VDC a grounding bond is not required, above 50 VDC it is required. Keep in mind the open circuit voltages during cold weather can be considerably higher than the nominal system voltage. That is why I say some 24 volt systems may require bonding and some may not. I think it's best to bond in any DC system. Note that 48 is the generally acknowledged point where DC voltages become life threatening.
The 12 volt system would be exempt from this bonding but is required to have a properly sized DC rated current overcurrent protection device (fuse or breaker) in each of the negative and positive conductors. These can be expensive and it may be cheaper to install a bonding point and have a disconnect and overcurrent device in only the non grounded wire (positive wire). Also note that low voltage fluorescent lamps start with greater reliability in a grounded system.
The DC connection to the grounding electrode can be confusing. If more than one DC equipment grounding conductor is attached to the grounding electrode, those ground conductors must be the same size as the largest power conductor in the system. This would be the battery cable size in most systems. If there is only one conductor connected to the grounding electrode, the NEC allows DC grounding electrode conductors as small as number 6 AWG (copper to be used. Go figure; I dunno. ??? The best solution to this problem is to use a common single grounding bus bar in the system. Connect the components to this point. Then connect the equipment grounding conductor from the bus bar to the grounding electrode. For this reason it is also best to use separate grounding rods for AC and DC.
Grounding would not be complete without the mention of lightning protection. The grounding wires connecting the modules to the frames and down to the grounding electrode will serve as a protective path for lightning strikes on an array. However there is still the danger of high voltage surges coursing down the wires to the charge controller and other components or yourself. A lightning arrestor is required. There are ones designed for DC and ones for AC. On the DC side an arrestor should be mounted on the combiner box. There are three wires. One is connected to the positive, another to the negative wires, after all module outputs are combined. The third wire connects to the common ground bus and then to the grounding electrode. If lightning causes a high voltage spike it is diverted to ground.
Thanks Don - a lot to digest there.
For uninspected systems a solar electrical system designer clued me in on a low cost alternative for a lightening arrestor.
An automotive spark plug grounded at the base, with the hot terminal connected to the positive lead from the wind turbine or it could be for an array. The negatives would be grounded. In the case of lightening it would easily jump the spark gap of the spark plug on the positive leg, but the generator or array voltage would not.
Have I done it yet.... no d* d*
Interesting idea. :D
What heat range plug is suggested?
Should it be an resistor type?
Maybe a Bosch 4 electrode platinum, or a SpltFire? ???
rofl rofl rofl rofl
Delta arrestor modules are only $40.
Lighting just traveled a couple miles to the earth, I don't think you have to worry about the temp rating of the spark plug, that little bit of a tolerance won't matter. d*
Also If this spark plug works, which I see no reason not too, its kind of pointless. just make sure you have a heavy duty grounding wire with in a few thousands of an inch away from a bare terminal between the PV array and any electronics. The charge will jump this gap and bypass the electronics.
I would be more worried about the charge passing through my PV array and the wiring, So I would do what ever possible with a Lighting rod at the array instead of trying to deal with it in the house ;)
Re: Lightning.
I was hoping I had made it clear that you need both types of lightning protection.
The module frames, mounts, etc. all need to be grounded to at least one 8 ft rod, or equivalent.
You also need the circuit to be protected to prevent equipment or people down the line from electrocution from lightning strikes.
"heat range, etc." was a joke... I added a rofl ... didn't stop to think not everyone was familaiar with my sense of humor. :-[ :-[
I caught your sense of humor, its mine that was mistaken d*
Quote from: MountainDon on May 18, 2009, 03:31:50 PM
Interesting idea. :D
What heat range plug is suggested?
Should it be an resistor type?
Maybe a Bosch 4 electrode platinum, or a SpltFire? ???
rofl rofl rofl rofl
Delta arrestor modules are only $40.
I have a Delta arrestor at the power controller as he suggested, (Delta arrestors are pretty wimpy compared to a bolt of lightning - likely better to arrest it before it all makes it to the Delta) but he said that is likely not enough and that the plug should likely be put at the wind generator tower base area on the positive cable and the negatives all earth grounded - likely following your guidelines above.
He is a real pro and does testing for Outback - they send him free stuff for evaluation. I would suggest a non resistor type.
Batteries. I've talked pros and cons of various ones previously. I'm not sure if I stated what I was going to use. I've been asked what I'm going to be using at our cabin. The quick short answer is golf cart batteries, arranged in series/parallel for a 24 VDC based system.
Golf cart batteries are usually 215-225 amp-hours and are 6 volt units. I believe we have pared our electrical use down to where these will do the job for us. I've run the 'numbers' a number of times over 2 years time.
I selected golf cart GC2's for several reasons, even though they are not highly recommended by many alternate energy parts suppliers.
One reason is my experience to date with a bank of golf cart batteries in the RV. I try to follow a rigid maintenance schedule and have pulled 5 years of practical use from a set.
A better choice would be the L-16 type; also 6 volt with 370-400 amp-hours. I wouldn't need as many batteries and would have fewer parallel strings. L16's weigh about 130 pounds apiece. GC-2's are about half the weight. That is important to me.
The batteries will be sitting through several winter months. I believe that the equipment I've selected, from pV panels through to the charge controller is among the best. However, if something goes wrong and the batteries do not keep receiving their maintenance charge, there's a good chance the batteries could be harmed by the freezing weather.
When I look at the costs per year of the GC-2 vs the L-16, plus the other mentioned factors I decided to go "golf". Admittedly, it's a trade off.
Earlier on here, I spoke of grounding the PV system.
My grounding lugs finally arrived. Here's what they look like with the parts laid out and assembled.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property3/mini-P1000994.jpg)
They are made by Wiley Electronics. I got mine from thesolar.biz Some vendors charge $10-11 each; they were half that. The thin stainless steel plate has 4 punched holes with tooth-like edges, on the bottom side. These grip and dig into the aluminum panel frame and make a very secure ground connection. The tin-plated clamp is suitable for AL and CU wiring. Here's the WEEB exploded installation image. The nuts, bolts and washers are stainless steel.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/oddnends3/WEEB.jpg)
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property3/WEEB2.jpg)
I got stalled by the rain and forgotten parts, so that's all the photos until next time.
More on the grounding...
Here's the ground rod. Right at two inches away from legal NEC depth I hit a rock that stopped the rod cold.No amount of pounding made headway.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property3/mini-P1010048.jpg)
I figure dirt piled on top will make it 8 feet or greater.
Here's the 'combiner' box I decided to use. It's an off the shelf Square D item. I added a block on the left to make it easy to connect the Delta lightning arrestor. The box is plastic; I used a nylon bolt to mount the block. It may not meet actual NEC code, but it is as safe as a more expensive 'proper' PV item. Since there's no inspection this is what I've used.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property3/mini-P1010043.jpg)
Please also note that the disconnect, although rated for up 48 VDC is not really legal under NEC. However, I don't plan on using it as a disconnect much at all. It's mainly a convenient and inexpensive item to use to connect the 10 AWG wire from the panels to the heavier 2 AWG wires that lead up the hill to the batteries and cabin.
The number 2 wires are not shown.
Also on the grounding theme...
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property3/mini-P1010047.jpg)
Here are the grounding lugs as mounted to the PV frames.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property3/mini-P1010049.jpg)
The panels are not tilted as yet as the wires up the hill are not yet installed. That's the dirt that will be moved to cover the in ground rod.
I drilled and tapped the steel pole and connected the ground wire there using a stainless steel 1/4 x 28 bolt and two S/S washers.
Nice Job Don!
I have been lurking! I have one last step for you (there never really is a last step) on your grounding.
The line from my mentors back at HP was "nothing electrical is complete unless it has been tested"
To test your ground system you need 2 ground bars or 2 ground systems. Here is how you find out if you need more. It is pretty simple! ??? OK, ready? Connect a decent ohm meter between the ground bars or if you have a UFER (wire in foundation) One wire to one ground bar and one to the other system. The two systems cannot be connected for this test but should be later in most cases.
If you do not read below 25 ohms you need to add another ground bar to find out which bar is not working.
Most people never do this but since we know you want to increase your odds of surviving lightning you should do this. Forgive me if you already discussed this after all I am a new guy with old tricks! Take care!
Good point on the testing Dave. Thanks very much. It is appreciated.
No problem! I almost ended up down by you instead of by Glen. It was a tuff call!
Since as I said "there never is a last step" and you are still getting this system together, I will give my humble opinion on Lightning. You want to do all that you can, the arestors, spark-plugs, MOV's and the ultimate an 8 foot long bundle of wire from the array that you can disconnect and move so there is an 8 foot gap.
The sad part, even the bundle disconnect can fail if your number is up! All the other steps are great if you are not at home when it hits. They are worth it!! The Arrestor may look wimpy but it is one hell of a lifesaver, if you are up on your luck!
Good Luck!
My luck has been pretty good so far. :D I've been close personal witness to three strikes within close proximity; 100 foot range. Hair standing on end (that was years ago ;D ), bright flashes, big noises, bark flying off trees, sparks from hand to vehicle door, and so on.
A recent post elsewhere made me think of this... How does one calculate the proper angle for the solar panels?
This is a function of latitude and time of year. Ideally the panel surface would be perpendicular to the rays of the sun at all times. (note angles are measured from the horizontal.) With the sun low in the winter sky the panels would be tilted more, to a larger, steeper angle.
There is a rule of thumb for panel tilt. That is for winter (December 21) the angle should be your latitude PLUS 15 degrees. For summer (June 21) the angle would be your latitude LESS 15 degrees. Our location in NM is 35.75 degrees. Therefore winter = 50.75 degrees and summer = 20.75 degrees.
In most locations winter sunshine is less than in summer. So if you do not wish to get into seasonal adjustments, optimize the installation for the winter. Another approach would be a twice yearly adjustment. Set the tilt for the winter position in about mid October and back to summer position in mid March. Some folks will make 4 seasonal adjustments.
For those who are more anal about things like this (moi Grin ) there is a more accurate formula. Take the latitude and multiply it by 0.9. Then add 29. That provides me with a winter optimum tilt of 61.175 degrees.
The angles apply to all things solar, PV panels as well as hot water heaters, etc.
Quote from: Dave Sparks on June 26, 2009, 09:41:43 AM
Nice Job Don!
I have been lurking! I have one last step for you (there never really is a last step) on your grounding.
The line from my mentors back at HP was "nothing electrical is complete unless it has been tested"
To test your ground system you need 2 ground bars or 2 ground systems. Here is how you find out if you need more. It is pretty simple! ??? OK, ready? Connect a decent ohm meter between the ground bars or if you have a UFER (wire in foundation) One wire to one ground bar and one to the other system. The two systems cannot be connected for this test but should be later in most cases.
This seemed like a good point. My problem with performing the test was that the 8 ft. ground rod is only a foot from the steel pole in the ground/concrete which is the only other ground at this end of the system. The ohm meter gave a reading of only 6 ohms when connected between the two, which is good but is also meaningless because of the closeness. At least it's my interpretation that two grounds that close are acting more or less as one.
My solution was to add another ground rod down by the array. I sunk a second 8 foot 5/8" copper clad ground rod in the ground 8 feet away from the other and connected the ground wire to it as well. Testing the reading between the two rods came up with 12 ohms. So it appears to be within the allowable limits. :)
I'm uncertain if I mentioned this before... When the array and the balance of the system (charge controller, batteries, etc.) are distant the NEC allows the system to not require a third wire (ground) between the two system sections.
The NEC does not define "distant", but my research has come up with 50 feet or greater as being generally recognized as distant. My 300 foot distance would qualify. This saves the expense of a third run of expensive wire, #2 AWG in my system.
To omit this ground wire between array and charge controller there must also not be any other possible current paths; no metallic conduit, no wire fences, metal water pipes, etc. Again our system qualifies.
I just ran non metallic conduit and the #2WG wires from the array to the cabin.
http://countryplans.com/smf/index.php?topic=2335.msg95631#msg95631
It's not connected yet at either end. That will hopefully be completed in the next week we spend up at the cabin. Photos at that time.
In an attempt to avoid the basket of snakes look that sometimes occurs with a battery bank of series and parallel connected batteries I have elected to use copper buss bars and copper bar battery interconnects. I built the buss bar assembly today, and here it is.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/electrical/P1010383.jpg)
![](https://i133.photobucket.com/albums/q75/djmillerbucket/electrical/P1010384.jpg)
![](https://i133.photobucket.com/albums/q75/djmillerbucket/electrical/P1010386.jpg)
The mount board is 3/4 plywood. The standoff insulators secure to the board with 1/4 x 20 bolts; ditto for mounting the bars to the insulators. The fasteners are stainless steel. The buss bars are 3/16" x 3/4" copper bar stock, 72 " long. I have drilled a few pilot holes for the charge controller and inverter connections. The battery connection holes will be drilled on site when the battery positions are determined.
As indicated the upper bar will be positive 24 VDC and the lower bar will be negative 24 VDC. That size of copper bar can safely carry 250 to 300 amps. At full output my inverter is rated to draw 170 amps so there is reserve capacity for momentary overloads.
More pictures later.
Nice busses, Don.
I want to make mine similar so I can isolate each bank of batteries for equalization. More than one bank of batteries on equalization at a time will not work well especially if one bank has a low cell. Most of the power will flow to the good set rather than correcting the low cell.
Isolating and equalizing each series set will eliminate that problem.
Here's an article on a new battery..............
http://www.heraldextra.com/news/article_b0372fd8-3f3c-11de-ac77-001cc4c002e0.html
Interesting battery Harry. I think I would like more panels also, but we are steadily getting better.
Don,
I know the NEC is not clear on distant grounds but you definately want the array ground bars and lightning system connected to the house or panel/battery ground system. A # 6 would be fine for this. With you second bus bar how does the 6ohm path to the concret bar ground measure? You may want to tie that ground in also.
Ciao!
The grounding information I have used comes from my own reading as well as from John Wiles at the Southwest Technology Development Institute at New Mexico State University in Las Cruces, NM. I have used his recommendations for grounding our system.
The array position has the aforementioned twin ground rods, plus the steel pole in concrete in the ground.
Up at the cabin the AC system has a ground rod from when I did the original interior wiring. The AC system at the cabin also includes a Delta arrestor. Sixteen feet away from the AC rod is what I call the DC ground rod, even though the two are connected. The reading between them (disconnected) was less than 12 ohms; can't remember exactly. It seemed good enough and that was all I cared about.
As well, the steel roof and steel chimney have their own grounding leads and ground rod at the other end of the cabin.
I have a small fortune invested in copper and copper clad steel rods. :D Hope it all does its job. I was thinking I had it pretty well covered, or at least covered better than many. Maybe I'm only almost there.
Cool Beans! Just remember some of Wiles info is continuously updated with code changes and some of it is for residential which may or may not apply offgrid! Also not a bad idea to have plants that get watered in summer near your ground systems if your ground resistance goes up in summer.
Excellent point on the updating of the information over time. I've read everything I've found that he's written since the mid nineties. It is interesting to note the changes since then. I sometimes have to go back and verify what the latest info is.
Great idea on the watering. I guess that is a side benefit of the current graywater drainage area from the kitchen sink. It's near the DC ground rod. Maybe I should route the shower drain line over near the SC groun d rod. (I refer to them as the DC rod or the AC rod to keep them sorted in my mind... I could have numbered them but I find SC/DC easier... DC on the left (south) and AC on the right (north). ???
I began building cables to connect the battery series strings to the bus bars this evening. I purchased the Brute crimping tool and gave it a try. The two ends in the photo show one lug connector just crimped and the other end with the shrink tubing. I did each end of the length of 2/0 I bought to try it out. I'll fit, cut and complete them up at the cabin this weekend.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/electrical/P1010463.jpg)
The lugs are tin plated solid copper from Quickcable, as is the heat shrink tubing. I also realized the Brute tool is marketed by Quickcable; never realized that before somehow. $30 for the tool.
I did one crimp using the vice and the other using a big ball pein hammer. The hammer was easier to use and crimped a little tighter.
I took a reading with the cheap meter I had here at home. It didn't prove anything as the reading was the same as touching the probes to each other. My good meter is up at the cabin.
The Quickcable heat shrink has a heat activated adhesive inside the tube that helps with sealing the tubing to the cable and lug.
I also have 4/0 cable and lugs for the inverter.
Cool cable lugs, Don. Looks like that beats mashing a piece of copper tubing over the cable with a hammer and drilling a hole in it - while securely holding it with a pair of pliers. d*
Yeah, hanging onto the mashed tube while drilling a hole in copper can be a bear. The bits sure like to hog into the copper.
I broke a few bits while trying to drill holes in the buss bar stock holding my Ryobi 18V rechargable. The bar stock was clamped to the trailer and the drill braced against my leg, so the bit was the weak point. Results were better with the drill press though there the bits would hog in and the belts slip.
In case anyone is interested...
My source for the lugs... http://solarseller.com/quick_cable_copper_cable_lugs.htm (http://solarseller.com/quick_cable_copper_cable_lugs.htm)
the heat shrink tubing... scroll down a little http://solarseller.com/distribute_quick_cable_battery_and_power_cable_products_compression_connectors__.htm (http://solarseller.com/distribute_quick_cable_battery_and_power_cable_products_compression_connectors__.htm)
the brute... http://solarseller.com/quick_cable_crimper_cutter_stripper.htm#brute_hammer_crimp_tool (http://solarseller.com/quick_cable_crimper_cutter_stripper.htm#brute_hammer_crimp_tool)
So my cabin PV system is now operational. It works!!!
I finally tilted the array up into power producing position. The angle adjustment brace is not completed, so this is a temporary unit. Pictures of the adjustable model after next weekend MTL.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property4/P1010464.jpg)
Closer view...
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property4/P1010465.jpg)
Here's the completed battery chamber with it new set of 12 golf cart 6 volt 210 amp hour batteries. There's room for 4 more plus room for the battery water dispenser, hydrometers, etc. I keep the hydrometer that's being used stored in that section of PVC pipe. The cap on the bottom collects any acid that may drip out of the hydrometer in storage. You can see the ends of the 4/0 cables to the inverter on the right. Number 2 cable comes in from the charge controller on the left. The white cable that disappears mid wall is the CAT5e communications cable from the Outback inverter to the Mate (remote control and programming tool) that will be mounted on an interior wall. There will eventually be another CAT5e cable from the Outback charge controller that will tie into the Mate via a hub. Then both the CC and the inverter can be monitored and programmed remotely.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property4/P1010475.jpg)
I used a length of 2 AWG cable as the connector between the two small ground buss bars. The charge controller, inverter, etc., on the DC side of the system, are all connected to this ground buss. The ground wire to the ground rod is connected to the ground buss as well. That way there's only one connection to the ground rod. This is the preferred method according to the NEC.
Closer view of the batteries...
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property4/P1010476.jpg)
The negative end of the series strings showing the 2/0 cables I made up with Brute crimper.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property4/P1010478.jpg)
and, the positive end...
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property4/P1010479.jpg)
You'll note that while I did use red shrink tubing for the positive leads I used black and then applied white electrician's tape to each cable end. That is because the NEC recognizes black or red as being "hot", or in the case of DC power, a positive conductor, it insists that only white be used to indicate the neutral or negative conductors. On larger wire/cable sizes it is okay to use white tape or paint on a black wire/cable to indicate the negative.
By the time I had everything connected the weather turned cloudy. Even with near full cloud cover the charge controller was putting 4 amps into the batteries doing a bulk charge at 26.something volts.
Anyone who grew up before the age of maintenance free car batteries and also tinkered with the cars of the era should know what this is. They are hard to find these days.
The neat thing about them is the spout has a valve in it. When the dispenser is tipped the water does not pour. The tip is inserted into the battery cell opening and pressed down. The water flows until the level is at the full mark, then ceases. No overfilling the cells and no need to bend over the batteries with a flashlight trying to see the level as you pour water from a bottle.
Here's where I got mine
http://www.armysurpluswarehouse.com/product/battery-water-filler-jug-2765.cfm
Alright, our cabin now has its electrical power coming from the sun! Whoo Hoo!! :) :) :)
It didn't take long to get used to not having to go outside, start the generator, switch the power feed, go inside and use the microwave, then go back outside turn off the generator, switch the power feed back and go back inside. Whew! All that to warm something up quickly.
Now I'm going to have to change my generator habits a little. It's been used so much that I seldom have worried about the fuel going stale. Now each and every tankful will get a dose of Sta-Bil. Ditto for any fuel stored in cans. In the past I've treated the fuel meant to last over the winter with stabilizer, but have not been concerned about it the rest of the year.
Here's the panel tilt setup. The angle iron is bolted across the two longitudinal frame arms. The square steel tube has an insert welded inside and the 3/8 bolt allows the angle to change.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property4/P1010506.jpg)
The lower end of the tilt bar has several holes drilled at intervals to allow best winter, summer, spring and fall angles. There's a 1/2 inch carriage bolt, with the head removed, mounted through the steel post. The headless end is drilled for a hitch pin clip to allow toolless adjustment.
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property4/P1010505.jpg)
I used
this triangle calculator (http://countryplans.com/smf/index.php?topic=7537.msg96848#msg96848) to compute the distances between adjustment holes.
My first impressions after a week - 10 days are that I oversized the panel and battery capacity. But that's all to the good, there's room to grow and I am certain we'll find ways to use the power. It's a little strange having a 0.5 to 1 second delay in the light coming on, or the power saw starting, with the power search function enabled. However, I'm getting used to it and the feature supposedly does save battery power by greatly reducing the inverter stand by loads.
Even under partly cloudy skies the battery bank has been recharged through the bulk stage, in and out of the absorb stage and into float with hours worth of sun time left in each day. Plus, so far at least, I've barely been into the top 10% of the battery bank capacity. That's good for battery longevity. This may change some as the days grow shorter, but I believe we're good.
There has even been sufficient solar power to run through a battery equalization sequence using the power from the PV array. So [cool]. I'm a very happy camper right now. :D
I find myself being distracted throughout the day as I watch the numbers on the Outback Mate remote control panel. Hopefully the novelty will wear off. Or maybe it's okay; better than watching TV?
I added some insulation to the buss bars after one inadvertent display of fireworks.
Don:
The insulation on the buss bars is a great idea. It is so good to see it all coming together for you guys. You both seem to have put in a lot of work up there and it is good to see it paying off.
We own a ranch in the mountains and where we are going to build is on the grid. However I have been toying around with the idea when we retire, build and move up there full time to incorporate some solar. It almost makes sense yet I really just have a hard time justifying it. What are your ideas and takes on the matter.
I am looking at two years in September before I can make the transition into retirement. So I know that things may very well have changed a lot by then. I am not really looking at saving a ton of money not buying electricity. I am more concerned with flipping a switch and something happening; like in the middle of a January blizzard or April ice storm or power poles burnt up in a August range fire. Or is a back up generator a better idea. Or just how safe is the power grid going to remain with terrorist threats and even solar flairs being tossed around? The latter I really don't think anyone could really predict.
Any ideas are welcomed
Rick
Thanks Rick. I'm looking forward to being completed. Nothing is ever completely done, of course, but it will be nice to have no more obvious loose ends.
If the power company up there would have put power in to the property line for less than $2.5K we might be be grid tied. As it was they wanted twenty times that, so it became a no-brainer for me to choose PV solar. Local wind conditions made wind unfeasible and there's no hydro potential at all.
To have a grid tied system with battery capacity for those emergencies when the grid goes down would be great. You would need to calculate what loads would be deemed indispensable and how long you'd need to power them. The refrigerator, freezer, furnace would be the biggies on the list. A few lights too. Then the problem is to isolate those circuits into a separate breaker panel so it and only iy can be supplied with power from a generator or small PV system. That's easy to do on new construction, a little harder on existing buildings. Separating things out like that would allow the alternate energy system to be smaller than otherwise.
A standby generator for power outages would be a great comfort. The best would be fueled by either natural gas or propane, with diesel second and gasoline third. That's my opinion. Liquid fuels have storage issues. Also, in my opinion, a standby generator must have auto start capability for those times you are not there to manually start it if the need arises.
Batteries coupled with an autostart generator would be excellent. Our cabin inverter has the capability to be programmed to start a generator if the battery voltage falls to a pre-programmed level for more than x number of minutes. The cabin generator is not compatible though.
My ideal, and somewhat expensive, home would have electricity as the only energy source. Of course that would require a considerable array and a large battery capacity. If one was building new and took extra care on the insulation and sealing it can be done. There are a few homes around my state that are either totally off grid or on grid, but generate all the power they need. They use the grid as the battery. It works but if the grid goes down you're out of power too, unless you have a battery bank as well.
I came across another cool tool for anyone contemplating solar energy, be it a PV array, or an air or water solar heating panel.
Rather than involving latitude figures this one makes use of drop down menus where you can choose from countries; USA, Canada, UK and Ireland. Then you work your way through a state/province list and a city/town list. Some states like NM have only one city, others like neighboring Colorado have more. Once the location is selected a list with the optimum angle for each month is presented.
I have placed the link on a topic in the Referrals section,
http://countryplans.com/smf/index.php?topic=7582.msg97318#msg97318
Well good job Don...!
I had to smile about you looking at the mate a lot...not sure if it ever goes away...
In the year or so i was off grid it was a good part of my day...watching the mate...meters and wind gens...lol...
Just something neat about the independence of making your own power...can't wait to do it again...hopefully soon...Dan...
Here's a handy page from Trojan battery. The link goes direct to the charging rate information. There are other sections available from the menu; cleaning, watering, etc.
http://www.trojan-battery.com/BatteryMaintenance/Charging.aspx
A tidbit of interest.
New PV panels are introduced with the frequency o celebrity diets and the old ones are discontinued with matching speed. Therefore if one has an existing system and decides one day to increase the number of panels a quandry may arise.
If one has an MPPT charge controller it is generally agreed that the ideal situation is one where all the panels on that charge controller are the same. When it is impossible to obtain the exact same panels what is the best compromise?
There are 2 answers. If one is matching panels in series it is more important to try to match the Voc and the Vmp values. If one is matching in a parallel connection then it is best to try to match the Ioc and Imp values.
and for anyone playing with the...
idea of solar the trojan t105 re's may be a good choice right now...they bumped the warranty to 5 years now...
they are relatively cheap for a small system like Don's or for someone who wants to get there feet wet...
batteries need some work yet...but some new tech is getting there...hopefully the battery problem will be solved soon...
something the size of a breadbox that stores 50kw and goes for a grand would be a hot ticket...! Dan...
I have 8 T105's that are 10 years old
they still hold a charge (even after experiencing the unforgivable sin of letting them completely self discharge *doh*)
it did take a few hours at the equalizing rate to get them back
that said -- the Rolls/Surrettes are probably cheaper on a per-year-of-service rate (and highly recommended by a guy with over 30 years of experience at the Midwest Renewable Energy Fair) "I would buy a big 2 volt battery in a red case made in Canada --- Surrette"
he also recomemnded going with 2 volt batteries -- if one goes bad it is easier to find and 'cheaper' to replace
cheaper is a relative thing though -- the cheapest RS 2 volt is $910 for a 1700 AH battery
(hhmm times 24 cells for a 48 volt system :o
For me, I think a 4 volt compromise is in order --- 546 AH for $592 would give me a nice 12KW Hr storage for about $7000 still an ouch
prices from here
http://www.staabbattery.com/
hey windpower...
yeh 24-2 volts is a lot to hook up...i had 16, L-16-6v..2 banks of 8's for my 48v system...i think i saw somewhere
that you were going to use some air-x's in your sytem...i had 3 and was going to add a few more...for me they worked pretty good in my location...they also have the breeze now...kinda the same as the X but they shifted the range down lower so they put out more power at a lower wind speed then the X...if i get back to it i'll probably have my X's switched over to breezes...which they can do...
an extra 50 watts over time per unit in the 8-15 mph windspeed would be a big benefit...
many days in my location the X's spun all day and most of the night...but they really need 15 mph or higher to put out some decent power...they did real well in the winter when the solar days were shorter but the wind was usually higher...kinda neat making some
power in the dark...lol...in any case something to check into depending on the wind at your location...
I'm not sure if i were starting now i would put that kind of money in batteries with the new tech stuff hopefully coming...
yes those batteries are probably the best out there now for are very pricey...it's a tough call right now not knowing what
may be available in a few years...hopefully some money will finally flow into this battery tech...
the cars could really be key as the application is simliar to a solar power app...some of the same ideas from electric cars could apply
to home power...rentable battery packs...things like that...people will drive cars...they just have to change to making millions of batteries rather then gas motors...maybe some day we'll get there...heck i wouldn't even mind if XOM or BP came up with a solution...they can keep there record profits...
help the oil problem...and help the people and planet...what a silly idea...Dan
I'm adding this post mainly for those who are thinking about using alternative power in stead of the grid. This centers around my Outback 3524M inverter, but is applicable to most any good to high end inverter.
When sitting there, turned on but supplying zero AC power to anything, inverters still consume battery power. My 3524 uses approx 22 watts of DC power at 24 volts. The better inverters have a "search" function. That is, a setting that allows the inverter to sleep, or coast along, using less power until AC power is needed. They send out a short pulse of power and see if anything in the AC circuits wants it. In search mode my inverter uses only 2.6 watts od DC power.
22 watts for 24 hours is 528 watts hours or slightly more than half a kilowatt-hour. 2.6 watts for 24 hours is 65 watt hours or only 1/8 the amount.
There are drawbacks to using the search function. Small loads may not trigger the inverter to life. There can be a delay in the time the switched on item activates. The sensitivity can be adjusted to higher or lower values on my 3524. The time between pulses can be adjusted to save even more power. That however, means a longer delay in the light or whatever coming on.
When I wired the AC circuits in the cabin I installed several switched outlets. One for the TV, one or the stereo, another for the microwave, ones for a few lights. On some I installed pilot light switches so we can tell if the power to the TV, stereo or microwave is still on even though the items may not be in use. The idea there was to do away with the phantom loads these things cause. With the TV it's the remote control, with the microwave it's the internal computer for the touch pad controls.
I have managed to program the inverter search mode sensitivity and pulse length to activate the inverter the moment the TV wall switch is turned on. Ditto the stereo. I found it impossible to get it set to allow search mode to function and have the inverter become active when the microwave power switch was turned to on though. The m-wave computer just doesn't draw enough power to trip the power cycle. ???
That meant that a light had to be turned on to activate the inverter, then the microwave would power up. That was a bother. >:( I hit upon the idea of using one of those 1 into 3 outlet adapters. Plug the m-wave into one socket and a night light (with black tape over the photocell) in another. It worked! The 7.5 watt night light tripped the power on. Then I tried an LED night light. It draws only 0.3 watt. It worked too! So that solved that "problem" I just thought I'd pass that along.
I could have avoided all that by not using the search function, but the Scotsman ;) hidden inside me balked at the power waste. ;D
This weekend I also installed a simple DC swirch in a corner of the cabin to turn the inverter on-off without having to access the menu in the MATE remote unit. I don't think it likely we'll need it but it was so simple to do with the bathroom walls still unfinished. Easy now that later. When we leave the cabin for an absence we still throw the breaker disconnect that supplies battery power to the inverter. That's because using the remote on off doesn't kill the inverter dead. There's still some low watt power that's used being ready for the on-off switch to be turned back on.
:) We've got enough solar/battery capacity that I switched from heating water for coffee, hot chocolate and tea from the propane stove to the microwave.
From Sandia Labs, Albuquerque, NM
A Study of Lead-Acid Battery Efficiency Near Top-of-Charge and the Impact on PV System Design
It's a PDF document that can be downloaded HERE (http://www.google.com/url?sa=t&source=web&ct=res&cd=1&url=http%3A%2F%2Fwww.sandia.gov%2Fpv%2Fdocs%2FPDF%2Fbatpapsteve.pdf&ei=3qKtSo_LC4a0sgPo1ODtBA&rct=j&q=batpapsteve.pdf&usg=AFQjCNEPUW8iKyzyB82BBrhufkmbhAjLfw&sig2=-MEPCppGMDcgW4H5Odt2ew).
Some interesting items from the study...
Battery charge efficiency is also a function of charge rate, with lower rates resulting in higher efficiencies.
...from zero SOC (State of Charge) to 84% SOC the average overall battery charging efficiency is 91%, 91%, and that the incremental battery charging efficiency from 79% to 84% is only 55%.
Charge efficiencies at 90% SOC and greater were measured at less than 50% for the battery tested here, requiring a PV array that supplies more than twice the energy that the load consumes for a full recovery charge. Many batteries in PV systems never reach a full state of charge, resulting in a slow battery capacity loss from stratification and sulfation over the life of the battery.
All that agrees in what I see with mine, Don.
Solar pricing going down.
http://www.ecobusinesslinks.com/solar_panels.htm
http://www.discountpv.com/charge_controllers/mppt500.htm
500 Watt MPPT controller for $179 - takes up to 100 open circuit volts for smaller panel to controller wiring.
I'm going to copy several posts from another thread over to here as the dialog may be of some use to somebody contemplating a PV system.
Glenn Kangiser:
We ordered our PV panel add on a few days ago and I had Sassy order an extra BZ controller, since I have been adding the panels in modules of 500 watts each - plus or minus a few depending on what the bargain is on. $1.98 per watt this time- getting better. :)
In this way when I have a failed controller, as I do now, I can send it in for repair and put the spare in. The BZ MPPT 500 is an easy way to have MPPT in small modules. Each one takes care of its own group of panels so they don't have to be the same as other groups of panels to benefit to the maximum from the MPPT.
The best deal I have found is here in California - bad thing is that means I have to pay sales tax on it. d*
http://www.discountpv.com/charge_controllers/mppt500.htm
The one I ordered from the above link a few days ago arrived today.
~~~~~~~~~~~~
Mike870:
Glen,
Did you buy the sun 130s? If not ignore the next set of questions. I'll be very interested in hearing a review. Is there anything wacky about them like a positive ground? 17.8 volt VMP essentially means they are 12 volt panels? I am thinking of buying some of these for a rainy day.
~~~~~~~~~~~~
GlennK:
Mike, yes - I ordered the Sun 130's. Looks like they added a note about UPS considering the ones I bought oversized.
They were newly added to the site.
They are 12 volt panels or could be but two in series makes them 24v panels and since the BZ will take up to 99.9 volts open circuit voltage I can put 4 of them in series and not exceed the voc by being 87.2 if I did the math correctly. This will let me use small wiring from the roof to the regulator with low losses. The BZ will run the panels at the maximum power point and convert it down to 24 volts nominal for my system.
The panels were shipped - I will update you on them, but I did not see anything weird advertised on them.
I could also run them at 35.6 vmp with 2 in series then parallel them with no problem - the BZ would take care of them.
I plan on setting my system up to equalize with my welder with each set of batteries so there is no need for a fancier controller.
There is not another controller that I can find by others in the 500 watt MPPT range, so I decided to standardize on the BZ. I have a 45 amp PWM Trace also but they work together fine as they are all independent.
My wind generator is also hooked to the system - together on the same batteries but all work independent of each other.
I see the BZ claims to be a desulfator also due to the PWM I guess so that is likely why I still have 2004 batteries online and functioning. Yes - they heed some care but they are working.
~~~~~~~~~~~~
MountainDon:
I gave serious consideration to the BZ 500 MPPT charge controller. It looks like a good unit. However, for my installation it's limit of 100 VDC input meant I could not use it with the panel and wire configuration I wanted. I would have required to use larger wire and much of the savings in the cost of the CC would have disappeared into the wire cost.
I was curious about those Sun130 PV panels and how they got the price so low, so did some research. First, I could not find them on the discountpv website, maybe they sold out already?
Full data sheets were difficult to find, and I found two different sets of basic specs, both being called Sun-130. One gave the Voc as 21.8 and another as 24.1 The 21.8 Voc panel is larger and on sunelec's website they are referred to as oversize.
http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=357
http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=345
One concern popped into my head when Glenn mentioned coupling into a series string of four panels. The combined series Voc of 87.2 is correct. However, that does not take into account the increased voltage that occurs at low temperatures. Panels are spec'd out at a standard temperature of 25 degrees C measured at the cell. As the temperature goes up the output voltage will fall. As temperatures fall the output voltage will rise. Now Glenn's CA location probably doesn't get as cold as my NM mountains but it can be chilly in the early AM I imagine.
Usually a multiplier of 1.25 should be applied to the Voc value to determine the highest likely open circuit voltage that could occur. Take that 87.2 Voc figure. I ran the numbers or the 21.8 Voc panel through the Outback string sizer tool and it would seem that at zero degrees C (32 F) that could rise to at least 97 V which is really too close for comfort. At zero degrees F (-17 C) that Voc could reach 105 V. That = toast.
Just for the record and enlightenment of viewers of this thread, those high Voc's occur on cold mornings when the panels get the early morning sunlight. It may only peak briefly, but it could be enough to zap the charge controller.
One other thing I found on one web page would indicate the unadvisability of connecting more than two of these panels in series. The maximum system voltage is given as 70 V. This was or the 24.1 Voc panels, and therefore may not apply to the 21.8 Voc panels. I found that on this website where a copy of the spec sheet is listed.
http://cgi.ebay.ca/SUN-130,-130-Watt-Solar-Panel_W0QQitemZ250484550370QQcmdZViewItem
Most panels are rated 600 V. That means that connecting four of the 21.8 Voc panels in series would surpass the manufacturers rating even at the Vmp value of 17.8 V. So if the system maximum for the 21.8 Voc panels is the same 70 V then I would keep these panels limited to a series of two.
MountainDon:Quote from: Mike 870 on September 23, 2009, 11:04:42 AM
Is there anything wacky about them like a positive ground?
I found nothing about pos or neg ground on the sunelec web info. I did come across one reference to positive ground on another forum, but it was posed as a question similar to yours. Until it is known whether or not these panels have a positive ground all we can do is speculate.
BTW, positive grounded equipment is commonplace in the telecom industry. A few years back there were some folks selling some PV panels that were cheap and were positive ground. They can be difficult to incorporate safely into an off grid system. For a grid tie only system, with no batteries, apparently the neg or pos ground thing is not important. I don't know why, but that is what I've read.
~~~~~~~~~~~~
Mike870:Quote from: MountainDon on September 24, 2009, 11:40:59 AM
Most panels are rated 600 V. That means that connecting four of the 21.8 Voc panels in series would surpass the manufacturers rating even at the Vmp value of 17.8 V. So if the system maximum for the 21.8 Voc panels is the same 70 V then I would keep these panels limited to a series of two.
You lost me here, did you mean 60 V ? I wonder if that limit is based on small wire size internal to the panel?
~~~~~~~~~~~~
MtnDon:No, the real figure is 600 volts. My Sharp panels for example are rated to 600 V, just like the house wiring is rated. Those come from UL and the NEC generally requires everything to be UL tested/approved. In a grid tie system it is not uncommon to have panels wired together into a series array that produces 250 - 400+ volts. In a big system that cuts down on the amps and that lowers component and wiring costs.
So yes, I would assume that the internal panel connections are skimpy, or the wire insulation is not up to higher voltages. I also noted that these are not NEC approved panels, probably due to the voltage limit on the internal wiring. I know that is of no concern in this application. I simply wanted to bring the points forward as something that should be considered by others contemplating alternate energy sources. I could easily see someone not familiar with electricity plugging several of these together and running into problems.
Another case that illustrates the validity of codes and the reasons they should be followed.
~~~~~~~~~~~~
GlennK:Thanks, Don.
I have been kicking series or series/parallel around a bit. Think I will go series/parallel for more of a buffer and the MPPT will still run them at optimum. The other thing is that if the controller goes out, I bypass it and hook the panels direct to the batteries. In series/parallel the voltage would be low enough to do that - - straight series, it would not.
Feel free to copy this over to the off grid topic also if you like, Don.
BTW, what voltage would the Outback take on VOC?
~~~~~~~~~~~~
MtnDon:Quote from: glenn kangiser on September 24, 2009, 07:34:21 PM
BTW, what voltage would the Outback take on VOC?
The FM60 and 80 will handle Voc up to 150 VDC input. They also have a wide operational range, -40 degrees C up to 60 degrees C.-, de-rated some above 40 C. Some others are not rated for below freezing, some like the BZ 500 are rated to -20 C (-4 ) which could be ify up at the cabin.
FWIW, some inverters are not very well suited to cold weather. The Xantrex I was considering was not rated for below freezing. >:( Considering the weather in the mountains that would not be a good one for winter, or even some spring and fall days. Another vote in the favor of the Outback equipment.
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end of copy
Just popping in to say thanks :)
I've been reading the first few pages but there's a lot here!
Now I'm getting carpo tunnel I think so I'd better move away from the keyboard!
Glad you are enjoying it- we enjoy sharing our experiences - especially if it does someone else some good. :)
My head is swimming a little but I'm learning!
I love it! I can see being busy for years!
Anyway, thanks again...I've got a lot of readin to do!
Quote from: MountainDon on September 24, 2009, 08:39:57 PM
MountainDon:
Quote from: Mike 870 on September 23, 2009, 11:04:42 AM
BTW, what voltage would the Outback take on VOC?
The FM60 and 80 will handle Voc up to 150 VDC input. They also have a wide operational range, -40 degrees C up to 60 degrees C.-, de-rated some above 40 C. Some others are not rated for below freezing, some like the BZ 500 are rated to -20 C (-4 ) which could be ify up at the cabin.
FWIW, some inverters are not very well suited to cold weather. The Xantrex I was considering was not rated for below freezing. >:( Considering the weather in the mountains that would not be a good one for winter, or even some spring and fall days. Another vote in the favor of the Outback equipment.
~~~~~~~~~~~~
end of copy
Rated Temperature Range (meets all
specifications) XW
32–104 °F (0–40 °C)
Operational Temperature Range -13–158 °F (-25–70 °C)
Storage Temperature Range -40–185 °F (-40–85 °C)
Don,
I do not know what Xantrex you are talking about but all the SW's and the new XW's have always been the best for temperature extremes. They are all over the world and I have a customer with one up near 12,000' that is over 12 years old.
You know that Outback started from Xantrex/Trace engineers that went out the back door.... Outback CC's shut down at 145V and some have been damaged at 155VOC. Two that I know of.
The XWCC is similar and rumored to be going up to 250VOC soon.
Better go back to hauling firewood......
Hey Dave. We were going out the door when you posted that query.
I don't recall the exact model I was considering. It was a year+ ago. What I do remember was I could not readily find the operating temperature range so I emailed Xantrax customer support. I told them my temperature range. They responded with the statement that my location was too cold; it was outside the operating temperature range they recommended.
When I asked the same question of Outback they responded with the answer that their eqipment was rated to -40 degrees. Same on their charge controller.
My installation may not be normal. I wanted both the charge controller and the inverter out in the cold. That's for a couple of reasons. I did not want the hum or the sound of the fan inside. I did not want to give up space inside either, or have the equipment dictate how the space in the one room cabin would be used.
I was aware of the story about the ounding of Outback. I heard it happened some time aroun the time Trace became Xantrex, or shortly after.
It would be great to see charge controllers with a much higher voltage rating. Series strings of PV panels make a lot of sense and panel Voc's keep getting higher.
Cold temperatures can really be the worst enemy of electronics. My other job is kind of rocket science for a little outfit here in the foothills. Anyway, we have alot of experience with -135F and it turns out that around 0 F electrical components will crack when they start heating from cold storage. That is why if you look at the specs most manufactures will list their operational and storage temp specs. What kills electronics is quick temperature changes.
For instance a charge controller at -5F overnight and a cloudy cold morning and a sudden clearing of full sun.
Full power heating from cold. No matter who puts there name on the equipment there are only so many times you can do this and sometimes once is enough. Same scenario with the inverter sitting really cold all night and you start a generator and want to charge batteries, run laundry, and maybe something crazy like pump deep well water all at once. If you do not want to have spares for all this gear let it warm up. If you are storing electronics and batteries where humans are uncomfortable keep this in mind. Being rated at the temp of -40F is alot different than operational for power devices. Making a reasonable (time) transition is what will keep your electronics operational over the long haul. Good Luck with winter!
Thanks for the insight, Dave. Good thing I live in mild climate as I am known to abuse equipment. d*
I think I have finally read over the whole topic. If I missed something, I am sorry for reposting.
Speaking of the cold I was looking for direction on two topics.
I am building a power shed (4'x4') for a small system (100 watts).
My thoughts were that batteries self discharge faster at colder temperatures. Battery discharge kills batteries. Large swings of temperature also can destroy electronics.
Does anyone know about insulation and ventilation recommendations/requirements for battery banks?
I believe that ideally the batteries would be in a conditioned space. That is, not exposed to high or low temperatures. In practice that can be difficult, the more so if like mine the cabin is left vacant and unheated for a week or more at a time.
Self discharge should not be a problem if the batteries are still connected to the charge controller and PV panels. Of course that would necessitate having the equipment rated for the expected temperature range. True, electronics don't like big temperature swings. Again, ideally you would not have them. I bought good equipment rated for the range that may be encountered. Hopeully that will help. Hopefully the solar gods will appreciate my efforts such as they are.
FWIW, my neighbor in the mountains has a system similar to mine. His golf cart batteries are going into their 6th year. He plans on new ones next year as their performance has dropped noticeably this past summer. They have been abused slightly with occasional deeper than recommended discharges.
Batteries do heat up when "working". So theory says that if in an insulated box that heat will be retained better. In my case the problem I have with that is when we are absent our batteries are sitting there not being asked to do anything. There are no discharge loads other than sel discharge. The charge controller hits them daily with a short bulk charge, then a short absorb charge and then floats them till the end of the day. There is very little heating involved in that. I dn't know that insulating would make much difference. ???
If you insulate well then you have to figure out how to ventilate enough to avoid the gassing danger without sending the warm air out and bringing cold air in. One of the last things I want is to be forgetful and blow the battery chamber up, and maybe me along with it. Worse would be an unsuspecting third party.
I know someone who uses a small power ventilator. The charge controller activates a relay that turns it on when the batteries are under charge.
If you have a 100 watt system (Is that the power output of the panels?) I wonder if they is enough electrical energy going in and out of the batteries to actually make a measurable difference to the temperature.
Yes 100 watts is the power of the panels and inverter. Conditioning would be impossible. I will make a separate post for the simple system.
My concern was that
"All batteries, regardless of their chemistry, will self-discharge. The rate of self-discharge for lead acid batteries depends on the storage or operating temperature. At a temperature of 80 degrees F. a lead acid battery will self-discharge at a rate of approximately 4% a week. A battery with a 125-amp hour rating would self-discharge at a rate of approximately five amps per week. Keeping this in mind if a 125 AH battery is stored for four months (16 weeks) winter without being charged, it will loose 80 amps of its 125-amp capacity. It will also have severe sulfation, which causes additional loss of capacity. Keep your batteries charged while not in use!"
http://www.progressivedyn.com/battery_basics.html
and
"For instance, flooded cells typically use lead alloyed with Antimony to increase their mechanical strength. However, the Antimony also increases the self-discharge rate to 8-40% per month. This is why flooded lead-acid batteries should be in use often or left on a trickle-charger. "
http://www.vonwentzel.net/Battery/00.Glossary/
IIRC, lead acid batteries can discharge 5% overnight in below zero degree temperature, but I can not find any charts for lead acid discharge rates at various temperatures. So even two 100 amp 12v batteries could self discharge up to 240 watts a day in below 0 degree weather. My fear is that a week of cold stormy weather could damage my batteries if left unattended. My goal would be to reduce the lowest temperature swings and discharge, but I run into the gas build up problem when insulating. Does anyone know if the gas in heavier than air?
Just doesn't seem to be a lot of info on the to insulate or not to insulate question.
Lead acid batteries lose capacity as their temperature drops. That is, they are unable to provide the same amount of usable power at lower temperatures as they can at 75 degrees F which is a fairly normal rating temperature. Their self discharge rate decreases as well so that is not as big a potential problem in winter as in summer. That's my understanding.
As for the gasses.. the Hydrogen is very light and rises to the battery box top quite readily. Oxygen is very slightly heavier than air. I'd say the H2 is more of a hazard than the O.
As for the batteries all I can say is that my RV batteries, 4 x 6 volt golf cart types, have sat thru 3 winters in the mountains with nothing more than 20 watts worth of PV panel and a cheap charge controller connected to them. Of course there are no loads either as I pull the disconnect. The charger is connected directly to the batteries. The panels don't get much full sun either. I leave the batteries fully charged and full of fluid in the fall and in the spring they are still charged and the fluid level fine. That goes or the cranking battery as well. It has a small 5 (?) watt panel.
I'd be worried too if there was no input into the batteries, but my experience has been good with the 20 watt panel. Of course, that is no guarantee that everyone will have the same positive experience.
An excellent battery reerence is...
http://www.windsun.com/Batteries/Battery_FAQ.htm#Temperature%20Effects%20on%20Batteries (http://www.windsun.com/Batteries/Battery_FAQ.htm#Temperature%20Effects%20on%20Batteries)
Thank you. It is good to hear from someone with experience. My weather conditions are similar to yours and if you batteries can handle it with 20 watts mine should with 100. I will unplug the inverter when I come an go.
Don, have you thought about a thermostatically controlled electric heat element inside the power shed? I'm thinking something like a heated floor set to keep the shed interior at, say 50o F.
I've thought of it, but not very seriously. The only electrical power on site is in those batteries and what is replenished by the PV panels. I don't count the generator as it is a manual start. I have 15,000 KwH total storage capacity. That gives me about 3 KwH of useful capacity @ a 20% maximum discharge.
I simply never figured it would be feasible to use my own electrical power for resistance heating of the batteries themselves. A well insulated compartment would be needed to avoid battery run down. That leads to the question of how to safely ventilate without loosing significant heat. Related to that puzzle is the similar question of how to ventilate the charge controller and the inverter. I believe these two items must be isolated from the batteries as they do contain relays that might be able to ignite any hydrogen present. There are also circuit breakers or fuses associated with them. They also must be vented for cooling in warm or hot weather.
It presents many questions to my mind. It might be worth a discussion if anyone has any ideas. One thing to remember is any system should be able to run itself, ideally with little or no user/owner intervention. I don't even like seasonal adjustments such as inserting or removing baffles, insulation panels, or whatever might be thought of. Any system should be forgiving of forgetfulness ;D and able to run unattended for a few months.
Ideas are welcome! :D
Outside low overnight temperatures typically may fall into the single digits down to zero degrees F (possibly a few hours with 3 to 4 hours at a few degrees MINUS), with daytime temperatures possibly only rising into the twenties during the coldest periods, December through February. That said, it is also possible to see minus 20 degrees at some time during snow storms. No, or little, sun at those times.
???
The self discharge is not really noticeable if the batteries are in daily use or have some charge daily. I even put a small regulator on small systems as it is possible to boil a battery out if unattended.
I did a one battery horse watering system at a ranch near here. I have not had to service it since installed. Likely I should go check the water levels for the customer or hopefully they have.
This is what I say. If it is part time do most of what you can to take care of the battery system. You are really not totally dependent on it are you if it is part time? Expect that the battery will not last as long and it is the price you pay.
If you are full time, then all should be done to address keeping the batteries above 40F and below 90F.
I'm just starting to read up on off grid solar stuff. The more I learn the more I'm convinced that I want my 12x16 house to be off grid.
I've read this whole thread, and have learned a lot! Also checked out the Backwoods Solar articles, along with Homepower.com.
It's just a ton of stuff to wrap your head around. d*
Any recommendations for good how to solar books? Looking for something that could take me all the way from design to install of a small off grid solar system.
Thanks,
Beavers
No recommendations on any books. I gleaned most of my information from websites.
One that I ound useful is the collection of Codecorner (http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/codecorner.html) articles by John Wiles of the College of Engineering, Southwest Technology Development Institute at New Mexico State University (NMSU) in Las Cruces, New Mexico. Being in sunny southern NM his focus is on PV power. It's hard to say where one should start the series as the information in many of the older articles have been superceded by later articles that reflect the ever changing NEC in regards to PV alternative power. It can be interesting though to see the progression.
The Renewable Energy Handbook by William H. Kemp IS amazing, full of info, and explains it for any skill level, he even starts with the basics of how electricity works, but don't get me run, he goes into details for a pro to
Thanks,
I'll check out Amazon for the Kemp book.
I did read a few of the Codecorner articles, seemed like good info to know. I've just scratched the surface of the Homepower website, there is just so much info there! :o
I have not gotten through all of the Kemp book, but I found it to be rather preachy. Seemed out of place and offputting if his intent was to expand the number of people using renewable energy. (Not everybody approaches solar as a genuflection to Gaia!)
Edited to add: The Dummies book on solar was a good overview, but it only has a single chapter on off-grid applications. Maybe you can find it at the library. (Do they still have libraries?)
Quote from: Pritch on November 24, 2009, 12:44:43 PM
(Do they still have libraries?)
yes, at least we have a good one :D The best thing about the library is it's free to read their books. Ours has a suggested purchase program. They don't always take my suggestions but if they do I have first dibs on the book.
Regarding the Kemp book, Amazon.com has reviews that cover the gamut, excellent to poor. The reviews are one thing I like about Amazon.com.
I have the kemp book. I have read it twice (there is some stuff that I skip over like hot tubs biodiesel). I will say that it was helpful. It has some good ideas, but I found it lacking on the technical side. I'd say it is good for primer to mid level stuff but it wont get you all the way there. The nice thing is that it is mostly dedicated to off grid. It is preachy. I wish I could suggest a better book but have not come across one yet.
Wow, the Sun 100 watt panels are at $1.74 a watt at sunelec.com Has anyone ever seen a price that low?
Thanks for the book reviews guys.
While I'm ordering books, I'm want to order a copy of the NEC. Is there much change from the 2005 to the 2008 version, as far as solar stuff? The 2005 edition is way cheaper.
The NEC 200x Handbook is more valuable to most DIY'ers as it contains the entire NEC plus explanations and diagrams that do not appear in the code itself.
As for which version to get/use, what does your locale use? That's what I'd use. If they use 2005 note that there are over 300 changes. Some are big, like the requirements for AFCI and some are small, like renaming self threading screws to be known as self cutting screws. Go figure that. ???
You might want to read a free download by John Wiles, entitled Photovoltaic Power Systems and the National Electrical Code: Suggested Practices. To quote from the NMSU website...
This guide provides information on how the National Electrical Code (NEC) applies to photovoltaic systems. The guide is not intended to supplant or replace the NEC; it paraphrases the NEC where it pertains to photovoltaic systems and should be used with the full text of the NEC. Users of this guide should be thoroughly familiar with the NEC and know the engineering principles and hazards associated with electrical and photovoltaic power systems. The information in this guide is the best available at the time of publication and is believed to be technically accurate; it will be updated frequently. Application of this information and results obtained are the responsibility of the user. Be mindful that it is still based on the 2005 NEC, but there may have been some updates.
That guide may be found at...
http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/PVnecSugPract.html (http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/PVnecSugPract.html)
I used the NEC in the public library (reference only, no check out) for some research as well as a lot o John Wiles information. As well I have a small handbook that covers in simplified form the basics of regular house wiring.
I also have seen a paper from the STDI, where Wiles works, PV INSTALLATIONS, A PROGRESS REPORT Only 50% of the systems surveyed passed all provisions of the NEC.
There's also a Code Corner article, #108, that goes through some of the 2005 to 2008 NEC changes.
http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/codecorner.html
Quote from: Mike 870 on November 24, 2009, 04:04:47 PM
Wow, the Sun 100 watt panels are at $1.74 a watt at sunelec.com Has anyone ever seen a price that low?
I get a solar industry mag that says there is a glut on them now. This could be a good time as who knows what the future will bring. Lack of profits may close some of the manufacturers if it doesn't get better.
I have some that were from them for $1.98 a watt which was the best I had seen earlier. Still haven't installed them though. d*
Thanks Don, I really appreciate the help! I'll be sure to check out the links you gave.
Nebraska uses the 2008 NEC...makes sense to get that. :-[
I used the load calculator at the wagonmaker site the other night.
I think it's all starting to click, but would like to run it by you guys to see if I'm close to being on the right track. :)
This is all based on using propane and no electricity for heat, cooking, refrigeration, and hot water heater.
My total connected watts = 192
Watt hours = 1188
Adjusted Daily AH Load (24v) = 58.28
So with 5 peak sun hours I would need 279 watts of panels minimum.
For three days of storage I would then need 437 AH capacity if I only discharge to 60%.
Using Trojan 6v T105's I would need 8 to get 450 AH of capacity.
Am I looking at this right? ???
With a 24V system and 6V batteries the number of batteries in the bank have to be a multiple of 4?
With charge controllers is it best to go with the most amps you can afford?
As far as converters for a small system, will a $300 Samlex, or Exeltech type converter be just fine? A $3000 Outback converter can't really be necessary for a small system, can it? :o
>>Am I looking at this right? ???
Looks okay from here. :D
Power use seems to grow with time. We already have a couple of small appliances that were not in the original plans. You might want to consider that possibility and leave room for another string of batteries. The battery gurus warn against adding batteries to an existing system. Maximum time interval seems to a year, though others have ignored that. Remember if you only draw the batteries down to 80% they will last longer than if drawn down to 60%.
>>With a 24V system and 6V batteries the number of batteries in the bank have to be a multiple of 4?
Absolutely correct.
>>With charge controllers is it best to go with the most amps you can afford?
Well, looking ahead to growth it may be advisable to have the ability to add more panels without needing a larger controller. :-\ The flip side of that is if you add on panels at some time, you can always add a second same size controller and have the protection of some paralleled redundancy. :D
I bought the 60 amp Outback, not because I needed the capacity right now, but because it will allow me to install another paralleled set of panels and use the same 300 feet of cable if in the future we want more power. There were other considerations as well.
>>As far as converters for a small system, will a $300 Samlex, or Exeltech type converter be just fine? A $3000 Outback converter can't really be necessary for a small system, can it? :o
It's not necessary, unless you want to be able to run a microwave (1200 watts draw) and not have to worry about someone (I won't name who) also popping some bread into the toaster (800 watts). Or similar things. The microwave was the complicating appliance in our case. PS. I got ours for $1650. I had some luck and hit on a clearance loally. They'd had it in stock for over a year. It was a special RV/Marine model, but ideal for our small cabin.
I'd use a pure sine wave type in any event. Square wave can bring along problems.
I like the Exeltech inverters. I had one of their 1100 watt units in the RV for several years until I cooked it. >:(
Keep in mind that the better quality inverters ($$) are also chargers. The ones I've looked at have the capability of performing an equalization charge with the generator running. Most standalone chargers can not do an equalization charge.
Speaking of equalizing... The principle is basically to apply a higher voltage charge (15 volts on a 12 volt battery) for a period of time. If you have loads attached to the batteries while equalizing it is possible to run into the situation where you may "over volt" something in the system. This is why good inverter/chargers switch the inverter o when the generator is activated. They will usually use a "pass through" mode where the genny now supplies the power to the cabin while also using some genny power to charge the batteries.
Anyhow, I'm rambling on as one thing reminds me of another. :-[
Bevers,
Don't forget about water pumping. I don't know how you get your water, but it is a factor I frequently forget to add into my calculations. Most DC deep well pumps seem to use around 150 watts an hour for 60 gph rate. So if you use 120 GPD per person per household that averages to 300 watts a day per person for electricity. This is off the top of my head and I welcome any corrections.
Good point. I tend to forget that too as our water comes in a trailer tank.
would it be feasible to design and build a off grid soler system that had several stand alone smaller systems. Like one for lighting, one to run the refigerator one to run a fan ect.
Not really because its not the batteries that makes the difference its the other hardware
lets say you have a 500Ah 28v system with each battery being 100Ah at 6v, and then you want to add another load needing 100 Ah more.
A) one large system
so first you have 5 batteries in a sting to get 500Ah combined, and you need 4 strings to make 28v. then in order to add another 100Ah all you do is get another 4 batteries and connect one each to a string. and you need to buy a bit of cable and connectors.
B) multiple systems
Lets say you have the same system as above, 5 batteries a string and 4 strings. now you want to add another 100Ah. we know you need 4 more batteries, cable and connectors. But you also need a charge controller, inverter, and power source (solar, wind, hydro ect). buying a smaller system at first might have saved you money, but buy two small systems instead of a medium one cost way more because your doubling up the equipment.
(the numbers used aren't real, you need many more betteries to take into account trying to keep a couple day reserve and not depleting all the power from your cells each day)
Think of it this way, you can either buy two 1/2 ton trucks to pull two horse trailers, and burn tones of gas in both, plus wear and tear on both trucks and trailers, or buy a larger trailer and a 3/4 ton truck and save tones of money on not doubling things up. and pull the saem nubbier of horses. :)
Quote from: Bob S. on November 25, 2009, 05:06:47 PM
would it be feasible to design and build a off grid soler system that had several stand alone smaller systems. Like one for lighting, one to run the refigerator one to run a fan ect.
The problem that first arises in my mind is that it is more difficult to properly size three or more small systems than one larger system. A larger system with everything drawing off one large battery bank would be more forgiving if you found it necessary to run extra lighting for some occasion for example. That's my opinion.
Quote from: Squirl on November 25, 2009, 10:08:57 AM
Bevers,
Don't forget about water pumping. I don't know how you get your water, but it is a factor I frequently forget to add into my calculations. Most DC deep well pumps seem to use around 150 watts an hour for 60 gph rate. So if you use 120 GPD per person per household that averages to 300 watts a day per person for electricity. This is off the top of my head and I welcome any corrections.
No water to pump, we are on city water. Forgetting to add in water pumping could be a bummer on a real small system like what I'm planning on. :o
My pump pulls about 10 amps at 240v or 2400 watts for 1.5 hours per day in the summer, when pumping for the garden. That is why I need the bigger system. The smaller pump would still have the same horsepower requirement, but just run for more time.
I already had the pump 320 feet down the well when I decided to go solar. I like having plenty of power so I can weld and run my shop - band saw, air compressor, etc.
Horsepower requirements change a lot and go a lot higher on a deep well. The Grundfos SQ Flex is likely one of the most efficient but the numbers should work out similar to mine I think. We use around 600 gallons per day or more for the garden in the summer.
Quote from: glenn kangiser on November 25, 2009, 08:59:26 PM
My pump pulls about 10 amps at 240v or 2400 watts for 1.5 hours per day in the summer, when pumping for the garden. That is why I need the bigger system. The smaller pump would still have the same horsepower requirement, but just run for more time.
I already had the pump 320 feet down the well when I decided to go solar. I like having plenty of power so I can weld and run my shop - band saw, air compressor, etc.
Horsepower requirements change a lot and go a lot higher on a deep well. The Grundfos SQ Flex is likely one of the most efficient but the numbers should work out similar to mine I think. We use around 600 gallons per day or more for the garden in the summer.
I am trying to remember your garden but.... Glen, that is alot of water! Our drip system in (3) 4x8 sq.ft. garden boxes used 1500 gallons all season! What do you get an hour from the pump? I actually like your set-up over the grundfos for solar as you can get it done fast during the afternoon. You do need the panels though! I am doing one like yours now with an xw6048 in NM.
Had Heirloom tomatoes off the vine yesterday....ah California
I found a PDF Inspector guide to PV systems. [cool]
It gives suggested checklists for inpectors, and what to look for.
Would be real handy for anyone dealing with inspections, along with the PV code guide that Don posted a link to.
http://www.builditsolar.com/Projects/PV/InspectorsGuide0306.pdf
That made my head hurt Beavers. Thanks. ;D ;D It does give one an idea of what to expect. That seems to be focused a lot on grid intertie, but it is indicative of the hoops a legal installation must have.
Just a note on one thing I saw.Figure 4 illustrates a ground wire connected to what appears to be an aluminum PV panel frame. In some of the information I've read that may not be allowed anymore or maybe at some time in the future... depends what the local code enforcement gurus are doing/using.
Here's the theory... All other electrical connections must be able to be un-fastened and re-fastened ten times with no deterioration in the fasteners effectiveness. Self tapping or self threading screws do not meet that criteria. It does make some sense. So there was talk about changing this type o connection to requiring a tapped connection with a certain minimum number of threads engaged, or requiring the use of stainless screw machine screws and nuts with stainless steel washers, or those special ground lugs I used. So while I don't know for certain what is what, I went with the special clips.
http://countryplans.com/smf/index.php?topic=6059.msg92455#msg92455 (http://countryplans.com/smf/index.php?topic=6059.msg92455#msg92455)
![](https://i133.photobucket.com/albums/q75/djmillerbucket/jemez%20mountain%20property3/mini-P1000994.jpg)
http://countryplans.com/smf/index.php?topic=6059.msg92455#msg92455 (http://countryplans.com/smf/index.php?topic=6059.msg92455#msg92455)
Quote from: MountainDon on November 30, 2009, 08:01:50 PM
That made my head hurt Beavers. Thanks. ;D ;D
Really, I didn't think it was any worse than any of the other fun to read code stuff. :) ;)
I noticed it was written in 2006, so some stuff might of changed. I've got a copy of the 2008 NEC on the way from Amazon, so hopefully I can figure out what the latest and greatest methods are.
Those clamps look pretty heavy duty!
They are nice. The thin plate is stainless steel, with punched thru holes that have a rough edge that digs thru the anodized aluminum to make secure contact. The clip itself is tin plated for conductivity and comes with stainless steel hardware. I got them from TheSolar.Biz
I was looking at the Trojan Battery site and noticed something either new or something I missed.
They have an RE series of some batteries. RE = Renewable Energy. I don't recall seeing the RE's before. The capactites are the same as their industrial relatives, but the warranty is better. 24 months free replacement plus 60 months pro rated on the L-16RE series (7 year total). The 6 volt T-105 batteries have the 24 month free replacement plus a 36 month pro rated warranty (5 year total).
The real interesting this is they have an L-16RE 2 volt cell. I recall Dave Sparks mentioning in some other thread that Surrette now had an L-15 2 volt cell available so I looked it up too. It looks like the case size is in the L-16 series too.
The Surrette S-1380 is rated at 1050 amp-hours and the Trojan L-16RE-2volt at 1110 amp-hours, both at the 20 hour rate. Either one would be just about perfect for many of grid users. The one visible thing different on the T-105RE 6 volt, compared to the other iterations of that 6 volt battery are the terminals. The T-105RE has lug terminals only.
Here's a shot of the T-105RE-6 volt, the L-16RE-2 volt and the Surrette S-1380 2 volt
![](https://i133.photobucket.com/albums/q75/djmillerbucket/electrical/T105_RE.jpg)
![](https://i133.photobucket.com/albums/q75/djmillerbucket/electrical/L16RE-2V.jpg)
Did anyone notice the oddity?
Quote from: MountainDon on December 01, 2009, 01:40:25 PM
Did anyone notice the oddity?
With the new T105 you can use 50% less cable? I'll have to get some of them, should save me a lot of money. :)
Mmmm, no, unless I don't follow what you mean. ???
It's to do with the L-16RE-2 volt battery ..........
Looks like only one battery terminal in the T105 pic. ???
I have an Evolution 1 tent trailer with a built in charger that works when AC power is connected to the trailer. I'm thinking of hooking up the connections to two batteries in parallel in a box with a solar panel to provide a charge when the AC is off. I'd like to connect both the trailer and a camper to this and be able to leave it for extended periods of time without damaging the batteries.
The plan is to be able to drive back to the site where I am building my cabin and not have to worry about the battery being low when I need to power a propane heater (built into both) and lights (we arrive most times at night) becuase I hate to have to pull out the generator right away -- much rather settle in and relax after the long drive.
Of course this will help me learn about solar power so I can build an off grid system.
I've found this panel which seems at a decent price: http://www.siliconsolar.com/85-watt-solar-panel-p-501611.html
and this controller: http://www.siliconsolar.com/solar-charge-controller-p-16156.html
Have this battery: http://www.lesschwab.com/batteries/rvdeepcycle.asp
And will use it on this trailer: http://www.colemantrailers.com/e1 as well as an old 1978 camper with 12v lights, fan and propane heater (which may not work).
I've also got an old car battery that I'm using to power my well (12v pump) but plan to get a 2nd deep cycle battery to put into the box with the first one.
So, there are 3 wires coming to the battery in the trailer and then a standard trailer hookup on the camper (which I figure I can get a female hich connector and wire to the batteries directly).
What are your thoughts on doing this and could I install an inverter that would give me the power to run a laptop if I wanted to? Or a toaster?
Thanks!
Quote from: Beavers on December 01, 2009, 07:00:08 PM
Looks like only one battery terminal in the T105 pic. ???
It's just the angle of the shot. It has two terminals.
What I noticed was that the 2 volt L-16RE has three watering caps just like the 6 volt L-16 version and the 6 volt T-105 batteries. That struck me as unusual. Have a look at the 2 volt Surrette S-1380. It has one cap, because it is a single cell. It might be that the L-16RE-2 volt battery is simply a standard 6 volt L-16 that has the three cells internally connected in parallel instead of in series. If that is true the L-16RE-2 volt is not really any better than a collection of the normal L-16 6 volt batteries. It would cut down on the cabling though compared to a series/parallel system of L-16-6 volt batteries.
The Suerrette is a true 2 volt cell and the L-16RE is a 2 volt battery. That would make the Surrette a better choice from the view of the number of cells to water. The Surrette likely costs a lot more than the Trojan, but may really be a better unit. ??? So ya' gotta look it over and make your choice.
Quote from: OlJarhead on December 01, 2009, 07:24:43 PM
....and this controller: ........
That controller is not suited to that panel. The panel has a maximum power current rating of 4.71 amps. The charge controller is rated at "4A maximum input charging current".
The place to start designing any system is to start with what the daily load total will be. Do that before jumping at parts.
Make a list of all the DC items you want to use. Get the power ratings on the lamps or whatever. Multiply the DC wattage of each unit by the number of hours of expected use. Be honest. Total that up to get the DC watt hours for the DC total.
Make another list of any AC loads you wish to run. A Kill-A-Watt meter is handy for determining how much power is being used by the various AC powered items. Multiply the AC wattage of each unit by the number of hours of expected use. Be honest. Total that up to get the AC watt hours for the AC total.
Then come back with the list. With those numbers the battery capacity required to run one, two or three days can be calculated. With that known the PV power required can be calculated. You also need to know expected number of hours of usable sunshine. That changes summer to winter so you need to decide where are going to aim for.
Or
go here (http://countryplans.com/smf/index.php?topic=6059.msg80681#msg80681) and use one of the calculators.
I don't like to just say, here, do this or use this and everything will be fine as your deiniation of "average" or "normal" can vary from mine. But I'll be happy to help sort it out.
I mention the Kill-A-Watt because I noticed that in some cases the actual power consumed is less than the rating on the name plate. My laptop is a case in point it uses about half the label rating in normal use. That was based on measuring consumption over an actual period of several hours of typical use. The LCD TV in the cabin also uses less, averaged over several hours of use. On the other hand the microwave uses every watt it says it will.
On determining power used by a microwave... note that the rating that is advertised, 650 watts, 800 watts or whatever is the cooking power not what is needed to power the unit. To illustrate what I mean our home microwave has a cooking power of 1100 watts but consumes 1630 watts out of the wall socket. The cabin unit, rated at 650 watts cooking power, consumes 1100 watts.
On picking an inverter, square wave inverters are common and lower priced than pure sine wave. As I've noted before, not everything runs well on square wave. Our small microwave does not heat on square wave; it runs the fan, the light, but no heat becasue it doesn't like the square wave power. Our vacuum runs hotter on square wave. The blower on the wood stove air inlet makes more noise on square wave, and likely runs hotter as well. Hotter operation can mean shorter life. Running hotter is also a waste of battery power as heat = power.
Yes, I am biased towards pure sine wave. It depends on how what the inverter supplied AC power is going to be used for.
I also like only pure sine wave after low efficiency pumping and burning up power tools on modified sine wave. My 220v water pump put out appx twice the water in the same amount of time with the pure sine wave. Most will not pump using as much power as I need though. I already had the big pump in the well so built the system up to handle it. There are various adapters to smooth out the pump for modified sine but I felt that I should just do it right.
I only use modified on my small stuff or things that don't mind the choppy electricity.
Quote from: MountainDon on December 01, 2009, 08:06:49 PM
Quote from: OlJarhead on December 01, 2009, 07:24:43 PM
....and this controller: ........
That controller is not suited to that panel. The panel has a maximum power current rating of 4.71 amps. The charge controller is rated at "4A maximum input charging current".
The place to start designing any system is to start with what the daily load total will be. Do that before jumping at parts.
Make a list of all the DC items you want to use. Get the power ratings on the lamps or whatever. Multiply the DC wattage of each unit by the number of hours of expected use. Be honest. Total that up to get the DC watt hours for the DC total.
Make another list of any AC loads you wish to run. A Kill-A-Watt meter is handy for determining how much power is being used by the various AC powered items. Multiply the AC wattage of each unit by the number of hours of expected use. Be honest. Total that up to get the AC watt hours for the AC total.
Then come back with the list. With those numbers the battery capacity required to run one, two or three days can be calculated. With that known the PV power required can be calculated. You also need to know expected number of hours of usable sunshine. That changes summer to winter so you need to decide where are going to aim for.
Or go here (http://countryplans.com/smf/index.php?topic=6059.msg80681#msg80681) and use one of the calculators.
I don't like to just say, here, do this or use this and everything will be fine as your deiniation of "average" or "normal" can vary from mine. But I'll be happy to help sort it out.
Understood, and was doing -- but my question is specific to what I'm doing now. You see I'm planning on doing far more, but I want to charge a battery now -- maybe two.
Perhaps I'm not explaining myself well, but I tend to take small steps. I run off one battery now -- I know that does what I need for the most part but also realize that will grow.
So, for now, today, I just want to run off that battery but add a 2nd for the camper and be able to charge them both.
Power tools are run off the generator.
What he is saying is with that panel and controller set up, your going to release the smoke c*
In direct sun light on a cold day, your going to cook that controller before you ever get the peak output on the panel.
Oh, I understand now OJH.
In that case we need another look. But that charge controller has to go or that panel would cook it.
But before that, what is the amp-hour rating of those batteries? You want two in parallel as I understand it.
OR pick a panel that's smaller.... have to run some numbers.....
Quote from: MountainDon on December 02, 2009, 12:11:57 AM
Oh, I understand now OJH.
In that case we need another look. But that charge controller has to go or that panel would cook it.
But before that, what is the amp-hour rating of those batteries? You want two in parallel as I understand it.
OR pick a panel that's smaller.... have to run some numbers.....
Thanks -- I'll check the amp hours (thought maybe it was on the link I gave)...the idea was the I needed to hook up one battery for the camper but figured it would be better to put them both in parallel so the trailer could draw on more reserves if needed (it's used the most).
In the end I figured it might be a good way to break into the world of solar stuff instead of trying to go full force into off grid systems like yours (which I drool over) [cool]
The specs didn't come up on the link, but I'll wager a donut that you have group 27's with 105 amp-hours at 12 VDC.
So if you put two of them in parallel you have 210 amp-hours total.
Limit running them down to a max of 50% so that gives you 105 amp-hours of usable power.
Keep in mind the available capacity decreases with cold.
Anyhow 105 amp hours @ 12 vdc = 1260 KwH
I ran two such batteries in our RV for years, when it was a real RV that we drove around in. Those batteries would give us a good day/night of use in cold weather with most of the power being used by the RV furnace blower. I think ours draws about 4 amps.
So if you used up 1200 watts of power and a panel puts out 85 watts, you would need 14 hours to recharge. Not good. It would be best to not use that much power, batteries last longer i not sucked down so much. To regain that sort of power fast you need 20 amps or more going into the batteries. That's about 240 watts.
The 85 watt panel would slowly charge the batteries up over a few days with no use and would definitely maintain the charge over a period of time with no use.
:-\ :-\ :-\
Quote from: MountainDon on December 02, 2009, 01:12:40 AM
The specs didn't come up on the link, but I'll wager a donut that you have group 27's with 105 amp-hours at 12 VDC.
So if you put two of them in parallel you have 210 amp-hours total.
Limit running them down to a max of 50% so that gives you 105 amp-hours of usable power.
Keep in mind the available capacity decreases with cold.
Anyhow 105 amp hours @ 12 vdc = 1260 KwH
I ran two such batteries in our RV for years, when it was a real RV that we drove around in. Those batteries would give us a good day/night of use in cold weather with most of the power being used by the RV furnace blower. I think ours draws about 4 amps.
So if you used up 1200 watts of power and a panel puts out 85 watts, you would need 14 hours to recharge. Not good. It would be best to not use that much power, batteries last longer i not sucked down so much. To regain that sort of power fast you need 20 amps or more going into the batteries. That's about 240 watts.
The 85 watt panel would slowly charge the batteries up over a few days with no use and would definitely maintain the charge over a period of time with no use.
:-\ :-\ :-\
Interesting.
I'll have to do some checking to see what I'm using, at the moment with one battery I can drain it over night if it's very cold and we run the heat a lot. I think we ran the heat one night for about 4 or 5 hours and the battery began to drain (might have been longer) so I killed the heat and we waited 'til morning to kick on the generator and were able to kick the heat on again then.
Bear in mind this is a tent trailer and it was around 5 to 10 degrees outside! My water in the coffee pot (I always set it up the night before) froze solid!
But most nights we don't have that issue at all.
We had issues with running the battery down in cold weather when we had one battery. Those RV furnaces are power hungry. When we went with two batteries it was much better and the last time I replaced the batteries I went with 4 six volt golf carts batteries in a series/parallel set up. That's even better. I never bothered with solar panels as I figured I needed more than I had space for. Plus I didn't want a system for the RV once the cabin was built. I knew I wanted more PV for the cabin and I had also decided the cabin would be based on a 24 VDC system so 12 VDC things like the charge controller and the inverter would not be usable in the cabin.
That's how it worked out for us.
Quote from: MountainDon on December 02, 2009, 02:35:27 PM
We had issues with running the battery down in cold weather when we had one battery. Those RV furnaces are power hungry. When we went with two batteries it was much better and the last time I replaced the batteries I went with 4 six volt golf carts batteries in a series/parallel set up. That's even better. I never bothered with solar panels as I figured I needed more than I had space for. Plus I didn't want a system for the RV once the cabin was built. I knew I wanted more PV for the cabin and I had also decided the cabin would be based on a 24 VDC system so 12 VDC things like the charge controller and the inverter would not be usable in the cabin.
That's how it worked out for us.
Interesting.
Not sure what the cabin will need or I'll want -- I figure that's a long way off. But I know the water pump in the well is 12v and my plan has been to put the RV battery (one of them anyway) in there with a solar charger to keep it topped up. Of course I'd have to build a pump/well house too...but my thought was that once we're done camping in the trailer and staying in the cabin we'd use the setup for the well and start to seriously think about the cabin.
Having learned on the trailer of course :)
There is also the likelihood that the camper and the tent trailer will get lots of use still since we hav ea big family.
Anyway, that reminds me, I ought to toss the batteries on the charger for a while.
With all the concerns with batteries getting too hot and too cold and other components as well having to sit outside in battery sheds and boxes would it pay to build a cellar? For example into a hillside to house all the components in. I understand it would have to be vented perhaps with a small fan to carry away hazardous fumes. That seems as if it would be a good solution to stabilize temps in larger systems that might have one or more banks of large batteries. ???
I believe that would be a great way to stabilize the temperature fluctuation Rick. One could build a simple cellar set back in a slope for just the batteries. As long as there was a vent tube exiting upwards at the highest point of the enclosure I'd think the H2 would vent off readily. Some battery chambers have powered vents with the fan being activated only during equalization, when there is the greatest volume of gasses produced.
Most flooded batteries should be charged at no more than the "C/8" rate for any sustained period. "C/8" is the battery capacity at the 20-hour rate divided by 8. For a 220 AH battery, this would equal 26 Amps. (http://www.windsun.com/Batteries/Battery_FAQ.htm#Battery%20Charging)
Any idea how long a "sustained period" is? Does that mean a couple of hours charging with the generator if the panels aren't keeping up with the charging, is a no go?
I've got a cheap 3500w generator that I've been running tools with while building. I'm thinking that making one of these lawn mower engine/car alternator generators might work better for keeping the batteries charged. I'm pretty sure that it would use less fuel, it would be DC power (I could run it right into the charge controller), and I should be able to idle it down to put out less than 26 amps. Anyone built one of these or have any thoughts on how well they actually work?
http://theepicenter.com/tow02077.html
One last question...
Even the small system that I'm looking at is going to run about $3000, with a pretty good chunk of that being the cost of the panels.
If I started off with just batteries, charge controller, and inverter, I should be able to keep it all charged if I ran the homemade generator 2hrs. a day.
Within 6 months I would be able to add the panels.
What to you guys think, good or bad idea?
Thanks,
Beavers
Good question on what does a "sustained period" mean, Beavers. ??? I never worried about it as the Iota IQ smart charger (http://iotaengineering.com/dls.htm) I used on the batteries in the RV switched itself beginning with the bulk charge, then absorb and ending in float. With 420 amp-hours of batteries the 55 amp charger was just about perfect. My generator is a Yamaha 2800i inverter type and it would throttle down as the charger took less current. The Hondas throttle down even better/more.
A note on the Iota DLS chargers. It is possible to 'stack' them in parallel to increase capacity if needed. Same models only.
I believe that if you charge at the C/8 rate you will not be likely to overdo it if you cease the charge when the batteries are full.
If you built an auto alternator based generator I'd think the built in regulator should keep the batteries from being overcharged. A manual throttle control to keep the starting charge rate down to the C/8 rate would work. You'd need a good ammeter to set it. If you were to use an auto alternator charger I would rely on the built in regulator and not try feeding the charge current through a PV charge controller. Most charge controllers are really designed for use with a PV panel input. I've seen discussions on the Outback user forum and the recommendations regarding inputs other than PV are always pointed out to be ill advised by their experts, especially when it comes to mixed feeds. Some charge controllers that have diversion load capability (like you'd need with most wind generators) could likely be used to control a generator output but I don't see any advantages to that. Perhaps some else may have some solid information on that.
Note that the better PV charge controllers have a battery temperature sensor, usually as an option. They are worth it. The charge controller will make adjustments to the charge rate. If the temperature gets too high the charge rate will be reduced. The better sine wave inverter/chargers also have remote battery temperature sensors which is valuable when using them to charge the batteries.
I basically ran a small system with 4 six volt golf cart batteries (series/parallel for 12 VDC) in the RV for 3+ years with no panels. I put something like 700 hours on the Yamaha. I did have a couple small panels (http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200263174_200263174) hooked up through a cheap controller to keep the batteries floated during our absences, which included 3 - 4 month winter stretches with no visits for the first couple years. 30 watts worth which became about 20 after one panel suffered some damage. They were excellent for that purpose.
So I believe you could get everything but the PV panels and the charge controller and add them later if you can't buy it all at once. I would say that would work as long as you don't have any prolonged periods where the batteries would just sit there self discharging. I would recommend a disconnect switch so you can easily remove all loads when you are gone. Our RV had some phantom load I could never find; the disconnect fixed that when we'd leave.
Appreciate the info, thanks Don.
I'm just trying to slap something together to provide a minimum amount of power for a few months while I learn more about solar, and come up with cash to pay for a larger system.
I was thinking that I would still need a charge controller, but if the alternator regulator would work that would be great to save the money on the charge controller.
In a full system the generator hookup is through the inverter, and then back into the batteries? Looking at inverters it looks like only the higher dollar inverters are set up for generator use. So with a cheaper inverter you still need a charger like the Iota to have a generator backup?
Quote from: Beavers on December 02, 2009, 10:21:54 PM
In a full system the generator hookup is through the inverter, and then back into the batteries? Looking at inverters it looks like only the higher dollar inverters are set up for generator use. So with a cheaper inverter you still need a charger like the Iota to have a generator backup?
Depends on where you draw the line for becoming a higher dollar inverter, and how much power and what wave form you want/need.
Xantrex, for example does have a square wave inverter/charger, 1500 watts inverter, priced at something like $800. To me that's not cheap, nor is it overly expensive; model TR-1512 (also in 24 VDC models I think). A unit like that has three stage charging and an equalization charge setting. I looked or quite some time for a stand alone charger that had equalization capability and never found one that made economic sense. It was better to go with a combination unit, IMO.
You should have an equalization setting if you are using flooded lead-acid batteries. If you go with AGM batteries you don't need equalization capability, AGM's don't like the higher voltages.
I had some other thought rolling around and it got away on me... maybe I'll be back in a bit. ??? d*
Oh!
It was simply to note that inverter/charger units operate in a pass thru mode, when the AC generator power comes online. When generator input is sensed, the inverter section switches off basically, and the generator power is passed thru to the house/cabin power circuits. At the same time the battery charger section will accept incoming generator AC power and begin to charge the batteries.
If a big AC load in the cabin comes on the generator input into the charger may be reduced until the AC load is removed. I only mention this as I found it interesting. I've watched the generator power automatically split and change between charger and AC use on my Outback Mate monitor, as Karen used the toaster or microwave while the generator ran.
Since my generator is smallish I have my inverter/charger programmed to accept only up to 20 amps generator input. The inverter on the other hand can pump out 30 amps continuous. I've seen the situation where all 20 amps (2400 watts) from the generator goes into the cabin AC loads and the inverter supply an additional 800 watts from the batteries. Then with the big AC loads removed the inverter/charger goes back to charging.
Arizona Wind-Sun has excellent information on batteries (http://www.windsun.com/Batteries/Battery_FAQ.htm) available.
Beavers, you've seen it, but I mention this for others. According to them "At approximately -22 degrees F (-27 C), battery AH capacity drops to 50%. At freezing, capacity is reduced by 20%."
My battery bank was sized taking this into account. I also thought long and hard about insulation. :-\ In the end I decided against the bother of insulating. I may have mentioned my reasoning before; I don't recall. So will the reader please forgive me for boring them if I am repeating myself.
My cabin is seasonal use. Mid-May through August we are up there virtually full time. In winter (December through March) the cabin may sit for 2 to 3 weeks (hopefully never longer ;) ) with nobody there. My collected data shows that in periods of inactivity the PV system puts 300 watt-hours maximum into our 15,120 watt-hour total rated capacity battery bank. That may change upwards as the batteries age. That is so little input I seriously wonder there would be any measurable warming effect? I believe it is so insignificant an amount that there would be no benefit to the trouble and expense of insulating while still providing ventilation. That's how I see it. Others may have differing opinions. ???
If, on the other hand, our cabin was used continuously through the winter months there would be much more power flow in and out of the batteries; with the resultant internal battery heating byproduct, it would most likely be worth the effort involved to provide insulation. As with so many things regarding homes and cabins there is no "one size fits all" answer.
One thought I have had is that it is a shame to be wasting all that solar power when the system sits idle. It would be cool to be able to use that excess power in the manner of a diversion load as used in wind generation. The excess power could be used in a resistance heater to either warm the batteries or perhaps to keep the temperature inside the cabin from falling as low as it does. The Outback FlexMax charge controller has an auxiliary function that I'm sure can be used for something like that.
other brands may have similar features. I have not taken time to check it out. If anyone has any thoughts on that I'd be happy to hear about it or carry on a discussion.
In our cabinets in MNN we installed battery blankets. These are DC powered blankets that are designed to keep the batteries from freezing in serious sub zero weather.
I'm wondering if something like your ap Don, would benefit from that? specially since it could be used as a diverter for the unused power :)
Something like that would help keep the battery temperature up with the excess power. It would be akin to Glenn's use of excess power being used to pump water.
Quote from: MountainDon on December 03, 2009, 12:22:40 PM
Something like that would help keep the battery temperature up with the excess power. It would be akin to Glenn's use of excess power being used to pump water.
I could look for who the manufacturer was if your interested. We use them for Cellular backhaul sites where we've got SONET transport nodes and MW transport gear [cool]
cool. see if their are 24 VDC models. Thanks
:o :o d* d*
This place is a great source for info, and I really appreciate the help! But man...the more I learn the more I realize how much I don't know!
I got my copy of the NEC in the mail today, and after skimming through it, I realize I have WAY more to learn than I thought!
Oh well...a year ago I didn't know the first thing about building a house, but with a lot of studying and the help of this forum, I've managed to figure it out. :)
Guess it's time to get serious with studying up on the NEC first.
http://www.watlow.com/literature/specsheets/files/heaters/colfrzs0407.pdf
Comes in 12vdc, 48vdc, 120vac and 240vac
But at 12vdc you might be able to work it no?
Check them out :)
Those guys have a whole world of available heaters. They would be able to supply whatever was needed by the looks of it. Whether or not their equipment would be cost effective is the thing.
This will need some more thought and research.
The first step will be to come up with a realistic estimate of how much excess PV power there is in summer and winter...... more to come.
I'm going to park this link to those guys website here as a handy thing.
http://watlow.com/products/heaters/ht_flex.cfm
Well Don, now you have to start planning your battery box insulation retrofit! ;D d*
Quote from: MountainDon on December 04, 2009, 06:20:06 PM
Those guys have a whole world of available heaters. They would be able to supply whatever was needed by the looks of it. Whether or not their equipment would be cost effective is the thing.
This will need some more thought and research.
The first step will be to come up with a realistic estimate of how much excess PV power there is in summer and winter...... more to come.
I'm going to park this link to those guys website here as a handy thing.
http://watlow.com/products/heaters/ht_flex.cfm
We use them to keep the batteries from freezing when it's -40 in MNN ??? d* But they do work. I'd also like to check and see what the cost is (I ought to find out who our rep is -- *chuckle* maybe I can get a deal on some ;) )
Quote from: Pritch on December 04, 2009, 06:41:25 PM
Well Don, now you have to start planning your battery box insulation retrofit! ;D d*
something to think about over the winter. :D
Okay, if anyone has been holding their breath on this "excess PV power" idea you may as well take a breath now. This has become very low priority for me right now. I've done some research and more thinking. Here's my reasoning....
First let me say that the procedure to setup the Outback inverter to use the excess power is straightforward. Matching the load to the available excess would be the main trick. Too large a load would have the system continually cycling the diversion load on and off too much.
Standard Test Conditions (STC) in the PV industry are based on an irradiance of 1000 watts/ square meter. In summer we get 6 - 8 very good hours of sunshine a day with 2 to 3 hours over 1000 watts/m*m, the balance over 700 watts/ m*m. In summer I don't have much use for that extra power. We could use it in winter, though and that was what I was hoping to do.
In winter we get about three real good hours of sunshine, 11:30 AM through 2:30 - 3:00 PM. Real good in winter meters out at 450 to 550 watts/m*m. Much less than summer.
Let it be noted there are three stages in charging the batteries, bulk, absorb and float. During the bulk stage all the power from the PV panels is used to charge the batteries, assuming an MPPT charger. In absorb and float there is waste, some power from the PV panels is wasted. On a day after typical loads the day/night before, it takes until 1 to 2 PM for the bulk stage to be completed. This past weekend we didn't even make bulk on Sunday; very cloudy.
So if I say the winter maximum output is about one half that of the summer, that would be approximately 624 watts total rated panel capacity x 50% = 312 watts.... round that up to 325 for good measure. 325 x 3 hours is 975 watt/hours, lets call it 1 KwH. That's like running one of my electric heaters on medium for an hour. Not much warmth for the trouble. 1000 watts = 3412 BTU
In summer though there may be enough excess to run something like two of these pads: 12 volt / 30 amp / 370 watt from solarseller.com .... scroll down the page about 2/5 the way.
http://solarseller.com/diversion_load_heating_air_water_wind_hydro_solar_loads.htm
They could be wrapped on the water heater tank and the foam insulation replaced. I'd have to do some calculations to see if it would be practical or not; cost vs benefit.
Thoughts welcome.
Don: I am tossing a dream or two but if you went to a tracker system. How much more output do you feel you would see from your panels? The literature I am seeing is all over the place everywhere from 25% to 50%. 25% would hardly be worth it cost wise I would think. However if you could achieve even 35 to 40% that would really be getting into the more doable lets take a look at this would it not? Especially if it were in more of a every weekend to full time residence application or say a remote pumping application?
In your location do you have any problems with ice accumulation on your panels and cutting down your output that you have noticed? I would think they would be dropped down now to almost no chance unless you have a lot off freezing rains mixed with snow.
rlr
A tracker system would increase power or sure, how much though, I don't know. Glenn built his own tracker and I believe he has the bugs worked out, but I don't know if he has quantified what the power output increase is.
In our case the tracker would have to be "bullet proof" as we are not on site all the time to catch a problem.
Snow/ice. I've been up there during and after snowfalls. Even with the winter angle there was a covering of an inch or so. It did melt off within a few hours of the sun coming out bright though. If we were on site we would be able to sweep the snow o with a long handled broom, or tilt the panels to vertical and cause it to all that way. The slight amount of ice melted off too but took a little longer.
The tracker was working until the seals went out of the cylinder - it was old.
I replaced the seals, and I think the only problem is that I have to recharge the west side of the tracker - filled it once but I think the liquid went down to fill the cylinder so I have to fill it again. Meanwhile it is just aimed south.
Don and Glenn,
Or anybody who wants to put his or her two cents in on the question.
I've been playing around with the generator for charging our battery bank and have learned that if I allow the bank to drain to about 24.2 volts, which should be around 50% discharge, it takes roughly four to five hours to bring the bank back to float. If I recharge at 24.8 to 25 volts, however, it only takes one hour to return to float. Am I better off recharging once a week for about an hour, or every other week for a four to five hour run on the generator?
I understand this is really a personal choice, but I was wondering what you guys think about running the generator more frequently for less time and what this might mean for battery life.
Thanks.
The deeper you discharge the shorter the battery life! The manufacturer (good ones) will specify the number of discharges that the battery will take. There are dozens of strategies for charging and some are definately better if you are trying to get 10 to 15 years out of a battery.
You should also be checking specific gravity to calibrate your own strategy! Good Luck!
Ditto what Dave said.
I'd be charging them every 2 - 3 days
Found some pretty good battery info from Rolls Battery.
Might be kind of basic for some folks, but for a guy like me who is just learning it was educational. :)
http://www.rollsbattery.com/files/userfiles/Rolls_Solar_Instructions.pdf
Beavers,
Yes the Rolls info is very handy. I have most of my 32 customers now on them offgrid.
You must keep in mind that they are in the business of selling batteries! Some of their info is geared for that. There are definate strategies to get 10 to 15 year lifespans and they are, let us say not always going to steer you that way!
Good Luck!
Quote from: MountainDon on December 08, 2009, 01:54:38 AM
They could be wrapped on the water heater tank and the foam insulation replaced. I'd have to do some calculations to see if it would be practical or not; cost vs benefit.
Thoughts welcome.
I saw no one responded and I haven't been around much
1 BTU will raise 1 pound of water 1 degree from 60-61. I usually drop the 60-61 for rough estimates.
So if you have a 20 gallon hot water tank you have 166 lbs of water.
If you have 600 watts power you could get 2000 btu a day in a perfect world with no losses.
2000 btu/166 lbs of would raise the temperature around 12 degrees by my math.
In a small tank you would see a significant rise. In a 30 gallon tank you would get 8 degrees a day change. You would probably lose that overnight.
On the other hand you could probably build a drain back solar hot water panel for under $216. At 3400 Btu per square meter per hour you could get 10,400 BTU (3kw) of power in heat even if you only had a 50% absorption rate.
[/quote]
I saw no one responded and I haven't been around much
1 BTU will raise 1 pound of water 1 degree from 60-61. I usually drop the 60-61 for rough estimates.
So if you have a 20 gallon hot water tank you have 166 lbs of water.
If you have 600 watts power you could get 2000 btu a day in a perfect world with no losses.
2000 btu/166 lbs of would raise the temperature around 12 degrees by my math.
In a small tank you would see a significant rise. In a 30 gallon tank you would get 8 degrees a day change. You would probably lose that overnight.
On the other hand you could probably build a drain back solar hot water panel for under $216. At 3400 Btu per square meter per hour you could get 10,400 BTU (3kw) of power in heat even if you only had a 50% absorption rate.
[/quote]
If they are getting below 40F and your using the batteries you would have to do both or use an exchanger on a generator for bad weather.
I go through this from time to time and try to get people to build the battery house/room very close to the house so it can be conditioned from the house. Lot's easier!
Dave,
One of these days a set of Rolls batteries would be nice! I think I'm going to start with a cheap bank to learn and practice with. :)
What in the Rolls manual do you think reduces life span? Their suggestion for what seems like infrequent equalizing (based on other stuff I've read)...or something else?
I'm thinking of mounting my batteries attached to the house in a set up like Mountain Don has. If the batteries need to be vented, how do you condition the space using the house without sucking all your heating or cooling out through the battery box vents?
Thanks,
Beavers
Beavers,
I am still laughing from a Crash Test Dummies xmas album about Beaver pelts. I will try to take this seriously. On the Rolls life or avoiding end of life there are many things that over the years they have sort of changed. Some of these things I keep close to my chest for my customers but the one pearl that I will add here is to design so that you "complete" charge most every day. On their site I have seen them say once a week, once every 2 weeks, on and on.... The charge system should be big enough to daily charge and bulk charge at the exact rate or slightly less. If you drag this out too long during the day, you just use more water, expose the terminals to more acid, creat more maintenance.
Yes Don's is similar to the goal and remember that the gas is really only there during bulk near the set-point and during absorption. There are things here that are close to the chest also but one way is to use the AUX on the inverter or the CC's AUX to contoll a very small fan based on voltage set-points. Charge during the middle of the day, use solar, and avoid wind or hydro that has 24 hour gassing, or make these other sources float during the hours that it is really cold. There are other ways and you might pry them out of me over time. You could become #33?, Nah, you can do this!
Merry Chrristmas
Amorphous-Si PV vs. Crystalline-Si PV modules?
Is this a deal? http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=543 (http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=543)
Quote from: RainDog on December 28, 2009, 09:24:18 AM
Amorphous-Si PV vs. Crystalline-Si PV modules?
Is this a deal? http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=543 (http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=543)
It might be, if they listed snow loading specs and explained more about who provides the warranty. For Offgrid the high voltage controller you would need may be out soon but is not yet! No problem for a grid-tie batteryless though. I do like the high voltage for long distance applications. Sun has great prices but sometimes poor service!
Thanks Dave!
I've seen those powered battery box vents you mentioned. With the cold winters I have, I like the idea of keeping the batteries warm.
I saw a movie called off the map and it had a line in it like your quote.
"working for someone else is expensive,
you spend so much time there that you never have enough time to do things for yourself"
There is a nice way to do the battery venting passively in a very cold garage and keep them warm! Do you want to guess how?
Can you compare this system to say, the one you built with separate components?
I'm looking for an idea of the price difference when doing the work yourself versus the convenience of buying a completely put together package versus the component reliability etc in both.
Thanks
http://sunelec.com/index.php?main_page=600_watt_off_grid_system
Quote from: OlJarhead on December 29, 2009, 01:31:26 PM
Can you compare this system to say, the one you built with separate components?
I'm looking for an idea of the price difference when doing the work yourself versus the convenience of buying a completely put together package versus the component reliability etc in both.
Thanks
http://sunelec.com/index.php?main_page=600_watt_off_grid_system
Sure you can compare! The problem doing this is the intangible questions and their answers.
Like what is it for? How long? Do you expect to add on to it? There are many more questions like how much effort you will put into it? Budget? And the big one, how much energy will you need? If this is for living offgrid keep in mind that there is a very high incidence of failure on these first systems. Half of my customers are someone else's deign that I help the owner design and use properly.
Where did Don go? Snow cabining?
Quote from: Dave Sparks on December 29, 2009, 02:01:56 PM
Quote from: OlJarhead on December 29, 2009, 01:31:26 PM
Can you compare this system to say, the one you built with separate components?
I'm looking for an idea of the price difference when doing the work yourself versus the convenience of buying a completely put together package versus the component reliability etc in both.
Thanks
http://sunelec.com/index.php?main_page=600_watt_off_grid_system
Sure you can compare! The problem doing this is the intangible questions and their answers.
Like what is it for? How long? Do you expect to add on to it? There are many more questions like how much effort you will put into it? Budget? And the big one, how much energy will you need? If this is for living offgrid keep in mind that there is a very high incidence of failure on these first systems. Half of my customers are someone else's deign that I help the owner design and use properly.
Where did Don go? Snow cabining?
Good points (and I've heard them all but tend to get over excited and forget to include them)....
Off grid cabin -- not living -- with minimal usage (like Don's). 12vdc pump (that may actually be 24vdc) pumping water out of a 205' deep well into a cistern about 80 feet above it (don't know if that matters at all but I haven't checked amps yet)...maybe some 12v lights and a 12v ceiling fan (or maybe 24vdc) with some 120v outlets for small TV (maybe), DVD player (maybe), toaster, maybe even a small MW oven...who knows really? After all it's a vacation cabin and not a home.
Don (c'est moi) is in Colorado for a few days, to see some real snow (quantities).
We should be back home tomorrow PM sometime, as long as it doesn't snow heavily in or around Raton Pass.
I'll catch up then.
Quote from: MountainDon on December 29, 2009, 11:40:05 PM
Don (c'est moi) is in Colorado for a few days, to see some real snow (quantities).
We should be back home tomorrow PM sometime, as long as it doesn't snow heavily in or around Raton Pass.
I'll catch up then.
Snowing on Raton
http://video.google.com/videoplay?docid=-6717780685002939476&ei=F2I7S6nVJY6-rALRiOm-Cg&q=snowing+on+raton&hl=en&client=firefox-a# (http://video.google.com/videoplay?docid=-6717780685002939476&ei=F2I7S6nVJY6-rALRiOm-Cg&q=snowing+on+raton&hl=en&client=firefox-a#)
Well, it did not snow on Raton, but it was cloudy and windy and threatening snow north of Santa Fe (south of Raton). Now it's snowing at home. I'm glad the roads were dry for driving; it is hard dangerous to do 82 mph in snow.
Is that system any good? How does it compare to what you would put together yourself?
You have not answered the question; how much power am I going to use in a day or a week? That has to be answered first, before trying to see how much it's going to cost or if system "xyz" will do the job.
It's tedious, yes. I made my best guesses several times over many months. You must be honest about expected hours of use for each light, microwave, etc. Make two lists, one that you need AC for (microwave type stuff) and the other DC things you might use. Use watts rather than amps and volts as you can change the DC watts into 12 or 24 VDC based systems at any time. Make the list, round up any odd numbers.
Once you know how much you will use, then the battery bank size can be calculated and from that and the number of sun hours the total PV panel wattage can be determined. Then the charge controller can be picked. The amount of AC power will indicate how large an inverter is needed.
A note on the inverter: you mentioned a small microwave. Be aware that a microwave that is marketed as an 800 watt unit will likely consume 1100 - 1200 watts while operating. That 800 watts (or other advertised number) refers to the cooking power, not the amount of power used.Maybe you knew that, maybe you did not. As it makes a big difference I wanted to be sure on that.
One size does not fit all. You will likely need more PV panels than I would for the same size battery bank, for example because of our different latitudes.
Quote from: Dave Sparks on December 28, 2009, 02:56:41 PM
There is a nice way to do the battery venting passively in a very cold garage and keep them warm! Do you want to guess how?
I'm trying to guess, but my imagination is failing me, Dave. ???
One more clue! The very cold 30F garage is attached to the house. :o
Hmmmm....
Is the battery box up against the warm wall?
Insulate the battery box, vent it at a high point and remove any insulation from the house wall where the battery box is located?
Quote from: OlJarhead on December 29, 2009, 01:31:26 PM
Can you compare this system to say, the one you built with separate components?
I'm looking for an idea of the price difference when doing the work yourself versus the convenience of buying a completely put together package versus the component reliability etc in both.
Thanks
http://sunelec.com/index.php?main_page=600_watt_off_grid_system
OK point has been lost in translation. The amount of power required or desired is in fact irrelevant to the question asked :) So let me try again.
If you built a system yourself (so Don, you have what? a 900 watt system?) then go out and find a 900 watt (or similar) package (anywhere is fine) and then compare it to yours.
Why? let me explain:
I used to build PC's. I went out and found the Motherboard I wanted, the processor, the fan and heatsink, the hard drive, disk drives, CD Drives, graphics cards etc etc etc. My systems cost less then the big box systems and were better.
To this day my home built PC, while old and outdated, still is a better system then what you can buy in a few ways. For example, I have more memory slots then most box systems do, I have more PCI slots, more drive bays, more room overall, more fans, bigger power supply, the list goes on and on...and it cost me less (at the time) then something similar from Hewlett Packard.
Now, today, I'm not sure since I no longer go out and buy parts to build a PC -- though I may yet again -- and I've seen a lot of CHEAP box systems that would probably suit me fine today (I probably won't try to stuff in half the things I used to)...
So from this kind of perspective, can you compare one of these 'kit' systems to your home made system?
I'm specially interested in Don't set up becuase I think it's a very similar situation/scenario to mine. Cabin in remote location for part time use.
I will probably build my own system using what I'm learning here and have a good friend -- who's probably reading this post now ;) -- who's been educating me on the technical side of things (electrical) that I don't know. I've built Microwave Transport Node sites to back haul Cellular traffic to the MSC (mobile switching center) which includes installing DC power controllers, rectifiers and batteries (series parallel) so I'm not new to the construction aspect of what we're discussing -- might even have a lead on some good batteries to use and will be checking into that since we install them in all of our sites to provide battery backups for the MW gear (-48vdc systems). Anyway, I digress :)
The computer analogy may still be still valid. I used to build desktops too. It was always a lot of fun selecting the components and the machines did usually come out cheaper than store bought. I'm not sure about today; when we last needed a new desktop I went to Dell. I wouldn't even think about building a laptop, though, which is what the last two computer purchases were. However, there's still a ols desktop in the corner of the office with an overdriven AMD 900 Mhz CPU that serves as a backup media storage unit.
Anyhow on to the PV system question. If one measures the system size by the panels, our system is 624 watts; three 208 watt panels. We have a charge controller that is higher quality and more versatile than what is offered most any pre-packaged kit. Ditto the inverter. My batteries are only golf cart GC2's. From Sam's Club they are dirt cheap compared to any other battery. Picking them up locally I saved a lot on freight costs. So far they are working well, and my past RV experience with them leads me to believe they will be cost effective.
I did spend a lot more money on our system than that one you referenced. Looking at it, I see we have more panel watts and more battery capacity. We also have a lot more inverter. And I have a lot more cable from panel to charge controller. :D
Tell you what... you should now have my prototype almost-ready-for-prime-time ;D PV system sizer tool. Run some numbers through the probable power load sections and send me the file, and let's go from there and have a look at alternative equipment choices.
What are the specs on those batteries that are used in the cell communications trade? Those could be great to have when priced right.
Nice sheet -- one thing is for sure, I've got a LOT of thinking to do...just running lights for 10 hours a day can change a plan from 6 panels to so many you might as well run and hide! Sheesh!
"What are the specs on those batteries that are used in the cell communications trade?"
Yes this could be very interesting.
These aren't the exact models we're using but pretty much the same sort of thing. They are used in sites which must provide a minimum run time for the MW gear (transport nodes, routers etc) of 8+ hours.
What this means is that it should take at least 8 hours to go from -56vdc to -46.5vdc (where most systems die)....though sometimes the equipment will run around -46vdc they are usually dropping like flies then.
I can log into my controllers (in 5 states) right here :)
http://www.sbsbattery.com/category_desc.php?cPath=3
We get ours from "Telecom Battery Solutions" more or less -- actually from Magnatek.
But I don't know that they are any better...I would just expect them to be since we're carrying E911 traffic which is well, kinda critical :)
Wish I had that reliable grid power, eh. [ouch]
Hundreds out of power since last week - power not expected back for days to come. I'm so glad the state forced me to hook up to that reliable grid... OK so they told me I had to and I didn't... [waiting]
http://abclocal.go.com/kfsn/video?id=7238715
http://abclocal.go.com/kfsn/story?section=news/local&id=7240825
Quote from: glenn kangiser on January 26, 2010, 11:39:06 PM
Wish I had that reliable grid power, eh. [ouch]
Hundreds out of power since last week - power not expected back for days to come. I'm so glad the state forced me to hook up to that reliable grid... OK so they told me I had to and I didn't... [waiting]
http://abclocal.go.com/kfsn/video?id=7238715
http://abclocal.go.com/kfsn/story?section=news/local&id=7240825
Too bad we all weren't rich enough to fight them in court over these kinds of things.
I have an DC electrical question.
We have a Sundanzer DC electric fridge and we're planning on moving it a little farther away from our power supply. The manual says we should use 12 gauge cable for the distance we'll be at and the fridge comes with a fairly short 14 gauge cable. Should I just get 12 gauge to run from the DC box to the 14 gauge fridge cable, or should I replace the 14 gauge with 12 gauge for the entire distance? To be perfectly clear, do I remove the 14 gauge from the fridge and wire in the 12 gauge directly to the fridge?
Thanks,
Dave
http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=255
Found these and was wondering if they sounded like decent panels for the money?
I want to put together a system for as little as possible but that will be reliable (within reason)...basically I can't afford $10k in solar power and budgeted $2k but could go a little more.
I need 2 of these 18Vmp panels, 4 Trojan L16RE-B 6v batteries, not sure what kind of inverter but my corrected watt hours per week is 6347 as calculated right now. Also need a charge controller for the panels.
Since those panels list at $348 that's $696 in panels
Those batteries run about $330 -- so that's $1320 (ouch -- I think I might take Don's approach -- heck, 12vdc deep cycle RV/Marine batters aren't that expensive. In fact I could get Optimas and save $400 at least and they've got to be decent...maybe I'm thinking wrong?)
http://store.solar-electric.com/xaxwmp60amps.html
I'm still learning (have a long way to go) but this appears to be what I would need for a controller? I know I could go cheaper but I thought I read the MPPT's were the way to go???
That's $529
http://store.solar-electric.com/xatr15wa12vo.html
$760 for this inverter which has the charger plug in for the generator.
OK so if I went this route then the cost looks like:
$3305 for a 400 watt system with 1500 watt inverter and MPPT controller as well as 4 good batteries.
Hmm...also I have a 3000 watt generator that peaks at 4000 watts and will use that as a back up for the batteries as well as running saws and such (for construction at the cabin).
Thoughts? Am I choosing the wrong components? Did I miss something? Could I reduce costs by going with 6v golf cart batteries? Is the contoller/inverter combination incorrect?
It's kinda fun mind you, doing this. I'm using Don's spreadsheet and trying to figure out what kind of power we will need at the cabin since all we've done to date is camp out in the trailer with ONE battery (except one time I had 3 becuase it was very cold) and the main thing that used the battery was heat which we've solved by buying the wood stove :) And better insulation.
Anyway, thanks in advance.
WOW! Just read that the Sams Club GC-2 is $66 at most places and can be found for $44 in some places (Costco maybe?)...in any case that changes my above cost considerably if I went that route.
So, 8 (need 8 due to the lower amp hour rating) x $66 = $528
Overall cost reduced to $2313 for the system I put together
I'm interested and learning here also. I have not built a system, just read on it, my input does not come from experience.
I went to google Sams GC-2 for power storage and the first link I found was pretty clear that the lifespan of these is in the ballpark of a year. While saving money (up front) is great, it might not be soo great to replace them every 12 months.
http://www.power-talk.net/golf-cart-batteries.html
Our Experience with Golf Cart Batteries
The third set of batteries to store power for the Ranch was a set of Sams Club GC-2's. We had two sets of eight hooked in series and then each bank was connected to a buss bar for a 420 AH capacity. These lasted 12 months. Thinking that maybe we just got a bad batch, we tried the same thing again. Twelve months later we were again looking at 16 depleted little batteries.
We kept them charged, watered and clean and didn't abuse them with microwaves and such. The largest DOD they were subjected to was 35% with the average more like 20% - 25%. Even if you considered each day for a year as a "cycle" that would be only be 365 which is short of the average 500 which we see on a lot of charts. If we had been hammering them daily with high load devices, this might be understandable but the typical draw we have is in the 3 - 10 ampere range. One thought was that we should have added another bank of 8 the second time around, for a total of 24 to ease the average load per battery.
It depends on how off brand you are willing to go and how much risk you are willing to take. There are many 40 Amp charge controllers on ebay made by smaller wind and solar energy companies that can be had for under $100. Many have good feed back. Here is one I have been looking at.
http://stores.ebay.com/Coleman-Air-Parts
Personally for such a small system that doesn't get regular use, I probably wouldn't go so high end, but that is just my personality. A 1500 watt square sine 12V inverter can be purchase for $150. You could by 4-5 of them for the price of the Xantrex.
Quote from: Squirl on January 29, 2010, 01:55:07 PM
It depends on how off brand you are willing to go and how much risk you are willing to take. There are many 40 Amp charge controllers on ebay made by smaller wind and solar energy companies that can be had for under $100. Many have good feed back. Here is one I have been looking at.
http://stores.ebay.com/Coleman-Air-Parts
Personally for such a small system that doesn't get regular use, I probably wouldn't go so high end, but that is just my personality. A 1500 watt square sine 12V inverter can be purchase for $150. You could by 4-5 of them for the price of the Xantrex.
Do they have the Generator hook up to provide a charge on the batteries when the gen is running?
Good points all -- this is a limited use cabin which I hope to eventually improve to the point that we could spend a lot of time there -- maybe 5 to 10 years later but certainly not as long as I'm working as much as I do!
Quote from: muldoon on January 29, 2010, 01:49:55 PM
I'm interested and learning here also. I have not built a system, just read on it, my input does not come from experience.
I went to google Sams GC-2 for power storage and the first link I found was pretty clear that the lifespan of these is in the ballpark of a year. While saving money (up front) is great, it might not be soo great to replace them every 12 months.
http://www.power-talk.net/golf-cart-batteries.html
Our Experience with Golf Cart Batteries
The third set of batteries to store power for the Ranch was a set of Sams Club GC-2's. We had two sets of eight hooked in series and then each bank was connected to a buss bar for a 420 AH capacity. These lasted 12 months. Thinking that maybe we just got a bad batch, we tried the same thing again. Twelve months later we were again looking at 16 depleted little batteries.
We kept them charged, watered and clean and didn't abuse them with microwaves and such. The largest DOD they were subjected to was 35% with the average more like 20% - 25%. Even if you considered each day for a year as a "cycle" that would be only be 365 which is short of the average 500 which we see on a lot of charts. If we had been hammering them daily with high load devices, this might be understandable but the typical draw we have is in the 3 - 10 ampere range. One thought was that we should have added another bank of 8 the second time around, for a total of 24 to ease the average load per battery.
Pretty good points -- but Don seems to have done well running his -- so I'm wondering what he thinks? Could be that they over used them more then they admit??
I thought about RV batteries and even Optima's (I have an Optima Yellow Top in my jeep) which run about $200 but figured at that price I might as well get the Trojans -- of course, I might instead try to get some cell site batteries ;) Since I could probably get them direct from the factory :D
Quote from: OlJarhead on January 29, 2010, 02:23:56 PM
Do they have the Generator hook up to provide a charge on the batteries when the gen is running?
No. That is definitely a higher end very user convenient feature of this model.
If cost is in issue, and you are looking to lower it.
http://www.samsclub.com/shopping/navigate.do?dest=5&item=429487
You could probably find an equivalent 40-50 amp battery charger at most automotive stores. If you are willing to spend the money up front for a more full time system, Xantrex is always a good brand. I have had good experiences using their marine units.
Quote from: pagancelt on January 29, 2010, 12:05:26 PM
I have an DC electrical question.
We have a Sundanzer DC electric fridge and we're planning on moving it a little farther away from our power supply. The manual says we should use 12 gauge cable for the distance we'll be at and the fridge comes with a fairly short 14 gauge cable. Should I just get 12 gauge to run from the DC box to the 14 gauge fridge cable, or should I replace the 14 gauge with 12 gauge for the entire distance? To be perfectly clear, do I remove the 14 gauge from the fridge and wire in the 12 gauge directly to the fridge?
Thanks,
Dave
Ideally you'd run the 12 ga the entire distance. But if the 12 is 'fairly short', I'd probably just use the 12 for the extra length needed. If I already had enough 12 gauge laying about, and if changing the cord at the fridge was easy, then I'd likely change out the wire to all 12 gauge.
The 12 gauge will be running roughly 10 to 12 feet, if I don't change out the 14 gauge. If I change it out the total for the 12 gauge will be about 16 feet. I guess I'll have to pull the fridge out and see how difficult it'll be to change out the 14 gauge.
Thanks,
Dave
Quote from: OlJarhead on January 29, 2010, 01:13:15 PM
WOW! Just read that the Sams Club GC-2 is $66 at most places and can be found for $44 in some places (Costco maybe?)...in any case that changes my above cost considerably if I went that route.
Sam's Club has great pricing on their GC-2's nationwide. My Costco does not sell auto/truck/RV/marine batteries at all.
I believe it is normally impossible to beat the Sam's club GC-2 pricing.
Whether or not they are as good as the trojan, I have no idea.
Once you have the battery capacity required calculated, you can do price comparisons. Most likely the GC-2's will be the least amount of money spent. They likely won't last as long as any L-16, but if you estimate life and factor in $$ spent I believe the GC-2's are a good bet on a small system.
I'll at those other questions you posed later.
Quote from: pagancelt on January 29, 2010, 02:45:28 PM
The 12 gauge will be running roughly 10 to 12 feet, if I don't change out the 14 gauge. If I change it out the total for the 12 gauge will be about 16 feet. I guess I'll have to pull the fridge out and see how difficult it'll be to change out the 14 gauge.
Thanks,
Dave
Dave, You could also take the quick and dirty route and simply cut off the 14 gauge close to the fridge. Then spilce the 12 gauge to it. As long as you make good connections and tape/insulate well, you'd never tell the difference in power use or loss.
Quote from: muldoon on January 29, 2010, 01:49:55 PM
I'm interested and learning here also. I have not built a system, just read on it, my input does not come from experience.
I went to google Sams GC-2 for power storage and the first link I found was pretty clear that the lifespan of these is in the ballpark of a year. While saving money (up front) is great, it might not be soo great to replace them every 12 months.
I have a set of 4 of the GC-2's from Sam's Club in the RV. They are now coming up to the end of their 4th year of use. I have no idea if that is typical or if the other guys experience is. One variable that was not mentioned in that article was temperature. ANY wet cell battery will have a shorter life when used in a high temperature environment. Most of my RV batteries lives have been in a cool to cold environment. They spent their first year in the typical desert summertime 90's, but the last 3 in the cool/cold of the mountains.
Quote from: OlJarhead on January 29, 2010, 02:26:10 PM
even Optima's (I have an Optima Yellow Top in my jeep) which run about $200 ....
This is my personal opinion... I love the Optima for a vehicle battery. I have two red tops for the Cherokee. The plan is to replace them one at a time on a 2 year cycle. That way there will always be one battery that is at most two years old.
I believe the yellow tops are a good battery but too expensive for a stationary battery. Optima's big selling point, to me, has been their construction which is pretty much vibration proof. That's a big point in a 4WD that sees off road use.
AGM batteries are used successfully in many off grid applications. They will cost two to three times as much as a flooded wet cell battery, more if you compare to the Sam's GC-2. They don't require maintenance (watering). IF they are charged at too high a rate or overcharged they can be damaged. Overcharging can cause them to out gas and since any lost water can not be replaced that will shorten their life. For that reason AGM's are not run through any equalization charging. 15.5 volts (on a 12 VDC system) is about the absolute max charge voltage.
AGM's also have a much lower self discharge rate than a flooded wet cell battery. Lots of plus points for them. AGM's, by their nature, can only have their state of charge tested with a voltmeter.
Do not confuse a gelled cell battery with AGM. You do not want a gel cell for off grid power systems.
Thanks for the insights, Don.
Quote from: OlJarhead on January 29, 2010, 01:07:20 PM
http://store.solar-electric.com/xaxwmp60amps.html
I'm still learning (have a long way to go) but this appears to be what I would need for a controller? I know I could go cheaper but I thought I read the MPPT's were the way to go???
That would work but might be more than you need.
Another choice could be the Blue Sky SB3024iL MPPT. http://store.solar-electric.com/blskysbchco3.html
With it you could wire those panels in series to the charge controller. The controller can charge 12 VDC or 24 Vdc batteries. It has enough capacity for up to 540W (12V) & 800W (24V) panel output.
http://www.blueskyenergyinc.com/uploads/pdf/BSE_Product_Line_Overview.pdf
<$350 or just over $400 with meter.
As for the inverter, that Xantrex appears to be good... the charger section offers loads of power and offers the three stages plus equalization. 10 - 70 amps charger output. http://lib.store.yahoo.net/lib/wind-sun/TR-inv.pdf
A lot of folks forget about the charger they will need at some point if they buy a
cheap inexpensive inverter. Most, if not all, automotive chargers will not have an equalization mode. Something to keep in mind.
Question: Do you already own the small microwave you might want to use off the inverter? I ask because our small 800 watt (1100 watt draw) microwave will not run on the square wave inverter I own. It hums (louder than on sine wave) but does not produce cook power. I don't know of any way to predict what will happen short of plugging one into a square wave inverter and trying it. In fact I don't know enough people with square wave inverters large enough to know if there are microwaves that will run on square wave. No idea. Maybe someone will know. ??? I think I recall seeing some people using microwaves on cheap square wave inverters. I'm pretty sure my neighbor in the mountains runs a microwave; I know they have a square wave Xantrex inverter. Again, something to think about.
Thanks Don -- no microwave and I beleive I removed it when the wife told me we didn't need one :)
I removed the battery charger and some other items and reduced usage based on guestimations made on my last trip.
http://www.infinigi.com/renewable-energy-charge-controllers-c-2_37.html?page=6&sort=2a
this might save you a few bucks on the Xantrex
Quote from: Windpower on February 11, 2010, 12:40:18 PM
http://www.infinigi.com/renewable-energy-charge-controllers-c-2_37.html?page=6&sort=2a
this might save you a few bucks on the Xantrex
Thanks :)
If all goes well we will be making our solar power purchase within the next couple months :) Gotta get a roof on and some walls done etc first though!
Well finally got started on my off grid power system. This going to be gradual build, starting with a battery bank being charged by an alternator, with solar panels added as we have the cash for them. I figure we can still use the alternator down the road to charge the batteries on cloudy days.
I got a cheap Harbor Freight 6 1/2 horse motor, and ordered the mounting plates and direct drive coupler from the The Epicenter (http://theepicenter.com/cgi/order.cgi?page=power_sources_generators_and_batteries.html&cart_id=%%cart_id%%).
Buying the mounting plates from them saved a bunch of work. They are well made, looks like they cut them with a plasma cutter, they bolted right up to the motor and alternator. [cool]
So here is the meager start of my system...
The motor generator combo, and the Exeltech inverter I got from Considerations. I removed the small gas tank, going to hook up a 6 gallon marine tank. With the quick release fittings should make for easy fuel changes. Also have to come up with some kind of enclosure to mount the setup in...something along the line of what Mt. Don built for his generator.
![](https://img.photobucket.com/albums/v682/adbeavers/House/P2250009.jpg)
Close up of the couplers. The direct drive really makes for a nice looking unit IMO...almost looks like store bought, not redneck engineered! :)
That looks nice; rubber insert shaft coupler by the looks of it.
I see the engine has a cast iron sleeve; that's good too.
Quote from: Beavers on February 25, 2010, 08:08:58 PM
Well finally got started on my off grid power system. This going to be gradual build, starting with a battery bank being charged by an alternator, with solar panels added as we have the cash for them. I figure we can still use the alternator down the road to charge the batteries on cloudy days.
I got a cheap Harbor Freight 6 1/2 horse motor, and ordered the mounting plates and direct drive coupler from the The Epicenter (http://theepicenter.com/cgi/order.cgi?page=power_sources_generators_and_batteries.html&cart_id=%%cart_id%%).
Buying the mounting plates from them saved a bunch of work. They are well made, looks like they cut them with a plasma cutter, they bolted right up to the motor and alternator. [cool]
So here is the meager start of my system...
The motor generator combo, and the Exeltech inverter I got from Considerations. I removed the small gas tank, going to hook up a 6 gallon marine tank. With the quick release fittings should make for easy fuel changes. Also have to come up with some kind of enclosure to mount the setup in...something along the line of what Mt. Don built for his generator.
Great looking motor. Is this setup cheaper than a Champion 3500w generator for $299? Or is this more of a fun project by building it yourself?
I'll bet it cost a little less, depending on the alternator output and not counting the 6 gallon marine fuel tank.
The advantage being that for battery charging purposes (12 VDC) it puts out the required DC and has a built in regulator obviating the need for a 120 VAC to 12 VDC charger. On the downside it only puts out 12 VDC.
Close? ???
I got the motor on sale for $150 from HF, and the alternator, mounting plates, and couplers were $150 minus shipping. Not any cheaper, but like Don said it doesn't need a charger to charge batteries. I'm hoping that I will be able to idle it down and use less than full throttle to charge the batteries to cut down on noise, and fuel use.
I actually have one of the Champion 3500w generators. For just running power tools ect. on a jobsite the Champion would be the way to go. With the motor/alternator you still need an inverter and a battery to make 120v power. Once you factor in those it's much more expensive than the Champion. If you are looking to charge batteries though, the alternator would be better as far as I can tell.
One thing to keep in mind, A car alternator puts out about half its rated current at an idle 600 rpm"s or so. The ratio from the crank to the alternator is about 3 to 1.
At 1800 RPM's you'll be at half power output. at 3600 RPM'S to reach full output.
Either gear that sucker up or burn a lot of fuel to reach maximum output.
I like the mount though, It has a clean look.
If you could separate the two and mount something in between to increase the alt. speed.
I think its a 65 amp alternator. I can't remember where I read it but, you aren't supposed to charge the batteries at too high of amps. I'll have to dig back through all my info, but I think 30 amps or so was the most I would want to charge the batteries that I'm planning on getting.
I calculated that I should only have to run the motor a couple of hours a day to keep things charged up. If I can run it a half throttle I hope it won't be too bad on gas. It's definitely not a long term solution, but I think it should work for a couple of months until we can get some panels.
The maximum charge rate for a typical flooded cell deep cycle battery is usually given as C/8, where C = the battery capacity in amp-hours. If batteries are parallel connected C is the total amp-hour capacity of the battery bank.
So with a 210 amp=hour battery, that is 210/8 = 26.25 amps maximum for a sustained period.
I've also seen C/5 listed as okay for flooded batteries that are deeply discharged, and a rate of C/10 listed for batteries that are 85% or greater charged.
There are special rules for gel cells and some brands of AGM allow higher rates. Best to check with the battery manufacturer when in doubt.
Thanks for the number Don, saved me from digging through all my bookmarks to find it. d*
My calculated load for the house is 49.5 amp hours a day. Keeping under C/8 and charging at 25 amps would only have to run the motor 2hrs a day. I think I could live with that for the short term.
Hey guys, I have an battery related charging question i've been wondering for a while.
Right now I have a 75watt panel and Xantranx c40 charge controller charging a single Deep Cycle group 31 battery. The problem is we keep a Honda 4x4 quad on our property and the battery dies before we get back to use it.
Any way I can connect the much smaller ATV battery to the Group 31 deep cycle being charged from our solar setup?
I've never heard of dissimilar battery sizes being charged together but It would be really convient if I could! The ATV battery is $50!
How long does it take for the ATV battery to go dead? Many months or a shorter period?
Rather than try to hook the ATV battery into the existing PV system it might be easier to use a small PV panel just for the ATV battery. If the battery is fully charged, or close to full, a small panel should be able to retain them in full charge. We use 22 watts worth of panels to keep the RV batteries full over the winter.
It will go dead in 2 weeks. I have a crappy 1 watt panel but it's not meant for being outside so I don't want to leave it up there.
We obviously don't have AC power up there either, only our small PV system.
Can a small 12v battery be connected to a large 12v battery?
If it goes dead in two weeks I think the battery is "dead meat" already and there is no hope for it OR there is a "phantom" drain that is sucking the power. No battery, if in decent shape, should go dead that fast.
Have you tried disconnecting the battery from the ATV system? (pull the neg or pos lead off the battery) You could install a battery switch or an Andersen connector to make that easy. I have a disconnect switch in the RV "house" system because there is an unknown small load that sucks the house batteries down if left connected during prolonged absences.
I am not sure if there is any danger to one battery or the other if the ATV was to be connected to the PV system. ??? :-\
Hmmm...did you check www.rockymountainatvmc.com
I think I got a battery for our Yamaha for half that there...mine was doing the same thing so I replaced it -- no point in messing with it beyond that.
http://www.rockymountainatvmc.com/productDetail.do?navType=type&webTypeId=19&navTitle=Electrical&webCatId=20&keyword=BATTERY&prodFamilyId=8926
Thanks but it's still $50. Some are $100! That seems really high for an ATV battery! It's for a Honda Foreman 400 ES. The ES stands for electric Shift and it has 3 lights on it and a cigarette lighter so I suppose it uses lots of juice...
Quote from: OlJarhead on January 29, 2010, 01:07:20 PM
http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=255
Found these and was wondering if they sounded like decent panels for the money?
I want to put together a system for as little as possible but that will be reliable (within reason)...basically I can't afford $10k in solar power and budgeted $2k but could go a little more.
I need 2 of these 18Vmp panels, 4 Trojan L16RE-B 6v batteries, not sure what kind of inverter but my corrected watt hours per week is 6347 as calculated right now. Also need a charge controller for the panels.
Since those panels list at $348 that's $696 in panels
Those batteries run about $330 -- so that's $1320 (ouch -- I think I might take Don's approach -- heck, 12vdc deep cycle RV/Marine batters aren't that expensive. In fact I could get Optimas and save $400 at least and they've got to be decent...maybe I'm thinking wrong?)
http://store.solar-electric.com/xaxwmp60amps.html
I'm still learning (have a long way to go) but this appears to be what I would need for a controller? I know I could go cheaper but I thought I read the MPPT's were the way to go???
That's $529
http://store.solar-electric.com/xatr15wa12vo.html
$760 for this inverter which has the charger plug in for the generator.
OK so if I went this route then the cost looks like:
$3305 for a 400 watt system with 1500 watt inverter and MPPT controller as well as 4 good batteries.
Hmm...also I have a 3000 watt generator that peaks at 4000 watts and will use that as a back up for the batteries as well as running saws and such (for construction at the cabin).
Thoughts? Am I choosing the wrong components? Did I miss something? Could I reduce costs by going with 6v golf cart batteries? Is the contoller/inverter combination incorrect?
It's kinda fun mind you, doing this. I'm using Don's spreadsheet and trying to figure out what kind of power we will need at the cabin since all we've done to date is camp out in the trailer with ONE battery (except one time I had 3 becuase it was very cold) and the main thing that used the battery was heat which we've solved by buying the wood stove :) And better insulation.
Anyway, thanks in advance.
http://sunelec.com/index.php?main_page=615_watt_off_grid_system
This system is very close to the one I priced out -- but has what might be better batteries, 3 panels and all the other goodies I hadn't added.
Thoughts?
Well, the panels ARE made in the USA, nice to see. It's okay being blemished. No UL approval could be a problem if there were an electrical inspection.
Other thoughts in no particular order:
What is the shipping on the batteries going to be? They have a marginally higher rating than the Sam's Club batteries but cost more to begin with, plus shipping.
Xantrex states the amperage draw on that inverter is a max of 77 amps at rated power. Allowing 25% for a surge that means a 100 amp input breaker to the inverter is large enough. They are selling a 250 disconnect, which appears to be a breaker. You need a breaker, or fuse, in the inverter feed, but not one 2.5 times the calculated likely maximum current. Way too much breaker for the inverter. At least I'm assuming that the 250 amp disconnect/breaker is meant for the feed from batteries to inverter.
Their package offers no discounts over buying each item picemeal from them.
Another assumption is that they mean the panels are to be connected in series. I say that as the charge controllers I am familiar with all want/need an input voltage that is greater than the battery bank it is going to charge. A 24 V battery is usually powered by 48 volts input from panels. So that fits with the 20 amp breaker being used at the combiner as a disconnect/breaker.
IF the panels are in series, and if your system is not going to be inspected, you can likely come up with a substitute box and disconnect for less than 79 + 15 = $94 as with the panels in series you really have nothing to combine. Parallel panels would be different.
I'm confused why they include two 60 amp breakers. Xantrex recommends 50 amp for the charge controller output breaker. You only need one breaker in the positive line if you have the system properly grounded.
I can tell you where you can get the C40 for $104 instead of $145
Anyhow that's some thoughts about their "kit"
:D
Thanks Don,
I asked mostly becuase I wanted to get some thoughts on their package vs. the one I put together with your help. I was curious why they did some things and at the time hadn't looked closely at the batteries which I then discovered were golf cart batteries too -- interesting.
Anyway, I was also curios about the voltage and wanted to see if the package we came up with compared.
I see that with your assistance my package has more thought into it (thanks to your spreadsheet too) and price wise is very competitive :D I like that.
Still learning a LOT/TON and am excited becuase we may be starting our buys REAL soon :D [cool]
I plan to stick with what we came up with actually and was going to ask about running the panels in series for a 12 vdc system and I think you just answered that! Series to 24vdc to charge the 12vdc battery bank for the cabin right?
One other thing, I'm considering trying to run a 24vdc feed to the well pump (but I need to check the pump out first) if it's actually 24vdc rather then 12vdc and the panels will be closer to it if I put them where I plan, but the batteries further away (I need to do a drawing) -- what are you thoughts about that?
By the way, this is an amazing resource and at times I just smile becuase I know I'm going to learn something!
The inverter Sun spec'd is meant to run on 24 VDC. That's why the 24 v battery system.
The panels in parallel would not be able to charge the 24 V system. At least using equipment I am familiar with, that would not work. I have not used the Xantrex or looked heavily into their specs and operation. BUT the ones I am familiar with require a higher voltage INTO the charge controller than the battery pack voltage. This is partly because the panels may not be putting out much voltage on a cloudy day... not enough to push the current into the batteries. So with a 24 VDC system you need more than 24 VDC output from the panels to be able to have sufficient power to charge the batteries on cloudy, low voltage panel output days. Those panels singly put out a max of something like 18 VDC.
I'm being wishy-washy, waffling, on that answer because I doubt that Xantrex has any magic power boost built into the charge controller but I don't know for sure.
OTOH, with a 12 VDC battery system the panels would be okay in parallel, but the cables etc need to be bigger, and that inverter would not work.
Re: the pump. Yes, you need to verify it's voltage and current requirements, or volts and watts. Add a nice diagram with distances between components.
I might be wearing out my Honda eu1000i. It seems that for the last few days that when the charger on the Prosine 2.0 inverter is enabled, it just keeps cycling back and forth every 10-15 seconds from standby to charging. Nothing's changed recently. When the inverter cycles to the charge mode, the generator "lugs" for a second, recovers, and the charge phase on the inverter cycles back into standby mode.
It's like the gen isn't responding with enough power soon enough to keep the inverter in charge mode.
I'm careful about the maintanence on the gen, change the oil once a month, add some every 5 days, etc.
I'm a little worried about all that cycling....all I need is for the inverter to go boots up as well.. :(
Tomorrow is Monday and I'll be making some calls to see what sort of tech support I can drum up.
Have you tried using the generator to power some regular AC loads, like a power tool or toaster?
"Have you tried using the generator to power some regular AC loads, like a power tool or toaster?"
Yes, the power from the gen is still going into the inverter and then into the house and still running the whole house and the electric fence, I just have the charging mode on the inverter turned off.
I think that rules out the possibility that the quality of the sine wave being produced by the gen is inadequate, or I don't think I'd be able to run the house on the gen through the inverter.
If I turn on the charge mode, the inverter switches to charge for 7 to 10 seconds, the engine lugs down, then the inverter switches back to standby, and the gen revs back up to normal, then the inverter switches to charge mode and the aforementioned repeats until I turn the charge mode off.
I tried shutting off the house to eliminate all AC loads and then turning on the gen and the inverter's charge mode...no dice.
I get the gen serviced each summer....but there have been 4 summers and there are a lot of hours on it. I wonder what the life expectancy is. Having a "spare" so I could take one offline as servicing is needed is a goal.
I have a 5500 watt B&S gen but it won't run the house through the inverter, I'm pretty sure its the type of sine wave it produces.
Anyway, the PV panels are keeping the battery bank charge in good shape, and I just shut down every nonessential electrical item at night. As the days lengthen and the sun shines more, and I get another job (always helpful), I'll be able to explore the issue further.
In the meantime I think I need to figure out how to hook the big gen directly to the house in case the Honda goes completely gunnybags.
considerations,
Your Honda generator is 1000 watts? Did the Prosine charge controller work fine with the Honda prior to these events?
I do not know your inverter/charger and only use the Outback and Xantrex (SW's XW's) but your inv/chg has to be able to limit the charge current to run a small generator. You could have other problems also but this first step has to be adjustable in the programming of the inv/chg.
A long distance diagnoses is more a guess.
I too am not familiar with your inverter/charger.
It more or less sounds like the inverter is drawing more current than the generator can produce. That could be why the generator lugs as if overloaded and then goes back to normal, only to repeat the cycle. It could be the inverter circuitry sensing the overload or the generator itself. I'm not familiar with the little Hondas either.
The only generator failures I've experienced are total failures to produce power, never a partial failure.
Have you tried pulling all the AC power to the cabin distribution system to see if the charger alone will repeat the scenario? Is the charger section programmable as to maximum AC current use or maximum output? I'd try limiting either of those if possible to slightly below the generators maximum continuous output rating.
"Your Honda generator is 1000 watts?" Yes
"Did the Prosine charge controller work fine with the Honda prior to these events?" Yes
"Have you tried pulling all the AC power to the cabin distribution system to see if the charger alone will repeat the scenario?" Yes, I shut off the big breaker in the power shed...no AC going out at all, and the scenario repeats.
"Is the charger section programmable as to maximum AC current use or maximum output?" Ummmm..There are default settings, and there was a setup programming sequence that I had to go through. The setup programming was ridiculously complex. I haven't changed the settings since the initial programming...and I don't remember....so back to the book, that is next. A cursory reading says the Prosine won't charge if the input voltage drops below 95. I have to go back to the programming sequences to see if that can be altered...just seems logical that if it was working before I shouldn't have to change anything.
Today I also got an "instant" readout voltage meter on the gen to see what happens when the inverter switches to charge mode. It's only sucking about 6 amps from the gen when the charge mode comes on. The trouble is that it won't wait for the gen to get back up to speed before it kicks out of charge mode. A week ago it did, and was working just fine since December 20 until the last few days.
I also plugged a 7.8 amp drill into the gen, revved the drill up and put it to hard work several times. The gen didn't mind and although there was a short (1 second or so) initial period when the gen's rpms dropped, they came right back and the drill didn't notice...held its performance steady.
So now I'm going to find out something like there are different kinds of amps....thought I understood (mostly), but maybe not. ???
I enjoy electricity because it makes so many things so convenient, but...this is probably the most difficult part of the entire project for me to get my head around.
If it worked fine at some point within the last few months and you've changed no settings on your inverter/charge controller I'd say the problem is with your generator. Not that it's in the throws of death, but that something is interfering with the power getting to the charge controller before the charge controller kicks it off.
Maybe try putting a load on the generator before the charge controller so the generator is already running at a higher RPM. It might just be the time it takes the generator to rev up and increase the power output is too long for your charge controller.
OK People this is completely out of my realm of comfort. ??? I need to get busy and develope a system to operate at the cabin. My main power and charging source will be a 12KW propane generator. I would like to operate the generator as a charging system for a battery bank and run the cabin when the batteries are depleted. Here is a list of what will I will be using. Some of which are not listed as watts but rather amps and some I am not sure what they draw.
1100 watts of lighting. That is a total but only a portion will be used at one time.
9.8 amp 110/120 well pump
1100 watt Microwave
2- exhaust fans. One is a bathroom exhaust and the other a 600CFM kitchen fan
1- Sure flow DC pump
3- ceiling fans
I know nothing about sizing the inverter or charging system or even the size or the amount of batteries.
Any information will be greatly appreciated. If you have any sites that list the equipment that you feel are a good buy that would also be useful.
Thanks
Dilemma time.
When I began playing with Don's spreadsheet I was able to put together what I envisioned as a minimalist remote cabin off-grid system. 400watts delivered via 2 200watt panels through a Blue Sky SB3024iL Charge Controller into 8 Golf Cart batteries and then feeding both 12vdc items as well as a Xantrex TR1512 1500 Watt, 12 Volt Inverter. This would power some lights, a well pump, maybe a radio and a composting toilet fan. Not much, but perhaps with enough reserve to make use of some other things (like maybe charging an ipod, or a cordless drill etc).
However, I may (may being a very operative word here) be able to afford to go with a little more...so I'm playing with the following:
3 of these panels: SUN ES-A-210-fa3 210 watts, 11.48 Imp, 18 Vmp
I'm wondering if running them in series at 3100 feet in altitude would be too much for this controller:
Blue Sky SB3024iL Charge Controller 30A 24V MPPT
With 8 batteries as originally planned (need 8 in the winter and 6 in the summer except for at the coldest time of year when I'd really need 10-12 and probably more panels -- it's a trade off right?)....
And....
Xantrex Prosine 1800 Watt HW 12V Sine Wave Inverter w/transfer Switch
That would give me 1800 watts of AC and no modified sine wave so if we did decide to add a small MW oven we could.
Cost? 630 watts for about $3136 plus shipping and of course all the wiring etc.
vs. 400 watts for about $2328
A little more charging juice in t he winter might be nice I'm thinking and true sign wave may be handy at some point. This doesn't really change my system much I think (1500 watt inverter vs. 1800 watts) except that it will produce a lot more power in the summer (north country -- could get more then double the sun I'd get in winter! In fact, in the winter I'll get maybe 3 solid hours of sun but in the summer I could see 12! ???
I doubt we'd need the generator for anything but heavy tool use in the summer but in the winter can imagine that we might need it during longer stays if the clouds are out and we can't get good sun exposure.
Anyway, please fire away!
Also, Don, you mentioned something about using higher input voltage to charge the batteries. I took that to mean that on a 12 vdc battery string you would want 24+ vdc coming into the charge controller?
Also also :) ;) I'm looking at wiring needs to the panels and was thinking that running the three panels in series triples the voltage to 54.9vdc right? (if they are 18.3Vmp) and that Blue Sky charge controller is rated at no more then 57v I think....would I be better going with a slightly more robust controller?
I was thinking this is where the Xantrex XW MPPT 60 Amp Solar Charge Controller would come into it's own since it allows a higher input voltage to charge the 12vdc battery bank.
Thoughts?
THANKS! [cool] c*
John,
No PV panels, no wind, right, IIRC?
If that's correct you should seriously reconsider, or choose an inverter/charger unit that is smart enough to be able to sense battery voltage and then automatically start the generator. Otherwise you will drive yourself and your wife batty with constant monitoring the battery state of charge and/or deplete the batteries past the danger point too frequently and shorten their life.
The only inverter/chargers I have knowledge of, with that capability are Outback and the better Xantrex. There are others though. An auto start kit (relay & stuff) is required as well. There are 2 wire and three wire types as far as the generator connections go, I believe 3 wire can be considerably more expensive. I haven't looked into this much as for the present I'm not doing an auto start system. It's also handy to have an interior control for manually starting the generator.
The system is programmed so when the battery voltage drops to a certain value and for a certain length of time, the generator will start.
Note that the better units have the charger and inverter in one unit. The batteries normally supply the current needed for the AC demands placed on the inverter. The generator can be used to supply extra power when the inverters capacity is being overloaded.
Okay, what is the panel setup for? 120 VAC only or a 120/240 VAC? That will determine the inverter setup. If you need 240 VAC in most cases you will have to have two identical inverters that are designed for stacking in series, to produce two 120 VAC legs. Also if 240 VAC is required the generator must be 240 VAC split phase. Better inverters can also be installed in parallel to increase available current. Series/parallel also is used at times in larger systems.
As for how much inverter output required yo will need to make a list of everything that is likely to be used at the same time. You can use the PV sizing tool http://countryplans.com/smf/index.php?topic=8192.0 (http://countryplans.com/smf/index.php?topic=8192.0) for doing the load and battery calculations. You need to enter watts, so just remember amps x volts = watts
For the well pump: 9.8 amp 110/120 well pump, that is more like 10 x 120 = 1200 watts with a starting surge. ??? on that
The manual/literature for the various fans should indicate power consumption. Or try the internet resources.
I hope that helps some.
Quote from: OlJarhead on March 09, 2010, 02:09:28 PM
...... you mentioned something about using higher input voltage to charge the batteries. I took that to mean that on a 12 vdc battery string you would want 24+ vdc coming into the charge controller?
...... I'm looking at wiring needs to the panels and was thinking that running the three panels in series triples the voltage to 54.9vdc right? (if they are 18.3Vmp) and that Blue Sky charge controller is rated at no more then 57v I think....would I be better going with a slightly more robust controller?
A quick partial response, no time at present for more.
The voltage going into the battery must be higher than the rated voltage of the battery system.
That also generally means the voltage going into the charge controller must be higher than the battery voltage. As a rule of thumb that working voltage input to the charge controller should be 1.5 times the battery bank/system voltage. That provides a safety factor for cloudiness as well high temperature voltage losses. Having the input to the CC even higher is fine with most of them. There is an upper limit listed in any good CC specs. You can not exceed that without (a) damaging/destroying the CC and (b) voiding the warranty.
When calculating the theorteical maximum voltage from the panels the
Voc (voltage, open circuit) value must be used. Than fudge factors must be applied. Multiply the Voc x 1.25 x 1.25, That's right multiply by 1.25 once and then a second time. That will supply the likely maximum voltage that could ever be produced on a very cold, but very sunny morning as the first rays of the sun strike the panels. If that calculated value is near, at or greater than the charge controller maximum input do not use that panel and CC combination.
I'm pretty sure that Blue Shy model would smoke with that proposal: check the specs.
There is a PV panel string sizing tool available at Outback. It uses a database of hundreds of panels. Of course it is only 100% useful for system sizing when using Outback Charge Controllers, but it can give you the panel values and combination values that may be handy. It is also temperature compensating so you can dial in your own conditions and see how the outputs change. Placing the mouse cursor on a colored square produces the cold Voc as well as other data.
Don you are correct No solar or wind (not at this time).
The generator that I have and posted a picture earlier is a standby generator which will monitor the incoming power and when it notices a depletion it will automatically start. So my thinking was to utilize the inverted power as my primary feed (just as grid power is normally used with the generator) and let the generator determine when it needs to start. I guess I need to contact the manufacturer and determine if this configurations with a inverter can be made.
The panel is completely 110/120 now but I did reserve a couple 220/240 breakers for future use.
The pump is a slow start and supposeably does not have a surge.
The fan paperwork does not list any of the technical information only the installation guideline. They used to put that in there was it's not on the particular fans that I have.
I guess the load and battery size will determine the inverter size?
John, The total simultaneous loads will determine the inverter size. How long you want the batteries to supply those loads without the generator running will determine the size and number of batteries.
I'm having some trouble trying to get what I want to say condensed into a compact coherent paragraph or two. What I'm trying to clarify why what you propose could have problems because that's not what the standby generator designers nor the inverter designers had in mind when they set out to build their products.
First, a standby generator will sense when there is no 120 or 240 VAC present at the house service panel, as in a grid power failure here at my home. That loss will cause the generator to start to replace the grid power. When the grid power returns the generator will shut down. A proper grid setup like this will also include an automatic changeover switch to be certain there would be no feedback from the generator into the grid. A standby generator itself has nothing to do with the batteries or an inverter.
Inverters. The better type like the Outback and Xantrex include a charger in the inverter. Inverters have a low battery voltage sensor and a circuit that turns the inverter off when a certain low battery voltage is reached. On the better ones that LBCO (low battery cut off) voltage is user programmable. There is, or should be, a battery voltage setting that will turn the inverter back on when the battery is recharged to a higher voltage; the LBCI low battery cut IN) voltage.
Every inverter has a pair of DC input connections as well as an AC output connection. An inverter/charger also has an AC input connection. When AC voltage is applied to the AC input terminals that current is passed through the inverter and split between powering the house and charging the batteries.
Inverters also consume a small amount of power just sitting there at your beck and call. It's not much but adds up. Over time the batteries will be drawn down to the LBCO and the inverter will shut down. To get around this waste the better inverters have a search function. Virtually no power is used until something is turned on to demand power. At that point the inverter clicks on and things light up, hum or buzz.
These inverter/chargers are meant to be the main supplier for the AC house power. They are wired up so that when there is AC input to the inverter/charger they can charge the batteries and seamlessly continue sending AC power to the house panel.
It's the charging connections I have trouble when trying to use the existing auto start system that is built in to the standby generator. Specifically where to hook the AC input of the charger up to. If the AC from the generator is connected to the AC inputs of the inverter/charger, that will charge the batteries. However, that will also send power through the inverter/charger (via the built in "pass though" that is a part of such units) to the service panel. There the AC power would be sensed as a return of the "grid" power and shut down the generator. At least that's how I see it. I could be wrong, be misinterpreting something.
If you want the system to run without user intervention I believe it gets more difficult than need be.
If you used a separate inverter and a separate charger it might be easier, but that also might cost more than a single unit.
With all that in mind the first thing to do is determine the capacity required for the inverter output and the capacity required for the battery bank.
While you do that check the standby generator specs, or call the supplier. You would want to know if the remote start capability of the generator is a two or three wire setup. Also see if there is a delay system built into the generator. That is when it is called to start, is there a preset or a programmable delay between engine starting and connecting AC power output. I would think so, but not having worked with generators that were designed as a standby I'd like to know. It think there should be.
I hope I did not muddy the waters with that. d*
Yep clear as mud Don. But no fault of yours. Just a mental block on my end.
I do have a automatic transfer switch and seperate breaker for the generator supplied by the manufacturer. Normally there is a 60 amp wires ran from that transfer to the house panel box. Normally the circuts for the house are wired to the 12 circuit generator panel (transfer switch). I know it does have 3-4 smaller wires which I think are the monitoring wires which detect the power failure from the grid (via generator transfer panel)to the generator and that activates the generator. The transfer switch has two modes which are automatic or manuel.
I know I could probably just go with a battery charger from the generator to charge the batteries once the inverter shuts down and it would remain deactivated until the batteries are restored. I think that then the power would be restored to the panel and the generator should shut down after it detects power. Or at least in theory.
You have given me a good bit to digest and I was aware that it would not be easy but I still think it can be done. This is just one area that I am completely lost and it will take me a while to get it figured out.
Maybe someone has crossed this bridge before and may enlighten me some.
Thanks.
Quote from: OlJarhead on March 09, 2010, 02:09:28 PM
Dilemma time.
A..... I'm wondering if running them in series at 3100 feet in altitude would be too much for this controller:
B..... Xantrex Prosine 1800 Watt HW 12V Sine Wave Inverter
C..... I doubt we'd need the generator for anything but heavy tool use in the summer but in the winter can imagine that we might need it during longer stays if the clouds are out and we can't get good sun exposure.
D..... 54.9vdc right? (if they are 18.3Vmp) and that Blue Sky charge controller is rated at no more then 57v I think....would I be better going with a slightly more robust controller?
A..... Altitude has small effect on increasing the amperage output of a PV panels. No effect on voltage. Hot temperatures decrease voltage output, cold temperatures increase voltage output. Clearer skies, no clouds or less atmosphere sue to higher elevations increase the amount of sunlight that reaches the panels and that increases amperage output.
B & C..... No battery charger in that and you will need one.
D..... I think we covered that already. bad idea for those 3 panels and that charge controller. But do remember use Voc and those correction multipliers when totaling the input voltages.
Hope that makes sense...
:D
My head/jaw hurts tonight.
FYI, on the cold weather and PV panel voltages.
The Outback online calculator predicted a Voc from the panels in series, at the lowest temp I've recorded up there this winter, of 129 volts. The Outback FlexMax charge controller recorded a peak voltage of 127 volts for that time period. Pretty close, although I should add that I have also recorded 125 volts at temperatures that the calculator predicted would be 10 volts lower. ??? Goes to show there can be real world variance from theory. However, I have enough safety factor that even using a worst case scenario everything should be safe.
Take that as a hint to not cut theoretical peaks too close to the stated hardware maximums.
Note: if your panels are not listed in the Outback calculator you can enter your own data. I believe Xantrex has a similar calculator with their equipment listed.
Quote from: Redoverfarm on March 09, 2010, 09:21:09 PM
I know I could probably just go with a battery charger from the generator to charge the batteries once the inverter shuts down and it would remain deactivated until the batteries are restored. I think that then the power would be restored to the panel and the generator should shut down after it detects power. Or at least in theory.
I believe that is correct. That system though will have to be finely tuned to allow the generator powered charger to bring the batteries up to an absolute true full charge, before the inverter kicks back in and causes the genny to shut off. It should be possible but may require fiddling.
I now remember there was something I wanted to add. Beware of cheaper inverters that have the LBCO voltage fixed at something like 10.5 to 11.0 volts. As far as I'm concerned that is too low a voltage to use. The LBCO and LBCI shoiuld be adjustable by the user.
The charger you select should have the three types of charging; bulk, absorb and float as well as an equalization option. The EQ is not available on a number of stand alone chargers. You will need to be able to disable the generator start/run when you want to do an EQ or even treat the the battery to a complete full charge.
Quote from: MountainDon on March 09, 2010, 09:36:25 PM
Quote from: OlJarhead on March 09, 2010, 02:09:28 PM
Dilemma time.
A..... I'm wondering if running them in series at 3100 feet in altitude would be too much for this controller:
B..... Xantrex Prosine 1800 Watt HW 12V Sine Wave Inverter
C..... I doubt we'd need the generator for anything but heavy tool use in the summer but in the winter can imagine that we might need it during longer stays if the clouds are out and we can't get good sun exposure.
D..... 54.9vdc right? (if they are 18.3Vmp) and that Blue Sky charge controller is rated at no more then 57v I think....would I be better going with a slightly more robust controller?
A..... Altitude has small effect on increasing the amperage output of a PV panels. No effect on voltage. Hot temperatures decrease voltage output, cold temperatures increase voltage output. Clearer skies, no clouds or less atmosphere sue to higher elevations increase the amount of sunlight that reaches the panels and that increases amperage output.
B & C..... No battery charger in that and you will need one.
D..... I think we covered that already. bad idea for those 3 panels and that charge controller. But do remember use Voc and those correction multipliers when totaling the input voltages.
Hope that makes sense...
:D
My head/jaw hurts tonight.
Thanks Don -- so the Xantrex contoller if I want to run series then.
I was thinking the transfer was for the gen -- guess I need to re-read that. Is there a decent true sine wave inverter for similar cost that also has the battery charger?
Yikes! Just looked up true sine wave inverters with charge controllers and got shell shocked! Guess it's back to modified sine wave for now.
With the Xantrex controller and the Xantrex inverter charger I should be set anyway, I was just toying with the idea of true sine wave becuase if we wanted a MW oven it might matter.....I think we ditch the MW idea *chuckle* and stick to the propane stove and cook fires!
Quote from: OlJarhead on March 10, 2010, 12:31:36 AM
Is there a decent true sine wave inverter for similar cost that also has the battery charger?
Xantrex Pro-Sine 2.0..... 2000 Watt Sine Wave Inverter/Charger
Magnum Energy..... 2000 Watt Sine Wave Inverter/Charger
More bucks though.
"OK People this is completely out of my realm of comfort." Roger that
"With the Xantrex controller and the Xantrex inverter charger I should be set anyway, I was just toying with the idea of true sine wave becuase if we wanted a MW oven it might matter.....I think we ditch the MW idea *chuckle* and stick to the propane stove and cook fires!"
I have a microwave and a Prosine (Xantrex) inverter. I still use the franklin stove and the crock pot for cooking. The most use the MW got is popcorn (it was a load test). I heat rolls, melt butter, that's about all....My system is small for a "real" house and an MW is a wattsucker.
Quote from: considerations on March 10, 2010, 07:41:43 PM
"With the Xantrex controller and the Xantrex inverter charger I should be set anyway, I was just toying with the idea of true sine wave becuase if we wanted a MW oven it might matter.....I think we ditch the MW idea *chuckle* and stick to the propane stove and cook fires!"
I have a microwave and a Prosine (Xantrex) inverter. I still use the franklin stove and the crock pot for cooking. The most use the MW got is popcorn (it was a load test). I heat rolls, melt butter, that's about all....My system is small for a "real" house and an MW is a wattsucker.
What size microwave do you have? I looked at a 700 but there is just enough room to warm a cup of coffee. But hey that's about all I will use it for. Not a big fan of cooking in one anyway.
We have an 800 at the cabin. It serves us well for warming things. Keep in mind that the rating you see in the ads is cooking power. Our 800 draws 1100 or so when working. That may seem like a lot but when it's only for 2 minutes that is almost 37 watt hours which is like an 18watt lamp burning for 2 hours. It doesn't seem like so much when I look at it like that. Maybe it's me.
John, looking over that list of power loads you provided, I had a thought. You listed a pump that draws 1200 watts and a microwave that draws 1100 watts. (That was the power use on the microwave, or was it the cooking power?) Add those: 1200 + 1100 = 2300 watts. Or if the 1100 was cooking power the actual use is likely around 1650 (ours in the house is that), so 1200 + 1650 = 2850 watts. Unless you want to have to check if the pump is running any time you want to use the microwave (and hope it doesn't start while the microwave is in use), you need an inverter that will handle a load of 2300 or 2850 plus some extra in case there are some lights or whatever in use at that time.
Does that make sense?
Completely. Thanks Don
Quote from: Redoverfarm on March 10, 2010, 08:57:59 PM
Quote from: considerations on March 10, 2010, 07:41:43 PM
"With the Xantrex controller and the Xantrex inverter charger I should be set anyway, I was just toying with the idea of true sine wave becuase if we wanted a MW oven it might matter.....I think we ditch the MW idea *chuckle* and stick to the propane stove and cook fires!"
I have a microwave and a Prosine (Xantrex) inverter. I still use the franklin stove and the crock pot for cooking. The most use the MW got is popcorn (it was a load test). I heat rolls, melt butter, that's about all....My system is small for a "real" house and an MW is a wattsucker.
What size microwave do you have? I looked at a 700 but there is just enough room to warm a cup of coffee. But hey that's about all I will use it for. Not a big fan of cooking in one anyway.
The inside of the MV oven is about 12 x 12 x 9 inches.
The little label on the back says .95 Kw, but just like someone on this forum said, it pulls 1100 watts (I have a Kill-a-Watt) when running. I don't use it if the gen is on and unplug the fridge and the freezer till I'm done. Almost not worth the trouble, but I don't always have a fire going with spring coming.
My mother gave (force fed) it to me recently, and I felt compelled to make her feel good by reporting that it works, she cannot imagine life without one...and it does, just have to be sure nothing else is going to tax the system when its in use [waiting]
The microwave uses a lot of watts but only for a short period of time, so it is not all that bad on the batteries if they are decent sized. It all depends on the system though.
We have a 1250 watt inverter microwave. It gets the job done fast. I am still not convinced that it will kill me.... [waiting]
Quote from: glenn kangiser on March 14, 2010, 12:06:14 AM
I am still not convinced that it will kill me.... [waiting]
Only if you can figure out how to get your head inside and turn it on. [crz]
"The microwave uses a lot of watts but only for a short period of time, so it is not all that bad on the batteries if they are decent sized."
I'd love to have a battery bank that is double or triple the current size as well as 3 times as many panels.....its on the "list".
Quote from: MountainDon on March 14, 2010, 12:34:46 AM
Quote from: glenn kangiser on March 14, 2010, 12:06:14 AM
I am still not convinced that it will kill me.... [waiting]
Only if you can figure out how to get your head inside and turn it on. [crz]
I heard it's hell on cats.... Note to self... do not dry Fluffy in the microwave....
![](https://i302.photobucket.com/albums/nn110/dragon_4_life_05/Funny/cat_microwave.gif)
The extra capacity is handy, considerations.
Nothing like a delayed response, eh? [waiting]
Who is using what for 12v sockets?
I'm curious because I thought there was a typical household receptacle for 12vdc but um, not so much.
I don't mess with 12v. I invert everything and run 120 or 240 full sine. Others have done some though I know.
There is no such thing as an off the shelf
quality low voltage DC receptacle or plug.
However a NEMA 6-20P configuration receptacle or plug makes a good choice. They are 20 amp 250 VAC rated and accepted by the NEC for use in DC circuits as long as there is no 220/240 VAC in the same structure.
![](http://www.homedepot.com/catalog/productImages/300/10/10dbd6ee-3725-43b9-8c30-eb4ce031f032_300.jpg)
![](http://www.homedepot.com/catalog/productImages/300/e0/e0b41290-3e36-4e84-aae3-b571bdb43fdd_300.jpg)
I use them. I wire the 'vertical' connector + and the 'horizontal' one negative. That's with the units oriented as pictured.
Thanks Don -- just saw that also at BackWoodsSolar.com
I'm not sure how much 12vdc stuff I'd need (or 24vdc for that matter) but want to plan to run some lines for it incase I find a use (or buy a chest freezer or fridge in 12 or 24vdc).
Just in the planning stages right now.
Saw COSTCO has 6v Golf Cart batteries for $78 ea. 220 ah rating. Didn't buy them becuase I wasn't ready but I wonder if maybe I should have just got them anyway.
Need to look around more though. But Walmart doesn't carry them so that's out.
And remember common wall switches areAC only.
My SamsClub has 210's for $68. $9 core. I pa7d no sales tax either as in NM everything used in PV or wind is tax exempt. Check on WA state.
Those are what I bought. They've been the same price for over a year. Don't buy too early as they age just sitting there.
check...
http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=WA04F&re=1&ee=1
Thanks
Was playing with the PV calculator again and am wondering about something:
If you run a 24vdc bus / battery bank -- what do you do for 12vdc appliances?
1. Run a center tap to take off 12 VDC with a hot wire tap. bad.
2. Use a 24 VDC to 12 VDC converter. They are solid state, high efficiency, and usually work in either direction. 24 to 12 or 12 to 24. I have one made by Solar Converters.
http://www.solarconverters.com/product_frame.html
Select Battery Equalizers/DC Autotransformers
Quote from: MountainDon on April 05, 2010, 12:53:13 AM
1. Run a center tap to take off 12 VDC with a hot wire tap. bad.
2. Use a 24 VDC to 12 VDC converter. They are solid state, high efficiency, and usually work in either direction. 24 to 12 or 12 to 24. I have one made by Solar Converters.
http://www.solarconverters.com/product_frame.html
Select Battery Equalizers/DC Autotransformers
Great! Thanks.
I'm thinking 24v might be better to use and have noticed some differences when using the calculator (which I found interesting).
My solar panels (by the way) will be 46 feet from the cabin when I plan to install the batteries (assuming I plan to put them where I've chosen). The well head is 125 feet from the solar panels and over 150 feet from the spot where the batteries should be.
My cistern is 446 feet from the cabin corner (24 feet from battery corner) and about 50-70 feet above the cabin in elevation.
I'm thinking that the 46 feet from the panels to the cabin won't be a problem for 24v given that yours are MUCH further away.
I have planned a 400 watt system but if finances allow I'll probably do 600 watts. If I did that I'd be running something like 54+vdc from the panels (3 in series) which again will have no problem with the 50 foot run I'm thinking.
I also plan to run 8 of the 220ah batteries.
With all my current calculations this is more then I need but I suspect that once we start using it we'll want more...we're human after all!
I also found some 60 watt CFL's that run about 12watts so that will help a bit too and I read that it's better to use more direct lighting to reduce the need for lots of overhead lighting.
My next thing to check is LED's. I might like to install some DC LED's in the kitchen and in areas where reading might be done.
The bathroom should have a fan too so I have to add that but all in all I think we'll have a great system
I have a wire size calc if you to run some numbers. Need max amps, distance, voltage.....
We have no ceiling lights at all, mostly table lamps with 23 watt CFL... 100 watt incan equiv
We have provision for bath fan, but no fan. Window opens.
I'm designing and installing my electrical and solar setup right now. I'm trying to work out what sort of panel to get - a "main lug" (without breakers on the power feed) or "main breaker" (with breakers). The feed to the panel will be protected already as there will be a pair of linked 30A two-pole breakers forming a transfer switch between the inverter and a direct generator feed. The cost difference isn't huge - I'm more worried about doing what's gonna work best and what the inspectors expect to see rather than saving $20.
"I'm thinking that the 46 feet from the panels to the cabin won't be a problem for 24v given that yours are MUCH further away."
My panels are 75 feet from the cabin, and it is a 12v system, but the inverter is in the power shed (panels being on the roof of the shed) and the cables from the panels to the inverter are only about 8' long.
I think where the distance issue comes up is with DC...not so much with AC....
Quote from: considerations on April 27, 2010, 07:26:30 AM
I think where the distance issue comes up is with DC...not so much with AC....
AC or DC does not matter.
Long wire runs become a concern with higher loads (amps or watts) running on low voltages. Powering a 1200 watt device on 12 volts, AC or DC, requires heavier wire than the same load on 240 volts, AC or DC.
Quote from: davidj on April 27, 2010, 12:31:15 AM
I'm more worried about doing what's gonna work best and what the inspectors expect to see rather than saving $20.
I like to think of the electrical as being made of two parts; the regular AC portion from the main service panel into the rest of the cabin/house and the alternative power portion. That would mean there should be an AC mains breaker in the main service panel.
We are finally nearing the point that we will be buying all of our solar power stuff and this is what I'm contemplating:
1 -- it is most likely we will use the cabin on weekends only with maybe 2 or 3 one week trips per year. Thus a large store of battery power may not be required. So 6 batteries should suffice if using the calculator is any indication.
2 -- 1500 watts is plenty of AC power for our application (I'm thinking 1000 watts would be adequate but couldn't find a decent inverter/charge in that range.
3 -- due to winter conditions and the possibility of low sun exposure due to trees and the north west climate (actually we probably get 275-300 days of sun there but it can also be cloudy for a while) and the desire to possibly run the well pump longer or use the heater on the composter 600 watts is more desirable then 400 watts -- this gives us better charging in low light conditions.
So this is what I am thinking of doing:
3 SUN A-200-fa3 (11.05imp) panels in series (600 Watts)
6 Costco 220ah Golf Cart batteries
SUN-1012 Sinewave Inverter (if it will work but I think it should)
http://sunelec.com/index.php?main_page=product_info&cPath=6_40&products_id=788
And the Xantrex C40 charge controller.
That puts me around $2000 :)
Something to keep in mind when designing the system, is that many of the electronics (inverter, DC-DC converters) consume electricity even if you are not applying them to a load.
Note the Sun 1012 inverter... it has a MAX efficiency of 85%. This is almost always calculated at full output power. So if you are using a full 1000 Watts, you are burning 150W just to run the inverter. Same with DC/DC converters. There is a quiescent power draw for all of these devices, even if you are not using the power that they are putting out.
If possible, find a way to supply power to these converters only when you need to use power. Many of them have an enable input that allows you to turn them on and off.
That inverter does have a Loading Sensing (Power Saving)mode listed in the specs. That means it can be set to put itself in a standby mode. What they do not list is the power used while in standby. They do list 150 to 220 watts next to the Loading Sensing (Power Saving) line. That seems to be very high. My Outback will do it's standby thing and be using 24 watts while waiting. It will sense down t0 something less than a 3 watt load to go out of standby to working. It would seem that the Loading Sensing (Power Saving) feature of the Sun may not be very useful.
It would be nice to be able to get a download of the manual someplace. Perhpas it would explain the Loading Sensing (Power Saving) better. Another thing that would be good to know is is there is a connection point to have a remote on-off switch for the inverter. I have one with the Outback and a cheap Cobra I used to have had provision for one as well, though I never used it.
It's nice to see the charger built in, but it would be nice to see if it was capable of equalizing. The spec sheet lists 2 modes, so I'd guess that could mean no equalizing, but that's a guess. . Again it would be nice to read a manual.
Quote from: MountainDon on May 11, 2010, 09:51:10 AM
That inverter does have a Loading Sensing (Power Saving)mode listed in the specs. That means it can be set to put itself in a standby mode. What they do not list is the power used while in standby. They do list 150 to 220 watts next to the Loading Sensing (Power Saving) line. That seems to be very high. My Outback will do it's standby thing and be using 24 watts while waiting. It will sense down t0 something less than a 3 watt load to go out of standby to working. It would seem that the Loading Sensing (Power Saving) feature of the Sun may not be very useful.
It would be nice to be able to get a download of the manual someplace. Perhpas it would explain the Loading Sensing (Power Saving) better. Another thing that would be good to know is is there is a connection point to have a remote on-off switch for the inverter. I have one with the Outback and a cheap Cobra I used to have had provision for one as well, though I never used it.
It's nice to see the charger built in, but it would be nice to see if it was capable of equalizing. The spec sheet lists 2 modes, so I'd guess that could mean no equalizing, but that's a guess. . Again it would be nice to read a manual.
I've requested more information. My thinking was that the cost is so much less then comparable inverters by Xantrex etc that it might be worth the expense to try it out and see how it lasts.
It's possible it will be junk and need to be replaced in a year or two but then who knows really and at about $500 cheaper.....
No reply -- I've had this problem before :( I hate it when people don't reply.
I'm trying to decide on what's the best way to connect my solar panels to my 12:12 standing seam (clip-style) metal roof.
The obvious way is to use the Unirac standing seam clips (http://www.unirac.com/pdf/ii220.pdf) but the guy who is selling me my system advised against them as they are fiddly to install. Given our 100psf snow loads, it also seems somewhat lightweight of a connection.
The alternative is to use a Unirac rail system (http://www.affordable-solar.com/unirac.smr.stuff.htm), which has L brackets to connect the rack to the roof (#6 on the diagram). Apparently I can just screw through the roof panels into the framing with lag screws and caulk (or butyl tape??) in the hole and under the bracket will make it waterproof. My worry here is that the movement of the metal during hot/cold cycles will lead to water leaking through the penetration and/or buckled roof panels.
Does anyone have any experience with either of these approaches? Any opinion on what would work best?
I meant to comment sooner but got side tracked.
Was eliminating all those holes that you'd have with a ribbed panel roof one of the reasons you selected standing seam metal? If so it seems a shame to drill even a few holes to mount the rail system. On the other hand there would not be many holes and the use of self sealing butyl tape would go a long way to help prevent problems. Fasteners with synthetic rubber washers tightened properly (= not too tight) are a must.
Another thought of mine. Panels need to be spaced high enough off the roofing to allow for good air circulation behind the panels. As the panel temperature rises their output falls. Most panels manufacturers should be able to supply that info. It becomes even more important to ventilate the panels properly in warmer/hotter climates. Almost any knid of a roof will radiate a lot of heat around the panels elevating the local microclimate temperature.
The panels, being dark colored, get hot anyways. Restricted air circulation can make that worse. On a bright sunny day the panels can get hot enough to be uncomfortable to touch.
Something to keep in mind..
(someplace I have (had?) the typical highest temp a panel in full sun can reach on a roof. It's higher than one might think. I can't find it though. ???
Come-on Don! Tell him to put them on a top of pole mount and be done with it! It is the only sane way short of what the trogledite did. d*
Yeah Dave, poles are actually king in my book. :D I was thinking of expanding on the original thoughts, but I was rushed and concerned my response with the original roof question. I do like poles a lot more than roofs though, for PV panels, no doubt on that.
No scrambling on the roof required.
No penetration problems (with the roof)
Excellent circulation of air around panels.
Easy to adjust the angle, see my quickee adjuster with the month positions marked.
http://countryplans.com/smf/index.php?topic=2335.msg97225#msg97225 (http://countryplans.com/smf/index.php?topic=2335.msg97225#msg97225) scroll down one image
I am happy with the way that turned out. 1x1, 11 gauge (1/8" for those who don't do metal gauges) steel tubing
Easy to adjust left-right to pick the best sun orientation line.
On roof panels seldom have perfect sun orientation lines.
Easier to clean when necessary. I have a long handled (extended with PVC pipe) broom and a long handled mop.
Buy old drill pipe. I got 4" ID 1/4 inch wall quite cheaply, compared to new. THe Uni-Rac mount is sturdy and well made, easy to mount the panels to. I added my brace arm for two reasons, ease of adjustment to as a wind brace.
Personally, I would not want to have to access panels, or anything else, on a 12:12 roof if I didn't absolutely need to. As a last factor, a special GFCI may be code required for panels on a metal roof. Not sure if that in for Grid Tied only or if for Off Grid as well? I'd have to check in that.
Ground level racks are also usable in some place.
Dave knows a little bit about solar. ;) http://www.sierratel.com/offgridsolar/ (http://www.sierratel.com/offgridsolar/)
In retrospect, pole mount sounds good. Or, more to the point, working on a 12:12 roof sounds anything but good! Unfortunately I've got a lot of 100ft high trees on my lot and only two open areas - one where I put the house (positioned so the S facing roof gets the most Sun!) and one 200ft from the house right on the road (if you can call our dirt track a road). I guess I could put something by the road, but it would definitely distract from the otherwise wilderness feel of the approach (and would be more likely to be stolen). Cutting down trees is also an option, but it would be hard to clear out enough space without changing the feel of the lot.
A pole-mounted system would also need to be pretty solid (or very easy to tilt) as we get a lot of snow (100 psf snow load).
Re the thermal issues - I'd think there should be pretty good circulation thanks to convection on a 12:12 roof. There has to be at least an inch of space due to the seams, and there should be plenty of temperature differentials to get air moving. And the roof itself has an inch of ventilation underneath it too.
I was planning on using a GFCI on the panels as my supplier (Sierra Solar - very helpful company) said that I'd need one.
Quote from: davidj on May 18, 2010, 04:05:37 PM
Unfortunately I've got a lot of 100ft high trees on my lot and only two open areas - one where I put the house (positioned so the S facing roof gets the most Sun!) and one 200ft from the house right on the road
Trees up to 75 feet with us. Same sort of situation. That's why our cabin is where it is and the panels where they are; 300 feet away. Works well, but it needed all that copper wire (#2AWG) and conduit.
The Uni-Rack site gives wind loads on their model of racks, not sure about snow. The panels would have to be raised enough to allow for clearance height with all the snow that slides off. Our experience has been that the snow has little problem sliding once the sun comes out. If we;re there at the snow time I usually snowshoe down to them and brush them off. I keep the broom and washers tied vertically to a nearby tree rather on the ground so I can find them in winter.
I'm spitballin the idea of setting a solar array on my vacant property ( currently structureless).
Will I first have to connect to the "grid" utility company?
If I did this, would I be able to sell electricity back to the utility company for cash? Or would they simply issue credits to an existing account.. am I making sense?
If your possible building plans include being grid tied you should check with the local power company before doing anything. The power company we use at home has a great plan for grid tied residential customers. With them it's possible to select from a plan that just gives credits to your account when you produce more than you use. They have another plan where they will pay credits by monthly check. The company we could connect up in the mountains by the cabin has no such buy back offerings at all at this point. So it not only varies state to state, but it varies company by company.
Being grid tied can save you the cost of the batteries needed to be fully off grid. That has the drawback of leaving you in the dark when their side fails.
Note that even if your location is remote enough to be lenient on building codes, or maybe no codes at all, if you connect to a power grid, they will almost certainly have rules that need to be met, including minimum equipment standards. They may also require a professional electrician for part or all of the PV installation and actual grid connecting.
I did not know about the minimum standards, rather; never considered it. Sounds like a permit may be in the future. I'm a pole away from power. Can I get power dropped to my parcel, (without ant site plan or building plans?)say to use for temporary 3-4 weeks stays in a travel trailer. I could always boondock
Once again that is sometimes a local thing. To get a permanent hookup here in the suburban area one needs a building permit first. But up in some more rural areas here you can get a power pole and meter by simply asking and paying for it. There will likely be a monthly fee, just for being connected, even if you do not use power. Ask on that. If they have a good buy back PV program the energy made when you are not there could pay for that and leave money left over. But as I pointed out the way the companies do that is all over the place, good to bad and worse.
G/L It would be nice to have checks coming in the mail when you aren't there. :)
Checks coming in the mail when I'm not there would be ideal. I'm doing a recon trip out there in July.
If you know the name of the power company you might be able to find all the info online. My city company has everything available online, all the rules and docs that are needed. Then again the mountain coop has nothing.
That was my heading: online search, phone calls and documentation. The July trip is for information gathering from a real world perspective. I like to be hands on and meet/greet as many people on the mountain as possible. The owners behind my parcel have spent considerable time clearing deadfall,etc. I want to meet them. I also discovered 2 lots with driveway, septic and electric for sale on my road. FWIW- one piece or land for sale has the drive, septic and electric with a log home kit bundled and sitting there. It's been like that for at least 2 years- the bundles of precut ready to go logs laying on the property at 10,000ft-snow, and all the elements. I actually remember seeing this debacle in the summer of '07 so that's pushing 3 years. What a shame.
Hope this is the right thread for this.
We plan to start a 20'x32' cabin this summer. The first task is to build a 10x12 shed to camp in and store materials and tools. We will eventually have solar power and the solar panels will either be on the shed roof or next to it. The shed is directly behind and to the north of the cabin. Both the shed and the cabin will have have their roof ridge oriented east/west.
We are at ~43.5deg lat. Our sun altitude alternates between 23deg and 70deg. I need to make sure that the solar panels on the shed roof will not be in the shadow of the cabin. I need the angle A between the ridge of the cabin and the eve of the shed to be less than 23deg. Any more than that and the solar panels will be in the shadow of the cabin in the winter.
![](http://lh6.ggpht.com/_YXA0QhaNyCg/S_YPixwg6TI/AAAAAAAAD2c/5EfZ0sQHyf0/s800/SunAngleCalc.JPG)
First a few numbers to work with:
Cabin to Shed Distance 33ft.
Cabin Depth to Roof Ridge 10ft.
Cabin Base Elevation 0ft.
Shed Base Elevation 3ft.
Cabin Max Height 24ft.
Shed Height to Eve 10ft.
We can use a little trigonometry to find the angle A between the cabin roof line and the shed eve. The tangent of an angle is defined as the opposite side divided by the adjacent side.
Op---- = tan(A) The inverse tangent or arctangent will give us the angle A which is the slope from the cabin ridge to the shed eve.
AdjThe cabin height is the base cabin elevation + the max cabin height or 0 + 24 = 24
The height of the shed eve is the base shed elevation + the shed height to the eve or 3 + 10 = 13
The
Opposite side is the difference between these two or 24 - 13 = 11
The distance between the ridge line of the cabin and the shed is the distance between the shed and the cabin + the cabin depth to the roof ridge or 33 + 10 = 43. This is the
Adjacent side of the triangle. Now reach for a calculator with trig functions or find a web calculator.
11
--- = tan(A) = 0.255814 The arctangent or inverse tangent of 0.255814 is atan(0.2555814) = 14.34 deg.
43
14.34 deg is less than the minimum winter sun angle of 23 deg at my location so I don't have to worry about a shadow on my solar panels in the winter.
Hope this might help someone with a similar situation. It should be useful if you have a cabin or trees due south of your solar panels.
Mike,
That was a nice post and I am sure helpful. One of the other ways is basically using posts and being at the site during the winter solstice. Kind of the no math version. I think it is best to always live thru a year at the site! It is amazing how many different things will occur to one. Hey Don! c* What time is happyhour?
Oh yea, the reason I posted was to tell you guy's that some of these long runs of cable we have to do, will be getting easier. Magnum energy has a 250V charge controller out this summer and there is another that I can't talk about that will enable some very, very long runs with small wire.
That's cool. Good of you to share this trig lesson. It goes to show there are good reasons to pay attention in class. :D
I've done due diligence part 1. Contacted county planning, power company and mapping. Seems like the bottom line is to get power on my property I need a rought site plan, driveway, septic and well and an engineer to coordinate all. Sine the lots is less that 2 acre it need to be wetlands free. What I did not ask was if I could get power dropped to the lot for use with a travel trailer- yikes! I want to be able to use my place sooner than later. It may be 5-7 years before I have the financial bump ++ to get a permanent structure built. I was considering extended stays. The solar was a way to maybe get cash when I am not present.
Quote from: MikeOnBike on May 21, 2010, 12:54:52 AM
14.34 deg is less than the minimum winter sun angle of 23 deg at my location so I don't have to worry about a shadow on my solar panels in the winter.
I was just thinking about similar things myself. One thing to watch out for with this calculation - you need to have an angle that's quite a bit less than 23 degrees (as you have), otherwise you'll get Sun in the middle of the day but only for a minute or two!
We're at a latitude of about 39.5 degrees north, so I think the Sun gets up to more like 27-28 degrees mid winter. Looking at some graphs (http://www.gaisma.com/en/location/reno-nevada.html) I found on google, if you have a 20 degree vertical angle to an obstruction, with at least 30 degrees each way horizontally to the SE and SW, then you get Sun from 2 hours before midday to 2 hours after. It looks like this'll probably cover almost all of the solar energy you're gonna get at that time of year. Time to get out the inclinometer I bought from John (http://www.jshow.com/sunkit/listings/7.html), stand on top of a step ladder and see if Don's suggestion of pole mount panels is gonna work...
David, you have a good point. My model is a fairly simple representation. It does not consider the varying angle of the sun from sunrise to sunset. It is only 2 dimensional, a snapshot in time.
If we use the middle 5 hours of the day, the sun at our site alternates between 15 deg. and 23 deg. I can probably get by with making sure the angle between the cabin ridge and the shed eve is at least 15 deg.
Since the angle in my example is 14.34 I will just barely be clipping the panels with a shadow during that 5 hour window. At my site the 4 hour window that you suggest is 18 deg. so that period would be shadow free.
Having considered my dilema of the well being located too far from where I plan to install my battery bank (about 150 feet) I've thought seriously about buying a Costo 60 watt system which includes 4 15w panels, a 7am charge controller and 200 watt inverter. It's $269 and a deep cycle Marine battery with 85 amp hours of reserve runs about $62.
My thought is that I can install this system on the small pump house I plan to build and put a switch in it so I can turn on the pump easily (today I have to clamp the battery to the pump using the alligator clamps coming out of the well head).
What do you all think?
I plan a 600 watt solar system for the cabin with 1000 watt inverter but thought perhaps this would be a good second system for the pump and perhaps someday a small shed can be put there also with some lights running off the inverter (or 12v). Also I was thinking I could use the inverter to charge my Ryobi drill batteries.
Thoughts?
OK I took the plunge and bought the Costco system and a Deep Cycle 12v battery (85 AH) for the well. Once home I tested it all out and found each panel kicked out ~20-22 vdc and the Charge controller ran about 20vdc (it tells you 5-10% of panel output). The panels are in parallel and produce a combined 60 watts in optimal conditions according to the booklet that comes with it.
I hooked up the battery which was running ~12.5v and in about an hour the controller kicked off. Which, according to the booklet happens at 14.2v.
When we get to the property I'll build a small pump house to house the battery and controller as well as the inverter and set up a station to charge a second 12v battery (I like a back up battery and keep my old jeep battery for the well) and a station fore the Ryobi charger (need to check wattage).
I'll let you know how this works out for us but I'm hopeful we can run the well pump at least a couple hours a day and not have to use the generator any longer to charge a battery to pump.
We used to run a trickle charger (2amp) during the day while working on the cabin and then hook it up for a few hours (the battery) on the well -- then repeat in a couple days.
This last time we got busy and forgot to charge the battery for the well and the cistern ran pretty low (pressure at the spicket was way down)...so I need to get 1000 gallons (or close to it) back into the cistern and keep it up there for the summer months of cabin work.
It's VERY nice having ice cold water in the summer!
This investment was ~$330 and I'm hopeful in the end that it will save generator usage and gas as well as the need to plumb electric from the cabin solar (12vdc) to the well.
OlJarhead,
I'm really interested in how this works for you. I have a similar situation. Our main cabin's solar/battery is about 250ft from the spring. I was thinking about the same kind of setup you are using.
We will have three cabins on our property. Mine is the furthest and highest elevation gain from the spring. I'm about 1200ft. away and 150ft. above the spring.
I'm considering this pump to give me a couple of gallons/min to fill the water tanks in each cabin.
Solar Pump
http://www.firemountainsolar.com/waterpumps.html#solarslowpump (http://www.firemountainsolar.com/waterpumps.html#solarslowpump)
Elevation/GPM Chart
http://www.firemountainsolar.com/pdf/solarslowpump.pdf (http://www.firemountainsolar.com/pdf/solarslowpump.pdf)
Quote from: davidj on May 18, 2010, 04:05:37 PM
In retrospect, pole mount sounds good. Or, more to the point, working on a 12:12 roof sounds anything but good! Unfortunately I've got a lot of 100ft high trees on my lot and only two open areas - one where I put the house (positioned so the S facing roof gets the most Sun!) and one 200ft from the house right on the road (if you can call our dirt track a road). I guess I could put something by the road, but it would definitely distract from the otherwise wilderness feel of the approach (and would be more likely to be stolen). Cutting down trees is also an option, but it would be hard to clear out enough space without changing the feel of the lot.
After wandering around the lot for a while I've found a point by the driveway that's a fair distance from the "road" and that has a decent view of the Southern sky. The trees to the South are about 25 degrees above the horizon, so it's not gonna get much sun December and January, but I guess that's what backup generators are for. What's more I can put the generator/inverter shed and propane tank near by, and run LPG and 240V side by side for the 200' to the cabin.
This is good news, as I thought my cabin was facing almost South, but it turns out it's facing roughly magnetic South, not true South. What's more it's the wrong side of magnetic South too, so it's almost 25 degrees off. I guess it's a good idea to check the magnetic declination before you have the whole cabin built....
So goodbye scary chicken ladders and fussy roof clips, hello solid and dependable schedule 80 steel tube.
Now all I need to do is find out how much pole and concrete I need to hold up 50 sq ft of panel centered 10ft off the ground in a fashion that the building inspectors don't object to and the snow won't destroy...
Quote from: davidj on June 15, 2010, 01:29:13 AM
Now all I need to do is find out how much pole and concrete I need to hold up 50 sq ft of panel centered 10ft off the ground in a fashion that the building inspectors don't object to and the snow won't destroy...
UniRac, manufacturer of pole mounts and so forth, has info on pole sizes, depths, etc for various combinations of panels and expected wind loads. Sorry, I have no link at hand but have a printed brochure someplace. Google UniRac Albuquerque
I have been watching this topic for guite a while. And it has accured to me that you could build a coverd patio/out door kitchen ect. with a shade made from solar panels. Not protected from rain but protected from the sun, should work well.
Sure. The Intel Fab here has an array that is the shade roof for parked cars, I believe.
(They have it I'm not sure on the parked cars.... Car shades are common in the SW)
Quote from: MikeOnBike on June 14, 2010, 11:47:42 PM
OlJarhead,
I'm really interested in how this works for you. I have a similar situation. Our main cabin's solar/battery is about 250ft from the spring. I was thinking about the same kind of setup you are using.
We will have three cabins on our property. Mine is the furthest and highest elevation gain from the spring. I'm about 1200ft. away and 150ft. above the spring.
I'm considering this pump to give me a couple of gallons/min to fill the water tanks in each cabin.
Solar Pump
http://www.firemountainsolar.com/waterpumps.html#solarslowpump (http://www.firemountainsolar.com/waterpumps.html#solarslowpump)
Elevation/GPM Chart
http://www.firemountainsolar.com/pdf/solarslowpump.pdf (http://www.firemountainsolar.com/pdf/solarslowpump.pdf)
Just got in but the first trial has been a good one, albeit a learning one!
First off, it rained almost the entire time! I'm not sure how much that hurts solar panels but I DO know that it's a calculation that you must take into account when designing a system. Cloud cover means poor performance.
So, having experienced rapid charging in full sunlight (rapid is a subjective term of course) I was surprised at how slowly the panels charged the battery in cloudy rainy weather. But not really ;) I was actually surprised how well they did despite the clouds though I did move them to track the sun to maximize the solar power generation.
I hooked up the 85ah deep cycle battery to the well when we arrived and began pumping water right away. Once we had 26 gallons in the tent trailer I let the pump run until the battery dropped (without panels) to 12.3v. I then shut it down.
The next day I assembled the panels and let the battery charge to 12.9v by making 3 adjustments to the panels -- 7:30am they faced East (to catch the morning sun) and by about 1PM I faced them South and finally around 5PM I faced them West -- however, it was raining and pretty dark with clouds most days.
I pumped the well enough to drive the battery down to 12.3v again on Wednesday and it really down-poured! The weather was foul but the battery seemed to almost hold under the strain as long as the panels faced the sun.
Thursday after letting the battery hit 12.9v again I let the well pump and drive it down to 12.4v again then disconnected it. I did notice however, that in light clouds and almost sunlight the battery hovered around 12.4v as long as on the charge and didn't seem to drop lower.
On Friday the sun poked out a little more and the battery climbed about 13v for the first time :D It was working! I pumped more water and continued to track the sun with the panels.
I've now decided that a lazy susan would be a good way to track the sun -- just assemble on big enough to sit on top of a well house and then rotate it during the day to catch the sun...after all, why spend $1000 on a tracking pole for a $269 set of panels?
All in all I'm impressed with how well they worked and am certain that if the sun were out all day I'd have a full cistern. As it is it rained so much that when the sun finally did come out it was nearly a shock! Most days were in the 50's (is this really June?) and very cloudy and wet.
Last night it dropped to about 39 degrees and was clear....and we came home today.
Quote from: Bob S. on June 17, 2010, 10:02:02 PM
I have been watching this topic for guite a while. And it has accured to me that you could build a coverd patio/out door kitchen ect. with a shade made from solar panels. Not protected from rain but protected from the sun, should work well.
This was actually our second-from-last plan - a "solar gazebo". I was gonna build a timber-frame 10'x12'x10' structure, put a steel tube across the middle of it and mount a tiltable panel. In Summer we'd drop the panel flat and put the picnic table under it. In winter we'd rotate it near vertical and it would catch the low Sun and shed snow (and not be in the way at that time of year - "hanging out in the yard" isn't really gonna happen when there's 4' of snow on the ground!). It all fell apart when I realized that "cabin South" and "true South" were actually 25 degrees off from each other and hence it wouldn't get as much Sun as I'd hoped.
The Sierra Nevada brewery in Chico also has a parking lot shade structure made of solar panels. But I prefer their "recycling" - the brewing mash gets sent to a local cattle farm in exchange for (very tasty) steaks which they server at the restaurant!
http://www.theinverterstore.com/the-inverter-store-product.php?model=pwric150012s#
Found this today and wanted input. It's a little more then the inverter/charger I found on the sun site but this one has more information on it and is a 1500 watt inverter.
SunElectric tells me they will remove the batteries and inverter from the 615 watt system and sell it as a package including discount.
That system is so close to what I am building that I'm thinking it might work for me. Then I go get the Costco batteries and a different inverter and I'm in business :)
We're so close to making this buy that my fingers are getting itchy!
Quote from: OlJarhead on June 22, 2010, 06:16:06 PM
SunElectric tells me they will remove the batteries and inverter from the 615 watt system and sell it as a package including discount.
That system is so close to what I am building that I'm thinking it might work for me. Then I go get the Costco batteries and a different inverter and I'm in business :)
We're so close to making this buy that my fingers are getting itchy!
I should note that I'd like the Xantrex inverter but can't afford it. Perhaps someday I can afford a much better inverter but with me not working I've got to be cautious of the bills in order to complete the cabin. So I'm looking at saving $300-$400 on the inverter with the hopes of someday getting a True Sine wave inverter in the future (when I get work etc).
In the meantime, this package is basically what I had been trying to put together to begin with so it might work out. I don't save much money on doing cables myself but hey, every little bit counts! The only other area might be the boxes?? I've been looking at Home Depot and wondering if I could make some of the Square D's do the job. Would save me a couple hundred if I can I'm sure.
Ok Here goes! I hope I've not beed too rash!!!! But I was convinced to go a different route on my inverter/charger and decided it made sense. Not being an electrician I'm not 100% certain but it seemed like a good idea...so here goes:
55 AMP Charger: http://www.theinverterstore.com/the-inverter-store-product.php?model=chg-dls-55
2500 watt Modified Sinewave inverter: http://www.theinverterstore.com/the-inverter-store-product.php?model=pwrinv2500w-top-rgb
The thinking is that lower priced inverter/chargers often only have 3amp chargers which could take a week to charge up a 660ah battery bank (assuming the math is close to 660/3 and the batteries are basically dead and you've got 220 hours of charging to do :o ??? ) on the other hand this charger gives 55amps and should do the same job in 12 hours....my thinking is that I don't mind running the genny for 3-6 hours at a time if I have to but don't want to rely on it for days on end just to have to do it all over again in 3 days if the weather is bad!
The inverter is modified sine wave but with 2500 watts is more power then I felt I needed. On the other-hand it's got a lot of features and apparently AIM has been making them for over 10 years....let's hope I don't need the 1 yr warranty :P But honestly, at $229 if it doesn't work out I can take a look at a xantrex with no charger on it in the future :)
I also ordered 3 205watt panels from Sun Electric plus boxes, lightning arrestor, breakers and some cables.
Next I'll get the batteries from Costco and make the battery cables and get with a friend to plan, prewire what we can, plan some more and then hopefully by the end of July we will be powered at the cabin! :D [cool]
Quote from: OlJarhead on June 23, 2010, 03:39:11 PM
55 AMP Charger: http://www.theinverterstore.com/the-inverter-store-product.php?model=chg-dls-55
I have had that exact charger for several years in the RV. I bought the optional IQ Smart controller for it. That allows the unit to switch between two rates of charge automatically. There's a plug/jack on the charger that allows one to change the rate manually. The only thing that charger does not do is an equalization charge. It's a well made unit. Mine was made in AZ, I think they still are.
http://www.iotaengineering.com/ (http://www.iotaengineering.com/)
Quote from: MountainDon on June 25, 2010, 01:14:33 PM
Quote from: OlJarhead on June 23, 2010, 03:39:11 PM
55 AMP Charger: http://www.theinverterstore.com/the-inverter-store-product.php?model=chg-dls-55
I have had that exact charger for several years in the RV. I bought the optional IQ Smart controller for it. That allows the unit to switch between two rates of charge automatically. There's a plug/jack on the charger that allows one to change the rate manually. The only thing that charger does not do is an equalization charge. It's a well made unit. Mine was made in AZ, I think they still are.
http://www.iotaengineering.com/ (http://www.iotaengineering.com/)
Cool :) The one I bought appears to have a controller in it which allows it to adjust the charging rate from a bare trickle to full 55amps automatically. So perhaps an updated version?
Either way it sounds like I've learned a thing or two from you Don! hehe even if subliminally!
Erik
Yes, they sell a model with the IQ built in.
Just a side note; same outputl Iota chargers can be paralleled to double the current output. They sell a plug in controller for that.
The Iota people were very helpful when I had several questions a few years back.
Make sure to check the operating temperature range on your inverter!
Quote from: NM_Shooter on June 25, 2010, 04:31:15 PM
Make sure to check the operating temperature range on your inverter!
![](https://i998.photobucket.com/albums/af102/emcvay/Cabin/InverterandCharger.jpg)
I'll go check but I thought it was something pretty extreme on both sides of the fence.
Quote# No load minimum operating temperature: -15 degrees Celsius
# Full load maximum operating temperature: 55 +/- 5 degrees Celsius (automatic shutdown)
The books says 30 degrees F to 150 F operating range.
Kinda surprising because running below 30 degrees will just keep it cooler. Not sure why they would suggest that actually - though laptops have issues down there but that's more of a Hard Drive thing I suspect.
It sounds like I should probably install this in the wall below the service panel INSIDE the cabin. I can bring in the battery cables to a Square D or similar box (cheapest one I can find) which I can insulate the back of with fiberglass and/or foam and then run from there to the service panel above it.
That leaves the Charger and batteries in the battery box outside.
Has the added benefit of making it harder to steal the inverter.
Just a comment about batteries. I just went through the spaghetti lines and checked all of my battery cells for specific gravity. A good indication of bad cells.
About 6 months ago when refilling the batteries water I added EDTA - I found it at a chemical supply for mining and had read that it would chemically desulfate with some pretty good testing that I posted somewhere here earlier.
To my surprise, nearly all of the cells aside from 2 bad batteries, were over 1300 - top of the scale - and that has never happened before. I had one marginal one - added EDTA and threw threw pulse charger onto it - it also came up to over 1300. I have two that seem to have shorted cells, but not bad out of 12 batteries dating back to 2004.
I swapped out batteries to get 8 good ones running together - two sets of 4, and even using extra pumping, my power is better at night than it has been in ages. I also have 8 new batteries in another bank so running 16 batteries - L16's right now.
Went through my system today and did some diagrams etc but one thing I have to figure out still is where to install the Iota Battery charger (55a)? I'm assuming that I can't run it in parallel with the solar power so need to figure out how to disco the solar when running the genny and Iota charger.
Otherwise, I'm pretty good to go :) The 10amp cables I bought will be within spec for a 45 foot run from the panels to the PV box which will be mounted next to the load control box (not sure if that is what it's called -- it's the one with the main disconnect and connections to charge controller and inverter).
I'm planning something similar to what Don put in.
I'm also looking at installing the panels in a fixed installation until I can afford something else. So, here is my thought:
Build Carport Roof over Camper that we use on the Property and install Solar panels on a steel frame that I can tilt between 63 degrees in the summer and 33 degrees in the winter (we are at 48 degrees latitude and I read somewhere that you can add 15 degrees in the summer for more efficiency and subtract 15 degrees in the winter). My thinking is to install two different length 'legs' to the top of the panel rack and stack the panels one above the other (so three panels laying sideways -- I'll draw it).
I'm hoping this will have the added benifit of being somewhat secure and even hidden a little from view at ground level).
I just hook it to the + and - of the batteries, OJ.
As long as you are using a proper charger the other stuff should take care of itself, just as multiple charging sources - wind , more separate solar etc. can be hooked to the batteries.
Now I use a welder for a charger - running 160 amps sometimes - haven't blown anything yet but I try to be careful and keep my overcurrent device handy.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/overcurrentdevice.jpg)
That should be steeper in the winter as the sun is lower - I guess that depends on where you are measuring your angle from. About 45 degrees works pretty well for fixed.
Quote from: OlJarhead on July 11, 2010, 10:24:04 PM
I'm also looking at installing the panels in a fixed installation until I can afford something else. So, here is my thought:
Build Carport Roof over Camper that we use on the Property and install Solar panels on a steel frame that I can tilt between 63 degrees in the summer and 33 degrees in the winter (we are at 48 degrees latitude and I read somewhere that you can add 15 degrees in the summer for more efficiency and subtract 15 degrees in the winter). My thinking is to install two different length 'legs' to the top of the panel rack and stack the panels one above the other (so three panels laying sideways -- I'll draw it).
I'm hoping this will have the added benifit of being somewhat secure and even hidden a little from view at ground level).
Got them backwards. 63 degrees in Winter and 33 Degrees in Summer.
Quote from: glenn kangiser on July 11, 2010, 10:26:43 PM
I just hook it to the + and - of the batteries, OJ.
As long as you are using a proper charger the other stuff should take care of itself, just as multiple charging sources - wind , more separate solar etc. can be hooked to the batteries.
Now I use a welder for a charger - running 160 amps sometimes - haven't blown anything yet but I try to be careful and keep my overcurrent device handy.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/overcurrentdevice.jpg)
That should be steeper in the winter as the sun is lower - I guess that depends on where you are measuring your angle from. About 45 degrees works pretty well for fixed.
So you just connected your charger straight to the battery buss? Thinking about this I'm wondering if when you begin charging the Xantrex C40 detects that the batteries are 'charged' and backs off? Also the Xantrex is supposed to be able to protect the panels from power being backfed into them at night...I'm wondering if that works the same way when the charger is on?
I saw this today: http://www.interlockkit.com/squareDmain01.htm -- seems like it's $150 for a $5 part??? Probably approved by some bureaucrat but I'm thinking I could make the same thing for a few bucks...anyone make there own?
I called Xantrex customer support and this is what I was told:
"The Xantrex C40 Charge Controller will sense the voltage of the buss at 13.6vdc (supplied by the Iota) and shut down charging from the Solar Array as it will detect a 'fully charged' condition. It should be fine in this application and I don't see any reason it would be damaged."
So seems like Glenns idea will work nicely :)
I may toss in a break (60amp ought to do it I think) for the Iota charger so I can disconnect it positively when not in use but otherwise I think directly wiring to the battery bank is the answer! WhooHoo!
Now to get some wire, some batteries and start powering our cabin....oh wait, first things first, Chimney, Roof, siding and wiring THEN bring the solar and install....*chuckle* if I could do it all in one week I'd so be there!
The DC current can makea much longer arc than an AC current normally would hence only a few of the smaller AC breakers work on lower DC loads. So therefore the higher price tag for the breakers. There are some battery disconnect switches that may not be approved for solar but would be effective to their rated amp level - not automatic though.
I have been doing the welder charging in conjunction with the inverter charger for around 6 years now - many of the same 2004 batteries still in my bank - I haven't blown them yet.
Glen is right, of coarse! The DC arc also tends to burn thru the contact much faster! An AC arc is reversing polarity and the contact area can be smaller and of a lower quality alloy. The Square D type QOU line is what you want for low voltage solar. It has a din rail mount to allow you to fabricate your own panel or modify an existing. They also have wiring set screws on both input and output. They are harder to find than the type QO. There are series tricks for QOU's to get them over 100vdc also.
It hurts to hear about "blowing batteries" but you are that kind of guy! How about the inverters Glen? They are getting harder to fix (no parts) My repair guy in Oakland retired so I am looking for spare SW's. A replacement XW is near $3K now. It is all I would use though if pushed that way.
I haven't had any problem with the inverters at all, Dave, but in constant current, the welder voltage drops to some rate near but above the batteries. 24v systems and DC welders (on Constant Current) are a pretty good match. The massive amount of batteries buffer the charge current from the welder protecting the inverters. The problem with the DC welder is that it is not a tapering charge thus as the batteries continue to come up in charge, the welder still keeps pumping full amps into them therefore I monitor the charge on meters and only do it when I am there to monitor them.
There is a DC, Constant Voltage mode but it is a bit more scary as if the batteries are low it could put up to 300 amps into the batteries as the amps go full blast to bring up the voltage. I prefer CC and have spent a lot of time monitoring with meters to learn how to do it. I started around 60 amps and worked my way up to what I feel is a good combo of Inverter charger to provide tapering charge and welder at 160 amps for horsepower in bulk charging. Use meters and understand the system and what you are doing if you are dumb enough to try to do what I am doing...... By that I do not mean to imply anyone is dumb.... I mean that a screw up could have serious consequences even for me...... [ouch] :)
Without a pretty good knowledge of what is going on and what you are doing I am afraid I would have to say, Don't try this at home, kids...... [waiting]
Considering that I am charging 16 - L16 batteries, I have a bit of room to play. To equalize I am planning to disconnect sets of batteries and do them offline. Sparks are a big no-no around heavily charging batteries. They could fly all over spewing sulfuric acid and plastic shrapnel on anything within reach of their hydrogen/oxygen explosion.
I haven't screwed up and blown anything up on my system that I recall, but I do take great care to keep sparks away from the batteries. Connections are done at the other end of the cables away from the batteries.
![](https://i998.photobucket.com/albums/af102/emcvay/CabinSolar.jpg)
This is my proposed cabin solar power system.
Thoughts?
Note: Done in visio, the bus bars don't show actual connections.
Nice job -I was too cheap to buy Visio- :)
A couple things come to mind - make sure the charge controller you get is capable of taking the higher voltage from the panels and dropping it to 12 volts - not all controllers will do that. BZ MPPT will.
Some of the automotive modified sine wave inverters commonly only last about a year -
Possibly a Harbor Freight one with their added warranty could be a solution as I have had them fail in less than a year and some don't fail. [ouch]
If spending more then a good name brand inverter is best for reliability.
I only use sine wave inverters for the house and limit modified sine (really modified square wave) to automotive and field power uses. I have blown up a lot of things that don't like modified (square) wave.
Quote from: glenn kangiser on July 24, 2010, 07:43:04 PM
Nice job -I was too cheap to buy Visio- :)
A couple things come to mind - make sure the charge controller you get is capable of taking the higher voltage from the panels and dropping it to 12 volts - not all controllers will do that. BZ MPPT will.
Some of the automotive modified sine wave inverters commonly only last about a year -
Possibly a Harbor Freight one with their added warranty could be a solution as I have had them fail in less than a year and some don't fail. [ouch]
If spending more then a good name brand inverter is best for reliability.
I only use sine wave inverters for the house and limit modified sine (really modified square wave) to automotive and field power uses. I have blown up a lot of things that don't like modified (square) wave.
Visio was a perk from my work :) I didn't have to pay for it! Or I wouldn't have it.
The Xantrex C40 is rated to take up to 125 volts in and kick out 12/24/48 as desired :) Xantrex tells it's the right one for the job and will shutdown during auxiliary charging off the Iota.
I'd like a True Sine inverter but cost was a factor so I went with the AIM (American Inverter Manufacturing I believe) -- they tell me that's all they do but I don't recall the warranty. However, for $200 I figure it ought to do -- one thing I wonder about is whether CFL bulbs will be OK with Modified wave? They don't like dimmers and I wonder if the square wave might blow them -- guess I'll find out!
I mostly only intend to run small appliances (TV radio maybe a toaster) on it. My neighbor runs Modified (has for 30 years) and tells me it will run a fridge and freezer and small MW but the MW will run slowly....if it gets me by until I can afford a True Sine Wave inverter I'll get a Xantrex probably :)
Got my batteries and was hoping you could tell me what you used to recondition yours (I know it's in here somewhere)....
I have a pulsing charger that will recondition them if they are not too bad.
Best thing I did I think was to use EDTA to chemically break down sulfation. There are methods draining - charging and refilling them, EDTA added in the make up water was enough to bring them back decent.
I think the Xantrex charge regulator is already a pulsing charger so it should work with the EDTA to stop sulfation. I have a C40 but have not checked the input specs on it - got it before I studied up and added MPPT controllers.
My batteries from 2004 have been on the C40 since that time. Most of them are still alive and well.
One thing I do know about the C40 is that it does have an equalization mode that is pretty decent so when you want to equalize at a higher voltage, set it to equalize and tune up the batteries.
Quote from: glenn kangiser on July 24, 2010, 08:48:04 PM
I have a pulsing charger that will recondition them if they are not too bad.
Best thing I did I think was to use EDTA to chemically break down sulfation. There are methods draining - charging and refilling them, EDTA added in the make up water was enough to bring them back decent.
I think the Xantrex charge regulator is already a pulsing charger so it should work with the EDTA to stop sulfation. I have a C40 but have not checked the input specs on it - got it before I studied up and added MPPT controllers.
My batteries from 2004 have been on the C40 since that time. Most of them are still alive and well.
One thing I do know about the C40 is that it does have an equalization mode that is pretty decent so when you want to equalize at a higher voltage, set it to equalize and tune up the batteries.
Thanks -- do you wait a few years to ad the EDTA to bring them back or is it something you run all the time now?
I just added it this year with my oldest batteries being from 2004. I lost one from 2004 and one from 2005 I think. Possibly a bit of EDTA added earlier may have prevented that loss. The two had shorted cells and I haven't recovered them - but I just pulled them out of the lineup, and haven't tried to do any more serious work with them.
I left the EDTA in them once I added some. I put a couple tablespoons in a gallon of water and just used it to replace water as the batteries needed it. I went back to normal rainwater or distilled water after that except if a cell still showed signs of low specific gravity then it got another dose of EDTA water added. I monitor battery condition with the hydrometer and that is when I found that the EDTA had improved the batteries. I had never seen the specific gravity that high consistently before the EDTA.
Quote from: glenn kangiser on July 25, 2010, 10:50:58 AM
I just added it this year with my oldest batteries being from 2004. I lost one from 2004 and one from 2005 I think. Possibly a bit of EDTA added earlier may have prevented that loss. The two had shorted cells and I haven't recovered them - but I just pulled them out of the lineup, and haven't tried to do any more serious work with them.
I left the EDTA in them once I added some. I put a couple tablespoons in a gallon of water and just used it to replace water as the batteries needed it. I went back to normal rainwater or distilled water after that except if a cell still showed signs of low specific gravity then it got another dose of EDTA water added. I monitor battery condition with the hydrometer and that is when I found that the EDTA had improved the batteries. I had never seen the specific gravity that high consistently before the EDTA.
Thanks again for that post -- I plan to make use of this info :)
My pleasure, OJ.
On another note Sunelec messaged me that my new panels are on the way and I see that they once again dropped their prices with a sale.
http://sunelec.com/
I haven't found anything to beat them so far. They have thin film a lot cheaper too if you have lots of room for panels. Freight may cost more than more expensive panels though - I haven't worked that out - just went for the 190's
I put this post in the Off Grid section because the panels glenn and I ordered have the MC3 connectors. According to what I have read they are legacy connectors and the new standard is the locking MC4. For warranty purposes I read also that the factory ends must be left intact. Do you order the adapter cables and then cut the ends off of them to do your series or parallel connections into a combiner box??? Thanks in advance for all the info. Also, Mtn Don and Glenn if you have time to do a layout diagram like OJ did, that would be great for us first timers. God Bless
If connecting in parallel the connection to the combiner box is usually done by purchasing a premade cord with a female plug on one end and a male on the other. The cable is cut at the appropriate spot. The plug end attaches to the panel connector and the cut end wired into the box terminal like any other electrical box connection.
For series connections the panel plugs simply are plugged together in a series pattern.
You can also order custom made cables with an MC3 on one end and an MC4 on the other if needed. Places the TheSolar.Biz can do that.
You should still be able to use the MC3 panel connections. If you tape them with silicone tape they will be more weather resistant as well.
If in doubt and faced with an inspection, ask the inspector what he wants to see.
If you'd like to see a wiring schematic I can draw one and post in in a week or thereabouts. (off to the mountains today).
Tickhill, the way to keep your warranty intact is to order an extra cable and cut it in half using one end for the connection at the end of your string and same for each set of panels you must parallel.
I live in the boonies - such things are not available here - they didn't have them when I ordered my panels, so I take my chances and chop off the ends hoping the company has enough faith in their panels that it likely will not fail.
Likely you will have to void the warranty on at least one panel if you take the cut off end and put it on the other panel (cut off the female - plug it onto the male at the opposite end of the string or opposite way) for a connector....why didn't I think of that earlier..... [ouch]
Combiner box I guess is ideal and probably required for code, but I use wire nuts most of the time. Seems any box with a cover should meet code. I haven't checked it out.
Free Code suggested practices.
http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/PVnecSugPract.html
Quote from: glenn kangiser on August 03, 2010, 11:07:30 AM
Tickhill, the way to keep your warranty intact is to order an extra cable and cut it in half using one end for the connection at the end of your string and same for each set of panels you must parallel.
I live in the boonies - such things are not available here - they didn't have them when I ordered my panels, so I take my chances and chop off the ends hoping the company has enough faith in their panels that it likely will not fail.
Likely you will have to void the warranty on at least one panel if you take the cut off end and put it on the other panel (cut off the female - plug it onto the male at the opposite end of the string or opposite way) for a connector....why didn't I think of that earlier..... [ouch]
Combiner box I guess is ideal and probably required for code, but I use wire nuts most of the time. Seems any box with a cover should meet code. I haven't checked it out.
Free Code suggested practices.
http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/PVnecSugPract.html
Glen I use the Mariposa True Value hardware store! They have everything!!! ??? Fuse your parallel strings gentleman! We don't need a wildfire caused by a bad panel. It is rare but possible! Ow on the wire nuts for DC
but I like the spirit...
Thanks, Dave. Wire nuts... I guess they are not the best, eh?
What would you suggest as best? Crimp butt connectors? Terminals in the combiner box? Always a combiner box? Exceptions to a combiner box?
I'll check out the True Value - they have solar stuff too? The special cable end adapters for the panels?
Looks like I found some of the answers in the code I posted above - Though I haven't read it all, what I did read was both clear and interesting.
I highly suggesting downloading it. Looks like the big file and small one look the same - maybe resolution difference as far as I have seen. Many pics included.
If I could double the money i have recieved from troubleshhooting wire nuts I would get a newer vehicle. That is truck for you guy's in the trailerhood! New song for me!
I crimp or use the torqued square driver/slot terminals. You can buy them at home depot in a 10 or 20 screw strip. Just hack saw cut what you need, tape them, and pass inspection. I like the midnite combiner boxes if I am billing and build my own out of the weather tight comex boxes also H depot.
Oh yea, True value has it all ! They try! They have had some good people in there, at times! :-\
Thanks for the tip on the nut problem, Dave.
I'll look for the items you mentioned. I stayed away from True Value for a long time as things there were costing about three times what they were at Coast but they are better now I think under the new owners.... most of the time.... [waiting]
Mtn. Don, I would like to see a drawing/layout of your setup. I patterned my inital setup after yours, although I will probably go with the SUN 3024 inverter/charger when sunelec gets them in. The panels and Outback FM60 arrive this afternoon, I have camera in hand to document. Thanks
That is sure a deal on price for a pure sine wave inverter, Tickhill. I note a pretty good efficiency difference between it and a Xantrex, but there is no comparison in cost if it holds up well. I would go with it over a modified sine myself if money was a consideration (I don't mean that it is not for me--- [ouch]. I haven't seen any reviews yet.
http://sunelec.com/index.php?main_page=product_info&cPath=6_40&products_id=791 87% efficient max. $525
http://www.xantrex.com/web/id/47/p/143/pt/18/product.asp 94% efficient (peak) $2773
http://sunelec.com/index.php?main_page=product_info&cPath=6_40&products_id=583
Glenn, just got the panels and the FM60. No damage, now the work begins by removing the old panels and building a frame for the 190's. Also Elizabeth with sunelec emailed me today and said that the SUN 3024's have arrived and ready to ship out. I wish I could download a manual first, and yes $ is definitely a consideration!
I took one panel out and set it in the sun for a quick voltage check and it was 30.0 vdc just leaning against the shop. If prices stay this low, I will probably get another 3 this fall. I am going to build my frame to hold 6, it will just look a little empty till I fill it up with the other 3.
Cool. I have been having a bit of a communication slow down with Phoenix. Maybe Miami is better - I emailed Miami today.
Parts have arrived on time once I got the last order in, but getting it ordered if you have a question seems to be a bit slow.
http://www.alphapower.com.au/aps_ProductsContent.php?mid=2&lid=6&nid=104
Would you use these?
Specification
AlphaCell Gel GXL
> Service Life: Long
> Runtime (minutes): 210, 180 & 165
> Sealed VRLA: Valve regulated lead acid
> Heat Resistant: High
> Hydrogen Emission: Low
> Terminals: L-type with .28" hole
> Silver Alloy: GXL-HP (on 210 and 180GXL)
N/A (on 165GXL)
> CA/SN Alloy: GXL
> Cells Per Unit: 6
> Voltage Per Unit: 12.8
Operating Temperature Range
> Discharge: -40 to 71°C
(-40 to 160°F)
> Charge (with temp compensation): -23 to 60°C (-9.4 to 140°F)
> Float Charging Voltage: 13.5 to 13.8VDC
> AC Ripple Charger: 0.5% RMS or 1.5% of float charge voltage recommended for best results. Max. allowed = 4% P-P
A friend has a pair for sale (to me) for $75 (total).....
Not me. I won't touch a gel cell.
Lead acid for me. L16 or Golf Cart only pretty well.
Gel cells will not take any abuse. Charge them wrong - they are toast. They can also lose the moisture in the gel rendering them useless unless you pop them open if possible and try to work in the proper amount of distilled water to restore them - only practical in small aplications such as my gold detector... and even then they may not come back.
A special charger is required to keep from damaging them. Equalizing may damage them. Too unforgiving for me because I am a bit of an abuser.....[waiting]
One golf cart battery should be in the area of $90 to $100. Two are necessary for 12v
Quote from: glenn kangiser on August 05, 2010, 11:15:42 PM
Cool. I have been having a bit of a communication slow down with Phoenix. Maybe Miami is better - I emailed Miami today.
Parts have arrived on time once I got the last order in, but getting it ordered if you have a question seems to be a bit slow.
Still no response to e-mail questions on prices and sizing so apparently they are too busy to check e-mails or respond.
They still have the best pricing and selection for my needs for the solar pump for a customer so I put the order in with their automated online system.
Rec'd their (www.sunelec.com) automated response receipt with the following note: 8-6-10 appx 10:30 am
QuoteThank You! We Appreciate your Business!
Your Order Number is: xxxxxx
Checkout Success!...
Your order will be processed and shipped out to you shortly. For Solar Panels
Please allow up to 3-4 business days for your order to be processed and prepared for shipment
Thank you for shopping. Please click the Log Off link to ensure that your receipt and purchase information is not visible to the next person using this computer.
Log Off
Please notify me of updates to these products
SUN-75 $2.48/Watt
Recorded this to report to you on their follow through. I have never had a problem with order fulfillment from them. It looks like you mostly need to just figure out what you want from their in-stock items and order online. With lowest pricing available that I can find, they are probably too busy for the small stuff.
Forgot to mention that I got the Grundfos SQ Flex from the Solar Store in Bend, Oregon.
They have had every shipment of parts to me in about 2 days - maybe one on some of it.
http://www.thesolarstore.com/grundfos-m-50.html
Their e-mail and backorder notifications have been near immediate even to taking care of the Grundfos level switch I missed ordering.
So... received notice that UPS rec'd information to pick up the panels from Sun for shipping 3:23pm - about 5 hours elapsed time on this order. Not bad.
Looks like no problems with the online ordering and shipping if you know exactly what you need. Nice that they post complete panel specs online.
Quote from: glenn kangiser on August 05, 2010, 11:15:42 PM
Cool. I have been having a bit of a communication slow down with Phoenix. Maybe Miami is better - I emailed Miami today.
Parts have arrived on time once I got the last order in, but getting it ordered if you have a question seems to be a bit slow.
Call Tucson :)I found that talking to them was completely different! Very nice and curtious and very helpful.
I could never get through to Phoenix.
Thanks OJ - I was thinking Phoenix would be the one with their stuff together. I think I have it handled now.
FWIW, as requested, a schematic of sorts. The drawings are not my best, most careful and neat work, but I believe it gets the idea across. Feel free to ask questions make comments or laugh....
It's in two parts, the first all the stuff down at the PV panels in the meadow...
![](https://i139.photobucket.com/albums/q305/djmbucket/jemezmountainproperty2010-1/part1.jpg)
... and the rest up at the cabin, 325 feet distant...
![](https://i139.photobucket.com/albums/q305/djmbucket/jemezmountainproperty2010-1/part2a.jpg)
Please note that if the panels and the balance of the system had been closer together like most systems will be, there would have been a #2 AWG ground wire running from the panels combiner box to the balance of the system.
Thanks Mtn. Don! Easy understood drawing, it helps greatly. What is the voltage/amp rating of the CB in the combiner box. I am only 30' max from where the panels are mounted to the FM60.
I currently have a 4 conductor 10 AWG SJ cord buried from the shop to the panels.
Thanks for the drawing, God Bless
The breaker at the panels is rated 150 VDC.
Also note I made an error on the second drawing and corrected the values for the breakers listed there. I got most of the breakers from solarseller.com; some from affordable-solar.com
That drawing is a beauty, Don. I like it.
I use black for all of my DC grounds because I am used to automotive DC having a black ground and all other colors are hot. Just easy for me to remember - maybe not right.
I'm looking at getting 4 40 watt PV panels from Sunelec specs are below and wiring them in series to a MPPT charge controller. Any thoughts as to these panels in this application, dealing with Sunelec or the quality of their products?
Thank you.
Model SUN-40
Power (W) 40 Watts
Open Circuit Voltage (V) 21.90 Voc
Short Circuit Current (A) 2.54 Isc
Maximum Power Voltage (V) 17.50 Vmp
Maximum Power Current (A) 2.28 Imp
Dimensions 22" x 21 1/4" x 1 3/8"
$120/ea
Quote from: TheWire on August 09, 2010, 01:49:54 PM
I'm looking at getting 4 40 watt PV panels from Sunelec specs are below and wiring them in series to a MPPT charge controller. Any thoughts as to these panels in this application, dealing with Sunelec or the quality of their products?
Thank you.
Model SUN-40
Power (W) 40 Watts
Open Circuit Voltage (V) 21.90 Voc
Short Circuit Current (A) 2.54 Isc
Maximum Power Voltage (V) 17.50 Vmp
Maximum Power Current (A) 2.28 Imp
Dimensions 22" x 21 1/4" x 1 3/8"
$120/ea
They've done me well but for the $440 why not buy a 200 watt panel? I bought 3 205 watt panels for $364ea a month ago.
OlJarHead,
Do you have the SUN-40's? I'm curious if these are a quality or low end panel.
As far as going with 4 small panels instead of single large panel, my challenge is mounting them. My cabin is in a wooded area and I expect I'm going to have to get creative with placing the panels to avoid shade. The small panels give me more mounting options and using 4 wired in series allows me to go 48V to my charge controller to cut down on the size of the wire.
I am a believer in series wiring to raise the voltage and reduce the necessary wire gauge. When sizing things though, remember to use the Voc (open circuit voltage, the highest voltage the panel would be likely to put out) and then muliply that by 1.25 and 1.25 a second time. Use that figure as the maximum peak spike voltage you would likely encounter in the coldest of weather and size everything to be able to handle that voltage. Those multiplication factors will pretty much ensure nothing will blow.
There is a handy tool at Outback Power that is a great help sizing arrays when using the Outback charge controllers. It has high and low temperature adjusters. http://outbackpower.com/resources/string_sizing_tool/ (http://outbackpower.com/resources/string_sizing_tool/) I believe Xantrex has one for their equipment as well. ???
Also not illustrated is the single connection from the neutral (white, Glenn ;D ) and the ground within the 120 VAC service panel. If I was doing it over, or with more time available, I would have placed units in better positions to eliminate or reduce wire crossing in the diagram.
As far as what's hot, positive, neutral or negative, as long as one's system is not going to be inspected by a code nazi all that matters is not confusing oneself. My head seems happy to use white as neutral and negative within the confines of a non mobile unit (cabin, house...) It would be nice if there were distinctive colors used to tell AC wiring from DC wiring. So I label a lot of stuff that in my younger days I would not bother with.
I use white for neutral on A/C, Don. Seems I saw something about black for negative on DC systems once so have always done that - but as you said - if nobody is looking then lack of confusion is important too. Dave may jump in here and tell me I am all wrong though and I'd say listen to him - not to me. [ouch]
Just keep the emergency disconnect tool handy in case of confusion. ;D
FYI, for those who are looking to pass inspections, the NEC does state white is to be used for neutral and negatives.
BTW, I also keep a jug of a baking soda solution handy in the battery chamber as well as a dry box. I haven't figured out what to do when winter temperatures arrive though. Last winter I placed the solution in a couple half filled plastic jugs. It did freeze at one point. Perhaps a more concentrated solution would have a lower freeze point. Some research and experimentation may be called for.
... I do that also - or mix it once in a while for cleanup and I try to be sure I do not confuse it with rain water or distilled water for filling the batteries if I set it down.... [ouch]
A magic marker helps.
Quote from: TheWire on August 09, 2010, 03:48:00 PM
OlJarHead,
Do you have the SUN-40's? I'm curious if these are a quality or low end panel.
As far as going with 4 small panels instead of single large panel, my challenge is mounting them. My cabin is in a wooded area and I expect I'm going to have to get creative with placing the panels to avoid shade. The small panels give me more mounting options and using 4 wired in series allows me to go 48V to my charge controller to cut down on the size of the wire.
Actually mine is a Sun 205 watt panel (or is it evergreen? have to go check now)....but I have 3 of them :) I got them from sunelec for my system...I was just thinking that one panel would be easier to mount and provides more power for less money (mine was $1.82/watt). Something to consider.
Don,
I'm trying to decide on a MPPT charge controller for 48V PV array charging a 12V battery bank. I'm looking at 200watts of PV panels wired in series for 48V. I think I have it narrowed down to the:
Outback FM 60 $525 + $30 battery temp sensor
BZ Products MPPT250HV $120 + $30 case
Morningstar TriStar TS-MPPT-45 $415 + $80 display + $30 battery temp sensor
The BZ Products is by far the cheapest but has no data logging or other enhanced features.
I have a question about the Outback, does it completely power off when the PVs are in the dark or does it stay running off battery power?
Any other thoughts from anyone on my charge controller options would be appreciated.
Thank you.
I am sure the controllers will have a very minor draw when powered down so that they will know when to wake up. They need a little power to know when to work for you.
http://www.oynot.com/files/flexmax-product_catalog.pdf
Found it - standby - less than one watt. It will gain you much more than it uses on standby.
Here is the way I see it, Jerry.
If you want the cheapest with no equalization or other bells and whistles the BZ will work.
If you like gadgets, equalize and other capabilities then it is one of the more expensive ones - both are good.
If you plan to expand the bigger ones have room but you need to be able to get and use the same panels. If not planning to expand, you have one of the best but a lot of wasted capacity.
The BZ is not highly rated but most of them work and are guaranteed. I have had one failure out of three and did not try for warranty although they are supposed to take care of it. I jumpered around it but may have to change it when I hook up the new panels. $14 return shipping for repair plus sending it in.
This may be an advertising scheme but I looked at sunelec.com today and the price glenn and I gave for our panels have gone up a .10 cents since yesterday and they are saying "PV Industry Shortage is Happening Now!"
I wish I had done like glenn and went ahead and got 3 more.
Just thought I would put that out there that there may be something to this and that $$ may start on the way back up.
I meant to say .10 cents a watt increase....
Quote from: Tickhill on August 12, 2010, 03:58:42 AM
This may be an advertising scheme but I looked at sunelec.com today and the price glenn and I gave for our panels have gone up a .10 cents since yesterday and they are saying "PV Industry Shortage is Happening Now!"
I wish I had done like glenn and went ahead and got 3 more.
Just thought I would put that out there that there may be something to this and that $$ may start on the way back up.
I'd call it inflation -- I've seen it in many places and with Uncle Sam printing money like rain falling from the sky it's only a matter of time...
I heard it may go up - quite a few solar projects going on.
Anyone have any experience with Rasmond solar panels? http://ramsond.com/solarprod.php (http://ramsond.com/solarprod.php)
They sell on their site, Amazon & Ebay. The Ebay auction prices are competitive with Sun Elec.
I'm looking at their 80W Mono-Crystalline.
I really had to look at our property to find a spot that wasn't shaded by trees. I also didn't want to take down a lot of trees to gain solar exposure. Finally found a spot that should be good for 6-8 hours of full sun a day. Its the corner of the cabin. I'm looking at installing about a 16' pole that will get the panels above the eve of the cabin. I would attach the pole to a base on the ground and midway with a heavy bracket attached under the cabin's eve. Anyone know of any information on sizing a post with a certain square feet of PV panels mounted on it?
A standard wall three inch or 4 inch should work braced as you mentioned. Guys could be added to the top if in doubt. Trees you mention nearby should kill most of the low level wind.
There are lots of different voltages on different panels so if you are adding to your sun-elec panels you should get the same ones to keep your charge controller working most efficiently for all - otherwise you will be working at the most efficient level of an innefficient mix. If all from the new source then no problem. I haven't heard of them but that doesn't mean anything - - check their specs and compare them to sun - also check the vendor and see if it looks like they may be around for warranty.
Quote from: glenn kangiser on August 07, 2010, 11:44:38 PM
Thanks OJ - I was thinking Phoenix would be the one with their stuff together. I think I have it handled now.
These folks are as bad as it gets! But, there prices are usually the best! I said that 15 years ago BTW.
It usually helps if you spend 15 minutes each day thinking happy thoughts about Sunelec! Well it might help, OK, it has the potential to help.
When GEL's first came out and now the AGM's it was 2 X the price for 1/2 the cycles, 1/2 the capacity and unknown lifespans over 5 years.
That never bothered me as I would pass it on to the customer ( But I always talk them out of it!) What really would bother me is losing one of the best tools in my box, the specific gravity measurement! Now that would really be a loss living offgrid!
Quote from: TheWire on August 10, 2010, 05:10:00 PM
Don,
I have a question about the Outback, does it completely power off when the PVs are in the dark or does it stay running off battery power?
The Outback FM60 has some very small power draw even when it's not charging the batteries. For one thing, the display indicates that it in silent or sleep mode. That costs something in power use, but is negligible as far as I am concerned. It's nothing to be concerned about. Even a brand new lead-acid battery sitting there doing nothing likely has more loss due to self discharge than what the FM60 draws.
FWIW, I have the FM60 charge controller plus the VFX3524M Outback inverter/charger plus the Outback Mate and Hub 4 and two battery temperature sensors. (see note below) When we leave the cabin for a few days I pull the breaker disconnect between the batteries and the inverter. I do that just because I feel more comfortable knowing all the AC power to the cabin and outbuildings is completely off. As an experiment I have also left the system sit there for two weeks with the inverter still powered and in its normal standby mode. I can
not discern any difference in power use between leaving the inverter disconnected or in standby.
(note below) I have two battery temperature sensors, one connected to the FM60 and one connected to the VFX3524M. It is possible to have only one temperature sensor in the system when an Outback Hub and mate are used. However Outback told me that IF I depowered the inverter/charger I needed to have a temperature sensor connected to the FM60 inorder to have the FM60 read the battery temperature. IF I left the inverter/charger powered up, even in standby, I could use just one temperature sensor connected through the Hub and it would supply data to both the FM60 and/or the inverter/charger as required. If that's not clear don't worry about it unless you have an Outback Inverter/charger as well as an Outback Charge Controller.
Quote from: TheWire on August 10, 2010, 05:10:00 PM
Outback FM 60 $525 + $30 battery temp sensor
BZ Products MPPT250HV $120 + $30 case
Morningstar TriStar TS-MPPT-45 $415 + $80 display + $30 battery temp sensor
Thank you.
I think the BZ is great for those who are needing to stick within a tighter budget. My opinion on the Morningstar is "why bother with it when you consider the price is close to the Outback?" I'm sure it's good but I like having the system all Outback.
Quote from: TheWire on August 13, 2010, 07:37:50 AM
Anyone know of any information on sizing a post with a certain square feet of PV panels mounted on it?
UniRac (http://www.unirac.com/) has information on pole sizing, depth, etc available n their website. I believe it is in their downloadable catalog pages for their pole mount racks. Of course their info is centered around using their mount kits. Their info takes wind loads into account on various combinations of panel sizes and numbers of panels. They supply the required depth and concrete volume for a safe installation.
Quote from: Dave Sparks on August 13, 2010, 10:03:37 AMWhat really would bother me is losing one of the best tools in my box, the specific gravity measurement! Now that would really be a loss living offgrid!
Absolutely!!!!!!!!
OK, here is the Visio produced wiring diagram. Thanks very much to Tickhill for his fine rendition of my pencil sketch - MD
That's pretty much got it. :) :)
Thanks very much for the great work.
MtDon, I see the Outback inverter has a generator connection. Is it a hard wired or plug in type connection? Does this also supply a/c power to the house, as well as equalize the battery bank?
Thanks Shawn.
Quote from: Shawn B on August 14, 2010, 09:44:39 AM
MtDon, I see the Outback inverter has a generator connection. Is it a hard wired or plug in type connection? Does this also supply a/c power to the house, as well as equalize the battery bank?
Thanks Shawn.
The connection for the generator inputs at the inverter/charger is hard wired. I use a locking three prong plug to connect at the generator end to make it simple to disconnect if and when I want to move the generator. After all it is a portable generator. The generator also has its own ground rod.
The AC input at the inverter/charger is a pass through system. When AC input is applied to the inverter that causes the charger section of the inverter/charger to kick in and apply DC power to the batteries. Like the FM charge controller the inverter/charger can be programmed for different charge rates; bulk, absorb and float. There is also a manually activated equalization cycle.
AC input at the inverter/charger also causes the cabin AC requirements to be drawn from the generator rather than the batteries.
Thanks Don...That was exactly what I wanted to know. That Outback system has quite a few features.
Did some searching but did not find any definitive answers, can you deduct 30% of the cost of a off-grid solar power system from your taxes? Or is this only for grid tied systems?
Regarding getting a 30% federal tax rebate on off grid solar & wind systems:
Found this on the Federal Form 5695 (2009) http://www.irs.gov/pub/irs-pdf/f5695.pdf (http://www.irs.gov/pub/irs-pdf/f5695.pdf)
"Qualified solar electric property costs. Qualified solar electric
property costs are costs for property that uses solar energy to generate
electricity for use in your home located in the United States. This
includes costs relating to a solar panel or other property installed as a
roof or a portion of a roof. The home does not have to be your main
home"
From this it appears we can claim 30% of materials and labor cost our taxes even on off-gird and vacation homes.
Yep.
Note that with most things done by owner-builder your own labor costs do not count; only labor costs paid to someone else.
Credits start at the PV panels or wind generator and stop after the inverter though. The balance of the wiring, etc after the inverter is just like a regular home connected to commercial grid system.
Also if you are going this route check into your state rules. Some states, like NM, do not tax the purchase of the alternative energy equipment or contracted labor. However, you need to know how to make that work for you when dealing with companies that are not alternative energy specialists.
http://www.dsireusa.org/incentives/index.cfm?State=US&ee=1&re=1 (http://www.dsireusa.org/incentives/index.cfm?State=US&ee=1&re=1)
http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=US37F&re=1&ee=1 (http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=US37F&re=1&ee=1)
Quote
They've done me well but for the $440 why not buy a 200 watt panel? I bought 3 205 watt panels for $364ea a month ago.
Oljarhead,
I'm leaning towards bigger panels as you suggested. What 205 watt panels did you buy, how much was shipping?
Thank you,
Jerry
I have had my 2kw ProSine inverter and 4 -GC batteries running well for 2 years charging them with a generator. Now I want to make the next move to solar charging.
Here is what I'm looking at:
2 - Sun 190 watt PV B grade panels with a max power voltage to 26.7V $338ea.
http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=816 (http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=816)
1- Outback FM-60 Charge controller $508
http://sunelec.com/index.php?main_page=product_info&cPath=22&products_id=36 (http://sunelec.com/index.php?main_page=product_info&cPath=22&products_id=36)
Outback Battery Temp Sensor,
MOC 3 Connectors
$330 freight.
Any comments on any of my choices, better alternatives, issues with B grade panels would be appreciated.
Thank you.
They do not carry the UL or any other approval. That means they will not pass inspection. There could also be a problem with insurance, maybe after a fire if they caused one and the adjuster was sharp. Non approved may simply mean they skipped on that process and the expense to be able to sell cheaper. ??? Not approved may also mean the wiring is not good enough for the high temperature insulation rating. ??? Approved panels will usually have connecting wires rated up to 600 volts. One of the Sun panels I searched out a year or more ago had wiring only rated to something around 50-60 volts. That could make series connections iffy. Or maybe not. ??? Thing is we don't know from what they tell us. Non UL approval could also mean the glass surface is not up to impact (hail) standards. ??? Again, maybe not; maybe the panels are every bit as good as a UL, CE Tuv, approved panel and Sun is just saving us money. ??? I have no idea, but you asked for an opinion.
Cosmetic blemishes do not bother me at all. Other unknown or unseen possibly important things do. But that's me.
Quote from: TheWire on August 15, 2010, 08:25:11 PM
Quote
They've done me well but for the $440 why not buy a 200 watt panel? I bought 3 205 watt panels for $364ea a month ago.
Oljarhead,
I'm leaning towards bigger panels as you suggested. What 205 watt panels did you buy, how much was shipping?
Thank you,
Jerry
Disclaimer: I'm remote, Libertarian and don't give a rats behind.....*chuckle*
The panels I bought were $1.82/watt Sun A-205-fa3 205W Solar Module -- I basically bought their off grid system without the Inverter and batteries.
I was able to get a better deal going that route.
But as I see Don mentioned these panels aren't UL listed because they are blems -- though I see no reason to call them 'blemished'. They seem perfectly fine to me though I haven't had them in the sun yet...should do that today.
Anyway, I'll be 24 miles from the nearest town, 3 miles from the nearest county road and hidden in the trees where only planes and google earth can see me :)
Of course Google Earth has to update it's maps first too :P
Quote from: OlJarhead on August 16, 2010, 11:08:12 AM
But as I see Don mentioned these panels aren't UL listed because they are blems --
Hold a sec.... No, no, no, that is not what I said. I said "They do not carry the UL or any other approval. That means they will not pass inspection".
The fact that the panels are being sold as blemished has nothing to do with UL approval. UL doesn't care if they are pretty. Mostly UL tests for electrical and mechanical safety. Things like does the wire used have insulation that is rated for high enough temperatures, does the insulation have UV resistance, is the conductor large enough to carry the maximum expected amperage, can the module handle high voltages when series connected, and other stuff.
Other brands of panels are also sold as blemished from time to time. I missed out on some Sharp panels by a few weeks when I was looking. They had some kind of scratches on the aluminum frames. They still carried the UL, CE, Tuv approvals. Some Sun panels are simply not approved. Period. Doesn't matter if they have a perfect or blemished finish. On some models they come right out and say yes or no on UL. On others one has to search and sometimes still can not determine if the label indicates UL approved or not.
Maybe I worry too much. I wonder why the manufacturer has not had the panels tested and approved. Maybe there's nothing at all wrong with them. Maybe the panels are deficient in some way? I have no way of knowing. I see them as a long term investment and that's why I bought a "name brand". I'm not saying that the Sharp are better or that the Sun are crap. However, as with anything from soup to nuts I do wonder how two products similar in nature can vary so widely in price.
What I do know is that I have bought many things over the years. Sometimes I have gone for the low ball price just because I don't like to spend a lot of money. Sometimes that has been money foolishly spent when problems have developed prematurely. Sometimes I buy the cheaper thing with full knowledge that it is not going to be as durable as a more expensive item, but that's okay as it is being bought for a one time specific task. Sometimes the cheaper thing is wonderful and is at least as good as the more expensive brand name item. Costco's Kirkland brand AA alkaline batteries come to mind there.
Anyhow, I just would like to be quoted correctly.
Quote from: MountainDon on August 16, 2010, 02:04:15 PM
Quote from: OlJarhead on August 16, 2010, 11:08:12 AM
But as I see Don mentioned these panels aren't UL listed because they are blems --
Hold a sec.... No, no, no, that is not what I said. I said "They do not carry the UL or any other approval. That means they will not pass inspection".
The fact that the panels are being sold as blemished has nothing to do with UL approval. UL doesn't care if they are pretty. Mostly UL tests for electrical and mechanical safety. Things like does the wire used have insulation that is rated for high enough temperatures, does the insulation have UV resistance, is the conductor large enough to carry the maximum expected amperage, can the module handle high voltages when series connected, and other stuff.
Other brands of panels are also sold as blemished from time to time. I missed out on some Sharp panels by a few weeks when I was looking. They had some kind of scratches on the aluminum frames. They still carried the UL, CE, Tuv approvals. Some Sun panels are simply not approved. Period. Doesn't matter if they have a perfect or blemished finish. On some models they come right out and say yes or no on UL. On others one has to search and sometimes still can not determine if the label indicates UL approved or not.
Maybe I worry too much. I wonder why the manufacturer has not had the panels tested and approved. Maybe there's nothing at all wrong with them. Maybe the panels are deficient in some way? I have no way of knowing. I see them as a long term investment and that's why I bought a "name brand". I'm not saying that the Sharp are better or that the Sun are crap. However, as with anything from soup to nuts I do wonder how two products similar in nature can vary so widely in price.
What I do know is that I have bought many things over the years. Sometimes I have gone for the low ball price just because I don't like to spend a lot of money. Sometimes that has been money foolishly spent when problems have developed prematurely. Sometimes I buy the cheaper thing with full knowledge that it is not going to be as durable as a more expensive item, but that's okay as it is being bought for a one time specific task. Sometimes the cheaper thing is wonderful and is at least as good as the more expensive brand name item. Costco's Kirkland brand AA alkaline batteries come to mind there.
Anyhow, I just would like to be quoted correctly.
Sorry -- mistyped on my part.
Let me try again ;)
The panels that I purchased are 'Blems' and while you can buy the EXACT same panel that IS UL listed the manufacturer doesn't bother with the blems and dumps them on the market.
This isn't uncommon actually. When I worked in a food plant (pickles) the company made other brands then their own -- these other brands varied in quality assurance. The ones with the least QA were generally sold as generic brands but were actually the same recipe etc as the name brand -- just less concern over the quality of the product.
In this case the manufacturer (to my understanding) doesn't really want to sell their blemished panels as a 'normal' product and rather then get them stickered etc they dump them cheap to get rid of them.
They are supposed to work as described etc but weren't put through the same testing standards as those sold with the UL sticker on them.
make sense? You can actually buy the exact same panel with the UL sticker for around $800 rather then the $364 I paid :)
Not to initiate a flame war, but my understanding of the UL system is as follows.
A manufacturer submits a product for testing. They pay for the testing process up front. If the item passes the UL scrutiny the manufacturer gets permission to have labels printed and applied to the products they then can sell as an approved item. The manufacturer supplies the products to be tested and pays for the testing and approval process. The manufacturer then buys labels from authorized sources. Yes, the labels have to be approved too. The manufacturer also pays subsequent fees for follow up testing on items selected at random as they are produced. Not every item labeled is actually tested.
In other words, the manufacturer does not pay a fee based on the number of labels applied. If they get something approved and then don't sell any they have the up front costs paid. With the above being my understanding of the UL process I do not think it likely that the exact same products are sold as approved and unapproved and with such widely divergent prices.
Maybe I'm misinformed. If so point me in the right direction.
Quote from: MountainDon on August 16, 2010, 03:24:27 PM
Not to initiate a flame war, but my understanding of the UL system is as follows.
A manufacturer submits a product for testing. They pay for the testing process up front. If the item passes the UL scrutiny the manufacturer gets permission to have labels printed and applied to the products they then can sell as an approved item. The manufacturer supplies the products to be tested and pays for the testing and approval process. The manufacturer then buys labels from authorized sources. Yes, the labels have to be approved too. The manufacturer also pays subsequent fees for follow up testing on items selected at random as they are produced. Not every item labeled is actually tested.
In other words, the manufacturer does not pay a fee based on the number of labels applied. If they get something approved and then don't sell any they have the up front costs paid. With the above being my understanding of the UL process I do not think it likely that the exact same products are sold as approved and unapproved and with such widely divergent prices.
Maybe I'm misinformed. If so point me in the right direction.
No worries at all Don -- perhaps I'm mistaken in this case???
In truth, I think you know tons more then I do on the subject (actually millions of tons -- thanks for all the help!) so I suspect that in this case I'm wrong. I'll go see if I can find out where I got the impression I did.
Thanks
Erik
Can't find what I was looking for so quite possibly I got it wrong Don.
Gosh, shopping for solar panels can get tiring. ??? The shipping can be a big factor, up 50% of the PV cost, so that must be taken into account.
Per Don's concerns, I looked for an alternative to my first choice (2 - Sun 190 watt PV B grade panels with a max power voltage of 26.7V $338ea.)
$1.78/Watt panel or $2.66/Watt delivered.
The alternative I found was (2 - 165W BP Solar A grade panels UL rated SX6165N with a max power voltage of 35.2V $361ea.)
$2.19/Watt panel or $2.98/watt delivered.
Any feedback on the BP panels? Doesn't Glenn use Sun panels? If so can Glenn give his $0.02 on them.
BP has been producing panels for some years. They should be good ones.
Transportation costs were one reason I purchased my panels from a local supplier. I guess I was lucky in that respect.
I have my first set of Sun Panels running - No problems.
I have my second set - 1000 watts + but have not set them up yet. I'm not worried about them.
Third set for the pump for a customer arrived today 5 x 75 watt panels. I can take readings on them when I get working on them in the next couple weeks.
Sun has been in business for - what - 37 years, and they are not staying in business by ripping people off I am assuming.
I am taking them at their word and so far they have not given me a reason to doubt them.
"These modules are made available exclusively to Sun Electronics by one of the world's largest manufacturers. Made in USA! Identical Power specifications as A grade modules, complete factory light tower test is available. These modules have slight cosmetic blemishes. Sun modules are non-UL, Tuv or CE listed. Unlike most other brands which have power specifications within +/- 10%, these modules have power specifications within +-5%!"
I have BP panels too with no problem. I have BP panels made for Enron also - thin film - low watts (40) for a large area but no problem. I see watts as being watts.
Cost to ship my panels from AZ to WA was about $220 -- that's 3 panels, midnight solar boxes, breakers, some MC cables and more.
I was pretty happy with that actually.
I pulled one of the Sunelec 75's out of the box and put a meter on it yesterday.
VOC was listed as 21.7 measured at about 10 am on a hot day showed 20.52 - I think within reason
ISC was listed as 4.89 measured ~5.25 so a bit higher than advertised.
I don't think that there will be any problem with them performing to higher than the industry standard as they claim.
The wire was PV1F and rated at 1000 VDC, and the terminal box was rated at 1000 VDC.
I bought the 2 - 165W BP Solar A grade panels UL rated SX6165N with a max power voltage of 35.2V $361ea, Outback FM-60 and a Unirac 5001 pole top mount. Waiting for them to come in. :-\ Any ideas about where to get 20' of 3" pipe on the cheap? Does anyone know if galvanized rigid conduit is the same as schedule 40 pipe?
Look for a used pipe dealer. I bought my pole material from a nearby (50 miles) dealer in used drill pipe. It was a bargain compared to new steel, even with the drive to get it.
EMT (rigid metal electrical conduit) is not the same as schedule 40 pipe. Sch 40 has a wall thickness of 1/4 inch in three inch size pipe, EMT is much thinner.
TheWire, I put my panels on 3" rigid galvanized conduit. I have ~4' in the ground with concrete and I welded a piece of 2' long by 8" wide 3/8" thick plate on top of the threaded coupling that comes with the conduit. This acts as my swivel for turning the panels to the sun (manually right now). I have had no trouble with wind, I do have a hole drilled through both coupling and conduit so I can "pin" the panels in place if need be. I will be removing my old setup and putting the 3- 190 watters in place very soon. Blessings, Tickhill
Listen to Don on this one! Conduit is not schedule 40. These mistakes were made decades ago by folks like myself so that you guy's can move forward! :(
It's relatively easy to get confused with pipe/conduit/tubing
EMT (electrical metallic tubing): very common light thin wall electrical conduit. This is never threaded as the walls are too thin. Sold in standard 10 ft lengths
RMC and GRC (rigid metal conduit and galvanized rigid conduit): has a thicker wall than EMT, but not as thick a wall as PIPE. Used in industrial and commercial applications more than residential. Sold in standard 10 ft lengths
IMC (a thinner wall version of RMC): approximately 1/3 less metal than RMC. Sold in standard 10 ft lengths
PIPE (made in a variety of wall thicknesses or schedules; schedule 40 is most common) used for fluids and gases, etc.: thicker wall than RMC/GRC. The threads are the same number of threads per inch BUT pipe threads are cut with a taper whereas conduit threads are straight cut, non tapered. Taper thread is required to make fluid and gas tight connections. Sold in standard 21 ft lengths as well as shorter lengths called nipples.
For comparison, 3 inch RMC and GRC has a wall thickness of 0.13 inch and schedule 40 PIPE has a wall thickness of 0.216 inch
4 inch RMC and GRC has a wall thickness of 0.13 inch and schedule 40 PIPE has a wall thickness of 0.237 inch
Just a note on battery recovery - I had one bad cell in one battery in an old group of four of my 2004 batteries. I rehooked them to my system a week or two ago. The EDTA recovered a second one in the group that I thought would not come back.
The other battery was shorted and nothing I could do was bringing it back. I ran a pulse recovery charger on it day and night for several days. I didn't want to put a new battery in the string so started thinking about some scrap batteries that were given to me.
Dave - you know these batteries .... some very used Trojans..... [ouch]
I had one out of the eight that has been sitting about 6 months or better that it looks like I have been able to fully recover. It had significantly higher voltage than the rest -about 4.62 as I recall.
I mixed up a quart of rain water and a couple tablespoons of EDTA and split it among the three cells in the Trojan. I put the Xtreme Recovery 20A pulse charger on it and a companion battery for 12 v. The companion is the one that had a bad cell and returned from the dead. By bad cell I mean two cells were 1300 or more SG and one was below 1100. Point spread in SG over about 25 is not good.
The point here is that the SG measured with a hydrometer is a measure of cell health and all should be near 1300 on a fully charged battery with little difference in SG. If a cell is low compared to the others it is time to equalize all cells keeping water levels up above the plates during the process when the good cells will bubble profusely as the bad one is coming up. Once it is also bubbling profusely and the SG is up then equalization is done. Refill with rain or distilled water - do not overheat the batteries. I use the welder to do the equalization but if you are not aware of the procedures (mine) and dangers then again - don't try this at home, kids. [crz]
After 24 hours on the Xtreme Recovery charger both the old battery and the used Trojan are over 1300 in all cells. :)
As a substitute for the Xtreme Recovery charger, I think that any PWM solar charger will pulse the battery back breaking down the sulfation, or use a desulfator with the charger - just at a slower rate. Note - just a link that has it - Mikey B of our forum sells them also. http://www.chargingchargers.com/pulsetech/xcr-20.html
Battery and charging info... http://www.chargingchargers.com/tutorials/charging.html
The only pipe I use is 6 inch with an OD of 6 5/8". A 9 foot section of either the sched 40 or well pipe which is even thicker/stronger is between 200 and 300 pounds. I say this because offgrid people often want more power over the years and this is a reasonable way to add on over the years. 6 inch sched 40 will support 125 square feet of panels BTW. The 8 inch pipe is only for people like Glen who have heavy equipment service facilities!
I have sent folks down to Costco to buy a golf cart battery for emergency repairs to an L16 bank Glen. It has been very rare with Surrettes.
The best solar exposure I could find is pointing over the roof on one edge of my cabin using a pole top mount. My plan is to put up a 3" or 4" pipe pole from the ground up along side the cabin and attach it near the eve with a heavy bracket tied back into the studs of the in cabin at multiple points. If I used a 20' pipe, about 14' of that would be below the attachment near the eve. 6' would be above the eve on top of which I would put PV panels with an area of about 25 sq ft. I was also considering the possibility of using 2 10' sections of pipe with a coupling as the coupling would be between the eve attachment point and the ground.
The eve attachment would need to be quite robust. With a maximum wind speed of 90 mph there would be approx 30 lb per sq ft force. Times that by 25 sq ft = approx 750 pounds force total.
I'm not an engineer but I suppose the threaded coupled joint would be okay in this case although I'd want to securely connect the pipe to the wall just above the coupling to reduce bending stresses on that point. I would not want to use a threaded coupler an not have the pipe and rack above the joint supporting much weight.
I have 4 threaded couplers on maybe schedule 30 pipe (lighter than standard ) 85 feet tall for my wind generator. The catch is that I have 4 guy wires every 20 feet to take the side stresses. My design is based on what I could glean from Bergey Wind Generators information and phone conversation with them.
Good idea on slipping a golf cart battery in there to save the rest of the bank, Dave. I knew I didn't want to buy a new L16 but the recovered Trojan looks to be doing good now.
20 feet of heavy wall 8" - small potatoes.... :)
http://www.amazon.com/ERICO-611380UPC-Copperbonded-Ground-Rod/dp/B002KAU1X4/ref=pd_sxp_grid_pt_0_1
Looking for ground rods and I found this (as well as others).
The only thing I know about ground rods is that I've had to pound several into the ground (when in mobile switching in the military) and that they provide the 'earth ground' for the system.
From Don's posts and pics it looks like he used two at each location? Is this required? We only ever used one in the military.
Anyway, I need to get a couple (or 4) of these and was wondering what your thoughts were?
Also, I have VERY rocky ground and am not certain that I can even get a ground rod down 8 feet! In fact my well report shows topsoil for FOUR FEET and then granite. So ya, this might be a little tough.
In that case could a person run several 4 foot rods and make a 'halo' ground system instead?
Lowe's and HD also stock ground rods as should any other supplier who stocks service entrance equipment. My local stores carry them in the 5/8" diameter, sometimes the 1/2" Cheaper than that one that was posted. You'll also need a clamp to connect the ground wire to the rod.
![](http://images.lowes.com/product/converted/084644/084644071053lg.jpg)
According to NEC driving the entire 8 ft length is required, to the point where the clamp on the upper end is actually buried. NEC has alternate grounding methods using a buried perimeter wire. Off hand I do not recall what lengths are required.
I did use two rods at the pole and panels to be sure I had a good solid ground. The soil down there gets quite dry at certain times of the year. Two rods ensures a better ground. See the following post for more....
http://countryplans.com/smf/index.php?topic=6059.msg95643#msg95643 (http://countryplans.com/smf/index.php?topic=6059.msg95643#msg95643)
At the cabin and equipment I could have likely got away with a single rod as the grey water leach keeps the earth moisture content higher. But a second rod, clamp and wire was less than $25 and provides extra 'insurance'.
Does your well have a metal casing? Good ground there.
Quote from: MountainDon on August 20, 2010, 01:45:25 PM
Does your well have a metal casing? Good ground there.
I was wondering about that Don. Though the well is about 100 feet from where the panels will be. How far away can I put the rod (s).
I also have dry ground in the late summer and fall so having two makes sense. My biggest problem is that where I put the cabin and want to put the solar is quite rocky. Just digging two feet in some of these areas is nearly impossible without a hoe! We had to use the winch on the jeep to pull some of the rocks away from the area we dug up for footings and composter. Was tough.
If I could use the well casing that would help, but again it's a long ways away.
I think I can get a rod or two in within 25 feet of where I'd like them, and perhaps closer but have to explore more.
Thoughts?
Erik
My quick search finds nothing on the distance between the ground rod and the balance of the system.
I did find it listed that a metal well casing on a private well can serve as a ground.
I also found that the 8 foot ground rod can be driven at an angle up to 45 degrees (Cailifornia code item). No mention of angle driving in the NEC or IRC.
I found two grounding systems allowed as alternatives ...
Plate Electrodes
A plate electrode that exposes no less than 2 square feet of surface to exterior soil shall be considered as a grounding electrode. Electrodes of iron or steel plates shall be at least 1⁄4 inch in thickness. Electrodes of nonferrous metal shall be at least 0.06 inch in thickness. Plate electrodes shall be installed not less than 30 inches below the surface of the earth.
Ground Ring Electrodes
A ground ring encircling the building or structure, in direct contact with the earth at a depth below the earth's surface of not less than 2.5 feet, consisting of at least 20 feet of bare copper conductor not smaller than No. 2 shall be considered as a grounding electrode.
Picked up a 5/8" ground rod at Home Depot for under ten bucks :) Thanks Don!
I also picked up 20 feet of solid copper #6 (bare) to run from the box to the rod for $11.60. I figure I can try to put the rod in near where the battery box will be and will have plenty of copper to get to it even if I have to move it 5-10 feet from the box location.
I'll be wiring up the receptacles, lights and switches this trip and installing the main AC load center (bought a Homeline 125amp 8 position 16 circuits) at the same time and landing the circuits.
I pan to run seperate breakers for each area of the cabin limiting each run to 3 boxes and one light or less. This will give me a breaker for the lower sleeping area, kitchen, refrigerator (assuming I run the camper fridge on AC), 'living' area, small loft, bathroom (1 GFCI -- man those are spendy! and a light) and left and right side of large loft. Also running one breaker for ceiling fan and one for outdoor porch light.
I figure I can get away with 15amp breakers since these will be light loads and small areas (no more then one overhead light and 3 boxes per breaker) but plan to install 20amp breakers for anywhere that might have a heavier load (kitchen and bath). 12-2 w/ground romex for all but single box runs for desk lamps or clock radios -- which means I can upgrade the breakers to 20amp breakers if need be (which are the same price).
I plan to install at least one outdoor circuit while I'm at it and run a GCFI to the compost unit for the dehydrator and fan.
I've been told that DC likes stranded wire better then solid romex -- any thoughts on that? The reason I ask is that I was hoping that if the inverter died and I wanted to just change a circuit to 12v I could land the wiring into a seperate box for DC under the AC box. If not then I'll have to add a run of stranded for the DC circuits if I should want some.
DC lights are spendy but I've read that they are very efficient and draw low power (LED's) so might be a good thing to make use of on my small system.
Any thoughts?
Thanks again!
Erik
First, solid vs stranded wire.
1. In automotive uses, stranded wire is preferred. Not because it might be better able to carry the currents, but because it is flexible. Being flexible it will not fatigue and break from vibration as readily. It's also easier to run the wires in an auto when they are more flexible.
2. There is very little difference in the resistance of a solid vs stranded wire in DC applications. So little it is negligible. Solid wire has slightly better performance, less resistance, than stranded wire in DC applications.
Example:
SOLID WIRE
conductor size 12 AWG
area 3.309 mm^2 (square-mm)
area 6530 CM (circular mil)
diameter 80.8 mil (1)
diameter 2.053 mm (1)
DC-resistance 0.00521 Ohm/m
STRANDED WIRE
conductor size 12 AWG
area 3.309 mm^2 (square-mm)
area 6530 CM (circular mil)
diameter 93.3 mil (1)
diameter 2.371 mm (1)
DC-resistance 0.00532 Ohm/m
Notice I stated DC applications. In some AC applications that use high frequency currents, stranded wires offer less resistance and cleaner power.
MY thoughts on DC lighting, as in MY Opinion.
Let me start by stating that my original cabin designs included a lot of DC wiring for DC lighting. I did that because I wanted to avoid the losses involved in using an inverter to supply low currents for AC fluorescent lights. It's true that a large inverter supplying a small amount of AC power to one CFL light may waste a lot of power. Inverters are generally more efficient when working near their rated capacity. My mind was set on using every watt-hour of hard won solar PV power to best advantage. I was not going to throw any power away!
However, by the time I was finished I also had several AC circuits so we could use a variety of AC items, TV, CD player, radio, vacuum, microwave and so on. I had a horrific amount of copper wiring designed in. Some of those AC devices could have been supplanted with a DC device. That would be cool, but they would only be usable on DC. There is also much less selection in DC devices. Plus some of them are crap. (my opinion).
Added to that was the higher cost of DC devices. Add to that the fact that ordinary AC wall switches don't last long on DC power. They fail before the light bulb fails. Add to that if the DC light fails it may be more difficult to obtain a replacement.
So I decided to go virtually all AC. This choice was also made easier because I wanted to have an inverter large enough to run power tools, microwave, etc. without having to worry/think about whether or not anything else was on at the same time. Choosing the 3500 watt Outback inverter provided oodles of power and many frills such as a power standby system that really works well. (Okay, true I spent a bundle on the inverter; more than what I saved on eliminating the 'extra' DC wiring. But that's okay, I feel I won in the trade offs by having the extra AC power available. To my mind I won. ??? ) I used fewer feet of wiring. My AC CFL lamps are available everywhere and a great pricing. We do have three DC lights. Two are under the kitchen cabinets for counter lighting. I chose them because I wanted to have a couple DC lights inside the cabin just in case the inverter crapped out. Being at the kitchen counter they are more or less centrally located. They are Thinlite RV type Fluorescents. I know they are not NEC approved but so far no inspector has come round. ::) We also have a DC ceiling fan with electronic speed control.
BUT, I'll add that if I had built a smaller cabin, with less intended use, I very well might have gone with a system that was predominately DC powered with a provision for lesser SC use. maybe I would have done without the microwave, the largest consumer of AC that we have in regular use. Or maybe the generator would be used more? ??? The way things are are we could pretty much do without the generator at all. Since our solar system went active last year I have only run the generator to
(1) equalize the batteries (I have also run an equalization cycle once last summer using the PV panels as the power source. That was a great solar day!)
(2) run the generator just because it had not been run for a month or so.
(3) assist in heating up the RV interior once in cold weather. The generator ran 2000 watts worth of electric heater for an hour or so.
In my opinion, DC is more trouble than it is worth unless it is a very small system ... except I can't think of anything I would want to mess with it for - oh yeah..... tail lights on my truck.... [waiting]
We need to face the facts..... we are sold out to convenience... throw in a few extra watts to support the slight inverter inefficiencies and quit bothering ourselves with jumping over a dollar to save a dime.... [ouch]
OK - so I'm funnin you a bit but I don't want to mess with DC... :)
I'm contemplating moving my inverter and batteries out of the rolling cart (See http://countryplans.com/smf/index.php?topic=4640.20 (http://countryplans.com/smf/index.php?topic=4640.20) for pics) under the stair landing and into a more permanent location in the cabin's utility room. The cart with its AC & DC umbilical cables makes it hard to access the batteries to check the fluid levels.
My plan is to place each series set of 2 GC batteries on a shelf and run bus bar up the back of this vertical set of shelves to where each pair of GCs would tie to the bus. I currently have 4 GC batteries total, but will design for 4 shelves for a total of 8 batteries.
My inverter is a 2kw Prosine with 12VDC input. I currently have everything tied together with 4/0 copper cables. I have a couple questions.
I like the use of the copper bar jumpers between batteries the Don & Glenn have used. I was also thinking of using bus bar from the batteries to the bus. Aside from having to use wrenches to remove the batteries, does anyone see any issues with this?
Don used insulators on his bus. My + & - bus bars would about 2 feet apart. Would screwing bus bar directly to kiln dried wood be a problem?
The batteries would be in a room with potential ignition sources, RV water pump, macerator relay, light switch etc. Should I enclose the battery shelves put a door on it and run a vent out the top the outside, consider a fan for venting while charging, which the Outback charge controller can control or just vent the room to the outside?
I seen mention here of Storm Copper for copper bus, do they sell small quantities or are there other sources?
Lastly, Aluminum bus bar is less than 1/2 the price of copper even though it needs to be bigger than copper for the same current carrying capacity. Any reason I shouldn't consider using it for the 2 main buses?
Thank you!
In no particular order...
Storm copper: their prices on the web all include shipping. They sell any size listed. They will also cut to size, I had them cut the sheet for under the wood stove to the exact size I wanted. They also have a 800 number and were very helpful over the phone.
I had thought of running bar straps from the battery to the buss, but it seemed like more work to make the connections line up.
Aluminum bus bars. I wouldn't myself, but it can probably be done. Remember there are certain things that must be done when using aluminum in power circuits.
Insulators behind bus bars. For one thing I needed standoffs so I could get the wrench under the bar to tighten the nut and bolt for each connection. A wood block would likely do.
Batteries mixed in with other equipment. I (my opinion) do not like the idea. Batteries do give off hydrogen and oxygen. As well there may be some acidic vapors if the batteries are undergoing a serious charge. I would want to keep the hydrogen away from any potential spark or other ognition sources. Ditto on acid fumes. That's why all my electronics, switches, fuses and breakers are totally separated from the batteries.
Stacking the batteries vertically on shelving does not appeal to me. I want to have enough space above each battery so I can get in there with a hydrometer easily and read the calibrated float easily. I (again, just me) would like to idea of having to lift batteries up above chest or belt level.
You need to minimize the possibility of a wrench, watch band, necklace, whatever from causing a short circuit. That's why I insulated the bus bars over much of their length. I am not sure what the NEC has to say on this. I was/am more comfortable with the insulation since my bars are only inches apart.
If you are playing with different ways to lay out the equipment be sure to not put anything above the batteries. That's NEC as well as common sense.
You could use a positive vent fan for battery venting, but H rises so as long as there is a vent at the uppermost area they should be fine. The Outback CC can also be used to activate venting fans.
Forgive me if I missed it Don! Having two ground bars or two ground sources is the only way to know if you even have a good ground. The code is 25 ohms or less! I like alot less in the winter and accept that my Kharma will get me though the dry months. I tell my customers to pour 5 gallons of water on it if it looks like a big storm! Set it up so you can check resistance now and then if your area is prone!
I measured between the steel pole, some 5 feet in the ground and the first ground rod and I had quite low ohms. But since the rod and pole were fairly close together I didn't think it counted. I decided two rods would be good/better. Two rods are about 9 -10 feet apart and gave something like 16 between the two rods.
So I guess I ended up with "good" even though all I knew was to aim for 25 ohms or less. I can check by disconnecting the ground wire at one rod and metering between them. I should probably run a check next time to see what it reads with the ground well saturated, then again in November after things dry out.
Thanks, Dave. I try hard but am not in the professional league. I appreciate any and all assistance to give to clarify and help keep things safe.
Quote from: MountainDon on August 25, 2010, 03:37:26 PM
I measured between the steel pole, some 5 feet in the ground and the first ground rod and I had quite low ohms. But since the rod and pole were fairly close together I didn't think it counted. I decided two rods would be good/better. Two rods are about 9 -10 feet apart and gave something like 16 between the two rods.
So I guess I ended up with "good" even though all I knew was to aim for 25 ohms or less. I can check by disconnecting the ground wire at one rod and metering between them. I should probably run a check next time to see what it reads with the ground well saturated, then again in November after things dry out.
Thanks, Dave. I try hard but am not in the professional league. I appreciate any and all assistance to give to clarify and help keep things safe.
Most all homes and commercial have never had the ground connection checked even when new. Offgrid we always exceed code because we are the power company! The cutting edge of all electronics has always been from from marine and space systems. Offgrid is where we benefit and test it in my opinion!
I just got this in an email concerning the 2011 NEC Code:
2011 NEC® Changes
The 2011 NEC marks an important milestone—100 years of NFPA sponsorship. Throughout its 114-year history, the Code has continued to keep abreast of the state-of-the-art in technology. Major changes to the 2011 NEC focus on the major issue of the day, which is alternative energy. These changes recognize the demand for alternate energy by providing installation requirements that facilitate safe installations.
Covering solar, fuel cell, and green technology is not new for the NEC, but these latest changes in the 2011 edition keep the Code updated to reflect field experience and current technology.
The 2011 Code has revised Article 625 to include plug-in-hybrid vehicle charging systems as equipment that must meet the electrical protection and ventilation requirements of Article 625. In the future, plug-in hybrid vehicles may not only serve as a source of transportation, they may also be able to serve as a power source.
Article 705 is a key article in alternative energy system requirements for systems that interface with a utility source. It covers interconnecting generators, wind turbines, and solar and fuel cells with utility and other power sources. A number of editorial changes were made to improve its usefulness.
Another change to the 2011 NEC is the addition of new Article 694, which provides new requirements for the installation of small wind electric systems. This new article also covers requirements for individual generators that are limited to 100 kW or less. Multiple wind turbines can be used in accordance with this article, as long as no single turbine exceeds 100 kW. This article is patterned in format after Article 690 for photovoltaic systems.
Tickhill
Started generating solar power at the cabin this weekend. :) Albeit temporarily. I took the 2 new 165 watt 35volt panels and set them against a trailer in the sun. Ran a temporary wire to the Outback FM-60 charge controller. 220 watts max, in a wooded area. Its amazing to watch the MPPT controller adapt to squeeze the most power out of the panels even when partially shaded.
Don was right, its hard to not keep checking the solar power gen. status on the Outback.
Next weekend the panels get permanently mounted on a 20' 4" post along side the cabin. Lucked out with the post, stopped by a local welder to ask about having bracket made to brace the (yet to be purchased) post to the cabin and he said his neighbor had a bunch of galvanized 4" schedule 40 pipe for $30 a 20' length.
Reasonable price on the used pipe.
Quote from: TheWire on August 29, 2010, 07:23:40 PM
Don was right, its hard to not keep checking the solar power gen. status on the Outback.
It took about a year and now I glance at it only once in a while. But I do check the daily stats using the Mate inside the cabin.
Has anyone thought about mounting a voltmeter in the combiner box so you could actually fine tune the array for max voltage periodically? I mounted my combiner box and am seriously considering mounting a voltmeter that I can switch in/out of circuit to maximize voltage. Just wondering,
thanks
When it comes to this question my philosophy is "don't sweat the details".
If by fine tune you mean to optimize the horizontal angle and solar south for a particular day/time, what about tomorrow and the day after? What about the day that's cloudy until 4 PM and then the sun comes out for a couple hours? If the power needs were that critical a reliable tracker might be worth looking at.
Our solar system exists to serve us, not the other way around. I make an adjustment a few times of the year to the horizontal angle, maybe 4 changes maximum. That's it. As for pointing it where the sun should be in an east to west sweep, I picked more or less solar noon. We haven't had to run the generator tp make up for it yet.
Not sure I follow you, Tickhill. Wired in series gives the max voltage or if too high for the MPPT then series parallel cuts it to a usable voltage. The MPPT controller constantly samples and matches voltage amp draw of the load allowed to get the most watts out of the panel / load compination for whatever way it is wired - within it's capacities and specs that is.
I check with a handheld voltmeter for most testing specs or wire to the panel specs from the manufacturer for proper system design voltages.
Oh - now I understand you were talking about angles and max output.
As Don mentioned - seasonal changes are probably all that is helpful.
I see ya'll's point. Probably more trouble than it is worth then. I have been trying to do too much with 155 watts of PV, so maximizing has been a way of life for nearly a year. Dad and I hope to get the new panels up on the mount by the weekend. Glenn, the SUN 3024 inverter/charger came in today and I got it in the system this evening. Looks like one of China's finest but it has all the bells/whistles. It favors a Xantrex on the outside. Will definitely know more once the panels are up. Thanks for your input, blessings
Cool, Tickhill. Looking forward to seeing how it works. If you get a chance see if soft start or variable speed drills run on it or let us know about any odd things about it.
My Bosch soft start variable speed rotohammer will not start on my Trace 4024 sine inverter the first time unless I have a regular motor such as a saw running but after the first time it will restart subsequent times as long as it is kept plugged in.
Thought I would post a picture of the SUN SL-3024 inverter/charger. Mounted in vertical position.
Thanks, Tickhill. Much fancier than I expected.
This thread is packed with useful info and I've learned alot reading through it. I'm also planning on being off grid for a while, until such time enough new parcel owners come along to share the costs of bringing in power. I've been looking at inexpensive travel trailers to live in while I'm cabin building and noticed all the RV appliances I see are made for 12V. It seems if I were to keep the battery bank in a shed abutting the cabin, the run could be kept minimal and maybe eliminate the need to run a higher voltage. I'd be charging with a few panels while I'm not visiting and plan enough power for a 3 day stay and using propane for stove/hot water. Considering the RV appliances are all low wattage, geared to 12V, small in size, and come with a nice set of matching oak cabinets made to maximize on space, it seems gutting the inside of a $3000 RV whose equipment was in good shape would solve all appliance/aircon/heating/cabinet issues for a while, no? Has anyone done this and run into any unforseen issues?
Doc
Just guessing that the cost of bringing in power even shared could buy you a nice off grid system.
If you are going to be a full time resident you may want to get away from the 12v stuff for more flexibility. Inverters are pretty efficient and regular stuff has more choices as well as usually being cheaper. If part time it could be a toss up.
We bought a high end three burner RV cook top and it is excellent - Magic Chef made for Airstream. Quality varies but it could be all you need too.
I was originally going to use the propane range, fridge, furnace, water heater and the roof top A/C, and lights from an old RV in the cabin we were going to build. Oh, even the shower unit. In the end we wanted a bigger fridge. We decided we wanted a range with a bigger oven. We decided to use wood stove for heat and supplement that with propane. I decided against the RV furnace as those things are power hogs. The wall propane heater we use as backup can work without a blower; the RV furnace can not.
The roof top A/C was going to need more work to install than I figured it was worth. And the RV lights were fine in the RV, with a low ceiling and lights quite low over the table, sofa, all seating areas. Lifted to a higher 8 ft ceiling that wasn't going to work as well.
Also after working out the wiring for 12 volt and having some 120 VAC for microwave, etc, the total wiring cost was getting out of hand. You need bigger wires for low voltage, higher amperage.
We wanted to use a regular 120 VAC TV and DVD player. We wanted occasional use of a toaster, a blender. I wanted to be able to use power tools and recharge batteries for them, the laptop and the cell phone. A lot of those things could be done off 12 VDC, but in many cases not with the same carefree ease. Another factor for me was my desire to make our cabin more user friendly in not requiring special things like 12 V light bulbs. I wanted CFL lamps. I would like LED lights but still have not met any that I really like.
So for me, for my wife, I decided it was simpler to build the cabin in a more normal fashion using 120 VAC power for almost everything. That makes it easy to take things from home and use them in the cabin. We have a few 12 VDC Thinlite fluorescent under cabinet lights and the water pressure pump is a 12 VDC Shurflo. We also use an RV water heater (propane w/pilot flame).
That works best for us I feel. I know there are others who have made a 12 volt DC system work for themselves. It can be done.
One factor not yet mentioned, is whether or not your build will have to meet the conventional building codes. RV appliances are not approved for a conventional style residence. If code gets involved it does not matter if the structure is off grid or not.
When looking at what will work best for you in your cabin I'd begin with performing an energy audit, an honest evaluation of what your power use will likely be. I used a Kill-A-Watt meter to measure actual use on many things. Once you know that, add in a cushion for growth. There is an Off Grid Calculator available for download in the General section of the forum.
Anyhow that's how it all shook down for us. We use the RV we lived in before beginning cabin construction and through the first year or so of the build, as a guest 'house'. It actually hasn't been used as much as we thought it might be and unless that changes we may decide to sell it if we can get a minimal amount for it.
Thanks for the info. The code requirements are one thing I hadn't really considered. The cabin will be something in the order of 18 x 24, seasonal only. A local said that the town has different requirements for a seasonal cabin and year rounder, but I've not verified that, only that anything over 144sq ft needs various permits.
As for energy requirements, I came up with a rough estimate based on compact refrigerator, TV, microwave and up to 5 CFLs at 7 watts per, and occasionally the well pump. Heat is woodburning stove with propane backup. Hot water will be propane. I figured most of that would be along the same wall the battery bank would be up against, limiting the length of the wires.
I'll need to check in with the local building department to see if a full electrical system is necessary. Thanks for the good advice, and the heads up.
Doc
Hey Doc,
Your 7 watt CFL's have my eyes going nuts, but this may just be me. :( However, I like to mention this as at one time I could have done with 7 or 11 watt CFL's. But no longer for reading, unless the lamp is 'right there'! My 64 year old eyes don't handle dimmer light and lower contrast very well anymore. There are a number of factors at work, but the bottom mline is that is how it is. Younger eyes like our son's could easily do with half that. Possibly by the time he is older and may develop problems there will be lighting technology that will be as bright as toidays 23 watt CFL, but more efficient and very cost efficient to boot.
I have 23 watt CFL lights, more or less equivalent to 100 watt incandescent output.
Check on the code requirements. Local officials do have a lot of leeway when it comes to things like being off grid in the boonies. Here, even tho' we're off the grid and lost in the forest the state construction division was not going to approve any electrical unless it was code compliant right down to the spacing of receptacles, etc. Everything. I built according to the code that was in effect at that time, but never invited them to the party.
I hear you, Don. I gained my distance vision with Lasik surgery 10 years ago, but at 45, I'm holding everything an arms length from my eyes now. Hello reading glasses.
I wonder if LED bulbs will soon be as cheap as the CFL's. They tend to be more of a focused beam and need reflectors to spread the light cone but draw amazingly little. That's a nice type of light for reading. I'd imagine lights being a negligable part of our energy plans in the future, cabin or otherwise. That leaves the microwave and pump. No way around that, I'd guess.
Now from my experience in the last few years of looking at land and camps in upstate NY, it seems that many landowners have put up sheds and garages, not advertised as cabin or home. Once inside, it's clear from the bathroom and small kitchen they are cabins indeed. They're way off grid, and in questionable state of repair. Doubt any of them could get a CO. Maybe it's a wink wink, nod nod thing, but the brokers always say, it's a hunter's garage, with the ability for an "overnighter". Anyway, I'll call the building department on Monday and get more info on all that.
And speaking of off-grid, Long Island escaped Hurricane Earl tonight, along with the usual power outtages that follow. Nice to be online here using power to ponder the lack thereof.
Cheers,
Doc
Here is a link to some of the stuff I am doing with my new Sunelec panels and Morningstar MPPT controller making about 7 kwh per day from 1140 watts of panels stationary mounted to the roof. I didn't want to duplicate the post here. I'm happy with the new panels. :)
They are grade B but it seems all that makes them that way are - No UL listing and minor cosmetic chips around most of the edges of the solar cells in the panels. They fully perform to spec.
http://countryplans.com/smf/index.php?topic=151.msg121308#msg121308
NIce job, Tickhill - much fancier than mine. The Outback would have been my other choice for a controller but I have wanted to try Morningstar for a long time too so got it.
Thanks Glenn, I called Tony with Sunelec this week and asked when he thought they might have some more of the 190's in because they were no longer listed on the website, he asked how many I wanted, they had 24 left over so I have 3 more coming next week.
I will have to do some more bracing, probably will make them stationary at solar noon. Those panels weight alot more than the ones I took down.
Wow, Glenn you got 7 Kw-hr from 1100 watts of panels per day !!
I was projecting about 10 KwHrs per day from 2460 watts of Evergreen panels (12 205 watt panels from Sunelec)
based on zone 5 and this calculator
http://www.wholesalesolar.com/StartHere/OFFGRID/OFFGRIDCalculator.html
You are doing good !
I think I have talked myself into the Xantrex XW series charge controllers and inverters -- the charge controller can handle a max of 60 AMP DC (the panels should give about 50 A max)and the XW6048 inverter (6 KW output with 12 KW surge) should handle even the largest shop tool I can think of....)
Now if I can just get a winning lottery ticket for a bank of Hup batteries (or Rolls/Surrettes)
nice job on the mounts tickhill (and you too Glenn :) )
I almost have the solar panel mounts for the Red Rider "low speed vehicle" completed (4 50 watt panels and a Xantrex C-40 contoller...pics to follow ) and yes we did get the $5335 tax rebate and cashed the IRS check imediately, too -- lest they change their mind --
It did my heart good to know that our tax dollars helped to save the jobs of those Chinese slave laborers that built the LSV -- God bless our insane congress critters -- at least the batteries were built in North America (Canada) (NOTE: some sarcasm here)
I reset the counter again this morning - still having a hard time believing that myself, Windpower. Todays count was 7.310 kwh. [ouch]
I was not expecting over 5 or a bit more myself. That Morningstar is really grabbing all the watts. This is the first time I have bought a big enough batch of panels at one time to warrant getting the extra good controller.
Thanks for the compliment on my mounts, Windpower. I know I did a real professional and craftsmanlike job... heh
It is the kind of quality I have come to expect from myself.... at least they will probably not blow off the roof.
At about $10 for boards and $5.00 for screws, costs were getting a bit out of hand but I figured ...Hey lets splurge on this project.... Can't take it to the grave with me... [waiting]
Actually Glenn I really did like your mounts
I am big on practical and inexpensive solutions to problems
Maybe this has been covered here already but
I am trying to find a place for the batteries --what are the practical low temperature limits for winter operation
I have a cement "pump house" on the property I think it would be not too difficult to keep it at 50 F in the Wisconsin winters and of course in the summer it probably never sees much over 80 F
It is also right next to the windmill tower where I plan to mount the wind generators that may use the same battery bank or another bank
There is also a cistern about 15 feet deep that is very temp stable probably 50 to 60 F year reound -- not sure I want to put a bazillion pounds of lead that deep though or climb down there just to check and water the batts once a week
I think Dave Sparks mounted his extras in a similar fashion also as I recall.
Others have mentioned using wood also.
My batteries get into the thirties in the winter (air temp). As I recall it is harder to freeze a fully charged battery - I think Mtn Don is up in the cold weather and cars often sit out in the cold.
I think we fill our batteries ever three months or so but check them in between. Old batteries require more filling -use more water.
Glenn, I checked this morning and the new panels, according to the Outback, produced 4.0 kwH yesterday. Dad and I adjusted them most of the morning so they tracked with the sun. This morning I pinned rotation at solar noon and I will check in the morning to see what they get in a fixed position. There is not a cloud in the sky here in North MS today and a little wind. I'm just not used to so much power being produced because all we had last year was an 80 and 75 watt panel. Right now my Dad's shop lighting and storm shelter are being supplied by the PV's. We couldn't even keep the batteries fully charged til now. I really tried to make the wind work for us but we have breezes not wind here. PV just sits there and hammers out the juice.
That is great, Tickhill.
Note that with wind you need to be a minimum of 30 feet above the tallest obstacles - trees etc, in your area, but 80 to 100 feet is better and will have at least 3 times the wind you will on the ground. Surface friction - turbulence at ground nearly stops the wind.
I got another treadmill yesterday at the SPCA yard sale for $10. This one has a 130 volt 2.5 max DC motor in it. That will make a good wind generator with proper gearing. Some of them I have see have a multi-v belt running on a small and big pulley. I think that may gear it fine and the thin multi-v belts don't use much power. Haven't built one yet though.
I've read the entire thread and I've hurt my brain trying to follow all the useful info here.
I do have one question, I have seen on other boards where they promote forklift batteries for the pv system. I did not see any reference to this type of battery so here goes, Will a forklift battery work for a solar system?
Brian
It will...... but.... [waiting]
L16's are like a forklift battery - golf cart batteries are like a forklift battery but smaller - used in many manlifts etc. Most all have the lead antimony plates that are very durable like a forklift battery.
6 volt batteries in series or series parallel= the voltage and amp hours of a forklift battery.
If one in a set of 4, 6, or 8 in series (24, 36 or 48V) gets a bad cell you can replace it by itself with a used one if they are older , or a new one if they are newer for from $100 to $300 or so dollars.
Usually you will be running more than one set of series batteries on a larger system so you are not out of power while you get it fixed.
As Dave mentioned, you could go to Costco and get a golf cart battery to keep your system running -even putting it in with the old L16's
If a forklift battery loses one cell, you replace a multi-thousand dollar battery all at once. and likely you will not have backup until you get it fixed.
L16's and golf cart batteries are easier to find and not such a big expense all at once. One man can move either of them. It takes a crane or forklift to move a forklift battery. Can be done but not real practical. Possibly consider it if someone gave you one, but likely it would not be in great shape or have much storage capacity. :)
That makes sense.
Brian
Quote from: Windpower on September 05, 2010, 05:35:43 AM
I am trying to find a place for the batteries --what are the practical low temperature limits for winter operation
Battery capacity is rated at 77 degrees F, 25 C. The chart below shows how the temperature affects the capacity. At freezing temperature the capacity is reduced by about 20%. At the same time that capacity is falling the probable life span is increasing, so cool temperatures can be good as long as the battery bank is large enough to avoid over discharging. Cold temperatures also require an adjustment in charge rate which is the advantage to a charge controller equipped with a remote (battery) temperature sensor.
![](https://i139.photobucket.com/albums/q305/djmbucket/solar/Batt_temperature1.gif)
Higher temps offer increased capacity while cutting projected lifespan.
I would think that if you can house those batteries where they would run between 50 and 80 degrees F you would be doing good, getting good lifespan and being able to make pretty close to maximum use of the rated capacity. The batteries at our cabin run quite cold in the winter. Because it was rather oversized we've not had any capacity problems.
OK, have been struggling with my solar power. I have seven (7) 15 watt Northern Tool panels connected in parrallel and connected to a Sunforce 30 amp charge controller. However, even under the best lighting conditions I have only been able to produce .6 amps and usually only .2 amps to charge my battery bank (running a 12 volt system). Have used the connectors provided when I wired the system, but am wondering if I should cut the connectors off and use wire nuts to connect the wires or even soldering all the wires. No addditional wire has been added, so I don't think power is lost in the wire length. Shouldn't I be producing much more than that? Any help would be appreciated.
Nice looking installation tickhill.
Forklift batteries. My own opinion is that if you have a forklift go ahead. At 115 lbs apiece a Trojan L16 is already heavy enough.
My dream battery bank would be 12 Surette/Rolls S-1380 2 volt cells in series. More capacity than we now have; probably want some more panels too and then we could use an electric fridge most likely and save propane.
7 x 15 = 105 watts, divided by 12 volts = 8.75 theoretical amperes at panel rated output.
How are you measuring that amperage? Test meter wired into one of the wires between panels and battery, like in the + lead. Are the batteries fully charged when metering the charge rate? If they are full then the charge controller is doing its job and keeping the current to a float rate.
I have 1 1/2 of those panels hooked to the RV batteries to maintain their charge over the winter. (1 1/2 as one panel is cracked and the output has fallen ;D ) It's been a while since I metered them as the batteries stay up fine. But IIRC on a sunny day I was getting about one ampere from the one good, unbroken panel.
So with them all parallel connected you should be getting much more than the 0.2 to 0.6 amperes. Either the panels are not putting out or there is excessive resistance somewhere. With loses like that I would expect to find a warm to hot connection someplace (full sun and battery needing to be charged).
Wire nuts are a poor idea for DC circuits. If it was me I'd cut the leads so they are only a bit longer than required. Leave some extra length in case you have to reconfigure them someday. With a good terminal lug crimped or soldered on each lead you could make up your own combiner with some strap copper, a drill, S/S bolts, washers and nuts (in a weatherproof plastic box). Crimp connections are fine; better in those cases where joints end up being poorly soldered. Connect the charge controller to the bus bars with adequately sized wire. With each panel wired to a bus bar like that it is easy to remove a panel at any time if needed. Plus you would have less resistance with shorter leads and better connections.
Have you tried metering the output from each panel separately?
Thanks for the reply. I'm measuring the amps thru the charge controller. Checked each panel with volt meter during install and all read between 12 and 14 volts (didn't check amp reading though thinking back, probably should have). The connectors provided were plugs and with either cigarette lighter ends or just bare leads. Took the ones with the bare leads and crimped them all together. Plugged the panels in and ran wiring to the charge controller. Checked voltage at charge controller and got the same reading as directly from the panels. Purhaps a charge controller issue?
Do you think creating the bus bars inside a weather proof box would work better?
Also, can you separate panels to where half are in the sun during the morning and the other half during the afternnon? Or would you lose power to those panels not charging while the others were?
If your panels are like the ones I have on the RV they came with a "trailer light" connector, into which you can plug the 'extension' with the bare leads or the cigarette lighter plug. I would cut those connectors off. Before doing that I would carefully mark the positive and/or the negative leads. I use white tape on negative wires. Any system you can remember works.
If you have all the positive leads (7) connected together and then all 7 negative leads connected together (parallel connections) and measure the voltage in bright sunlight you should have something like 18 volts, maybe more with nothing at all connected to the panel outputs. This would be the same as the output from one panel.
With the charge controller input connected to the panel outputs and the charge controller output connected to a partially charged battery, in bright sunlight, you should likely see something like 13.5 to 14.something volts at the battery. Measure the amperage in either the positive or the negative lead from the charge controller to the battery. That will be the current the charge controller is passing to the battery. The battery needs to be partially discharged in order for this to be accurate. Theoretically the charge current could be up to 8.75 amperes, but most likely your real world result will be a little less.
As for half the panels facing one direction and half another direction, everything in parallel, and feeding through the same charge controller I'm not certain on the outcome. I think that should be okay with the equipment you have. I'm not convinced that will result in any better total power output for the day if the weather/sun conditions were the same all day. ??? You could improve the output of the set that was directed for best AM power but at the reduction of the power from the ones that were directed for PM output. With everything pointed the same direction, most likely south, I believe it will all average out, given the same weather/sun conditions.
Thanks for the temperature info, Don
I am thinking the 'pump house' is going to be a perfect location for the batteries and inverter and charge contoller
Thanks for the input Don. Next time I go to the Cabin, I think I will try and re-wire using your suggestion. I was suspect of the "plug-in" connectors and had thought about wiring differently from the start. I am new to solar power (as you can tell), but am eager to have an operational system and staying off the grid. Nothing major, just lights and a ceiling fan. At the most, 3 or 4 CFL's and a small fan.
My panels are wired to a small battery bank (2-35 amp hour batteries) and then to a small inverter. Doing my rough calculations, the 7 panels should easily keep the batteries charged.
Am open to an suggestions and will post later with more questions I'm sure.
With a small system like yours a fan that runs right off the batteries might be nice. DC lights too so you save the inverter loss. As much as I like my own inverter powered system, for something very small I would think about strictly DC. Just a thought. You can get DC powered CFL lights with the screw in edison base if you do not like the type of light LED's put out, or their cost.
Here's some info from the Trojan battery company. This may be specific to their batteries, or in other words, if you have some other brand of batteries this data may not be what the other guys recommend. This data is also for flooded lead-acid batteries, not any type of sealed or non lead-acid battery.
![](https://i139.photobucket.com/albums/q305/djmbucket/solar/batterychargevoltages.jpg)
http://www.trojanbattery.com/BatteryMaintenance/Charging.aspx (http://www.trojanbattery.com/BatteryMaintenance/Charging.aspx)
The Morningstar takes the L16's a bit higher to 32v on their special L16 battery setting which agrees with my experimental findings and info I rec'd from an knowledgeable solar dealer in Lake Powell area.
A question regarding Equalization was asked in another topic. I thought it might be best to copy it to here and respond here as well...
Flooded lead-acid batteries, imperfect things that they are, will develop inequalities between cells over a period of time. They may start out with more or less the same specific gravity (state of charge) but this may wander over time. The goal of equalization is to eliminate these variances between cells. This is done by applying a higher voltage than what is normally used, and at a low charge current. Equalization charges will cause excess gassing to take place, therefore the fluid levels must be watched. Equalization voltages also causes the "stirring up" of the electrolyte. Tall batteries may be more affected by stratification than shorter batteries. The rapid bubbling mixes things up.
Equalizing produces large quantities of hydrogen and oxygen. Good ventilation under equalization is necessary. I open the battery enclosure doors and leave them open.
Regular battery charging has three stages. All good battery charging equipment will have the basic three, Bulk, Absorb and Float. A better or best charger will also have the equalization capability. Whereas the bulk, absorb, float charges are programmed in and will automatically progress as the battery charge builds (in the best units they are user programmable), the equalization charge is usually initiated manually.
In the bulk stage, current is sent to batteries at the maximum safe rate they will accept until voltage rises to near (80-90%) full charge level.
In the second stage, absorb charge, voltage remains constant and current gradually tapers off as internal resistance increases during charging. It is during this stage that the charger puts out maximum voltage.
The third stage is float. After batteries reach full charge in absorb, the charging voltage is reduced to a lower level to reduce gassing and prolong battery life.
If battery power is being consumed during the charging the charger can shift back and forth between stages as needed.
Equalization should only be necessary a couple times a year. Too frequent use of the equalization cycle could reduce battery life. If the specific gravity readings show irregularities with increasing frequency that may be a sign of a batteries impending demise. Glenn had had some good fortune with desulfating processes.
Here's another chart with slightly different values....
![](https://i139.photobucket.com/albums/q305/djmbucket/solar/batteryvoltages.jpg)
That one is from TheSolar.biz http://www.thesolar.biz/Battery_charging_article.htm (http://www.thesolar.biz/Battery_charging_article.htm)
It probably can not be stressed too much that equalizing applies to flooded lead-acid batteries. AGM and gel cells are not the same. Flooded lead-acid means the type of battery with removable caps, ones you can add water to. Other battery types can be damaged.
Also, mentioned before but again....Keep water levels above the plates during equalizing or permanent damage may result.
Got it, Thanks ;)
Glenn, got the other 3- 190's yesterday and hope to get them online this weekend. Will probably add another set of batteries also. Then it is time to bury conduit and run the power to the barn. Dad and I will probably wait for some rain to soften up the ground.
Don and others! here is a link from a ways back where folks at the outback forum were trying to use energy wasted after the battery was mostly charged offgrid. They basically are heating water with a coil. It does work but I have always thought it was a big time waster as it is so much more efficient to use the sun to heat water directly. It is far better to use an electric heat pump for excess energy. It might give you some insight on your experiment Don. Let me know and I can get you a model number for and SCR.
http://outbackpower.com/forum/viewtopic.php?f=29&t=2865&hilit=electron&start=25
Thanks Dave.
Well.... I haven't posted the reason for what Dave just referred to before this. Here goes as succinctly as I can.
The PV panels don't need to do much when we are not at the cabin as there is no electricity used for anything. The PV system simply has to keep the batteries at full charge. So there is "wasted" power. Anyone with a PV system hates to waste a single watt, let alone a whole days worth.
What to do with the excess power? Heat something comes to mind.
One of the drawbacks to a cabin in the boonies is that during freezing weather, December to April, more or less, water freezes. Dry/dried foods such as beans, pasta, rice, flour, etc. goes only so far. You can only eat so much peanut butter. Frozen glass jars (spaghetti sauce) break. Metal cans (beans, meats, fish, veggies, fruit) may have seams crack and spoilage set in when it warms. Freeze dried food varies from so-so to okay in my opinion, with okay being a euphemism for "at least I won't starve to death as long as I have this."
So it occurred to me that possibly there was sufficient excess PV produced power to use with a resistance heater, in conjunction with an insulated box to provide a storage space that would remain above freezing.
I asked Dave if he could recommend a solid state relay to use with the diversion capability of the FlexMax charge controller. That would allow the excess power to be used for heat after the battery state of charge was assured to be full each day.
Obtaining an appropriate SSR is no problem. PV cells are the real problem. PV cells are still grossly inefficient.
I have collected weather data, including solar watts per square meter. Winter sun angles sure kill what's hitting the panels. I've run my figures a few times over a long period of time. Without getting into the actual numbers let's just say that maybe IF we had three to four times the number of PV panels, then maybe we'd have enough excess PV power to heat a small food storage locker. A well insulated locker with lots of mass to help make it through the night.
This needs some more thought. As Dave has suggested, it may be much more advantageous to use a solar water heater and storage tank with a small solar driven pump. The collector could be set up as a drain back type and used antifreeze as the liquid. More of the suns energy would be used. The downside, in my case, is the solar situation at the cabin is poor. That actually depends on the season. It's actually great having all the shade in the summer.
With some more thought this could be used to provide warm/hot water for domestic use. (In the winter we usually do not even use the water heater as the water system is left drained for freeze prevention. In summer this could save a little propane, not that we use a lot for water heating.)
If anyone wants to get into my numbers, calculations and theorizing, just say so.
Thoughts, comments, arguments, encouragement, discouragement, etc. all welcomed.
Spin off to a cold weather food storage topic? Or leave it here are it is related to Off Grid Power? Or perhaps an Off Grid, non electric power topic?
Don: Do you think some sort of root cellar would work?
Got the extra panels up, here is a picture. Will post kwH sometime tomorrow. We went from around 19 amps charging to 35 as soon as I brought the panels online.
Quote from: Bob S. on September 10, 2010, 11:42:58 PM
Don: Do you think some sort of root cellar would work?
I'm sure that would work. I simply don't want to dig a big hole and all the rest that would be required. It would have the advantage of being a place I could leave some potatoes, carrots, but considering that it is just to allow us to go up there for maybe a total of 20 nights from mid December thru March I'm not sure that's what I want to do. I may change my mind over time. Thanks for taking the time to respond.
I/we did more thinking about this while we were at the cabin the past couple of days. Some more thoughts, ideas and questions to come. Likely in a new topic.
I think you could keep a root cellar from freezing inside with a light bulb.
Quote from: Bob S. on September 12, 2010, 07:13:20 PM
I think you could keep a root cellar from freezing inside with a light bulb.
There are many places where that could be a solution. However, resistance electrical heating can be too big of a drain on small off grid systems. Thanks though.
A new off grid problem and solution.
DSL modems seem to be highly susceptible to power surges and resets as loads change on inverters. Nearly every pump start our DSL resets and then it is 2 minutes more to stabilize. A real pain when posting on the forum.
Apparently it is a common problem in countries without stable power. I often wondered but found the answer on a forum from Pakistan. The tech there said that the DSL modems were not made to handle the instabilities in inverter power. He recommended a UPS. Before that I was not sure if they smoothed out the surges or not. They do as the tech said.
A good quality UPS (un-interruptible power supply) takes whatever power there is available and smooths it down sending out stable power to the battery and surge protected outlets. I got one from Amazon and it arrived today. I have been running today through multiple pumping cycles without one interruption. Hooray. :)
This is the one I got - it was the most value and biggest for the money as well as being a good brand and having high recommendations - note that there are some that others would never buy again. Read the reviews before you buy anything.
http://www.amazon.com/APC-Back-UPS-Outlet-550VA-120V/dp/B0019804U8/ref=pd_ys_iyr1
I did read of one person trying to stabilize a cheaper UPS as he had problems with it, but good ones are pretty cheap and take care of the problem.
Today - second day of the UPS -
I can hear it switch over to battery (relays click) as the pump starts cause system surges. No internet DSL loss. It just happened.
That's cool! Another use for the old UPS we don't need. :D
Question for Glenn:
Glenn, does your Bergey dump directly to the diversion load when the controller says the batteries are full? That is the power is NOT fed to the batteries and then bled off. The excess power goes directly to the diversion load, a pump in your case IIRC. twin 12 volt ford starter relays.
Glenn's answer....
I did the above question originally via IM, then realized maybe someone else might be interested in his response. So here it is....
It dumps to the relays in my case
But now that you mention it... making me think here - The red light comes on - I assume it is dumping the power generated directly to a heater etc - or my relays, but the wind generator cannot stop producing and it is hooked to the batteries so I don't exactly know how it is done. My pump bleeds the load off of the batteries but not sure what the bergey does with the gen power.
The manual is available from the Bergey site I think for free download - XL1 wind generator.
The answer to this seems to be that the common diversion method is to charge the batteries but bleed or skim the excess off the batteries.
As the battery bank voltage approaches the battery
regulation voltage, the PowerCenter controller
will first try to restrain this voltage by applying the
5
optional Extra Load (or "dump load"). The Extra
Load function diverts current from the battery to
an air or water heater.
I've also found references to dump loads that indicate similar operation. It seems there is a reason for this method. Dump loads are made to operate within specific voltage ranges, such as 24 volts with a range of maybe 24 to 30 volts. A 24 volt wind gen could be putting out 80 volts at higher wind speeds. Without having a battery to even or smooth out the voltage the heater would burn out.
Similarly, and thanks to NM_Shooter for this, things like heater elements can behave strangely at voltages far from their design specs. The design impedance, resistance in other words is reached when the coils or nichrome wire reach operating temperature. At lower temperatures they may be quite different from their design point values. I verified this on two different electric heater elements. This can make it difficult to use a heater coil designed for one voltage at another that is significantly different. The calculated ohms at the design voltage can be very different at lower volatges where the element will not be able to reach design temperature.
Why am I bothering with this? I was looking into using the excess, the un-used power from my PV modules as they sit there in the mountains with the cabin vacant. I wanted to use the power for heat; perhaps an air heater, perhaps a water heater. I also thought it preferable to divert the power before it was processed by the charge controller. It seems more efficient to use it right away, rather than feed it through batteries. But that seems to have problems or issues.
Maybe this'll be of interest to some other tinkerer.
We probably have covered this already, but a reason for the dump load to be applied for a wind generator is that if the generator is not allowed to continue charging, ie: is disconnected from the batteries, it will or may increase in rpm's until it possibly destroys itself.
It must not be unloaded during overcharge conditions but rather furled or the load burned off in one way or another.
Keep in mind that anything you run off of your AC inverter will pull the battery power down also. Relays can be hooked to the dump load to run a water pump, heater or many other things also indirectly.
Can anyone recommend a good thorough book on residential solar systems. In particular I'm interested in the pro's and con's of grid tie versus off grid systems. I *think* I have a decent understanding of the wiring required for a off grid system. I haven't been able to find a decent schematic for a grid-tie system or the extra components required.
Is it worth it economically for a grid tie system? (spinning the meter backwards to reduce electric bills or even get a rebate?)
By grid tying is there any extra tax or fees from the power company or local gov't?
I live in N.W. Indiana and we get plenty of sun year round, except for a few short day stretches in the winter.
Thanks,
Shawn
After more research I don't think I would want a grid-tie system.
according to the below site a grid-tie system won't operate when the "grid" is down ??? What the heck, why buy a expensive PV system then be in the dark like everyone else during power outages? This does answer the question in the back of my mind, " What prevents the system from back feeding and possibly injuring a lineman when the grid is down?" Now I know....it doesn't produce voltage at all. I was thinking that there would be a auto-transfer switch disconnecting the grid from the house ???
http://solar.smps.us/grid-tied.html
Most grid tie systems do not have batteries. That's why they go down when the grid goes down.
Automatic switches prevent feedback, the same sort of thing is required if one has a generator backup with a normal grid only home.
It is possible to have a grid tie system with batteries for backup. Also possible to do grid tie with a generator for automatic backup if the grid goes down. Frequency of outage would be one factor to consider.
Sorry, I can't recommend any books.
Not all power companies offer the same payback deals for grid tie. NM's major supplier has an excellent payback. No guarantee they will always offer the same deal though.
Is it worth grid tieing? That depends on personal needs and wants. No batteries means money saved and less bother. Not everyone wants to tend the system. Of course some folks pay guys like Dave to do that.
Not quite right Don, but thanks for the plug! We only go where the power lines don't! I would be go bonkers otherwise! ;)
Quote from: MountainDon on September 20, 2010, 06:54:36 PM
Is it worth grid tieing? That depends on personal needs and wants. No batteries means money saved and less bother. Not everyone wants to tend the system. Of course some folks pay guys like Dave to do that.
I am thinking about tieing in some solar or maybe wind to our next phase in our 'moving to the ranch' build. We are on the grid, and at this time have no intentions clipping the power cord. However it would be nice to have back up. Talking to some of the ranchers and a store owner up there, it seems as if there is a major outage there are three places at this time they have to come and reset manually. Summer time this takes about a hour to an hour and a half. They are close to the road and easy to get to. In the winter [waiting]. Hey it is Idaho winter.
That said how much time is involved in tending to a system that is large enough to tend to the basic needs of a home in the winter time? Very easily heated with wood but would have some propane back up if need be so there would be a fan there. We would need to run a well pump, few lights, refrigerator and a couple computers up and going and what else am I missing? We have a wood cook stove for the winter time, electric or propane in the summer.
Any ideas?
Time; once everything is up and running. With quality hardware (inverter, charge controller, panels, etc.) there should be no real maintenance there. Keep the dust off. Wet cell lead-acid batteries require maintaining the electrolyte level. I have not had a lot of experience other than our own system. Our batteries use very little water. I've only added water about every 6 months. Batteries that are used more, discharged more deeply and then recharged more than ours probably use more water. BTW, water should only be added to batteries that are fully charged if at all possible. That's because the fluid level falls as the charge is depleted. If the plates are not covered they should have water added to just cover them and then charged. As batteries age they may need more frequent watering.
I take and record hydrometer readings every month or so. Mainly just to keep an eye on things, look for low cells. So far it has simply been an exercise in record keeping.
I bought golf cart batteries as a trial. I was worried I might do something stupid and ruin my first set. ??? I don't know what, but there it is. If I was doing this again for a cabin I'd give more thought to maybe buying L-16 batteries instead. If I was setting up a primary off grid residence I would like to have Surrette batteries.
As to whether or not to grid tie... ??? As with all solar generated power, the place to start is with an honest evaluation of power needs, not power wants. At present many power companies offer great buy pricing on user generated excess power. Who knows how that will play out in the future. Here in NM the main reason, as I see it, for the high buy prices on PV or wind power is that the state government has mandated that certain percentages of a power companies power must come from renewable sources. A grid tied home counts towards that figure. So they gain without having to spend any money for equipment. In fact they charge the home owner a hookup fee before giving anything in return.
In a similar vein, the local water utility has pushed water conservation heavily for years. Many people use less water today than a few years ago. The water company revenue has fallen and they have increased rates because we've saved water. OK, maybe the price would have gone up even more if we had not conserved. My point is, that if too many people installed grid tie systems would the incentive be reduced when they reach a point of too little demand from them?
One nice thing about looking at this early in the design stage is it would be relatively easy to divide the wiring up into "mission critical" things that one would like to have on some sort of a backed up power system, plus all the other stuff. Properly planned it could be fairly painless to switch circuits around down the road.
Watch that your grid tie system is designed to be used off grid also. There are many up here who only bank power with the grid and do not have batteries so if the grid is down they still do not have power - no storage - pretty useless in my opinion but it does knock their bill down.
Our 'neighbor' who's been on solar power for 30 years...ya 30 years....uses, get this, caterpillar batteries now. He says he's got almost 1000ah of batteries and his old 500ish watt solar panel array can keep the batteries charged reasonably well Monday through Friday in the summer. They run the generator on weekends for higher demand stuff and he tells me they run way to much as it is.
Anyway, he was telling me that he's tried nearly every kind of battery imaginable over the years and for some reason settled on these caterpillar batteries and likes them.
Personally, not being knowledgeable about these things (sure I've built cell sites in remove location but the engineers chose the batteries) I'd go with something recommend by those who do seem to know -- thanks to Don I'm using Golf Cart Batteries and see no reason why it won't work :)
Anyway, back to the point about power in Idaho, I don't see why you couldn't have a small system in place to provide backup. Since running a small 60 watt system for our well I'm very impressed and having installed (ok it's not complete yet but it's a start) a 615 watt off grid system I'm realizing the hardest part is the figuring out of what you can or might run and for how long -- but once the figuring is done and the system is in I figure we'll know soon enough what 'too much' is d*
I've been told by a solar installer that the golf cart batteries are best because they are designed for repeated discharges to fairly low levels followed by a nightly recharge. They have thicker plates and stand more abuse. The car and diesel batteries have plenty of amps but were designed for massive discharges over a moment or two, followed by extended periods of charging never cycling more than a few percent from full. Could Caterpillar be using heavier batteries? They may not be the run of the mill diesel engine batteries since their equipment may lay still in a field for months, then be called upon to start in frigid weather without fail. I'd love to see the specs.
I would say that gold cart batteries are better for off grid energy storage than a battery designed for engine cranking, but not best. Better than golf cart batteries would be the L-16 type. Best would be something like a Surette.
Also remember battery life is directly related to how deep the battery is cycled each time. If a battery is discharged to 50% every day, it will last about twice as long as if it is cycled to 80% DOD (depth of discharge). If cycled only 10% DOD, it will last about 5 times as long as one cycled to 50%.
I like golf cart batteries for a few reasons, their weight is one. Very cost effective when bought at warehouse (Costco, Sam's Club) prices, though they will need to be replaced more frequently than other types. Great batteries to learn your off grid battery maintenance skills.
I would love to have a set of Surette 2 volt cells, but price got in the way. We'll see how that goes in maybe 5 years.
Re: CAT batteries; links to applications and specs...
http://www.cat.com/cda/files/90229/7/PEGP7801_05.pdf (http://www.cat.com/cda/files/90229/7/PEGP7801_05.pdf)
http://www.cat.com/cda/components/fullArticle?m=37407&x=7&id=241185 (http://www.cat.com/cda/components/fullArticle?m=37407&x=7&id=241185)
http://www.cat.com/cda/files/1386197/7/PEHJ0073-02.pdf (http://www.cat.com/cda/files/1386197/7/PEHJ0073-02.pdf)
Just bigger versions of good quality car and truck batteries, more than likely. ???
A too-small bank of batteries has obvious drawbacks. But is there any reason not to buy and assemble an array somewhat larger than my expected needs.. sort of a "just in case", scenario?
I've been told by others that it's a bad idea to add new batteries to older. Is that to say used and unused should not be mixed, or is it the age of the battery? I was thinking to soften the outlay, I'd buy 3 or 4, then another few each month, until I had enough to set up my system. They'd be unused of course, but would the shelf life be different in this way?
Cheers,
Doc
This is timely
I am shopping for a 48 V bank
I think I have settled on the Surrette CS 6 17 PS
they are pricey (~$800 times 8 :o) but of a new design that allows replacement of individual 2 V cells
shipping is another PITA
and unloading them without a fork lift (OK the JD end loader will help alot) they weigh in at about 220# each
the SolarBiz seems to have the best price but again shipping is uncertain .... maybe another $500
the other option is to get a pallet of 18 Surrette S-530 (older design) but at 'only' $329 a piece and free (or nearly so) shipping from (below link)
would give me 16 for the 48 V bank and 2 spares (is there a 'shelf life' on batteries that have not been filled with acid ?) for about same money maybe a bit cheaper
https://solarconduit.com/shop/batteries/batteries-accessories-flooded-batteries?p=2t
plus they would give more capacity ~ 26500 Watt hours @ 50% discharge compared to the cs 6 17 PS at ~ 19250 Watt hours @ 50% discharge
and prices seem to going up too
Tough decisions ...
Quote from: AdironDoc on October 29, 2010, 03:48:19 PM
I've been told by others that it's a bad idea to add new batteries to older.
Depends what older is. If they were all put into service within a few months it's no big deal. Over a year older it is not advised, but people do it.
To go a little bigger is more than likely a good idea. When you are calculating was depth of discharge are you considering as your aim point.
I am certain that if you buy dry lead acid batteries they can sit in storage for years. The lead has nothing but air to react with and I doubt anything bad will happen. The cells are closed, any O2 will get quickly used up, and that should be that.
Seems to me I recall there being no discount for dry purchase, but shipping and handling is easier as they are not hazardous when dry. Unless you drop one on a foot. ;)
The handling weight sure is something to think about.
Way back when I was a lot younger service stations stocked all their batteries and added acid only when the customer bought it. It was easy to find the acid in 5 gallon collapsible plastic containers back then. Probably a little harder now.
Glenn, just wanted to pass on info on the SUN SL 3024 inverter/charger. I sent it back to sunelec yesterday. It was giving constant over voltage alarms and would not reset properly without having to completely disconnect the unit from the dc bus. I contacted Tony with sunelec and he said to ship it back to his attention, should be there by Friday. I have since rolled back to a backup HF 1200 Modified Sinewave inverter for lights/gargedoor opener.
The price on the inverter/charger was great but I guess you get what you pay for. Will probably be looking for Xantrex or Outback model after final dispostion.
I notice a number of folks in this thread have opted for 120V inverters, or 24V over 12V. How long a run of wire can I use before 12V either becomes ineffective cost-wise, or loses voltage? I plan to either run 12V appliances or use an inverter to 120V if its more cost effective. My cabin will be 20 x 36 with ceiling lights and the like, maybe 2KW/day with three days reserve. Batteries would in a small shed pushed up against the wall of the house, and 500W PV on the south facing roof. I'm pondering 120V versus 12V in terms of simplicity, cost of appliances, need for inverters or other add-ons, and wire costs. Any thoughts guys?
Doc
Thoughts, yes.
1. What sort of appliances would you like to have available for use?
2. Have you done any shopping for them in 12 VDC?
More later on wiring.
Have shopped but not yet bought:
12V ShurFlo Well Pump to cistern,
12V ShurFlo classic to fill pressure tank
12V RV Microwave
12V 10cu.ft. SunFrost Refrigerator
12V LCD TV/DVD Combo.
max of 8 15W LED lightbulbs
I'll state right up front that I do not believe a 12 VDC electric system is advisable in any but the most basic situations. Basic = a few lights and that's about all. But that is me and I wanted more than a few basic lights. I recognize this is my personal bias.
Note that when designing low voltage circuits it is desirable to keep the voltage drop to 3% or less over the run of the wire when under load.
Also note that standard home 120 VAC switches will fail after a very short time when used on DC circuits.
12 VDC RV microwave. Wow! The smallest microwaves are usually around 600 watts or so. That's cooking power. Most back of the case nameplates on a 600-650 watt m-wave will indicate a draw of about 800 watts at full cooking power. 800 watts / 12 VDC = 88 amps! :o That's what the math says, unless there's some kind of magic they've discovered or I don't know about. I am amazed. I must be missing something. But if there was a draw of 66 amps, 12 VDC a person would need #4 AWG wire ti run just under 9 feet and keep the voltage drop at or less than 3%.
If it's the item I saw on a Walmart ad it draws up to 20 amps at 12 volts and the reviews I read are mostly by customers disappointed with the speed; 8 minutes to make 10 oz of cold milk hot. Anyhow, 12 VDC, 20 amps, 3% max drop, #10 AWG wire, maximum length of wire = 7.44 feet. #10 is heavy wire. Solid Romex type is hard to work with. :-\
A 15 watt LED light would be drawing a theoretical 15 / 12 = 1.25 amps. For a 3% max drop that would mean...
2 lights total on circuit, #12 wire, 2.5 amps, a run of 37 feet is okay
3 lights, total on circuit, #12 wire, 3.75 amps, a run of 25 feet is okay
4 lights, total on circuit, #12 wire, 5 amps, a run of 19 feet is okay.
7 amps, like the max on the Shurflo Classic pump:
#12 3% drop 14 feet 5% drop 22 feet
#10 3% drop 22 feet 5% drop 35 feet
#8 3% drop 34 feet 5% drop 56 feet
How many lumens does the 15 watt LED put out? The 26 watt CFL's I have and like as they make it easy for me to read a book are rated about 1600.
Links for those 12 VDC items would be nice. Maybe some of them would sway my personal bias. ???
One of many available online voltage drop calculators.
http://www.windsun.com/Hardware/Voltage_Calc.htm (http://www.windsun.com/Hardware/Voltage_Calc.htm)
Select if you wish to solve for Distance or Conductor Size
For calculating wire runs in a cabin use the "overhead" in the Installation field.
Use "single phase"
Totally agree Don
the cost of an inverter will be paid for quickly by savings in wiring and 'special' appliances
a 12VDC system is useful for only very basic situations -- like maybe a popup camper -- and probly not even then if you are considering microwave or entertainment systems
Tesla was right Edison was wrong
Wow, I knew there would be voltage loss with 12V but hadn't really considered just how big a challenge it would be. A game changer was also a voicemail this am from the code enforcement officer who told me that my cabin would need to have conventional wiring even if "off-grid".
My assumption was that an inverter would rob some power while, um, inverting, and add to the expense of the setup. In light of what you have said, I'll plan around a 110V system. I'd venture to guess the appliances will be cheaper too. Moreover, running a considerable length of wire out to the well pump will be far easier in 110V. I figure 30-50ft to the well, then down 50-100ft. That's a long stretch.
Now if I run an inverter, are there any appliances that are better at 12V such as the ShurFlo, or can it just as well be all 110V?
Thanks for sharing your wisdom, guys.
Doc
Quote from: Tickhill on November 03, 2010, 03:58:24 AM
Glenn, just wanted to pass on info on the SUN SL 3024 inverter/charger. I sent it back to sunelec yesterday. It was giving constant over voltage alarms and would not reset properly without having to completely disconnect the unit from the dc bus. I contacted Tony with sunelec and he said to ship it back to his attention, should be there by Friday. I have since rolled back to a backup HF 1200 Modified Sinewave inverter for lights/gargedoor opener.
The price on the inverter/charger was great but I guess you get what you pay for. Will probably be looking for Xantrex or Outback model after final dispostion.
Hmmm, well I guess that settles that....
It was nice to think something good might be available for a low price. Looks like we have to stick with the standards who care about their name.
I'm with the rest, Boc.
Even a small good quality, FULL SINE wave inverter is better than running DC in my opinion.
Your list has way too much stuff that would be better on AC in my opinion. Not modified sine wave though.
Quote from: AdironDoc on November 04, 2010, 07:42:43 AM
Now if I run an inverter, are there any appliances that are better at 12V such as the ShurFlo, or can it just as well be all 110V?
The Shurflo is available in 12 and 24 VDC and 115 VAC. I run the 12 VDC version of the Shurflo cabin interior water supply pump. My reason was that it is easy to find a replacement 12 VDC pump if the need ever arises; any good RV dealer will have one on the shelf whereas the 24 VDC or 115 VAC would need to be ordered. Plus I could also pull the one out of the RV. Or vice versa.
Running the 12 VDC pump required additional expense to be able to hook it up as my DC system is 24 volt. I have a solid state voltage converter, 24 to 12 VDC.
Shown Here (http://countryplans.com/smf/index.php?topic=2335.msg65662#msg65662) That is better (for the batteries) than running a tap off them for 12 VDC.
I'm very happy with my AIM 2500 inverter. Cost was about $200 and I've run a sawsall and jigsaw off it as well as a TV and playstation, CFL lights, incandescent lights and the Composting toilets dehydrator. We also used it to charge my cell phone and Ryobi batteries for the drill :)
With 6 GCB's my reserve power is limited but with the SunElectric 205 watt panels (3) I'm getting the bank charged to 13.5vdc even on low light days. With full sun it goes up to 'fully charged' which is 14vdc according to the inverter lights.
All in all I'm very happy but have already thought about adding two more batteries and perhaps a 4th panel in the future. Of course the Iota charger will work fine to get the bank charged up more but I haven't wired it in yet.
Just got the quote from the Solar Biz for the batteries
(thanks for the Solar Biz tip, Don)
going with the 6V 546 AH 6-CS-17PS Surrettes @ $710 each
(8 of these for the 48 V bank)
![](http://www.dcbattery.com/rollssurrette_6cs17ps.jpg)
the shipping is only $120 (at least that is the quote -- I think I better grab it before they change their mind)
at over 1700 pounds (220# each) I know I could not get them with the truck for that
This is exciting !
eta
I just noticed there is no handle on these things -- but it looks like there is a molded 'hook' on the side -- anybody know where to get a handle ?
[cool] nice batteries, good choice 8)
Wow, moving those around is going to either take some sweat or some thought. I'm not a burly sort and if I had those, I'd slice the bottom off a dolly and spot weld two blades extending forward like a forklift to catch those grooves. You could roll up, tilt back and away you go.
As my wind project finally comes to completion, can someone tell me whether there is any difference in load on an alternator for a single 12V battery and an entire bank of them? My father says a larger bank of batteries discharged to, lets say 70%, will take more torque at the alternator rotor than one or two. I say once the voltage exceeds the battery's, it pours in like water into a tank, regardless of how many there are. Of course it would take much longer, but at the rotor, I can't imagine you'd know the difference? What say you?
The alternator has an upper limit as to how many amps or watts it can deliver. If the alternator is rated at 70 amps output (840 watts) that is the maximum it can deliver whether it is connected to a single 12 volt battery or to a hundred 12 volt batteries(in parallel). It would take 100 times as long to charge the 100 batteries but the alternator can't tell any difference.
You mentioned a discharge of 70%. I hope this is not your planned aimpoint for depth of discharge, but rather just an example. I would aim for no more than a 50% discharge (DOD).
If a battery is discharged to 50% every day, it will last about twice as long as if it is cycled to 80% DOD. If cycled only 10% DOD, it will last about 5 times as long as one cycled to 50%.
![](https://i139.photobucket.com/albums/q305/djmbucket/construction/cyclelife2.gif)
The graph is for a Concord Lifeline battery, but others will follow a similar pattern
Sorry for the confusion, guys. I meant as an example, and my plan, that the batteries are discharged 30% leaving a 70% charge. I was hoping not to discharge to 50% if can help it. d*
Ok, it's been a gusty day and I've finally come to the close of a wind turbine project. Cost was $96 for an aluminum high torque five blade 5ft radius design, $130 for the all-weather alternator. The 34 ft Rohn telescoping antenna mast ran $160. Building the frame and furling tail section proved frustrating at times, but the time spent with dad, priceless...parts, maybe $15 at Lowes. At 15ft up and in turbulent wind, today's gusts pushed the unit to average 20-60 open volts. With discharged deep cycle battery, between 1 and 4 amps or current. 15-50 watts isn't much and I'm not thrilled with the output for all the effort. Nonetheless, I wanted to get in cheap and test it's feasibility before taking the plunge on a much larger and expensive setup. I'm thinking no one single source will suffice. Now, back to microhydro and hello solar..
Doc
http://theadirondoc.blogspot.com/p/elements-running-with-wind.html (http://theadirondoc.blogspot.com/p/elements-running-with-wind.html)
wrapping up the frame: http://www.youtube.com/watch?v=OCMoJZ0kCcM (http://www.youtube.com/watch?v=OCMoJZ0kCcM)
today's open voltage test:http://www.youtube.com/watch?v=Jxep24RXgvg (http://www.youtube.com/watch?v=Jxep24RXgvg)
alternator vs. 12V dead battery:http://www.youtube.com/watch?v=3C3hxWOjK8U (http://www.youtube.com/watch?v=3C3hxWOjK8U)
Do you have equipment that would permit the collecting of data for a period of time, day, week etc? A little bit of power over a whole day can add up.
It was good to see real blades, not carved up PVC pipe.
I have no equipment for that yet but I did manage to find a good deal on a bank of batteries. I'm the proud owner of 8000 watts of potential energy.. ;)
The 50ft bluff on my Adirondack camp is likely to be windier than my "testing grounds" out on Long Island, NY. We'll see what it will put out over a week or two when spring rolls in and I hoist it up. I need to find a good charge controller with load diverter this week. Oh yes, a dump load as well.
Cheers,
Doc
Found a great online deal on Centennial 6V 220AH batteries, $89/each. After shipping, not so great. I was told by them that the Trojan T-105 is a much beefier battery and offers better lifespan. I appreciated their candor. They offered a local distributor location so there would be no shipping but there will be state sales tax. Unfortunately, locally they carry neither Centennial nor Trojan but the following:
6V 210Ah UltraLife $125/ea
6V 235Ah UltraLife $135/ea
There is a CORE fee of $15/battery
I've never seen any reviews of this brand. Can anyone tell me anything about them? I'm looking for an inexpensive entry-level set of batteries. Plans are for 24V so 8 in total.
No nearby Sams Club or Costco? My Sams stocks golf cart 6v 210 amp for $79 + $9 core. MTL the same as those Ultralife
Quote from: MountainDon on December 01, 2010, 09:59:49 AM
No nearby Sams Club or Costco? My Sams stocks golf cart 6v 210 amp for $79 + $9 core. MTL the same as those Ultralife
I have both but have never seen the batteries available. A visit to their websites yields no "6V batteries" or references to "golf cart". If so, I'd have bought 8 of them today....bummer
I've noticed that my Sams does not list the batteries on the web, but does carry the batteries in stock. My Costco does not carry batteries but the one across town does. ??? puzzling
That's good to know. The cheapest interstate and energizers I found on the web are $120 and up. I'll call the local Costcos and Sams' and scout around.
Doc
Hey Doc, Nice experiment on the wind turbine. Thanks for posting it. I think you will be a lot happier when you get it up higher and away from turbulence. Wind at 85 to 100 feet is about 3 times that at ground level but anything over 30 ' above treetops is better than near the ground.
I built my 85 foot tower and put it up by myself with a gin pole but it was a real chore.
Thanks, Glenn. I extended the telescoping rods up near their 34ft max to see how hard it would be. Lift the mast sections vertically, with the unit on top, and cables hanging is really at least a two person job. The gin pole method with a winch suddenly seemed attractive. I guess there's no easy way, huh?
Im really impressed that you build your own mast. That's no small feat. What's your turbine put out? I'm considering the windy nation 750 which is on sale this week only at $899. It's ratings are real world, the support has been great, and the unit has impressive stats. My Delco will never measure up to my energy use.
I have a Bergey XL1 - 1000 watts rated although I have seen more in a storm. I am a dealer but haven't sold others due to the fact that we are not in a great wind area and peoples unrealistic expectations could cause me problems. Last I checked it was over $2000.
My install was really rough as I did not want to cut my Oak trees so I had to work the side cables around them too. Took me about 10 and 1/2 hours to get it stood.
I based my design on the materials in the Bergey mast after I conned a few answers out of them. I used 20 foot sections of light weight 4" blow pipe I had left over from well drilling - threaded and coupled on the ends - I made a cable attachment collar to slip on top of each coupling so guy wires every 20 feet and I roughly copied their base tower and gin pole mount. Anchors are 3 foot long steel stakes driven through the base into the ground.
I want to build my own wind generator next time using PM motors - likely gearing up with a multi-v belt. I now have 3 off of treadmills. I have plans for a well designed carved PVC set of blades and commercial PVC -green - water pipe to make them from.
Wow.. that's a great plan. I saw someone on the web who also did their own and it worked out very well. Carved his own wood blades which, if I'm not mistaken, were 8 or 9ft in length. In the end, he was putting out over 1.5Kw consistently and said he had more power than he could use at that point. That's everyone's dream, I suppose.
I liked Hugh Piggot's diagram for a tower and might use that concept. His guy wires lie on the ground already taught, side to side, the one in the rear, slackened. It prevents any problems laterally while hoisting. I'd like to attach a hand winch to the gin pole, which when fully erected, would fit in a groove atop a cement block and get locked down. That would potentially be a one man operation if done right.
I'm intrigued at the idea that the swept area of the rotor has a great effect on the power as it is squared. That makes for an exponential curve upwards for radius increase. The loss of torque from gearing, however, is a simple ratio of teeth to teeth making the curve of loss linear. I'm thinking, capture a large swept area, then make up for the loss in tip speed by a simple two cog gearing at say, 1:3. Maybe we can capture the benefits of a large swept area and still stay in a high RPM range for optimal PMA output. I'd love to experiment with that.
I'm on the fence today about taking advantage of the windynation 750 one week sale. They tend on the conservative side and back up their claims with videos demostrating under real loads. After a tax rebate, the complete system runs me around $650. The alternative is to put in a bit more and do the solar now. Ah..decisions.
Just weighing this against intro solar kit. Wind is...well, sporadic and unpredictable. Solar, on the other hand is...well, same ;)
I find the hybrid system to be the best, Doc.
Some of each - wind works at night and in storms. Solar on cloudy days is about 10% or less of the total panels. Micro hydro could be good in the winter but doesn't work well with ice.... [ouch]
I think you may be able to do better piecing your own solar together than buying a kit - however there could be good kit deals too.
Sunelec - panels sometimes under $2 per watt plus shipping. Various good full sine wave inverters out there - sometime Ebay if you are careful.
Hey Doc, I doc-umented a bit of my wind generator installation for you. [ouch]
I took a few pix of it yesterday before I went off to work. Here is a pix of the whole thing - 85 feet tall. I forgot to mention that I did do the thing with keeping the side cables tight and tilting with a gin pole and come-along anchored to a tree, with a couple exceptions. In that area my ground averages 20 to 30% grade and I did not want to cut trees so the side cables had to be alternately extended or routed around trees as it became necessary ie: the west cables were anchored at roughly 6 feet lower elevation than the east cables and the south cables were at roughly 10 feet lower than the north cables.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/windgen1.jpg)
A telephoto shot of the generator at 85 feet elevation from the ground in front of my shop. Note that the Bergey uses slip rings and the cables hang down inside the tower - #4 wire to appx 150 feet to the controller.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/windgen2.jpg)
I cut out plates to the diameter of the pipe plus about 1/16th inch to allow them to rest on top of the pipe coupler but still rotate. I welded chain links to the plate to attach the cables to and prevent wear. Tight collars would not have allowed for screwing the pipes together and would not self align with cable tension.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/windgen3.jpg)
Here I drilled a hole in an existing natural rock with a roto-hammer and epoxied an eyebolt with a welded loop (can't unbend in a wind storm) into about a 6 inch deep hole. I wanted that much embedment to hopefully get past any chance of fracture. The hole was completely filled with epoxy (Hilti HY150) to prevent intrusion of water and freeze fracturing the rock causing a failure.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/windgen4.jpg)
Here is a natural rock I moved to location with my John Deere trackhoe loader bucket - estimated weight 6000 lbs. Note that I calculated cable lengths then added about 10 feet due to the uneven terrain. At install I ran the cables through the eyes and cut the cables with the extra length as needed. Tower elevation at the base was not the same as any of the anchor points, hence the problem with changing lengths. pull on any of the cables when standing is not over 50 lbs. Raising is another story.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/windgen5.jpg)
Here is my base plate and hinge for the tower - the round stakes are probably 7/8 sucker rod about 3 feet long - at least 4 of them there as I recall. The cable from the tower there is a ground and the gen cables are in the grass - not visible. I got the gin pole a little close to the tower pivot - it was removed when done and was mounted in a hole this side of the tower pivot. No worries about the loose nut there --- it is really just a pin retainer - no other function.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/windgen6.jpg)
And last - a shot looking from the base level up to the generator at the top 85 feet up.
![](https://i778.photobucket.com/albums/yy62/the_troglodyte/windgen7.jpg)
Cable clamps... "Never saddle a dead horse" - put the saddle over the live side of the cable and the u section over the cut off end - less chance of cutting the live side with clamping pressure over the years.
I hope that demonstrates the ease with which one can do it yourself and save money..... [waiting]
:)
Sorry for the late reply, Glenn. I've been up one last time to the camp to see how it's been cleared, and to take a water sample from what I believe to be a springbox. 6ft x 3ft concrete. The timbers and roof have fallen in, but I've poked a stick down over 3ft. Don't know how deep it is once it's cleaned out, but it's an interesting find nonetheless. Not even sure what use I'd have for it.
Your mast installation is great! I can't believe the height you achieved on your own. Is that sched 40 pipe you used? It looks larger than 1.5". I'm not sure what the local zoning is, but I hope to come up to at least 50ft to 60ft for cleaner wind. Hope since I'm on 35 fairly remote acres, nobody would say much in any event. Only thing is, the highest point (up on a ridge) is 150ft from my neighbors cabin lot. I'll scout around for a suitable location as far from him as possible.
I just bought a Superwinch portable winch in a bag to help out hoisting. Rated at 2500lbs and runs 12V. My Windtura750, with rotor and frame weighs in at 66lbs, so not too bad. They recommend sched 80 1.5". I'll more than likely go with common HomeDepot sched 40 galvanized instead, which is what many other wind turbine manufacturers recommend. Unlike your welds, I figure on using simple plumber's connectors and T-fittings. My welding needs some practice! Like you, I'll use a tree as a winch anchor and later remove the 30ft gin pole.
Thanks for the tips on solar panels. I've been browsing Sunelec's site and think a 480W setup on a pole will be perfect. You've inspired some new ideas, Glenn.
Doc
No problem, Doc.
My mast is using blow pipe I had left over from well drilling - actually it is a 4" tubing a bit heavier than 4" exhaust tubing - maybe 1/8 to 3/16 inch thick. Bergey uses a similar material on their tower. You can go to their site and download the tower manual for clues on building and installation. Downward loading is very low so heavy pipe is not necessary with the guy wires.
Wind generators do make a bit of noise but usually not unpleasant as the blades sweep through the air. Not too far from your batteries on distance or there is a lot of line voltage loss. I asked the county here if a permit was required and they said yes so I put it up without one anyway - my story was going to be that the installation was experimental and temporary with the stakes in the base, but that was 8 years ago and still no one has said anything at all. IN the meantime the county guy was fired for corruption and the second one was fired for messing with the citizens too much- lots of un-permitted buildings up here by public officials families. :)
I tested the Sunelec grade B panels - they are every bit as good as the more expensive ones in my opinion and meet all specs.
Glad I could kick in so useful info. [idea]
I was looking at some of your threads, Glenn. Really remarkable. oI think you should write a book.
I wonder if you'd make a recommendation on gin-pole length. Pipe lengths come in 10' here so I'd be at 40-60ft depending on final site inspection. Can I figure on roughly 1/2 of the mast height? Do you put a pulley on the end of the gin-pole or fix it securely and then on to near the top of mast? Did you find it necessary to double guy the gin pole to the mast at more than one point, such as near the top, and 1/2 way between?
Quote from: MountainDon on December 01, 2010, 01:28:22 PM
I've noticed that my Sams does not list the batteries on the web, but does carry the batteries in stock. My Costco does not carry batteries but the one across town does. ??? puzzling
Don, your advice paid off. No local batteries on the web, but I called around and found them at Sams. A $30 membership and a one hour drive later and I found myself now a member of 3 warehouse clubs. I did it to score 6 Energizer GC6 220AH batteries at $72 each. After opening a charge card so I could pay (all I had was visa and amex), I got an additional $20 off. After I put in for a 30% tax credit for all my solar project receipts, that's $48 per battery! Awesome!
Just wanted to say thanks for your advice!
By the way, my project calls for the batteries in a couple months. Until then, I don't want to harm them over the winter. Should I cycle them already or can I leave them be?
Doc
If you have them near power just keep a small float battery charger on them - series 2 6's if necessary and parallel the sets to use one charger for 12 volts. If they go down and stand while low they could sulfate.
A good charge once in a while could do also. Don't ask me if I take care of my batteries that well.... [waiting]
Quote from: AdironDoc on December 05, 2010, 03:56:34 PM
I was looking at some of your threads, Glenn. Really remarkable. oI think you should write a book.
I wonder if you'd make a recommendation on gin-pole length. Pipe lengths come in 10' here so I'd be at 40-60ft depending on final site inspection. Can I figure on roughly 1/2 of the mast height? Do you put a pulley on the end of the gin-pole or fix it securely and then on to near the top of mast? Did you find it necessary to double guy the gin pole to the mast at more than one point, such as near the top, and 1/2 way between?
I have thought about a book a couple times - looked into it a little but it seems I am a bit too lazy to do it so far..... [waiting]... but thanks anyway.... maybe someday.
The longer the gin pole, the easier it goes up - but be sure to lay it out so that when pulling it up it doesn't hit the gin pole pulling point/anchor. I used 25 feet on my 85 footer as there was a tree at about 27' as I recall.. so about 1/3 length of tower should do it. The gin pole hinges on a separate anchor at the base about 6 inches away from the tower and a bit higher than the tower anchor bolt would be good to allow it to lay down over the tower pole for hooking cables. A snatch block could be used at the top of the gin pole for more reduction or just a tough come along or chain hoist - truck winch etc. I try to think about whatever will work - - go through the steps in my mind - sketch it if necessary to think of possible problems. I use whatever I have to do the job safely - multiple ways it could be done.
I put a stake in the ground to the side of the tower at 90 degrees from it's base mount to temporarily find proper cable length then transfer them to the gin pole as proper length is found. Generally I figure 3 cable clamps for full cable strength but it varies a bit depending on size if I recall correctly. Note that the gin pole will attach to the cables temporarily somewhere around the top 2/3 of the cable length depending on anchor spacing. Seems mine were about 50 feet from the base in 4 directions.
Use the length of the gin pole for distance from base - shorten a few feet to keep the pole off of the ground when the tower is plumb. I used one cable at every 20 feet on the tower and attached them at their proper length to the gin pole so that the entire tower would come up at once as the gin pole was pulled down. Even a 4 inch tower is remarkably flimsy until properly guyed. I think a 20 foot gin pole would do you for 60 feet.
Another caution - be sure to have the back cables attached and not over loose or when it goes past center it will continue falling - possibly on you. I know - obvious but thought I would mention it. I calculated the lengths of the cables - left them extra long by 10 feet or so as I mentioned then fastened them a bit snug for when the mast was vertical , then adjusted each of them carefully until it was plumb - I used a nut driver for speed - . Side cables can be attached snug if on level ground - if like mine they may need adjustment - I raised - checked - raised - checked - adjusted - til done.
Great info, Glenn. On your recommendation, I've sketched out my plan for a 20 on 60 gin/mast setup. Please tell me if you see any room for changes or improvements.
Btw.. I knew the roots of cattails were loaded with starch, but after a visit to your youtube channel, I'm going to try cooking with them this spring. Now that should be interesting. Cattail "potatoes" and salted pine chips, pine nut cake, and spruce tea. I'll try anything once. c*
That looks pretty good, Doc.
I need to try the cattails also. Almost did but didn't quite get around to it.
I'm not an engineer so tend to go a bit on the conservative side and hope I'm good.
I used just the stakes and a steel base that I built from what I could gather from the Bergey info - clues. I am not worried about the concrete base and bars - you would likely want to relieve it in the area of the tee or add couplers to the short nipples to allow more sitting on the base for a little more support as it goes up - that is likely not even critical though.
The 10 feet of 1 1/2 above the last coupler with the generator bothers me a little - also the 30 feet un-guyed at the bottom. If it was mine I might add a 5 foot section of pipe at the top to mount the generator on cutting down leverage on the threads at the top above the guy, guy at 60', 40' and 20' and temp the three of those to the top of the gin pole for raising. Watch for binding where the bottom pipe sits on the concrete so it doesn't bend and snap off there - again something to watch - likely not a problem.
The ten feet may be OK with the generator but some rough rule of thumb stuff - wind exerts around 30 psf at 100 mph If I recall correctly. 5 foot 5 blade fan and about a foot generator - not sure how turning affects it - say 10 square feet of surface - x 30 psf =300 lbs push in a giant wind x 10 feet gives us 3000 foot lbs at the 1 1/2 inch cut threads at the coupler at the top guy. Cut threads weaken the pipe. I'd feel better at 5 feet and 1500 foot lbs at the last guy. Maybe I am way off and any engineers here feel free to correct me... just trying to make a good guess.
Sorry If I am late to the discussion, the Off Grid thread can be hard to keep up with. I studied the Bergey installation guide too. What I liked was how they used steel plate, angle iron, and large bolts for the gin pole design instead of the T.
Doc,I have never seen designs for 1.5" diameter pipe that tall. Most commercial towers I have seen sold are 4-6 inch. I have seen them as low as 2" at the top. I am with glenn in the distances of unsupported pole. Personally I would be using guy wires every 10 ft with that thin of pipe, starting at the lowest place to clear the blades. It might be cheaper to buy bigger pipe than more wires. Let us know how it works out. Otherpower.com has a great walkthrough with good pictures on tilting up towers. On estimating the wind, I did a walkthrough on a homebuilt wind meter here. You can find it by checking my old posts. There are also many wind maps for NY on the web. On the subject of permitting, anything over 16ft requires a permit in my county. I found a loophole in NY state laws. There are right to farm laws in almost every state including NY. There is a provision for wind turbines for power. This is to stop local municipalities from harassing farmers with zoning/permitting. My recollection was that it required 7 continuous acres to be considered under right to farm laws. I don't know if tree farming qualifies.
Edit:
Here is a link to right to farm laws:
http://www.nationalaglawcenter.org/assets/righttofarm/index.html
Quote from: Squirl on December 06, 2010, 02:16:01 PM
Doc,I have never seen designs for 1.5" diameter pipe that tall. Most commercial towers I have seen sold are 4-6 inch. I have seen them as low as 2" at the top. I am with glenn in the distances of unsupported pole. Personally I would be using guy wires every 10 ft with that thin of pipe, starting at the lowest place to clear the blades. It might be cheaper to buy bigger pipe than more wires. Let us know how it works out.
Thanks, guys. Although my new wind unit will come with a mount for 1.5" galvanized, I could always use a larger diameter for the base and reducers on the way up. I'll guy it as suggested, at 10ft increments, or, just above each fitting and as high as possible, say half way up the final length.
At the moment, my little 30lb setup sits atop a 34ft Rohn telescoping mast which although guyed every 8ft, is made of very thin pipe. The thickness reminds me of lightweight fence tubing that makes up the top rail of a chain link fence. Amazingly strong when guyed properly. 34ft ends up weighing only 40lbs. I figured at 60lbs, and an additional 25ft up, galvanized would be a big step up.
That was a clever loophole, Squirl. Don't know that I'd qualify on that one, but I googled wind turbine heigh restrictions and see most upstate county zoning laws put a height restriction of somewhere around 100ft give or take. Distance from property lines seems to vary greatly from a distance equal to the height, to over 300ft with sound limitations as well. I should be fine at a meager 60ft.
Ostensibly, my land is considered unimproved being raw acreage of forest. That doesn't stop the town/county from very high taxation. My 35 acres will end up costing me as much as my home in the suburbs of NYC. Now whether a wind turbine is a permanent structure or capital improvement, thus being taxable, will remain to be seen. I'm hoisting this on the QT.
Quote from: Squirl on December 06, 2010, 02:16:01 PM
I found a loophole in NY state laws. There are right to farm laws in almost every state including NY. There is a provision for wind turbines for power. This is to stop local municipalities from harassing farmers with zoning/permitting. My recollection was that it required 7 continuous acres to be considered under right to farm laws. I don't know if tree farming qualifies.
Edit:
Here is a link to right to farm laws:
http://www.nationalaglawcenter.org/assets/righttofarm/index.html
Seems if there are just steel stakes in the ground rather than concrete it is not permanent. That is the official Bergey mount.
Quote from: AdironDoc on December 08, 2010, 03:04:13 PM
That was a clever loophole, Squirl. Don't know that I'd qualify on that one, but I googled wind turbine heigh restrictions and see most upstate county zoning laws put a height restriction of somewhere around 100ft give or take. Distance from property lines seems to vary greatly from a distance equal to the height, to over 300ft with sound limitations as well. I should be fine at a meager 60ft.
Good luck. I always hope people just leave me alone too. The provision would be more of a backup. Zoning and permitting are two different things. If they want to be jerks, they can fine the crap out of someone after the fact. Anything over 16ft needs a building permit were I am at.
ill be looking forward to hearing more about how you do with your new turbine. it is the same plan i have to back up some solar panels. i guess since "fees" for permits are so high at my place, the cabin will start out at the 120 sq ft and will be off grid. i asked them at the placer county hijacking office about a wind turbine, they said no restrictions, but they may be looking at some guidelines going in somewhere in the near future. but at this time only need a electric permit. i think, correct me if im wrong, that would only apply if i were grid-tied.
yep, im not going to let them get to me, im just going to do the real cabin down the road. ill spend the time getting septic in and other things in place, at least we can spend quality weekends there with that. the good news is also my property taxes will only be about 500 a year until we build, and it sounds like a lot of places are higher than that.
adriondoc, did you buy your set-up, or is it something you set up on your own? i keep getting these emails from a DIY site who had plans for a homeade set-up you could build on the cheap, and it looked pretty good from an appearance stand point, but from what i am seeing they just really arnt that expensive to buy and install. anyway, i cant wait to hear how your project is going.
Thanks, and welcome to the forum. I'm learning something every day here from others who have walked our path before.
My first wind project was cobbled together from an alternator I bought on E-bay for $120 based on a rewound delco, blades from windynation.com, and some miscellaneous parts from Home Depot. I got a telescoping mast from Rohn for $140. All told, it's run me around $450. In a brisk breeze the delco type alternators max out at around 40-50W. Not much bang for the buck unless they run continuously. For me it was more of a feasibility test. It worked, that's clear.
I just bought a larger unit, the Windtura 750, from windynation.com. It puts out 400W in the same breeze the delco gave me 40W in. In a real wind, the numbers are double that. Normally $999, it was marked down to $899, plus 5% off for being a member, and a 30% tax rebate left the price not much more than what I paid for my homebuilt unit. I'm not trying to sell you on any particular model, just to point out that DIY doesn't save all that much in the end. The main cost this time around is 60ft of 2" galvanized pipe with all the fittings for the mast.
As for my cabin.. I looked for months at every conceivable kit available. I finally beat all the prices by finding a local mill owner/builder who would get permits, clear land, and frame the cabin at $36/sq ft. Remember, keep it simple. You can always add on and double the size of what you build later.
I encourage you to keep a photo journal of every step of your journey. Post them and write about your decisions, your projects. I've done that in a blog and hope years from now my kids will look back and smile.
cheers, Doc
Quote from: altaoaks on December 10, 2010, 10:51:27 AM
ill be looking forward to hearing more about how you do with your new turbine. it is the same plan i have to back up some solar panels. i guess since "fees" for permits are so high at my place, the cabin will start out at the 120 sq ft and will be off grid. i asked them at the placer county hijacking office about a wind turbine, they said no restrictions, but they may be looking at some guidelines going in somewhere in the near future. but at this time only need a electric permit. i think, correct me if im wrong, that would only apply if i were grid-tied.
yep, im not going to let them get to me, im just going to do the real cabin down the road. ill spend the time getting septic in and other things in place, at least we can spend quality weekends there with that. the good news is also my property taxes will only be about 500 a year until we build, and it sounds like a lot of places are higher than that.
adriondoc, did you buy your set-up, or is it something you set up on your own? i keep getting these emails from a DIY site who had plans for a homeade set-up you could build on the cheap, and it looked pretty good from an appearance stand point, but from what i am seeing they just really arnt that expensive to buy and install. anyway, i cant wait to hear how your project is going.
Quote from: altaoaks on December 10, 2010, 10:51:27 AM
....only need a electric permit. i think, correct me if im wrong, that would only apply if i were grid-tied.
Don't assume that if you are off grid you do not need a permit for electrical. For our location the county inspector still wanted to see all the requirements for inside the building to comply with code. Partly that is a safety issue. Partly is is the fee. Partly it may be because someday the grid may be connected to (they mentioned that). Partly it may be because that's the way it's always done. Even the low voltage parts have sections in the NEC.
Quite right. I'm off grid too and when I pressed the codes department on the issue of low voltage, I was told the same. I asked if the standard wiring rule was a "suggestion or requirement", to which the code officer replied, "a word to the wise, it won't cost you much to bring it to code". Understood. Now, good luck finding a way through the 3 miles of woods to inspect it. ;)
Quote from: MountainDon on December 10, 2010, 02:30:26 PM
Quote from: altaoaks on December 10, 2010, 10:51:27 AM
....only need a electric permit. i think, correct me if im wrong, that would only apply if i were grid-tied.
Don't assume that if you are off grid you do not need a permit for electrical. For our location the county inspector still wanted to see all the requirements for inside the building to comply with code. Partly that is a safety issue. Partly is is the fee. Partly it may be because someday the grid may be connected to (they mentioned that). Partly it may be because that's the way it's always done. Even the low voltage parts have sections in the NEC.
thanks for the additional info adriondoc, i appreciate knowing what you have done, and yes, as you say it helps to know the paths others have walked, as those steps are much easier to follow. and i really aggree with the deal about DIY, i had already noticed i could get a decent turbine for between $900 and $1200. and that is really fantastic! sounds much better than micky-rigged, and wow! thats a lot of difference in watts delivered, day and night difference.
i guess being off grid wont save me with the electric permit! real bummer! the thing im tossing around is and that power is extreemly close to my building site. i havent pulled out the tape measure, but i would guess only around 100'. thats a cheap hook-up.
so i was talking to one of my customers today. of course their situation is very different from mine. they have a 2800 sq ft, 2 story home. last month they had solar installed. today pacific gas & electric came over and installed their new meter--one that will sell back the extra to the grid. they have 16 solar panels, i figure most times they will be making a significent excess of electricity. its pretty smart to have your system working for you. i had heard that in calif. you wouldnt get paidfor the excess. but apparently you do, or maybe it depends on where you are.
as much as i dont like dealing with the local power company, maybe i should suck it up and go grid-tied up there. there sure are alot of decisions to make when you buy land with the intentions of building a cabin!
and thank you to you and mountain don for pointing out that getting around the permit wont be as easy as i was thinking. they dont have to go thorugh any woods to get to my building site, just drive on up when the weather is good. i guess i should have spent more time on the "buying land"section.
, and next to impossible. unfortunatly
In California the last I knew and still think it is the policy, the rules were of course written to favor the power company. They only have to pay you avoided costs which is about 2 cents per kwh. You in the meantime will supply them with a product they can sell for a profit. It does not pay here to provide them with excess power. Banking and using up to the amount you use annually could be good.
There were some changes made by the CA legislature last year. I'd check with the power company to see just what the current options are. I know PG&E at least allows one's own generation to be applied equally against any power that the customer buys from them. At the end of a year there is a settlement; I just don't know what the changes are.
Even here in NM where the company that supplies us in the suburbs pays actual cash for surplus (at a rate higher than the base rate) the power company we would be connected to in the mountains has no buy back plan at all. So it can vary.
that sure makes it tough for people to make plans, too bad there isnt some uniform guidelines that power companies would have to follow. but at the same time, that would create more bureaucratic bs, so maybe not. in a perfect world everyone would just do the right thing! nice dream...
im going to see my customer next friday, and i want some 411 from her. by the way, she also has a cabin at lake tahoe, but not the placer county side, shes closer to stateline (where calif and nevada borders meet). i hope new fair guidelines were legislated, but you know how likely that is.
mountaindon, thats too bad the power co by you doesnt participate. are they a small local co? by the way, how are taxes, and land prices your way. my brother is in st. petersburg, fl. he wants out of there by summer and has plans for that area outside of santa fe, a few acres, a storage container underground for emergency supplies,.... he misses NM alot, we all do. and the fl humidity is killing him.
Quote from: altaoaks on December 11, 2010, 10:40:15 PM
mountaindon, thats too bad the power co by you doesnt participate. are they a small local co?
Yep. Jemez Mtn Co-Op
Quote from: altaoaks on December 11, 2010, 10:40:15 PM
by the way, how are taxes, and land prices your way.
We just paid the taxes for the year: mtn prop; $104 city home; $1300
Land: we paid $19K an acre in the mtns. Depending on how close to Santa Fe it could be more. Or not. Santa Fe itself is nuts!???
http://www.jemezproperties.com/ (http://www.jemezproperties.com/)
Wow.. for unimproved (but subdivided) forest, I pay $600 per 5 acre lot. I own 35 acres. Dems' the breaks.. ;)
in "tax 'em till they bleed" Wisconsin I pay $2889 per year on 105 acres with a small house
guess I don't feel too bad .....
the CRP covers it for now -- expires 2014
You are safe then -- the world ends in 2012.... [waiting]
thats right, we wont have to worry about taxes and building permits after, what is that... december 21st, 2012. glen and sassy, i hope theres a standing offer of visiting your underground cabin about that time for us forum folks, ill bring food!
I thought it was earlier, but yes - just checked - Dec 21, 2012. All CP members are invited here to watch it from the ridge top. It will of course be a pot luck event to insure that there is enough food for the occasion....that way no matter how many show up, we are covered..... The view should be good from here. :)
There are apparently some predictions for 2011 also but that is too early for me.... I'm going to sit that one out and wait for the Mayan one.... [ouch]
ABC News: "doomsayers assert that Earth will be ravaged by a smorgasbord of cataclysmic astronomical events -- everything from a Planet X flyby to a "killer" solar flare to a geomagnetic reversal, ensuring we have a very, very bad day"
Sounds like a party! But...
Huffington Post: "According to a recent study by an associate professor at UC Santa Barbara, this fundamental "end date" may also be inaccurate. It could be at least 60 days out of whack."Better bring some extra beer, Glenn. ;D
Quote from: glenn kangiser on December 13, 2010, 01:33:55 AM
I thought it was earlier, but yes - just checked - Dec 21, 2012. All CP members are invited here to watch it from the ridge top. It will of course be a pot luck event to insure that there is enough food for the occasion....that way no matter how many show up, we are covered..... The view should be good from here. :)
There are apparently some predictions for 2011 also but that is too early for me.... I'm going to sit that one out and wait for the Mayan one.... [ouch]
OK... looks like sleeping bags will be in order with the extra beer. [ouch]
Reminds me of when we all used to get out the lawn chairs and sit on the beach in Oregon so we wouldn't miss seeing how big the Tsunami was. Nothing like being there in person.... [waiting]
I don't know how things go on your end of things, but whenever there's a storm coming, two things go fast; water and beer. I've started stocking long ago but test for quality on a routine basis.
Quote from: glenn kangiser on December 13, 2010, 05:35:52 PM
OK... looks like sleeping bags will be in order with the extra beer. [ouch]
ok mountaindon and adriondoc, 8) i got the message and i am stocking up on the water and the beer, tell sassy ill bring potluck with extra. (is that bud, or coors?)
hey, was that 60 days early, or 60 days late? of course, 60 days late would put up into 2013. some people are saying all of the numerous large earthquakes and volcanic eruptions, and a tsunami or 2 is early results of the event as the solar flares have already begun. stay sharp!
HAARP was accidentally left on high during some of the events. [ouch]
I am not sure if it was early or late so it would only be prudent to stock enough beer for 120 days..... [waiting]
...truth be known, for me that would be about 4 beers......
I drank enough when I was 17 to last.... :)
You can all just hang out & we'll keep the gardens going if the dates are off... and we'll put you to work on the underground cabin c* ;D
Being in an underground house, Glenn is most likely of all of us to survive any meteor strikes and solar flares. Maybe we should all start digging?
Also was thinking.. taxes are based on size of houes, number of bathrooms, etc. If my front door is a ladder down, good luck assessing me. Nice thought.
..and it is all accurately documented and sent to the assessor when you contract your rights away signing the line on the permit...Note that it is not necessarily easy or reassuring if you decide to try to avoid it either. Ex-post facto laws try to trump inalienable rights and common law (the true law of the land) in code situations.
As I mentioned before , one of our supervisors told a friend that the permit process was not for safety, but rather for taxation.
Safe practices used to be the responsibility of the master carpenter and old buildings attest that he did a pretty good job. Now they are given to a county inspector who many times does not really care. The failure of our DMV carport, The County Library in Coulterville, the flooding of the building and safety departments new castle lower floor, as well as the travesty linked below all attest to the same thing.
Collected the fees - charged the taxes - went through inspection motions, yet claim they have nothing to do with insuring quality or safety... primarily a taxation tool and guarantee that you will buy from those who have paid off the system....
http://goldrushcam.com/sierrasuntimes/mariposa-daily-news/92/1265-a-failed-driveway-and-mariposa-county-claims-immunity
Never been to California.........could visit Yosemite :) a party at Glenn's would probably be way [cool] Just one question are you the part of California that will fall into the Pacific or will you be the owner of new beach front property....if only for a few days?
Beach front property.... solid rock below us for almost 3000 feet to the new sea level.... we hope.... [waiting]
We have had some cool parties here .... muldoon, whitlock, harry51, adawgk, mikeyB, PEG got close but his sister wouldn't let him leave so we went to see him......others... We all feel pretty safe here. :)
We widened our driveway, which required a permit. Permit fee was over a grand. Later, an arborist was spotted traipsing about our land cataloging which trees they would allow to be cut. We put up $2K for a bond, "just in case", a tree got damaged. Whille 12 trees were removed, a sapling's bark got scarred by the backhoe. $2K gone. The town "owns" trees over 3 inches in diameter. Mental note: remove every gosh darned tree not yet 3". Groundcover may not be removed without permit. Mental note, stop cutting grass on the slope in front of the house.
Our neighbor, without permits, took down over 30 trees, regraded their slope, and did their driveway. They paid $3K in fines, and got a variance a few months later.
Next time, we do it, and ask forgiveness later. Welcome to the suburbs of Long Island.
.... I jus' couldn't live like that.... [waiting]
Permits are almost EVERYWHERE now. Texas is the last holdout and I don't think it will be long.
Last weekend I cut down a few big old dead and half dead Aspens. One of them fell on a small (maybe 4 inch) pine and smashed it flat. Too bad. I was going to cut it anyways. Next week I'm planning on cutting several more dead and mostly dead Aspens. Good firewood. Then I'm going to cut a couple of national forest trees that are endangering the south fence, already leaning and tangled in the uppers.
I asked karen. She said fine. Good enough for me. ;)
You ought to look at the West. No on second thought don't. Too many people here already. Well I might make an exception. ;D
How do they decide what to cut? I take out the small crap and those others that are too crowded. But I like being able to pick them myself. There are a couple I saved for shooting at. Trying to see how many 45 and 50 cal. rounds it'll take. Try that in NY.
Cool - stormy tonight and my wind generator is putting out about 800 watts. :)
Extra power from a home brew one could be a nice addition.
Quote from: glenn kangiser on December 15, 2010, 01:40:18 AM
Cool - stormy tonight and my wind generator is putting out about 800 watts. :)
Extra power from a home brew one could be a nice addition.
Thanks for getting me off my rant and back on topic, Glenn d*
My upstate land is my sanctuary from the madness of living in an area of 12 million. Like, Don, I enjoy using my 30/30 or 12 to keep a few unruly trees in line.
800 watts is awesome! Imagine if we could average 200W each hour every hour of every day.. Heck, I'd settle for 100... Send some wind over here
I wasn't necessarily trying to get you back on topic, Doc... I just had a power related comment to make....
My grandfather was born in Dolgeville... [waiting]
:)
For a moment I thought the topic of this thread was "OFF TOPIC; various thoughts on land ownership..." ;)
I love Dolgeville! Nice town, nice people, cut through by the beautiful West Canada Creek. When I drive through, my pulse quickens because I know I'm close to camp. :)
Quote from: glenn kangiser on December 15, 2010, 12:45:07 PM
I wasn't necessarily trying to get you back on topic, Doc... I just had a power related comment to make....
My grandfather was born in Dolgeville... [waiting]
:)
Really..... I wasn't sure what part of the state you were in... [ouch]
1890 - was a couple years ago....likely no one remembers us.... they went to Oregon shortly after that. Had other relatives in W. Winfield and one died In the Cooperstown rest home.
No wind on the wind generator tonight..... rofl
c*hi everyone, well i hit the jackpot today. when i arrived at the customers house with the new solar install, the solar rep was there following up on the job. i had the opportunity to ask about power buy-back and the buy-back rate.
well, our industrious public utilities commission gets the honor of setting the rate! and at this point they have not set this rate. we all know who the PUC reports to, the power companies! supposedly the rate will be set around march, 2011
the rep said that the way its going to work is the homeowner gets a bill of approx. $5 monthly, which is the transmission fees/taxes. 12 months from install, and every 12 months thereafter, the power company calculates what is owed either to or by the customer (this is called the "true-up") the customer either gets a bill or a credit.
should be interesting to see how cush a deal PG&E and SO CAL Edison get out of their buddies over there at the PUC. lobbiests rule!
Don't look for it to be anything fair.
That's more or less what I thought the deal in CA was. It does not pay to oversize the PV system when the years use is totaled. That's the way it was here in NM until a few years back. Now the participating power companies will cut a check.
Currently ;) our cost to buy is about 0.09 (average on December bill) and they pay 0.12 per kWh for any excess
In another thread I showed off the LED Christmas lights at our cabin. I also showed that we used 6 strings of LED C6 type white lights mounted down the cabin side and over to the shed for nighttime illumination. That works very well. Even on the darkest night we have plenty of light to see our way from the cabin to the shed and around the immediate area.
I noticed something odd though.
We use an Outback inverter. There are may programmable features. One I use is the search function. This allows the inverter to run in a standby mode when no power is being used. When a load is sensed the inverter turns on. It is adjustable for sensitivity. I have it set down to where a small LED night light will activate the inverter.
However, a single string of the LED Christmas lights or the single LED night light, must be plugged into the receptacle the "proper way". Reversing the plug the light?string will not trip the inverter on. Rather the light(s) pulse on-off in sync with the search signal. Changing the orientation of the plug resolves the issue. ???
Just interesting. If at first something doesn't react the way you think it should analyze what changes could be made.
LED's are
Light Emitting DIODES
a diode passes current in only one direction
so it kinda makes sense depending on how the inverter current sensor works
my 2 cents $2 worth (inflation you know)
The BIG RED Batteries are here !!!
Surrette 6 CS 17 PS 6V 530 Amp Hour
all 1800 pounds of them
Ordered from the Solar Biz (very good people) shipping was only $120
![](https://i55.photobucket.com/albums/g135/Crockette/IMG_5228.jpg)
Way cool! Those are the best batteries anyone on here has ever shown as their own. There should be many years of great service.
Thanks Don for the Solar biz tip -- saved me $1600 over the next best deal
they have a 10 year warranty-- hopefully we will be using them well into the next decade -- supposedly individual (dead) cells can be replaced, too
at 50% discharge we should have 10 KW-Hrs of storage
my FIL is going to FL near Miami -- I may ask him to pick up a Xantrex 6048 inverter down at Sunelec to go with these batteries
Impressive savings!
Glad you could benefit
Wow, those look almost like fork lift batteries. Impressive.
Speaking of which, has anyone ever considered using forklift batteries for their bank? I've heard of one instance, but never seen any discussion on the possibility, or not.
At home, my two widescreen TV's sit in standby mode most of the time, and, with the added burden of cable box and DVD, add up to nearly 400W/hr or 10KW/day!
I went looking for better options for my off-grid camp and happened upon this nice 32" TV at BJ's. It's an LED by Westinghouse that takes only 54W while on. Add an 8W DVD player and your talking about as much power as a light bulb. Not bad for bringing a couple evening hours of creature comfort to your battery run cabin.
http://www.amazon.com/Westinghouse-LD-3255VX-32-Inch-720p-Black/dp/B003SZRWBO/ref=sr_1_5?s=electronics&ie=UTF8&qid=1296411357&sr=1-5 (http://www.amazon.com/Westinghouse-LD-3255VX-32-Inch-720p-Black/dp/B003SZRWBO/ref=sr_1_5?s=electronics&ie=UTF8&qid=1296411357&sr=1-5)
Good, but remember, with any electronic device with a remote control, the main unit (TV, DVD player, etc) will have a constant low power demand. So there will still be a small draw, that will add up. Some like myself who just absolutely don not like to think about that wasted power will use power strips with a switch to really turn off those items. I did it a little different. I installed a wall switch with a pilot light beside the sofa/TV location. It is wired to a half outlet. When we want the TV on we flip the wall switch. The power that the TV wants then trips the inverter standby and powers up the inverter. The remote can then turn on the TV, etc. When we're done we flip the wall switch again and it all goes off. If no other devices are on the inverter goes to sleep.
The standby on the inverter does draw some power but it is far less than the TV or DVD unit.
Quote from: MountainDon on January 30, 2011, 01:48:40 PM
The standby on the inverter does draw some power but it is far less than the TV or DVD unit.
I've got to get around to using the new power strips I bought last week. My bill is outrageous considering I'm home only at night, keep all the lights (CFL) off and have gas stove/heat/water. I used the Kill-a-watt meter and noted my refrigerator (normally the largest household draw) uses only 1.5 KW/day. My bill says I'm using 15Kw/day. Other than refrigerator, I've got a 65" LCD TV, and a 50" LCT TV, 2 PCs, one of which is usually always on, and a hot tub. Sometimes I scratch my head and think it just doesn't add up. My pals have homes twice this size and half the bill. I've noticed I can keep my TV's off, but my cable box if turned off, takes some 5 mins to reprogram itself. Not worth the aggravation. I'll run everything through power strip except cable boxes.
My 5KW cabin inverter is on order and draws 0.9A at a rated efficiency of 90% and 95% at 1/3 load. I will turn it off unless we're using something electric. Figured if something doesn't run properly, I'll add a pure sine wave unit for that appliance alone. Can't see spending for filet mignon when most of my appliances will gladly eat leftovers. ;)
Sounds like you have a plan there, Doc.
We have built our system up to where about 90% of the time it handles our parasite loads too, so we just pretty much run like a normal house.
You might want to contact your power company and complain or have them do an energy audit. They had been making a mistake on reading our old meter for years.
Quote from: considerations on January 28, 2011, 10:54:47 PM
Wow, those look almost like fork lift batteries. Impressive.
Speaking of which, has anyone ever considered using forklift batteries for their bank? I've heard of one instance, but never seen any discussion on the possibility, or not.
My Dad Brother and I have 120 acres in Michigan's eastern UP. We got a used smaller 24v forklift battery 1100lbs. We have a 26' travel trailer with a 12'x20' room on it. We run the lights tv microwave ect for about 3 days on it before we have to charge it back up. Which usually takes 5 hrs with our home built chingfa diesel generator. We do have two small solar pannels on it but they are in the woods and generally just make up for battery losses while we are not there.
The biggest problem we are running into is that we have two cells that self discharge faster than the others. So when we use it our battery voltage drops off faster than it should and we have to charge it more often. Also the low cells are more likely to freeze and cause further damage. We have been trying to find a single cell battery charger but haven't had any luck yet. And trying to charge up the low cells and not over charge the good cells isn't working.
![](http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs243.snc4/39494_1282622720623_1681757389_541062_461818_n.jpg)
The box on the 4x4 is the charge controller for the solar pannel and the 750 watt wind-generator which we haven't put up yet. On the back wall is our 5000 watt inverter. Once I get the the tower up for the wind-generator I want to make a underground root cellar that will hold the generator and battery near the tower and help keep it from freezing.
Billy
Have you tried a desulfator? Or thought about a chemical additive? At this point there's little to be lost.
These chargers are expensive but I have heard good reports about them rejuvinating batteries
http://www.r-charge.com/RC-15A24-2412VDC-Industrial-Charger-Rejuvenator_p_99.html#
Thanks Don
Just looked up the desulfater. Looking at the plans I think my brother can figure out how to set it up to charge/desulfate 1 cell as well as the whole battery. Even as it is its not bad as we usually just go up for the weekend and we can run it friday nite to sunday and recharge it before we go home. But we would like to bring it back up as far as possible so we are not taking more life out of the battery than possible. Dad and I were up 10 days over new years. And only used four gallons of diesel to run the 10 days and leave the battery fully charged. For the $750 we paid for the battery 2/12 years ago it has just about paid for itself in fuel cost and not having to listen to the generator run.
Thanks Windpower
Nice looking unit but not cost effective for our use level. We are only at the farm once or twice a month for the weekend and a few weeks a year. If we were there full time it might be a different story.
Billy
Ok, I had promised myself to exercise at a least a modicum of fiscal restraint going forward but seeing the liquidation on sunelec.com, I took the plunge. My off-grid collection now includes 2 Sun panels, 200W, and a 30A MPPT charge controller. $1.68/Watt. Not bad. At 3 peak hours minus various losses, I figure in the order of a kilowatt daily. Added to the wind turbine it should be all I need. If not, there's always the Yamaha 2300 Inverter. Now I suppose I'll be needing to buy a shed to mount the panels on and store all the goodies in. Thanks guys for pointing me to what seems to be the most inexpensive solar site around. Now, is there a reallycheapsheds.com? :D
Ok guys. Let's say I've got a couple of SUN panels, 200W each. I run them through my MPPT Controller and into my 12V bank. I know there are always losses, I just don't know how big those losses usually are. My solar map shows 3.5hrs average peak. What kind of actual power output should I expect? How large a difference between a sunny day and raining?
Is that in the winter or summer? I have found many solar maps to be unreliable because the average 365 days a year. Some average by month and some by season. I once found a site with the raw data of average sun hours in a given day. This gave me the best perspective of how they came to that number. This also gave me the difference based on weather conditions. I think the best charts are broken down by month. Sorry, I can't find the site. I assume that 3.5 hours is peak summer sun. I have researched the Catskill area and in the winter the sun hours are far below that. Although I believe you said your place was seasonal anyway.
Links to monthly solar maps are available in ther first message in the Off Grid PV Sizing Tool (http://countryplans.com/smf/index.php?topic=8192.0) topic.
Inefficiencies in lead acid batteries can be as much as 20% of what the PV modules were putting through into the batteries. That figure includes the losses that occur when the energy is withdrawn and used to light a lamp, turn a motor, etc.
Have you run your projected use, etc through the PV calculator? Two biggest errors made with owner designed PV systems are:
1. insufficient storage or withdrawing too much energy and
2. insufficient wattage from PV modules.
Closest city to me shows 2.5hrs by winter, and 4 in summertime, avg 3.55. I'm assuming being there in all but winter. Just wondering what a "200W" panel would be expected to put out under real world conditions, assuming direct sun, peak hour, and in rain.
I've done a energy budget and it appears I will be using on the order of 1-2Kw/day depending on how often the pumps run. I've assembled 8 220AH batteries for 1760AH at 12V. I wanted to have a discharge depth of 50% to last a 3 day weekend, so figure I have now have 10KW to spend over a three day period. To lengthen the discharge period (or shorten the recharge period), I have the wind unit, and now the 400W of PV. It seems to me I have more than enough to cover extending my stay by a few days or using a bit more than I originally figured. I've toyed with adding another two panels if need be. My MPPT handles 1200W max.
Although the rated watts on all the panels out there look impressive, I still wonder what I'll be generating each day while I sit on my porch and enjoy a cold one.
What will 200 W panels do in the real world? ???
Pretty good if the sun shines brightly! :) In winter cold weather they do even better as long as the sun shines and as long as the modules are correctly tilted. Modules are generally rated at 25 C (77 F) degrees. When the temperatures rise the output falls and the opposite happens when temperatures fall. Voltages can spike quite high when the modules are first illuminated on a deep freeze day. That only lasts for a moment, just long enough to fry charge controller electronics if their over-volt point is reached. Our panels Voc is 36.1, the theoretical maximum. I've seen it as high as 42.6.
Our modules are rated at 208 watts each; three modules for 624 watts. In bright summer sun, even with elevated temperatures, our modules perform above their rating.
This past weekend we had some rather low temperatures at the cabin. Yesterday with the sun bright it was still only 15 F outside. The Outback recorded a maximum power of 701 watts at one point. :o I observed 665 to 678 watts myself over a period of a half hour.
Cloudy weather does drop the output, but on all but the blackest of cloudy days they still put out.
At least that's what our Sharps are doing. YMMV
Quote from: MountainDon on February 07, 2011, 08:33:23 PM
What will 200 W panels do in the real world? ???
Our panels Voc is 36.1, the theoretical maximum. I've seen it as high as 42.6.
Our modules are rated at 208 watts each; three modules for 624 watts.The Outback recorded a maximum power of 701 watts at one point. :o I observed 665 to 678 watts myself over a period of a half hour.
Cloudy weather does drop the output, but on all but the blackest of cloudy days they still put out.
Thanks Don, that's awesome! I expected disappointing results but it's nice to know the claimed rating is close to the real rating. My MPPT can handle up to 40W panels, and my VOC is 33.2V. Hopefully not an issue. I'm looking forward! :)
Ordered the Xantrex XW6048 Thursday
![](http://ep.yimg.com/ca/I/yhst-82241567817297_2144_10723099)
from Sunelec -- good price -- $2900
http://sunelec.com/index.php?main_page=product_info&cPath=6_38&products_id=54
The FIL is going to pick it up when he is down in Miami and drive it back for me
saved almost $400 shipping :)
Will you be able to use it either on or off grid or is it grid tie only, Windpower? Nice inverter.
Quote from: Windpower on February 12, 2011, 11:52:34 AM
Ordered the Xantrex XW6048 Thursday
![](http://ep.yimg.com/ca/I/yhst-82241567817297_2144_10723099)
from Sunelec -- good price -- $2900
http://sunelec.com/index.php?main_page=product_info&cPath=6_38&products_id=54
The FIL is going to pick it up when he is down in Miami and drive it back for me
saved almost $400 shipping :)
Nice unit. I hope you get great use out of it.
The cost to ship these items never fails to amaze me. My 2 Sun PV panels arrived 250 bucks later, strapped to what essentially amounted to a wall (header, footer, studs, 5/8 inch plywood). Irony was, the the other side was exposed, covered with a sheet of cardboard, and scratched along the edge leaving a jagged aluminum edge. I'll file it down but sometimes I wonder... I've got a running record of 2 returns for the last 5 items.
I'm so happy I was able to pickup many of my items locally. :)
Truck freight can be a killer
30-some years ago someone drove a forklift fork through our first Vermont castings stove; right from the factory to us.
Off grid, Glenn
shipping my 1800 pounds of batteries from Canada cost me $120 -- go figure
Doesn't make much sense but that's how it is I guess.
My 3 orders from Sunelec cost $60 shipping each time. I had 2 shipments of 3 panels each and the panels were strapped to oak pallets with plastic corner spacers between the panels for stability and to keep them off of each other. This also made the job of moving them from one end of the truck to the lift gate a lot easier with the hand pallet jack. I am closer to Miami than most.
If you can pick them up yourself, you are better off. I had actually started putting a pencil to the costs of me driving down to Miami and quickly nixed that idea.
MIL called (not FIL) and said that their friends from the Keys were going to meet them in Sarasota (IIRC) they didn't want to drive the extra 3 hours to Miami to pick up the inverter.(they are retired and on vacation "for a month or so")
"so can you still get it shipped ?"
Sure, I guess, seems I don't have a choice
"I hope it won't cost you too much"
Oh, no problem, it is only about $400 to get it shipped
"Oh good, I was afraid it was going to be expensive"
*shaking head in disbelief*
The only reason I bought it now from Sunelec was because he said he would be happy to pick it up because he was going to FL anyway. Otherwise I would have bought it from The SolarBiz this fall. This put a significant strain on our cash flow right now (with the Cessna annual and the $%K&***ing truck trans blowing up, real estate taxes due)
Told my wife....
she said, yeah that is the way he is ....
I don't get it. He is always bragging about what he does for people, and that he is a "man of his word" --- it is a side I haven't seen about him before.
Wife is not surprised at all
I don't get it at all
*end of rant*
Looks like the reason their price is so low might be because that is discontinued; still a good inverter but everyone else seems to be selling the new model that also does three phase. That sucks on the reneging on doing the pickup
alot more money for the new one though
I can't think of a good use for 3 phase at the farm
If It needs that much power I'll get a gasoline motor .... ;D
Quote from: Windpower on February 20, 2011, 12:37:37 PM
I can't think of a good use for 3 phase at the farm
Most of us wouldn't. It's like Xantrex fixed something that didn't need fixing.
X probably did it for Machinists and not Farmers. Hi Don! Been to busy to lurk, that is a damn shame! :)
I have a couple 3 phase machines that would like it....but I also have a rotary phase converter so I think I have it covered. Now if I would just hook them up. [ouch]
Hey Glen, I think we both could use a hook-em up guy.... 41 inches of rain on paddy hill so far!
I haven't kept a total this year Dave, but I'm sure we are right there with you and more rain and maybe snow on the way.
Got your rainwater tanks full already?
My little cow water pond is starting to seal pretty good now.
SunElec -- sale on used (new year ago - reject for slight cosmetic flaws) Solar panels -
See their letter
http://campaign.r20.constantcontact.com/render?llr=cgx9b8cab&v=001cHaZO6NvI5XvL0G5057uWbnJjdiUONtACcaI_kG1I7090fRgas-nwETNgXsv2OVd9zKek8NQe7iQ9f8f2__tSvVs-gxp6zsr9hQ05-hez3DUajHfDQphkgRPMjm5esgzS5clzyZ7N2_Ou5lGqE1nOk87_-7WcQ_PUXZdlX2rknMmibCVb3baNg%3D%3D
.98 to 1.34 per watt.
The .98s are laminates.
I got their grade B's and they produce right up to full capacity or better.
Glenn, got the email yesterday and it would be a good opportunity for someone who wanted to get their feet wet with RE to invest in some PV. I too am well pleased with the panels I got from Sunelec. In fact it is time for me to change tilt but may just wait til the summer. Tickhill
I think these panels would be as good as they say they are and would not worry about them at all. Watts are watts.
If there was a problem I am confident they would take care of it.
Wow great price. Now, if I could just buy the winning lottery ticket.
Did you folfs notice that Sun has a wherehouse in SF? As for their warranty keep in mind that it could cost you alot in shipping which may not be a problem now. I say may not because they still have a ways to go in the good service rating. Great price as long as you have time to hang on the line.
Hey Glen, do you know anyone who wants 4 of the 75V Dupont 100W panels from last year? I will beat the Sun price! They were used for running 300V for my high voltage charge controller testing that Xantrex/Schneider is building.
I have a couple of possibilities on a need for the panels, Dave - PM me a price or I can drop by on the weekend possibly.
On dealing with Sun, I found that knowing what you want and ordering via the internet is the way to deal with them.
I don't deal with Phoenix, AZ branch - they are the worst customer service. I have done well with Miami.
Problem with a Peoples Republic of California office is Sales Tax.... about 9%. Once there is a store in the state I think we are stuck for Tax no matter what.
I would rather pay tax than shipping! ???
I also have a unused outback mx-60 in the box and an xw4548 inv/chg that I will swap for an xw4024.
I'm not sure if the shipping would go down that much but it might.
Sometimes its worth paying extra just to keep the state from getting more tax..... [ouch]
OK Glen,
I get the point of not giving the state the money! Truckers are much more deserving, but those 4 panels were a dollar per watt and over 300 to ship to Mariposa.
I also think that going to the belly of the beast (SF) could be even worse than the Phoenix store. They are a funny company and the owner is the funniest! He once told me that a cracked cell was not a defect but an opertunity to sell! :(
Interesting.... I think those panels exceeded UPS sizes and had to ship by truck.
Seems order before last 500 watts or so, were crystalline rather than thinfilm I got from them, and fit UPS and were cheaper. Seems truck shipments from FLA have been running around $250.
I dealt with his daughter in Phoenix and got her on the phone only once. After that I emailed John Kimball. Soon I heard from her but when I tried email next order I got no response. Finally I submitted an order to Miami on the online order form and received my order but had to decide on appropriate panels on my own with no consulting with them as they just were not available.
Sun does have some great deals but I just can't send a customer there knowing there is a very good chance that I will get blamed for issues that develope. The nightmares about racking systems and panels that don't fit from other forums would shock you. So as long as you buy nice easy things from them all is well, some of the time...
Good to know that stuff, Dave.
I only buy the panels from them. I buy the 2x4 racking system at the local lumber yard... [ouch]
Quote from: Dave Sparks on March 12, 2011, 09:50:05 AM....nightmares about racking systems and panels that don't fit from other forums would shock you. So as long as you buy nice easy things from them all is well, some of the time...
As well as people being given info that was plain wrong... like being told it was okay to series wire too many panels for the charge controller being used. And people being unable to get satisfactory answers to their questions, so much that they try to get free answers from vendors they never bought from.
I haven't been able to get design info from them, but tend to forget that I already know what to watch for in system design on my own.
Hey Don,
Did you ever solve the keep the cans from freezing problem?
Dave, everything was going just fine with the undersink cabinet insulated and a small transmission oil cooler in a thermosiphon loop using water warmed by the water heater on low. Until the pilot went out. I think the pilot may have gone out because of an issue with an extreme cold snap and issues with drawing propane from portable cylinders. I'm not 100% sure on that, but since it's never happened before am leaning to that theory. I think the propane burner kicked in and the supply tank was low and very cold. It could not supply sufficient propane and flamed out. My theory anyways. I did more propane research and now know I didn't fully realize the issues with cold and propane. We had some below zero weather coupled with a week of heavy cloud cover.
Nothing in cans or jars froze solid but water in PEX lines froze. No problems with any valves or the tank though. I think we were lucky.
I have a new solution in mind for next year that involves a hole in the ground. More on that in a new thread later.
I was running a heat trace to keep my sewage pipe from freezing (to the composting bin for the toilet) but noticed that despite the low wattage (I think it was just 5 watts per foot and I used 6 feet) it was still too much for the 660ah battery bank and 615 watt solar power -- in the winter anyway.
I found my battery bank down to 12.0 volts when I arrived Friday and had to ration light usage despite using CFL's. We added a freezer which uses about 15-30 watts depending on it's cycle and once the batteries were charged up it ran fine but I can see the need to add at least two more batteries to get me to 880 AH's versus the 660.
At the same time, however, I hooked up my Iota charger (finally) and made use of it for a couple hours and brought the bank back up to 12.5v because the clouds just kept the sun from doing it's job!
I plan to work on the solar power in the near future and might installed another panel and battery just for winter use with the heat trace. I figure I can install a low voltage shutoff like Don mentioned last year as that ought to heat the pipe and then let the battery recharge and then heat the pipe again etc but I'm working on options still.
We want to add a small fridge too and I feel that it's likely ok to run the freezer and fridge (on low settings) when we aren't there to preserve things and provide cold storage when we arrive but I'm learning I need to get back to the drawing board to make sure the system can handle the usage. God forbid I wanted to LIVE in my cabin! hahaha I'd have to do some serious work on the solar (add a couple panels maybe and more batteries) to ensure I didn't have to run the generator very often.
However, in the end, it's just plane cool to have solar power :)
I had my concerns about that heat tape when you mentioned it.
What kind of freezer, if I may ask?
One of the issues with an unattended system is what will it do when it's cloudy for days on end? I planned for three days minimum of capacity (actually have more than that as things are). This past winter we had five days in a row on two separate occasions with continual cloud cover. The weather station records illustrated that starkly with the watts/m*m column never getting above two digits during those periods. (That is sun watts per sq meter, not the PV power output. Right now, sunny day it is at 766 watt/m*m. Summer it hits over 1000) That would not be an issue if we were at the cabin; I could start the generator. However, if we were absent and if there was something like a refrigerator operating there could be consequences I'd rather not deal with. For that reason I'd like to have an automatic start generator if we were running a fridge/freezer. Peace of mind insurance.
Quote from: MountainDon on March 14, 2011, 05:12:24 PM
I had my concerns about that heat tape when you mentioned it.
What kind of freezer, if I may ask?
One of the issues with an unattended system is what will it do when it's cloudy for days on end? I planned for three days minimum of capacity (actually have more than that as things are). This past winter we had five days in a row on two separate occasions with continual cloud cover. The weather station records illustrated that starkly with the watts/m*m column never getting above two digits during those periods. (That is sun watts per sq meter, not the PV power output. Right now, sunny day it is at 766 watt/m*m. Summer it hits over 1000) That would not be an issue if we were at the cabin; I could start the generator. However, if we were absent and if there was something like a refrigerator operating there could be consequences I'd rather not deal with. For that reason I'd like to have an automatic start generator if we were running a fridge/freezer. Peace of mind insurance.
I'll have to check the Freezer model -- my wife bought it at Fred Meyers. Our plan with the Freezer is to leave it set off unless it's needed. Once needed a Freezer can usually go without power for short periods of time (even days) if not opened. However, I am concerned, like you, that it could somehow run without power too long -- something to ponder.
I'm also looking at this fridge: http://www.pcrichard.com/catalog/product.jsp?productId=1533&parentCategoryId=7&categoryId=1104&subCategoryId=1104010020
I was told that getting a fridge without a freezer is the key to using less energy. I guess I'll be doing some learning!!!
An autostart generator would be very nice to have and I might have to put a small one on the shopping list.
As for the heattape, it does seem to be working nicely but uses more power then I anticipated :( I think it's going to be perfect for use when I'm there but will have to be shut off when we leave -- which might be fine.
I may look at a timer to turn it on and off daily though.
Quote from: OlJarhead on March 15, 2011, 11:13:41 AM
I was told that getting a fridge without a freezer is the key to using less energy.
Hmmm. Where did you hear that? How much less? A top load freezer or fridge will be use less electricity, so if the freezer is a top load that can be very good. I've also read and believe that a top load fridge uses less electricity than an upright. But they are the very devil itself for convenience of use.
Are you aware that residential fridges and freezers are meant for use within a temperature range of something like 60 to 100 degrees. It's obvious that when in a hotter location the unit will consume more power. But it is not obvious, in fact it is counter intuitive, to think that in a colder location (like 40 degrees) the unit may also use more power, not less.
Quote from: MountainDon on March 15, 2011, 12:17:54 PM
Hmmm. Where did you hear that? How much less? A top load freezer or fridge will be use less electricity, so if the freezer is a top load that can be very good. I've also read and believe that a top load fridge uses less electricity than an upright. But they are the very devil itself for convenience of use.
Are you aware that residential fridges and freezers are meant for use within a temperature range of something like 60 to 100 degrees. It's obvious that when in a hotter location the unit will consume more power. But it is not obvious, in fact it is counter intuitive, to think that in a colder location (like 40 degrees) the unit may also use more power, not less.
My neighbor who's been on solar for 30 years told me to look for a fridge without freezer. Something to do with the cycling/dehydrating/antifrost of the freezer I guess.
The cabin stays VERY cool in the summer (as low as 45 at night and remains cool until well into the late afternoon) so I figured the fridge will not have to work too hard in those conditions. I also plan to put the freezer on the North side to keep it in the shade 95% of the time (if not more).
I'm not sure I got my point about low environmental temperatures and residential refrigerators made. Refrigerators in cold spaces are not going to run as well as they would in their design temperature range. A fridge in a cold space may not save any power.
The common household refrigerator is not designed to operate at 45 degrees. At low environmental temperatures the internal operating pressure of the refrigerant falls below design parameters. That makes the motor run longer to do the same amount of cooling. So even though the unit might run with less frequency it will run longer than if the room was at 75 degrees. The system does not lubricate as well either and that shortens the expected life. Commercial refrigeration units that have the compressors sitting outside on a roof top have different, more complex, more expensive metering devices in the refrigerant section. They can operate in extremes of temperature without problems and with greater efficiency. A residential use refrigerator could be built to run at lower temperatures and still be efficient. That costs a little money and most people keep their residences at least at 65 - 70 degrees, so the manufacturers of residential refrigerators don't spend the few bucks.
There are refrigerators sold as "garage refrigerators" that are made for use in a cold space like an unheated garage. Expensive though.
My point is do not count on a cold environment making any savings in electrical use. I have some info saved someplace, but I don't know where off hand.
I believe the operating problems are most severe with fridges that have a cooling fan with the condenser. Units with the coils under the skin like many freezers, are more immune to the issues. Something to do with pressure head or something. ??? Low temp = low pressure = low flow = less refrigerant and less lubricant flow = trouble, is what I understood from what I read.
Ok, here goes. I have a question which I have been researching. It is about UL products in the solar setup. I have to pass a code inspection before a certificate of occupancy is issued. Based upon my readings of discussions here it appears that all products used in the electric system for a house must be UL approved to pass inspection. If this assumption is wrong, please correct me. I have been searching for products to build my system. There are a lot of products out there from some of the big names, but when I look them up most don't advertise if they are UL listed or not. I was searching through the Xantrex line in particular and found only 2 products advertised as UL listed and that was for UL 458 - Boats and RV's. I am particularly looking for this in charge controllers and inverters. Has anyone else run into this? Am I missing something? Also, is there a particular UL listing I should be looking for before I buy a product?
UL listed or ETL listed satisfies NEC. All Outback charge controllers, inverters and power panels are listed. Ditto on the Xantrx C series controllers; probably all their major inverter/chargers.
I noticed that the printed matter I have on my Outback inverter shows ETL clearly. Hidden is the fact that it is ETL listed to UL1741 standards. And if I remember rightly the label on the unit shows the UL symbol. Not everyplace I've seen the unit offered for sale makes mention of any approval. Reading the manufacturers manual seems to always mention UL or ETL listings.
Depending on how knowledgeable or "by the book" the inspector is it may be the little things that catch you up. Automotive wire and standard welding cables are not UL listed for example. Black wire is not suitable for a negative DC conductor. Run of the mill terminal connectors are not UL listed. The common RV / race car battery disconnect is not UL listed. Some PV modules sold as blemished or seconds may not have UL labels. (sometimes that is because the cells may be placed too close together to pass the high voltage test. Sometimes it may be because of the connecting wires not having UL labels. Sometimes it may be just that they never paid to get the right to use the label).
My battery cables are not UL-Listed. But I used white tape on the ends of the negative cables just like NEC calls for. I did not invite the inspector. There is a break point, above which white tape is accepted and below which it is not.
Side note: When looking at things like breakers and switches, for example, sometimes you come across things with a UL recognized label. These are for components that are used in devices. The entire device can get the UL listed label, but any components with the UL-R symbol are not approved as individual items. Clear? I had found some circuit breakers classed as UL-R. Good price. But by themselves they were not UL-listed. They needed a UL-Listed enclosure as well. Probably more than you needed to know.
Very nicely done Don! If you are going to be inspected then talk with the local inspector about any quirks he has! Do the best you can about what Don has said. Yes all of the Xantrex high end gear will work for code as well as Outback. The Outback gear came from Xantrex guy's who went out the back door BTW.
Magnum as well and anything from Midnite also! Good luck!
Thanks Don . I didn't know about the ETL. I found that the outback flex controller was, but it was not readily available. I had to go and pull the user manual for the product to get the information. After much searching I was able to find an owners manual for the C series from Xantrex to find that it is UL certified on page 23 out of 100. What a real PITA it is to find this information. With the cost of testing and the necessity of the certification to pass code, you would think this would be more prominently displayed. The Xantrex website no longer has any links to any of the C series products. Morningstar charge controllers also seem to be certified, but again, I had to dig through the manual, product by product to get the information. Very time consuming. I spent a long time on just three controllers. I can't imagine how long it would take for all the different inverters. Does anyone know if there is a reason for this? Is there just a general assumption that major brand names are certified? Or do inspectors just not usually check?
My view is that the local hardware stores and electric supply sell the UL wires and other parts I would need, but not the off grid components. Education and design of the electric system is the next step for me.
Thanks Dave. Inspection is certified by any licensed electrician.
Aw shucks :-[ Thanks Dave. :)
Quote from: Squirl on March 16, 2011, 09:46:40 AM
My view is that the local hardware stores and electric supply sell the UL wires and other parts I would need, but not the off grid components.
Don't forget that common everyday UL listed AC parts (disconnects, switches, breakers...) are almost always not safe to use on the DC side of the system.
Quote from: Squirl on March 16, 2011, 09:49:22 AM
Thanks Dave. Inspection is certified by any licensed electrician.
Actually that depends on the county, state, ect. You can do it yourself if you are the homeowner in most places.
to MPPT or not MPPT? That is the question.
Ok, here goes for discussion. I am looking to upgrade components of my small portable solar setup to slowly expand more towards a cabin sized system. These will be UL for a future electrical inspection. The first component I have settled on is the charge controller. Some advertisements seem to boast an up to 30% greater efficiency. Here is the breakdown of my understanding and factors that I used to come to my conclusions. The first factor was price. I will use similar devices for comparison (60 amp). The minimum price non-mppt charger I could find was a Xantrex C60 for $150. The minimum price MPPT chargers I found were the Outback FM 60 and the Xantrex XW-60 for $500. So what do you get for that extra $350? My understanding from some books and articles the MPPT technology has 2 main advantages. First it takes voltage over the necessary amount for the battery bank and converts it to current. An example if your panels are putting out 17v and the charging volt of the batteries is 14v the 3v difference would be lost if it were a non-MPPT charger. So on cold sunny days this would be most pronounced. The second advantage is that this conversion of volts to current can match higher voltage solar arrays to lower voltage battery banks. This can be a real advantage by not having to pick you panels as closely and mixing and matching panels. This can also have an advantage if you want to run the DC solar line a long distance (like don did), because you can use a higher voltage, lower amperage line and just let the charge controller do the work of matching the voltage. Did I miss anything?
So let me break this down into dollars and my system.
First, my I don't plan on running long DC lines. My hope on integrating passive solar into my home means I will have a clearing for solar access around the house. If I do run a line, it will be 120v AC.
Second, I believe I can shop and match panels in 12 and 24 volt and connect them in series or parallel to match the voltage of my battery bank of 24v to 48v depending on sizing and expansion. I will reconsider this if I find a great price on an only 12v inverter, but the cost difference in 12 and 24v inverters would half to be over $200 for MPPT to start to have consideration for this factor. I also would have to find an large difference in price between the panels that put out 100v and at 1 amp and the ones that put out 25v.
So the last factor was the power efficiency gain per $ spent. The efficiency gain seems to be largest for systems at 12v rather than higher voltage. The panels seem to come in average voltage ratings of 17, 26, 35 Vmp. So the tolerance of power lost seems to be greatest at the 12 v. level. I will go with this for maximum dollar differences. So if I have a 500 watt panel array at 12v, a 30% gain in efficiency (highest advertised gain) would be an extra 150 watts. This compares to that I can get a 150 watt panel for $300. So with weighting the greatest panel difference and greatest average gain, it is still cheaper to get an extra panel. This seems to change as you go for larger systems and more panels. Then the power gain from a $350 additional cost MPPT charger is greater than the percentage gain from adding more panels.
So for simple small to medium sized systems it seems cheaper just to add an extra panel rather than going with an MPPT charger, and for a medium to larger system the additional cost is worth it.
What did I miss/ get wrong? I would appreciate any critiques.
I have the Outback FM60. The FM60 has a maximum open circuit voltage (Voc) rating of 150 volts. That means if the incoming voltage from the PV array e\xceeds 150 volts the unit may toast. My Sharp panels have a Voc or 36.1. Three in series equals 108.3 volts. However, in winter with clear blue skies there can be a cold weather induced peak. It doesn't last for long but can still damage the charge controller. I have recorded readings of 141 volts on several occasions.
The maximum Voc of the Xantrex C60 is 55 volts. That is going to severely limit any series connections with PV modules. Voc from the panels should probably not exceed 36 volts.
Outback generally has a operating temperature range that goes to lower temperatures than many other charge controllers.
To add to the Voc notes above.
I used the string size calculator that Outback has online (http://www.outbackpower.com/resources/string_sizing_tool/). It has sliders for maximum and minimum temperatures. It comes up with recommendations for maximum number of panels in series and parallel. There is an extensive list of PV module data to choose from. You can also enter your own data for panels that may not have made it into their database yet. Using that calculator the maximum voltage my three panels should produce is 127 volts (three in series). Looks like I hit 12% more than that. Could have been extra cold or extra bright (8800 feet altitude has less atmosphere to screen the PV modules.).
I believe Xantrex has a similar tool; I know SMA (grid tie inverters) does.
I also believe that when running the numbers to keep everything on the up and up with NEC that there may be another safety factor percentage that needs to be considered. Another 25%, BUT I am not certain of that. So that is only mentioned as a caveat, something to be checked on, no guarantees one way or the other. I may be confused. That may apply to sizing breakers or wires. Darned if I recall for certain.
Maybe Dave Sparks can set us straight on that.
Squirl have you planned out how much battery capacity you will need when all is said and done? I think that is the place to start and then from that data work out array capacity and from that charge controller size.
Everypanel I looked at had a 25-26 Vmp, but the Voc was around 30. And all the 17 Vmp ones had a Voc of 23. The Xantrex C60 can only go 12v and 24v systems. The C40 can go up to 125 Voc, which should be more than enough if I want to go from a 24v to a 48v system. My understanding was any voltage differences from over 2-3 above the battery bank would just be lost if I didn't get the MPPT charger. That is just what I could glean from a few articles on it, not 100% though.
So for $100-$125 I could go for a C40 or TS-45 and a slowly expand a 24v system up to 960 watts, and if I went bigger I could switch to wiring in a series to 48v up to 1920 watts. If I went with a system over 1-2kw, then that it would probably be time to upgrade to an MPPT charger. I would probably have to run the cost/benifit ration if my system was over 1kw. So if you get 25% more power (average high advertised rate) it would be worth the additional cost at around 1kw. Although, I distrust the advertised improved rate. It seems like this would only be under certain conditions and would not apply some or most of the time. So if in reality, if over the life of the product, it gave you a 15% real world gain, it would become cost effective closer to the 1.5kw range. This of course is with distance run not being a factor. These are just my thoughts so far.
So operating temperature should be another factor to check. The Xantrex C series is 0 degrees C. The morning star and outback are -40 C. That and the warranty seem to be more brand specific than between the MPPT technology/ cost difference.
Does the FM60 have diversion control for use of excess energy?
Don,
A building department or inspector could calculate that you are overvoltaging a controller from temp data and make you rewire an array. I doubt they would... As far as safety, the wire is 600vdc, the breakers are 150vdc, and so if you overvoltage the controller it will record that and probably have problems, or will soon. Same with the breaker. The point here is it will not harm anything except your budget. Electrically the controller just stops working or internal circuit protection takes over. Some internal protection is one time only!
One of the extremely nice things about a 600vdc hi voltage controller is that you widen the design range. Also the issue of long distance and small easy wire gages for ease of use is very tempting, as long as one has the wallet!
Ok is the NEC 25% buffer down or up? Example if you have a 45 amp controller at 24v then it has a maximum rating of 1080 watts. A 25% decrease is 1080x.25 = 270 watts or a panel array of (1080-270) =810 watts. As opposed to X x 1.25 = 1080. Or an array of 864 watts. Either way, it is around the panel array size were MPPT technology becomes a cost effective alternative.
I have an idea on size, but there is a lot of time and money before this is all finished. I currently have a 100 watt 12v. single deep cycle marine battery system now. It is great for lights and a little bit of charging. I figure I can add a panel or two and keep it 12v, but I will need a new controller. As I spend more time there, I figure I will expand it. I would like to reach around a 500 watt 24v system with four T-105's by around when it is time for the electric inspection. This would give me 5400 watt hours, and around 2kw hours production per day in the summer. Good for a weekend, but not quite full time. If/when I am there full time, I would probably want up to 11000 watt hours capacity and maybe a 750 watt panel array. My estimate is around 1.5-2kw hours a day (what I have used in the past).
Since I am on the very top of the mountain, I figure I will want to add a small wind system eventually. I have read that the power output of these can vary from a little too extremely high. I think I would give it its own charge controller. I will probably install this type of system after I get a certificate of occupancy. Between the two systems I have an average estimate of 3-4 KW hours per day, which is less than my current electric usage.
This lead me to kicking around the cost/benefit of MPPT technology, so I thought it would make a good discussion topic.
on the NEC rules...
It's volts or amps.
(1.25 x 1.25 is 1.56, so rather than go through n * 1.25 * 1.25, I use n * 1.56)
Example. Sizing a circuit breaker to be used between the PV modules and the charge controller.
Take the short circuit current rating (Isc) of the PV module you plan to use and multiply it by 1.56, then select the next higher breaker size. So Isc = 8.13 x 1.56 = 12.68, probably use 15 amp breaker.
If the Voc is 36.1, then 36.1 x 1.56 = 56.3 volts, so the DC voltage rating of the breaker should be at least 56.3 volts.
More thoughts on selecting, or not selecting MPPT, later.
PS I never overvolted anything. I came close on two days but since it was during the coldest temperatures recorded in some sixty years it's not normal. The next highest recorded voltage was 127 which is very well within the 150 maximum. I know it would only take once. If I get concerned I have a choice of a higher volatage controller or a cold weather panel cut out. I have toyed with the thought of a cut out. :-\
I meant "you" in the same sense as "one".
Dave. I did not mean to imply you were picking on me. Just wanted to it clear my system got close to trouble but usually does not.
Wind generator: yes it would need it's own charge controller. One that has provision for a dump load.
FM60 and diversion. There is an Aux output. It can be prrposed for different tasks but only one at a time. The manual explains. (D/L at Outback) It could be used to trip a relay that would be sized to handle the required voltage and amperage for load diversion. I investigated that route when looking for ways to keep "things" from freezing in the cabin over winter. The conclusion I reached was that it is possible but likely not a good return on the money; not to mention the bother. I was wanting to use the excess for resistance heating. It really doesn't amount to a lot of useful heat was my conclusion. What were you thinking of using the unused PV module power for? Or were you thinking of a wind generator dump?
System planning: I get uncomfortable when discussing planning a new system and at the same time to be talking about how the system will be grown in the future. Adding a wind generator is different from increasing battery bank size or changing the system voltage. That is my opinion and may differ from that of others. Adding more PV modules in a second group as Glenn has done is fine too as those modules have their own charge controller. The absorb charge and float charge voltage points may have to be played with to keep one from interfering with the other. That's in theory; as I've never had the situation I can't say much more than that. Adding batteries is not great practice, IMO. Sometimes not avoidable, but that is where planning comes in.
MPPT: Again, just my opinion, but I do think MPPT has advantages no matter what the system size, except for all but the smallest system where two panels in place of one may be a better buy. Maybe the advantages are more quickly realized when the modules are wired in series making the PV array voltages much higher than otherwise needed. By that I mean 30+ VDC from the array for a 12 VDC battery, 60+ for a 24 volt battery.
In hot or cold weather I believe any system will gain in performance wired that way with MPPT. The PV output voltage always has to be higher than what is required to charge the battery. It is the PV cell temperature that matters, not the air temperature. The module temperature can be 30+% greater than the surrounding air temperature. In a system where the PV output voltage is close to the battery system voltage the module voltage may fall too low to do any charging on a hot sunny summer day. If the series voltage is higher (like 2 panels in series instead of in parallel) there will always be enough voltage and the MPPT controller will make best use of what there is.
Similarly on cloudy days. I am amazed at times that our system is still pumping out a few amps on cloudy dark days. Looking at the voltages being received at the charge controller I can see that without series and MPPT there would be no charging happening at all.
One of the things I like about what I put together is that it runs itself. I don't worry about it being cloudy anymore; I notice, but I no longer worry. My wife can "work" it too. I wrote a user guide.
And I have had a friend run a winter temp CC at close to 148V :o waiting for Midnite to release their 200V contoller. I am glad that you don't think I am picking on you! You would know if I was... Spring is coming! Although Glen may doubt this!
Wow! 148... makes you wonder how well everything is calibrated. :-\
Spring is definitely here, at least where our cabin is! A year ago we had three feet of snow in places, minimum of 12 to 24 inches everywhere, no ground or grass showing anywhere. This weekend it's all dry grass and pine needles save for north facing slopes.
I never thought about the advantage of going further over voltage of the battery bank with the panel array. This way when the array puts out lower voltage and would not be charging at all, it still gives it a little charge. That is another great factor to consider. I wonder if there is a way to quantify that. Also upon further reading of the subject last night I read that MPPT chargers are best to maximize power gained from the panel array, while PWM are used to maximize battery life. There weren't a lot of articles on this. Most of the books and articles I have read though give these as descriptions of each technology but not as a comparison. Such as the statement "pwm maximizes battery life", but not pwm gives longer battery life than mppt. There was no quantitative data on the extended battery life of PWM over MPPT technology though.
There seemed to be a lot of "if" and "possible" caveats in a lot of the marketing and advertising of certain devices without much information as to what the parameters of the scenarios they are referring too. I figured bringing up the topic with some like minded individuals would flesh out a the limits a little better. Thanks don and dave.
I've seen the claims that PWM produces superior battery life too. ??? Claims but no data to back the claims. I have no proofs either, but I'm willing to go out on a limb and state that no matter how much good might come from a PWM charger, it is more often than not countered by batteries that...
...get discharged too deeply, too frequently,
...are not brought back to full charge pretty much every day,
...have the fluid level fall too low too often,
I don't see big name battery manufacturers giving longer or shorter warranties depending on the charging technology being used.
Ok so here is a question: If a piece of electronic equipment does not list watts but rather lists kwh's (I'm sure amps was there somewhere but without my reading glasses I couldn't read it) could you not do the following to get average wattage:
Given:
24x365=8760 hours in a year
1000 watt hours equals a kilowatt hour
a 100 watt bulb running 10 hours = 1 kilowatt hour or 1000 watt hours.
Freezer uses 242kwh per year with an energy star tag.
Then:
1000 watt hours divided by the wattage of the device equals the amount of hours it takes to make one thousand watt hours or: 1000/27.65=36.16 and 8760/36.16=242
This would mean that a 27.65watt Freezer would use 242kwh per year assuming it ran 24x7x365 at that rate.
Reality though tells me that it draws much less then that most of the time and some number higher then that periodically as it cycles. SO I'm unsure if calculating this way really helps. What I'm trying to ascertain is both if I can use this kind of conversion to convert kwh to watts for the purpose of the solar calculator and if in fact I can use this as a base for a system or components of said system?
Mostly I'm just trying to see if my 3 panels and 8 batteries will handle the freezer running 24x7 in the spring, summer and fall when outside temps range above freezing most of the time (it can get as cool as 40 at night in the summer but mostly runs in the high 40's at night and 80's during the day.
I also plan to put the Freezer on the North side of the cabin to keep it cooler when it gets hot out rather then have it in the porch where the greenhouse effect will make the porch VERY warm during the day.
Thoughts?
Erik
I haven't seen one that small.
Seems a lot of my stuff uses around 125 or more watts but runs from 8 (Old efficient GE) to 40 or so minutes per hour (new fridge or freezer).
Offhand I don't recall the size panels and batteries - Total watts panels - Golf Cart Batts? Hours sun per day?
242/365=.66 kwh per day -
660 watts of panels for 1 hour - 330 for 2 hours 165 for 4 hours sun plus another third for losses and inefficiencies and ability to store about half of that for night plus draw the batteries down only about half way. A backup generator for cloudy days or several of them, will likely be necessary, as it is even at my place.
I have found this calculator to be very handy
you can plug in various Kw-Hrs per month and get an idea of the system size needed adjusted for your average hours of sun for your location
for mine I plugged in 300 Kw-hrs per month (about 10 Kw-hrs per day) in zone 5 (4.5 hours sun per day) and got 2222 watts of panel required (pretty close to my 12 evergreen 205 watt panels (I hope to get them operational this year)
So if your freezer uses 242 Kw-hrs per year, then divide by 12 months gives 20 Kw-hrs per month
plug that in, find your average sun (zone 2 = 5.5 ?) gives 121 watts of panels required minimum
http://www.wholesalesolar.com/StartHere/OFFGRID/OFFGRIDCalculator.html
I think your calculations are a good start. I don't know what the test conditions they use for determining power usage of an appliance. If it is with normal usage and you plan on only going in it every few days, I would say that the power consumption stated is above what is needed. If the test condition was no one going in it, and you will go in it infrequently, I would go with the assumption that you will use slightly greater power. Also don't forget the losses to the inverter and I believe there is a slight extra inefficiency if running a msw inverter as opposed to a true-sine. (not 100% on that) Also if your inverter doesn't have sleep mode, it can drain as much power from the batteries as the freezer.
I tend to average usage across a day. You will be lucky that the time you want to use it is when the sun stays out longer. IIRC you are in zone 4, so you will have slightly less than zone 2. I assume you panels are around 600 watts total, so an average of around 2KW a day in spring? So it seems like you would get enough power per day just based on the energy star rating. I would be more concerned with the DOD of you batteries. What are you comfortable with? Are they top quality batteries? My assumption is you have about 5 Kwh capacity. I have been shopping for inverters lately and most seem to be rated for 90% efficiency. Add in the power usage if your inverter doesn't go into sleep mode, and the freezer, you could easily be at 1kw a day based on your calculations. So 2 days of cloudy weather could bring you below .25% DOD. So it all depends on the level of discharge you are comfortable with. My assumption is if you will be there during times of use so you can monitor your batteries and recharge them when necessary.
If it still has its energy star tag, I assume it is new? Maybe buy it from a store with a generous return policy. Put it in on Kill-A-Watt meter and see if it performs as advertised. This would also be a good way to check your inverters usage too. If it doesn't perform as advertised, return it. The only thing you would be out is the effort to move it.
I look at those annual energy star numbers like this. The label says 242 kWh or 242000 watt hours.
8760 hours in a year
242000 / 8760 = 668 watts used in an average day, Call it 700 watts a day for good measure.
7 days a week = 4900 watts a week.
My PV calc has fields to enter the watts and the hours per week of use and is set up to calc an weeks worth of power to help average things out.
Enter 700 watts in the watts column and 7 in the Hrs/Week column and that produces the 4900.
So the first thing is to estimate how the batteries will stack up and then the array.
Squirl, in case you haven't looked the calculator/spreadsheet has fields to enter correction factors for inverter efficiency, battery cold weather performance, depth of discharge and autonomous days.
I do have to work on the PV array section at the end though.
From oljarhead in another thread (http://countryplans.com/smf/index.php?topic=8192.msg133658;topicseen#msg133658). Copied this part to here as it fits here better.
- I see voltage in another way Running under 48vdc from the panels to the charge controller limits range on 10awg wire to under 50 feet (not sure the distance) where as 48vdc will run 50 feet on 10AWG according to xantrex. In my case I'm pushing 60vdc from the panels which gives me a little better (I think) performance at 50 feet over 10awg.
I'm no electrician mind you, I'm just thinking that running 18vdc from the panels would cost me in wire size (read $$$).
So, question: and I should post this in the other thread, but here goes anyway: Am I losing something by putting the panels in series and pushing out 60vdc to the controller?
Another question is this: If I put 3 batteries in series I don't change the AH rating just the voltage so if I put 3 panels in series I'm wondering if all I'm doing is increasing voltage and not wattage? I figured 3 205watt panels would give me 615watts of charging power.
Anyway, good topic!
I'll have some response later. Dinner prep beckons....
QuoteI'm no electrician mind you, I'm just thinking that running 18vdc from the panels would cost me in wire size (read $$$).
I'm not sure of the exact numbers for your 205 watt panels, but if we say 18.5 volts and 11 amps that's probably close.
so... using 50 feet for the 10 AWG copper wire length...
55 volts 11 amps computes to a voltage drop of 2.4%
60 volts 11 amps = 2.2% voltage drop
18.3 volts 33 amps = 21.8% drop
20 volts 33 amps = 20% drop
Number 1 AWG wire would be needed to get below 3% with 18 to 20 volts.
So yes series wiring PV modules is a very good thing. Not only is the smaller gauge less expensive it is much easier to handle and make connections to. I know from my experience with the 2 AWG I used in our system.
QuoteIf I put 3 batteries in series I don't change the AH rating just the voltage so if I put 3 panels in series I'm wondering if all I'm doing is increasing voltage and not wattage?
You are increasing voltage by a factor of three and the current flow remains the same.
Using the example of a module rated at 18.5 volts, 11.1 amps, 205 watts...
Place three panels in series you get 55.5 volts at 11.1 amps, 615 watts
In parallel you get 18.5 volts at 33.3 amps, 615 watts
Quote from: MountainDon on March 24, 2011, 07:02:34 PM
You are increasing voltage by a factor of three and the current flow remains the same.
Using the example of a module rated at 18.5 volts, 11.1 amps, 205 watts...
Place three panels in series you get 55.5 volts at 11.1 amps, 615 watts
In parallel you get 18.5 volts at 33.3 amps, 615 watts
Awesome clarification Don! Thanks! [cool]
Quote from: MountainDon on March 24, 2011, 05:45:56 PM
From oljarhead in another thread (http://countryplans.com/smf/index.php?topic=8192.msg133658;topicseen#msg133658). Copied this part to here as it fits here better.
- I see voltage in another way Running under 48vdc from the panels to the charge controller limits range on 10awg wire to under 50 feet (not sure the distance) where as 48vdc will run 50 feet on 10AWG according to xantrex. In my case I'm pushing 60vdc from the panels which gives me a little better (I think) performance at 50 feet over 10awg.
I'm no electrician mind you, I'm just thinking that running 18vdc from the panels would cost me in wire size (read $$$).
So, question: and I should post this in the other thread, but here goes anyway: Am I losing something by putting the panels in series and pushing out 60vdc to the controller?
Another question is this: If I put 3 batteries in series I don't change the AH rating just the voltage so if I put 3 panels in series I'm wondering if all I'm doing is increasing voltage and not wattage? I figured 3 205watt panels would give me 615watts of charging power.
Anyway, good topic!
I'll have some response later. Dinner prep beckons....
Yes, the C40 is a PWM charge controller, not MPPT so everything over 18v is lost power. That is probably why you didn't fry the controller. 615 watts exceeds the recommendation of 40 amps and a 12v battery array (40x12=480 watts). But with your configuration you are probably only charging at 200 watts. Also check the maximum Voc of the controller, you may be exceeding that too. (could fry it) Many of Don's calculations work for the controller he has the Outback Flex60 with MPPT. See my discussion above of tradeoffs of the $400 extra spent on an MPPT charge controller. Although, I have spent the past week researching this issue through books, all the old issues of home power magazine, and internet articles since I started that discussion. I was able to find a Morningstar mppt-45(great reviews) for $350. This puts the price difference much closer to the PWM controllers and pushes me to the category that MPPT is worth it at any panel array over 1 panel.
Jarhead, correct me where I make mistakes, but I took a look at your set up the other day.
You have 8 batteries at (6v?) Wired to have a 12v battery bank.
You have a 12v msw inverter.
You have 615w panel array wired to 60v.
You have a C40 charge controller.
To get maximum power out of your setup you can change the panels to 18v, buy new wire, and get rid of a panel for a total of 410 watts. (least expensive)
You could get a new charge controller to handle the higher voltage and amperage. MPPT preferable and 60 amps if you are sticking with a 12v battery bank. As you saw in my calculation earlier even if you are limiting it to under 40 amps coming in, it exceeds the controller rating for amps coming out (12x40=480 watts). So you would need 60 to get over 615 watts out. (12x60= 720 watts) You would still need new wire for a 12v bank with a non-mppt charge controller. ($200-$360 estimate)
You could change you battery bank to 24v but you could have to get a new inverter, charge controller, and maybe an extra panel. (most expensive)
This is just off the top of my head. I hope it helps.
Squirrel the C40 is designed to allow up to 120vdc in and will convert to 12, 24 or 48vdc for the bank so I am in no danger there I beleive. I'm running half what the input voltage it can take limits me to.
As Don pointed out 11.27imp and 54.60vmp should give me 615watts of power...I think I'm fine.
Quote from: OlJarhead on March 25, 2011, 06:02:18 PM
Squirrel the C40 is designed to allow up to 120vdc in and will convert to 12, 24 or 48vdc for the bank so I am in no danger there I beleive. I'm running half what the input voltage it can take limits me to.
As Don pointed out 11.27imp and 54.60vmp should give me 615watts of power...I think I'm fine.
Actually that is what I was trying to point out that his calculations were for his MPPT controller, not the C40. The C40 does not convert the 54.60vmp to your 12v battery pack. PWM charge controllers do not convert any power. It only uses approximatly 14.4v of the 54.6v, so 40.2 x 11.27 amps or 453 watts is wasted. If it did convert it as you suggested, it would push the push the amperage to 51.25 amps (615w/12v), well over the rating of the controller. Morningstar put out a good manual about the difference between the type of charger you have (all Xantrex C - series are PWM)and the type Don has (Outback Flex60 MPPT).
It can be found here:
http://www.morningstarcorp.com/en/support/library/MS.WP.MPPTvPWM.01.EN.pdf
I
OK, I guess I had no idea that this is what was going on. I saw the max input power of the C40 (125vdc) but I guess I missed the whole thing about not using the full power of the panels (or even 70%) because it can't use all the current. I'll give Xantrex a call and confirm and then I guess I better start looking for an MPPT controller that can give me all 615watts (minus losses) instead of only 200! That might explain some things I've been wondering about.
Thanks
I would just add to what Don has said about picking a battery voltage and then the contoller. You guy's are starting out and so pick an MPPT controller as it will give you flexibility down the road. You have to choose from the XW contoller, the Outbacks, the Midnite and the Morningstars. The rest should be avoided as they will not network. Actually, in my opinion it is Xantrex or Outback as they will interface well as a system with the inverter/charger. I have to do this for my customers but you folks can mix and match as long as you know the short side of having a system that will not integrate over time. Good Luck!
OK spoke to Xantrex's tech support and they concur. They advised that getting a 20amp MPPT controller would do the trick as I'm only running about 11.23imp off the panels (15amps would even work but 20 gives a little room to play) and suggested I could find one around $100-$150 if I did some searching.
Has something to do with a DC to DC converter -- way beyond me now -- and that the C40, as squirrel indicated, isn't designed to utilize the power of the panels when running them in series as it's only using about 14.2vdc in bulk charging mode leaving the remaining 40+vdc unused and all that charging current d* d*
Thanks Squirrel! I'm off to find a new controller! DOH! d*
Trying to find a 20amp MPPT controller that can take the 615watts of power coming in seems hard. Each 20amp controller I find seems to be limited to 200-300 watts of charging power for 12vdc battery banks.
Any help would be appreciated -- also, I want to be sure I get a controller that will not blow up when I kick on the Iota 750watt charger running off the Generator. The C40 has no issue with it but cheap Chinese made controllers might start to smoke ;)
Actually you need a 60 amp charge controller. Yes you are right that you have 11.23 amps coming in, but it when it converts the power out you have 50 amps at 12 volts. So you need a charge controller that doesn't only hand the amps coming in, but the amps it is putting out after the conversion. I'm actually disapointed in the Xantrex manuals that they don't lay this out. I read the Xantrex, Outback, and Morningstar manuals. You can see from the product manuals the maximum array size per controller at which battery bank voltage.
Here are morningstar's mppt:
http://www.morningstarcorp.com/en/tristar%20mppt
As you can see the maximun nominal for a 45 amp controller with a 12v battery can handle a 600 watt array, and the 60 amp maximum is 800 watts .
Here is the Flex60:
http://www.wholesalesolar.com/pdf.folder/controller%20pdf%20folder/flexmax60_specs.pdf
Page 2 has the specs for the 60 amp version.
12 VDC systems 750 Watts / 24 VDC systems 1500 Watts /
48 VDC systems 3000 Watts / 60 VDC Systems 3750 Watts
Again, the "system" size voltage is the battery bank voltage, not the solar panel voltage.
Quote from: Squirl on March 28, 2011, 12:52:55 PM
Actually you need a 60 amp charge controller. Yes you are right that you have 11.23 amps coming in, but it when it converts the power out you have 50 amps at 12 volts. So you need a charge controller that doesn't only hand the amps coming in, but the amps it is putting out after the conversion. I'm actually disapointed in the Xantrex manuals that they don't lay this out. I read the Xantrex, Outback, and Morningstar manuals. You can see from the product manuals the maximum array size per controller at which battery bank voltage.
Here are morningstar's mppt:
http://www.morningstarcorp.com/en/tristar%20mppt
As you can see the maximun nominal for a 45 amp controller with a 12v battery can handle a 600 watt array, and the 60 amp maximum is 800 watts .
Here is the Flex60:
http://www.wholesalesolar.com/pdf.folder/controller%20pdf%20folder/flexmax60_specs.pdf
Page 2 has the specs for the 60 amp version.
12 VDC systems 750 Watts / 24 VDC systems 1500 Watts /
48 VDC systems 3000 Watts / 60 VDC Systems 3750 Watts
Again, the "system" size voltage is the battery bank voltage, not the solar panel voltage.
Hey, I appreciate that! I've been trying to grasp what I need and keep running into various questions but I think you just solved it. So I need the bigger controllers (read: spendy ones) that can take the power coming in from the panels and then convert it to the 12v battery bank and retain all the power that came in -- or as you said 60amps once converted to 12vdc. DOH! I guess I missed all that in the beginning when planning my system.
So I could use one of these: http://www.thesolarstore.com/charge-controllers-mppt-charge-controllers-morningstar-tristar-mppt-mppt-charge-controller-volt-wremote-sensor-mppt-p-451.html
Or one of these: http://sunelec.com/index.php?main_page=product_info&cPath=22&products_id=35
Or the Outbacks you posted.
Now it's just a matter of which one has the best reputation I guess d* ???
I hate to say it, but I'm kicking myself for not understanding this to start out but I get it now...and I'll be ordering very shortly! I also understand now why I didn't seem to have the charging capacity to keep up with the silly heat tracer I was running! Sheesh! I should have been able to run that without an issue this winter but nearly drained the batteries in a week on it. I've also noticed that the batteries haven't been fully charged very often when I've gotten to the cabin.
On a side note, when the Iota charger kicks on they do pick up pretty quickly but I don't like to run it if I don't have to as the whole idea is to have little use for the generator in the future....anyway, which controller do you recommend?
I have seen many debates as to which charge controller was better the Xantrex, Outback, or Morningstar. Most seem to agree that there is very little difference in performance. I have not researched midnight solar. They all seem to be priced around the same at around $500. Most posts I read seemed to agree outback had the best customer service. Others said they wouldn't know for morningstar, because they didn't need customer service. If Xantrex told you you needed a 20 amp charge controller, I would start to question their customer service representatives.
Dave Sparks would have great insight into the better product.
Like Dave stated; nice thing about Outback or Xantrex is the ability to integrate as a system. Charge controller, inverter, a central control panel for monitoring and programming. You can even hook them up to a computer with the right software and record everything the system does. I appreciate having the Outback Mate inside the cabin, mounted on the wall at a nice easy to read height, rather than poking my head into the crowded enclosure where the CC and inverter are.
Outback and Xantrex both have good reputations. Midnight is also good and has charge controllers with 200 and 250 volt maximums. Other than that I don't know much about them. They have been around for a few years too.
On the charge controller: note the difference the system voltage makes to the array wattage capacity; higher system volts makes for the ability to use a higher wattage array. That is one of the reasons I chose 24 volts for the battery system. And I believe one of the reasons Windpower chose to go 48 volts on the battery bank.
On the generator: Normally the only reason I run my generator is to "exercise" the engine. I do that once a month or so; probably more like six weeks on average. When I do that I may also run an equalization cycle, although that can be done with the PV array and charge controller if I have the right bright sunny day.
I did notice that one of the savings between the morningstar and outback was that the morningstar does not have an integrate LCD display standard. I did feel that this was a little deceptive because every picture they advertise has the LCD display in it, but it is not included. I had to read the massive manual to find that out. You can buy one separately for $100, or you can buy a remote one for around $130. It didn't matter to me because the morningstar stores twice as much data as the outback (200 days) and can be accessed by plugging a computer into it. (I already have some extra cheap laptops). Also the display doesn't matter if you were going to get a remote anyway. I think the remote display for outback was $150. I'm not really sure the necessity of the display because it just shows you the past performance. So, it is what it is, and many of the less expensive controllers don't record this at all.
It took me a week of researching the different components and options to figure out the difference. Don't feel bad for not getting it at first.
I understand the issue with the price. It seems like if you want to have a panel array over 600 watts you have to go with the more expensive controller or up the battery voltage and get a more expensive inverter. Seems like they get you either way.
Thanks and Thanks.
I'll probably get the Morningstar or the Outback. I found the Morningstar a little cheaper and can use a laptop to get the readings from it if I want -- truth is I have only a meter on my inverter right now and have to count lights to know what the battery bank voltage is!
I won't buy the Xantrex because 1. They really didn't make it clear in their documentation in the beginning that it wouldn't do what I wanted. 2. They advised me to get a different cheapo controller that wouldn't work either.
I've also decided not to buy from Sunelec now because they suggested the 10awg cable and running the panels in series and then sold me the C40 controller! DOH! d*
All in all, I'm not happy with Xantrex or Sunelec but also have to smack myself for not making absolutely certain that what I was getting was going to do what I thought it would....ahh lessons learned.
Now I just need to find good sources, check prices again and make a final decision on the Outback vs. Morningstar and I'll be set :) probably buy tonight so I can have it ready for the next trip to the cabin -- then I'm going to do some work on the system too I'm thinking (need to clean up cabling and equalize since i haven't done it yet).
I have a ton of other projects but this one matters the most at the moment :) Thanks again!
Quote from: Squirl on March 28, 2011, 02:03:32 PMI think the remote display for outback was $150. I'm not really sure the necessity of the display because it just shows you the past performance.
The Outback Mate provides full control of an Outback charge controller or inverter(s). Everything from setting the charge points, time for different charge modes, turning on or off the EQ mode, present battery conditions, input voltages and amps, volts and amps into the batteries, etc. If you have a compatible generator you can setup the auto start. The Mate is much more than a place to read past daily performance data, although it does that too.
The only thing I found slightly annoying is that a Mate is required as an extra purchase in order to program the Outback inverters. But there's a reason for that too. Their inverters can be stacked, series and parallel to increase the AC voltage (240) or the AC wattage capacity. If the Mate was included with each inverter that would be a waste.
Here is the response I got from Morningstar just now when I asked them if the 45amp MPPT controller would work:
QuoteHi Erik,
The TSMPPT 45 can deliver up to 600W to a 12V battery bank. Using 615W will not damage the controller, the controller will simply limit the harvest to 600W.
This, however, will be significantly more than what you will get with the C40 in your present configuration. The C40 will only be able to deliver up to the short circuit current rating of the array (likely 12-13A) in full sunlight. The TSMPPT 45 can deliver 45A with this array (in full sunlight).
Regards,
Adam Kehlenbeck
MS Technical Support
www.morningstarcorp.com
support@morningstarcorp.com
I decided to re-ask the question with the 60amp MPPT controller in mind...at least I'm getting somewhere!
That is a good thing to know. I did not know they were required to program the inverters and generator auto start.
I know this may be a little off Erik's question, but Don do you use the equalization feature of the charge controller. I have been meaning to ask this. It seemed like another advantage that many of the less expensive controllers didn't have. Does anyone have any opinions on this feature?
Yes Squirl. I normally use the equalization feature in the FM60 CC when I equalize. What works well for us is if I'm thinking about equalizing I hope for a sunny morning and afternoon on a day that we drive up to the cabin. By the the time we get there (11 AM or so) the system will have run through a short re-bulk charge and will be in absorb already. (Because there's been no use for a day or longer). I check the fluid levels in the batteries and if good use the Mate to initiate the equalization charge. It can be programmed to equalize for a predetermined length of time and the system would then go into float.
I sometimes use the equalize settings from the inverter/charger if I want to exercise the generator. The cool thing is I could most likely do away with the generator altogether. This winter at Christmas we spent several days up there and three of them were partly cloudy to very cloudy. We were in no danger of withdrawing too much power from the batteries. I did run the generator on the third day but only because it had not been run since October.
I have discovered a variety of features, abilities, that the FM60 and the VFX3524M inverter/charger can do. I will never be sorry I spent the money for them.
http://eshop.thesolar.biz/retail/Items.aspx?code=OUTBACK_CC&key=cat (http://eshop.thesolar.biz/retail/Items.aspx?code=OUTBACK_CC&key=cat)
Decided to go with the Morningstar 60amp MPPT controller. Price was almost the same so it came down to the discussions here and their support which I interacted with a bit yesterday (I'll post their response to my question about the 45a vs the 60a controller but in a nutshell the 60a won't ever be near max so will always use the full 615watts - if enough sun etc - for charging unlike the 45a controller).
Hope to have it in a few days (got it from the place in Bend OR which isn't too far from me actually). Then we'll see how that battery bank does! I'm assuming I'll need bigger wire to the controller then with the C40 but I haven't tied it all up yet anyway so swapping should be easy and I'll keep the C40 for the well system I'm planning. It might be overkill but ought to work fine with a 75watt panel and 12v deep cycle battery I'm thinking -- then I can plant those fruit trees! :)
Anyway, thanks again Don and Squirl for squaring me away! Now I'll be able to hook up that freezer and abuse the system and see what the controller tells me it's doing :)
http://www.thesolarstore.com/batteries-accessories-battery-accessories-desulfator-battery-life-saver-volt-desulfator-p-416.html
What the heck does this do and do they really work? I'm curious.
I was perusing the store and well, I can see several things I want now! Sheesh...I want a meter for the bank for a quick glance when not plugging in the laptop, those nifty caps looks like a good idea, the battery bank vent sounds like a good idea too and and and...sheesh I need to get back to work! hahahah I worked 8:30am to 10:30pm yesterday and will likely pull long days for the next two weeks which always gets me wondering what new gadgets I can get for the cabin ;)
No generators allowed at my place! So, yes the CC is used for EQ! In this industry you really need to know that most of it is dealer/installer driven. You can get decent advice from the manufactures and it can be spotty. The point is you really need to understand all that you are doing unless you can write lot's of checks.
I have huge respect for check writers! w*
I used less than 5 gallons of gas (heavy on the Stabil) in the last year.
Most of that was just to run it because it had not been run in a while. :-\
It was indispensable while building and pre solar system though.
Help! I was getting ready for my trip to the cabin and reading my new Controller manual to make sure I have the right cable for it (4awg sounds about right for 60amps over a short distance (2 feet)) and saw that I needed a 75 amp breaker and NOT the 60amp breaker I have in there now.
So here is the question: what will happen if I continue to use this: "60 amp 150VDC with 1/4" stud terminals. Uses one small 3/4" breaker space. Midnite Part Number: MNEDC60 Same as: OBDC-60, OBB-60-150VDC-PNL"?
I assume it will pop if there is full sun and the batteries need max charging but otherwise will be fine until I can find a 70 amp breaker? And does anyone have a line on one? I am having trouble finding a 75amp breaker of the same size etc...but that's 25% above the rating.
Thanks in advance.
[EDIT: changed to 75amp breaker to meat the 125% rating]
http://www.midnitesolar.com/productPhoto.php?product_ID=197&productCatName=Breakers&productCat_ID=16
Quote from: MountainDon on April 13, 2011, 10:01:17 PM
http://www.midnitesolar.com/productPhoto.php?product_ID=197&productCatName=Breakers&productCat_ID=16
I found this one there: OBDC-80 though no 75amp ones...I'm thinking 80 would be ok?
Did a little reading on the GC2's and it seems I can use the Trojan settings for the T-105's for my charging profile. Listed here: http://www.trojanbattery.com/BatteryMaintenance/Charging.aspx
So that means I need to set the voltages to the following:
Absorption: 14.80v
Float: 13.20v
Equalize: 15.50v
They are currently set at (setting #5 for flooded cell):
Absorption: 14.60v
Float: 13.50v
Equalize: 15.30v
I can custom set those using their software to build a custom profile but will have to leave as is for the next 10 days -- hope I didn't goof that up too much. The controller has only two flooded cell settings (in their canned settings) so I chose the lower of the two and left it. What I'm wondering is if it will make much difference?
I'm also wondering if the controller's telling me that it was down to 0-30% charge has anything to do with these settings? I'm looking to see if there are others I can change now, but the controller shows a min voltage of 12.62 for the day I saw the lights indicating 0-30% charge...I'm trying to figure that one out still.
![](https://i998.photobucket.com/albums/af102/emcvay/Cabin/solar2.jpg)
This shows a min voltage of 12.62 which according to Trojan is only a 10% discharge or 90% charge....thoughts?
There is likely little effective difference between those charger settings.
I don't know or understand where the 0-30% and "lights" you refer to are coming from?
On the low voltage reading.... don't forget that the voltage reading will drop lower faster when large loads are applied. If I microwave something for several minutes the instantaneous reading falls precipitously but then climbs back up to where it was. Also remember temperature effect. Hydrometers give most accurate readings for state of charge, and also require temperature corrections.
Quote from: MountainDon on April 18, 2011, 06:10:14 PM
There is likely little effective difference between those charger settings.
I don't know or understand where the 0-30% and "lights" you refer to are coming from?
On the low voltage reading.... don't forget that the voltage reading will drop lower faster when large loads are applied. If I microwave something for several minutes the instantaneous reading falls precipitously but then climbs back up to where it was. Also remember temperature effect. Hydrometers give most accurate readings for state of charge, and also require temperature corrections.
Thanks Don,
On the controller are 3 lights: Green, Yellow and Red. In the book it says that if the Yellow and Red are on then the batteries at 0-30% of charge. This confused me when I saw that the recorded lowest voltage was in the 90% range...maybe a glitch in the controller?
Could be. A hydrometer reading would clinch it. I use the voltmeter as a handy quick indicator to what's happening, but the hydrometer never lies when corrected for electrolyte temperature.
Quote from: MountainDon on April 18, 2011, 10:52:49 PM
Could be. A hydrometer reading would clinch it. I use the voltmeter as a handy quick indicator to what's happening, but the hydrometer never lies when corrected for electrolyte temperature.
I'm going to have to get one and a new Multimeter I think. Just found some 6awg 90c wire (THHN) that I can use in my install instead of the 4awg stuff I installed. I'm so NOT an electrician but the book says that as long as I use 90c wire I can use 6awg and I think it would make a cleaner install and since the controller isn't more then 2 feet from the battery bus I don't think the bigger wire will make a noticable difference (if any). Now I just need to get some conduit so I can put all the wiring in conduit next trip out and then I might just be nearing that point in which I can be proud of the install! :D
![](https://i998.photobucket.com/albums/af102/emcvay/Controller.jpg)
Here are the last two weeks of data from the controller. I've noticed that the lights still indicate a low charge on the batteries when they shouldn't and I'll have to call Morningstar on that. I think, actually, I just need to download their software and make some changes to the settings.
Meanwhile, thinks seem to be working nicely.
So im new to these forums and fairly new too offgrid power :) so hello everyone.
id like to first say i really like your cabin setup and detailed build especially your power center mountainmandon.
i liked the box setup you built so much that i built one this last week at my cabin in montana. its not quite finished yet but its getting there im down to running a vent out the roof and putting all the equipment in there and some paint.
that said i have alot of questions lol
1. where can i find the copper bar material you used for your bus bars i love that its sooooo clean.
2. at what voltage should i get scared when batteries drop too ?? 11.7?
and many other question i have but first ill tell ya myt setup
we started our cabin 20 years ago and started with a very small solar panel and 2 batteries well when i brought my kids over a few years back they brought all there gadgets and almost killed the batteries so we ordered a new kyocera 130 watt panel a ts-45 morningstar controller and 2 more golfcart 6 volt batteries.....my dad hooked it all up............not good he got a lot of wrong information so as of last week we had a 80 watt panel and the 130watt panel hooked together in parrallel and then running 55 ft with 8 awg large strand wire to the morning star controller needeless to say as far as the controller was telling us we were never getting past a 35% soc even on a nice sunny day so yeah i figured the wire had a lot to do with that i called a few place like montana solar out of misoula very good guys and arizona solar and wind which is who we bought most of our stuff from they both said to noit hook the 2 panels together and that it would make the 130 panel work like a 80 watt panel so now ive unhooked them im going to run 2 awg just for the 130 watt panel to the morning star controller and then hook the 80 watt panel to our old mark 15 controller with the existing 8 awg and both in parrale to the batteris (4x 6 volt cart batteris is series-parralell) Does this sound right ? and what percentage of gain do you thjink ill get from this ?
right now i think the biggest problem is not enough voltage is going to the batteries to ever get them even close to topped off.
oh and also again love your power center ill have to post pics of the one i built very similar to yours but not enough room for 3 seperate compartments so for the batteries i built a box over them in the big box and am running a vent just from the battery box throug the roof and the bigger room is also vented with eve roof vents.
any help here is greatly appreciated :) im so glad im found these froums so much great info my brain is going to burst lol
Copper from Storm Copper.
http://www.stormcopper.com/Copper-Landing1.html?gclid=CIDi1bbQ76gCFcgZQgod2H8MCw
Here's a voltage vs state of charge chart
![](https://i139.photobucket.com/albums/q305/djmbucket/solar/voltages-charge.jpg)
I would find 11.7 volts very worrisome.. We generally don't drop below 80%
Also note that a hydrometer is the best method to determine SOC.
If the panels are very mismatched as those two are you will be much better off with them having separate charge controllers. I did not take time to run the numbers but the change in wires should make for a better more efficient system. There are a number of voltage drop calculators online. We have some links here for them someplace, but I have to run right now.
![](https://i998.photobucket.com/albums/af102/emcvay/Cabin/SolarPower_may2011.jpg)
The last 7 days (up to Sunday) that I recorded. Found the voltage on Friday to be interesting as it was the first day I ran the Freezer much -- I did not run it all day mind you, just ran it a few times to keep it cool enough to use as a Fridge (I know that's not the best thing for it but it works until I get the Fridge installed).
Thoughts?
I should add that Friday (-2 on the chart) we arrived about 1PM and used the Freezer (to cool it down) and then ran lights and battery chargers a lot. Wasn't much sun out either.
Saturday (-1) we ran everything and then some all day and had very little drop by the looks of it -- it was a heavy use day as seen on the chart -- I think adding the two additional batteries will be wise if I want to run the Freezer and Fridge all the time....guess I'll find out!
My question is; is that watt hours row the watt hours going into the batteries from the panels? That's what I think it is. That indicates your system plowed 1140 watt hours into the batteries on Sat because your Friday use dragged the batteries down to a low point of 12.27 volts. And Friday you can tell you either arrived after the best sun had gone or it was a lousy sun day; 420 watt hours.
Saturdays absorb time was very low (70 minutes) which would lend itself to a long bulk charge before the sun went away or a day with clouds or a combination.
Then Sunday when you took the snapshot the system had not yet recharged much as the max volts were still down from where iy usually peaks. Also the watt hours are still low and the absorption charge only just reached 1 minute.
Quote from: MountainDon on May 17, 2011, 05:25:12 PM
My question is; is that watt hours row the watt hours going into the batteries from the panels? That's what I think it is. That indicates your system plowed 1140 watt hours into the batteries on Sat because your Friday use dragged the batteries down to a low point of 12.27 volts. And Friday you can tell you either arrived after the best sun had gone or it was a lousy sun day; 420 watt hours.
Saturdays absorb time was very low (70 minutes) which would lend itself to a long bulk charge before the sun went away or a day with clouds or a combination.
Then Sunday when you took the snapshot the system had not yet recharged much as the max volts were still down from where iy usually peaks. Also the watt hours are still low and the absorption charge only just reached 1 minute.
We arrived Friday just before the panels were in the shade (I need to remove that tree and make it into planks!) and the weather was mostly cloudy. I was also surprised by the heavy usage the next day and am guessing that charging batteries (18v Ryobi's) and running the freezer, lights, etc all must have really sucked the power.
I'm still so new to all of this I'm mostly doing this: ???
I think the watt hours are the amount of charge going into the bank. One thing I noticed is that the draw down to 12.27 still put me around 60% I think (haven't done the math) which would be ok I think.
One thing I've noticed is that my fully charged bank runs about 12.9v rather then what Trojan indicates 100% should be (12.7)...thoughts on that?
Do you have a meter you know for certain is properly calibrated? Maybe the meter in the CC is off?
Hydrometer check?
Time also! Trojan will have hidden away in there spec a resting period before you make the measurement. Not to worry on this one!
http://www.walmart.com/ip/Danby-9.1-Cubic-Ft.-Frost-Free-Refrigerator-in-Black-with-Stainless-Steel-Door/11368635
Using the calculator I see that running this fridge (at about 1030 watt hours per day) and the freezer I previously mentioned (about half what the fridge will use theoretically) then my system with 3 panels, 6 hours of sunlight per day (summertime I can probably get more then that but in general I should be able to get 6 hours of pretty much direct sunlight at 33 degrees for the time I'm running these both) and 8-10 220ah GCB's with the 60amp MPPT controller should do it.
That's taking it to 50% of discharge according to Don's spreadsheet.
Now, am I doing something wrong? Does it look right? I set it to 4 days without sun which might suck if I get 5 or 6 without it but the region only gets about 15 inches of rain a year and has around 300 days of sun.....so I'm hoping anyway.
Last 44 days of monitoring the MPPT controller and I've seen only 3 days where it had little to no charging. Rest of the time it seemed to do fine.
Also, I may not need to run them both at the same time but want to be able to.
My worry is mostly because I'm often gone ten days in a row so there will always be at least 10 days where I cannot put the generator on the system to get it back up to charge.
http://www.uakc.com/energyguides/dar1102we-danby.jpg
Found this for a fridge I'm looking at that doesn't have a freezer -- uses almost 200 watt hours less per day.
This http://www.refrigeratorexpert.com/danby-DAR1102WE.html fridge may do the trick as it's all fridge which is ok since we have a freezer already and I've been told that these use less energy (which appears to be possibly true from what I'm seeing).
I should also add that with this unit I was able to drop hours of sunlight down to 5 hours per day which still left me with 3 panels and 8-10 batteries (at 50% discharge).
It is most likely that I will only run the Fridge until late August or early September (deer season starts).
![](https://i998.photobucket.com/albums/af102/emcvay/MPPTlog.jpg)
Here is the latest log from my controller. I've hidden the days we weren't at the cabin unless they showed recovery from when we were there (more watt hours despite out no longer being at the cabin which I assume is recharging the batteries).
I have not yet checked water levels or equalized the batteries which I plan to do this weekend.
We seem to average above 600 watt hours per day which I assume is replacing energy we used while at the cabin (though the one day we used a lot more which I think is due to using the freezer more and not having much sun).
THis weekend it is supposed to be cloudy and raining so might be interesting.
I've noticed that absorption seems to run about 3 hours while float can run 7 to 10 hours -- which I assume is just as long as the sun is hitting the panels. On days that we were at the cabin it tended to be cloudy and I'm wondering if the float times were lower because of this??
Both the bulk stage and the float stage duration can vary widely in time spent in either stage. Too bad the data display does list bulk charge as it could help explain what is going on. You may understand the following. If so good and this is for anyone else.
Bulk charge is the first stage, the state the CC begins every day with. Duration of the bulk charge stage will vary because of factors such as; how deeply the batteries are discharged, the intensity of the sun on the PV modules (clouds, smoke, snow, etc.) as well as how much power is being used at the same time the batteries are being charged.
Absorption charge is next. This is the only charge state that can be programmed for duration. The manual shows 150 or 180 minutes, depending on battery type (page 36). Those times may be modified by the CC under certain circumstances.
Then the unit will switch to float charge.
So, on a cloudy day the CC may remain in bulk charge for a longer duration than "normal". Since the length of the absorption charge is fixed, on a bad day the CC may never even reach float. That occurred three times in that chart.
It is also possible for the CC to reach absorb and switch back to bulk if some heavy demand is placed on the batteries. That is determined by the battery voltage falling below a certain value and remaining low for a period of 30 minutes. There is a low voltage point that will actually cance; the float charge for that day
Thanks Don, I even went and double checked about the Bulk charge period which lead me to call Morningstar -- I've not yet had a reply yet but will bug them until I do -- also want to understand the lights and why they don't repflect the charge correctly but I think that may be a setting and I'm planning on working on the setup when I get there this weekend.
Thanks again for the response, it helps me a lot!
I have figured out the lights :)
It seems that while you can make changes to the controller via their software and tell it exactly what you want it to do, it will not do those things unless you switch the dip switches to 'optional' which sets the controller to run on your specific programming.
Thus the lights were showing stock indicators rather then my trojan adjusted ones. So that's solved :)
I'll post another set of data collected off the controller, what is interesting is the 'input' and 'output' power. Neither of which appears to be raw panel power. I do get array voltage and amps but if I want to see the actual 'wattage' of the panels I have to do some math (which is ok of course).
Anyway, so far I've seen pretty good production from the panels and my only weak point might be the batteries.
![](https://i998.photobucket.com/albums/af102/emcvay/July42011.jpg)
One interesting thing is the voltage on 6/30. I see no reason why this is so low??? The ONLY thing running during that time was the 12vdc fan on the composting toilet and the Charge Controller.
However, I've also noticed that the controller is set to a time that does not match my time zone and I have not discovered the mystery of how to change that just yet -- hmmm.....
Beyond that I've noticed that 'Max. Output Power Watts' appears to be the amount of power produced by the controller and sent to the batteries and not the power coming off the array (that may sound silly as one cannot be different from the other, but in fact it can. After all 60vdc off the array at 11amps is ~660watts where as 14.8vdc from the controller at 45 amps is ~666watts right?).
Quote from: OlJarhead on July 05, 2011, 12:29:45 PM
Output Power Watts' appears to be the amount of power produced by the controller and sent to the batteries and not the power coming off the array .....
The difference between power from the array and the power into the batteries is the loss in the charge controller. There are small losses usually noticeable at the CC heat sink fins. I think that into the batteries figure may also reflect some of the battery charging loss inherent to lead-acid batteries. Not + on that though. ??? IMO, what goes into the batteries, and what is taken out is what is most important.
Turns out I have a Surflo 9325 Well pump that with 24vdc power can pump as much as 100 gallons in an hour or more. It's down ~80 feet into the well which puts it about 40 feet below the last known water level (when the well was drilled).
So, I'm now in the market for a ~100 watt solar panel to power the well with as the 60 watts of 12vdc solar I was using is inadequate -- though I could rewire it to give me 24vdc it's just a tad shy of the recommended size and I could use it elsewhere.
So, if anyone finds a sub $200 panel that might work please let me know!
http://www.sunelec.com/sun-laminate-118-watts-2430-vmp-p-785.html
I'm hoping to get this panel for my well solar...if I can get close to the price they were offering for 10 of them.
Quote from: OlJarhead on July 19, 2011, 10:01:52 PM
http://www.sunelec.com/sun-laminate-118-watts-2430-vmp-p-785.html
I'm hoping to get this panel for my well solar...if I can get close to the price they were offering for 10 of them.
Didn't notice the 'Laminate' part and didn't really understand it. These do not have frames so I won't want them. Looking at other options now.
![](https://i998.photobucket.com/albums/af102/emcvay/July18th_log.jpg)
Another weekend another log ;)
This one is broken up a bit because of my messing with the controller. Each time it is reset it restarts the log (I was doing firmware updates and programming changes).
With the new Fridge running full time, running two battery chargers, a DC fan and 3 lights at night we used a lot of power! Drew the batteries down around 65% of charge (which isn't bad I think) and exercised things a bunch. v:)
I'll see what it's doing when I get there this weekend (I think) to see what happens when no lights or chargers etc are running and the fridge is on #3 setting (we had it on #4.5 when we were there).
All in all though, I couldn't be much happier!
Am I correct in taking the 65% to mean you drew the batteries down to have 65% capacity remaining? That's not bad but doesn't give much wiggle room for clouds if that was a typical single day.
Regarding the refrigerator. One thing I've noticed with our propane fridge is that while we are using the cabin the fridge maintains 35 to 40 F on our number 5.5, but when we leave the cabin for several days the fridge will freeze some things. So then our number 4.5 seems to work best. It would be interesting to see how the temperature in yours runs.
Random thought, sort of, directed towards those who are contemplating installation of a alternative power system.
From talking with people with PV systems already in use, both here, other places on the web and in person, the biggest single "failure" item seems to be insufficient storage capacity.
Temperature Compensated Battery State of Charge Chart,
12 volt. Being temperature compensated this might save someone some time and math.
![](https://i139.photobucket.com/albums/q305/djmbucket/solar/temp-comp-01.jpg)
or for
24 volt (below)
![](https://i139.photobucket.com/albums/q305/djmbucket/solar/temp-comp-02.jpg)
EDIT 09/25/2011 Made the spreadsheet the pictured charts were taken from available for download. Also expanded the flooded wet cell charts to include a 48 volt system. Separate download for AGM batteries.
... for
48 volt (below)
The above images are from a spreadsheet. It can be downloaded from below.
There are two flavors, flooded cell batteries and AGM sealed
The AGM charts
12 volt
24 volt
Quote from: MountainDon on August 19, 2011, 12:07:23 PM
Am I correct in taking the 65% to mean you drew the batteries down to have 65% capacity remaining? That's not bad but doesn't give much wiggle room for clouds if that was a typical single day.
Regarding the refrigerator. One thing I've noticed with our propane fridge is that while we are using the cabin the fridge maintains 35 to 40 F on our number 5.5, but when we leave the cabin for several days the fridge will freeze some things. So then our number 4.5 seems to work best. It would be interesting to see how the temperature in yours runs.
Yes 65% remaining. The lowest I've seen the system get to so far is 12.2vdc which I believe (I'll have to check) is around 50%.
Our fridge seems to run cold enough around 4.5 on the setting and that can cause some ice formation (droplets) on the back wall of the unit (inside it of course)...when we leave we adjust to 2.5-3 and that keeps a couple gallons of water quite cool/cold.
I could shut it off when we're gone but I want to see just how the system performs.
As for battery power, I'm concerned also. I used the calculator to plan the system and my calcs suggest 880ah is enough power to run the fridge and lights the way we do and not draw the system down but it appears to be incorrect. I'd not really expect an overnight drop of greater then 20% if it is to last 3 days without sun...let alone 4! So, perhaps 440ah of battery power ought to be added before it's been a year to ensure I can indeed run the freezer and fridge full time as I have not even tried that yet!
12.2 is about 50% with a big BUT.... but that can be thrown off by recent battery charges or discharges and needs temperature correction. Hydrometer is best, but needs temp correction too.
As far as fridge temperature, leaving a few gallons in it if there is not much food is a good idea; helps keep the cool working right. 40 degrees or lower is needed for best food preservation, BTW.
Quote from: MountainDon on August 23, 2011, 07:23:44 PM
12.2 is about 50% with a big BUT.... but that can be thrown off by recent battery charges or discharges and needs temperature correction. Hydrometer is best, but needs temp correction too.
As far as fridge temperature, leaving a few gallons in it if there is not much food is a good idea; helps keep the cool working right. 40 degrees or lower is needed for best food preservation, BTW.
Thanks Don,
I have to get a Hydrometer pretty soon! I've been relying on gauges and meters so far but it's a learning curve.
This past weekend I had a strange thing occur: the 60a breaker on the disco box that the panels are run to tripped. THe midnight solar 60amp breaker did not trip but this one did ??? Then the MPPT controller showed a Green and Yellow LED which should mean that I was down to 60% of charge but I knew that wasn't right since everything said 100% otherwise. So I reset the MPPT controller and it went back green...BUT it was during the main part of the day when I normally get a lot of my charging...so I double checked and the panels were giving decent power and the controller was indeed charging the string...something isn't right.
I logged into the box via serial cable becuase the Ethernet connection would not work...so at this point I'm not sure what happened.
Daily I'm getting a HVD alarm (High Voltage Disconnect) but I'm not seeing voltages high enough to trip that...another thing to try to resolve.
Lastly, my well solar tripped also! My Xantrex C40 was not running and the batteries (two group 27's in series) were dead! One was at 2.2vdc and the other was at 8vdc...something smells.
I checked the system and couldn't figure it out, removed and replaced the batteries (I had two spares) and everything worked fine again...then the sureflo pump shorted out (I think) and the bank went to 1.0vdc!!! Yikes! I disco'd the pump and the batteries were back to 25.6vdc.
So, I came home and ordered a new Surflow pump and did a little more of this: ???
What about night time temps versus day time temps?
Currently it can get to 85+ during the day at the cabin but drop to 40 at night...everything cools down.
So, if I figure my battery banks out at 40 degrees I suspect I'll need more batteries. No?
Our batteries are cool to cold all the time. In summer the cases may warm on a hot day but the fluid still measures colder. EG: When I checked the sp gr about a month ago when we were having 85 F highs in the afternoon, the fluid was still only about 62 F. Very few actual hours of the hot summer day have the high air temps; most of the day/night is spent below 65. I don't measure much in the winter but the last time I did the fluid was hovering somewhere around freezing. So yes, that does diminish what's available for use.
Now if I was to dig another, bigger hole in the ground and have the batteries down there, they would stay warmer in the winter. :D Perhaps the charging and discharging might even produce some heat that could be trapped? Probably not worth my effort though considering winter use is only for a few days at a time and a couple weeks apart.
This is actually why I decided to build the porch and put the batteries inside of it. I can use the windows for solar heating and found that even without insulation I can keep the porch 10-12 degrees warmer then outside. When it's -10 degrees that's probably a good thing!
Question for Dave Sparks....
For someone with an Outback FM60 charge controller and an Outback VFX 3524(M) inverter, what would you suggest as spares? Listed from most likely to less likely to be required.
Any MPPT controller needs a spare MPPT controller for offgrid unless you are willing to rewire the array for a cheaper non-MPPT controller while Outback repairs your unit. The 45A Morningstar MPPT is pretty inexpensive and I have a spare one along with the XW gear that I only install these days. Their 600V controller has really made my long distance array runs easy.
An inexpensive Inverter/charger can be bout used or?
I go thru all this with some of my real remote customers who live full time in offgrid homes. It often comes down to how their system and how "they" want to live during a failure in the depth of winter. I have one guy who is a Merchant Marine guy who is gone long periods and just turns off his electric reefer and uses a propane unit. No worries about bad weather with propane. Everyone offgrid fulltime basically has to have strategy for how they will deal with it.
"It always fails in winter and at night" OLD Sailor......
How was your summer Don?
Thanks Dave. I do have a square wave 900 watt inverter that is there for emergencies. But I haven't got anything to handle the charging chores as yet.
My summer? Well except for...
1. having the largest forest fire in recorded NM history come as close as 1.5 miles to the cabin,
2. having my jaw wired shut for a big chunk of the summer,
... it was a fine summer. :)
Since the fire missed us and my jaw works reasonably well now I guess I should not complain at all.
Heading back up in a few hours to thin some more trees.
Have a good trip and yes we heard about all the fires in the Southwest. I think that they are our version of the weather that the Southeast calls the "mean season".
If you look at your array, you may be able to figure an easy way to use temporary jumpers to sub a small controller in while the CC is in for repair. Most likely the only thing that would cause this with Outback would be lightning or the fan.
I've heard about the fan.....
It would be fairly easy to re connect two of the three modules to use in parallel with a cheap emergency controller. I should probably act to be covered "just in case". Hopefully I did a good job on the asrrestor and dual ground rods. We get lots of lightning.
I'm still struggling with my Morningstar MPPT 60amp (TriStar) charge controller. It works, but every evening it alarms out with a 'battery high voltage' alarm and then resets the controller.
I've had NO luck getting help from Morningstar and the logs do not show a high voltage on the batteries either. Very strange.
Also, I cannot change the time on it from GMT -- I'd much rather it recorded using my time zone rather then GMT....there are other items I'm not as thrilled about but after paying the $500 for it I'm not going to change it out with an outback any time soon :( But I doubt I'll buy another.
I should clarify though with this: other wise it seems to work perfectly d*
Quote from: Dave Sparks on September 16, 2011, 03:04:05 PM
... XW gear that I only install these days. Their 600V controller has really made my long distance array runs easy.
Ouch!!! $$$ Pricey but I can see how very nice one would be. :) I could triple the number of PV modules and pass the power through the same wiring up the 325 feet of hill.
Don, quick question. Others, feel free to chime in. Can you provide the vendor for your Uni-rac pole mount? Below is a link to a thread on Northern Arizona Wind and Sun that details and upgrade I am making from a 12V solar setup to 48V. In this move I would like to pole mount my 6 240W panels. I called Solar Biz and they told me that every rack that holds panels on top of the pole mount is custom made and that I would need to provide specifications on where the holes are located on my panels.
My problem is that I have some panels from different vendors, but all with similar amps and volts. I am looking for the bare aluminum struts or thereabouts so I can just drill holes for the mounting or use generic brackets that clip to the struts. Any suggestions?
http://www.wind-sun.com/ForumVB/showthread.php?p=97545#post97545
I guess I was lucky. I had all new panels, three of the same. The kit I needed was ordered thru Affordable Solar in Albuquerque. They had the rack kit from Uni-Rac in a day, maybe it was two. Uni-Rac is also in ABQ and the kit was available right away.
I don't remember the exact details of how the panels mounted, but there were clips that fitted into a groove in the extruded aluminum bars that connected to the cross arm. I don't remember any more than that. I'll look through my photos later today and see what I have that might help.
It would be nice to be able to buy just the top mount.
Yes, true. If I could just buy the top mount I would. I think I could make my own bracing using Unistrut or the other type bracket systems they sell at Lowes, Home Depot, etc.
With pricing from these companies it is looking like the mount with bracing would be ~$1,100, without the pole, concrete, etc. I am wondering if I could build my own tilt-able, but not turn-able, solar mount. Sort of like this one but larger/stronger...
Ojlarhead had a rack made.
One nice thing about an off the shelf rack is that it is designed for the wind loads that can come along with the large array.
I think this could be doable with an off shelf array, but you may need to be willing to do some jury rigging, changes, on your own dime and responsibility.
But first a thought. have you gone through the Unirac sizing charts? I'd look to see if the two types of panels you have are similar enough that by some fluke of chance they use the same kit for both panel types. IIRC you said you have three of one and three of another. See if 6 of one type uses the same kit as six of the other.
Or, the modification route... get a 3 vertical x 3 side by side type for the larger of the panels that you have. That type of array frame uses a single aluminum pipe cross tee with a pair of the long bars for each set of three modules. You should be able to make the second set fit. You may have to drill new holes and could void any warranty. You also would not want to drill through in a wrong spot.
This has been a great thread.
There are so many ways to skin this cat.
I have seen some build of PT wood and concrete in a design similar to what you posted.
Also many of the top racks I see are built with angle iron and bolted or welded together.
If you have set on a pole mounted system you may find this helpful.
http://homepower.com/view/?file=HP108_pg28_Schwartz&pdf=1
A little reading on tilt vs. no tilt.
http://homepower.com/article/?file=HP139_pg32_Methods
A little reading on ground mounts.
http://homepower.com/view/?file=HP144_pg114_McPheeters
Squirl, thank you for the links. Getting a pole mount up and running before the winter is looking like less of a possibility. I think I will buy a frame out of PT lumber for my 3 new panels, similar to what is already built for the other 3 panels, and attempt to raise and anchor them. I want a pretty aggressive angle, 85 degrees or so, to dump snow in the winter time.
Quote from: PorkChopsMmm on September 29, 2011, 09:31:13 AM
Squirl, thank you for the links. Getting a pole mount up and running before the winter is looking like less of a possibility. I think I will buy a frame out of PT lumber for my 3 new panels, similar to what is already built for the other 3 panels, and attempt to raise and anchor them. I want a pretty aggressive angle, 85 degrees or so, to dump snow in the winter time.
The angle of the panels should match your latitude or +/- 15% of said latitude. IN the winter my panels will be set to 63 degrees (90 being straight up and down and 0 being parallel to the deck), in the fall and spring 48 degrees and summer 33 degrees.
You can use a 4" sch40 pole sunk 3' into the ground and concreted there with a 1 1/2" angle iron frame like I did and it won't blow over easily! My neighbor built mine for under $400!
Quote from: OlJarhead on September 29, 2011, 09:44:13 AM
The angle of the panels should match your latitude or +/- 15% of said latitude. IN the winter my panels will be set to 63 degrees (90 being straight up and down and 0 being parallel to the deck), in the fall and spring 48 degrees and summer 33 degrees.
You can use a 4" sch40 pole sunk 3' into the ground and concreted there with a 1 1/2" angle iron frame like I did and it won't blow over easily! My neighbor built mine for under $400!
That theoretically works but I am up in zone 5 that sees lots of feet of snow. The snow won't melt or blow off if it is at a 63 degree angle. While you lose efficiency with the 85 degree tilt you can actually capture sun because your panels aren't covered in snow. I had to go brush down my panels a couple times a day when it was snowing last winter.
I will share the idea I've been kicking around in my head for a while. I believe I saw something similar in home power or build it solar, but I can't remember exactly where.
I would build it close to the one in the third homepower article. The difference would be that I would place the sonotubes closer together. This way the "joist" for lack of a better word that runs from the bottom to the top could connect directly to the post. I would connect them through the largest grade 8 galvanized bolt that I could fit. A lock nut with the plastic would give me enough tension on the bolt but allow the "joist" to rotate. I would then leave about 2-3 ft of empty space at the top of the "joist". I would drill holes along the length of the "joist" and the taller poles. I would use a clevis pin or bolt and simple raise and lower the "joists" to adjust their angle at different times of the year. I would of course have some bracing between members. The advantage of this is it uses smaller members to carry the wind and snow forces across a larger area. The smaller pieces can be found a lot easier from big box retailers in things like fencing posts and galvanized pipe. I have also seen these built with pressure treated wood. Just be cautious if touching dissimilar metals together.
I agree with Jarhead. The nice thing about a ground mount is that it is very easy to go out with a broom and dust off your panels. You will be sacrificing a lot of power at that angle. I am also in the northern part of zone 5. Is it really worth it to brush them off in the middle of a snow storm? You don't get almost any power while it is snowing anyway. Are you getting the lake effect snow of 4-5 ft per storm?
I have been dreaming of being off grid for years. I was looking at some outback equpment a while back. Does anyone have links for the cheapest sources?
Also what are your opinions on wether to buy it all assembled vs buying it seperatly and assembling it?
I would like to not have to worry about the dual invertors and stick with 120v. I do alot of jeep building and use 220 in the shop but i guess i can run a generator for that. I have a friend imigrating from australia and im trying to get him to make enough room in his container to bring me a lister motor for running a generator.
Quote from: CjAl on September 29, 2011, 11:02:02 AM
I have been dreaming of being off grid for years. I was looking at some outback equpment a while back. Does anyone have links for the cheapest sources?
Also what are your opinions on wether to buy it all assembled vs buying it seperatly and assembling it?
I would like to not have to worry about the dual invertors and stick with 120v. I do alot of jeep building and use 220 in the shop but i guess i can run a generator for that. I have a friend imigrating from australia and im trying to get him to make enough room in his container to bring me a lister motor for running a generator.
Jeeps are cool :)
I asked the same question a couple years ago with the bent that I'm an old computer guy and found it was cheaper (in the past) to build them then to buy them and what I built was always better then what you could buy for comparable prices.
In solar the case is the same IMHO. Building it yourself is almost always, if not always, cheaper. Sunelec had a system much like the one I built though, that was pretty cheap so worth a look to see what they have today.
Quote from: PorkChopsMmm on September 29, 2011, 10:00:33 AM
That theoretically works but I am up in zone 5 that sees lots of feet of snow. The snow won't melt or blow off if it is at a 63 degree angle. While you lose efficiency with the 85 degree tilt you can actually capture sun because your panels aren't covered in snow. I had to go brush down my panels a couple times a day when it was snowing last winter.
*chuckle* My cabin site is within 20 miles of the Canadian border in Zone 5...well in reality I'm Zone 4 for fruit trees because I'm also at 3200 feet in altitude.
I find that the snow often melts or slides off the panels and the only time I see any real covering is in the morning after a cold night there can be a layer of frost that burns off by late morning. And that was actually at 48 degrees rather then the steeper 63 that they should have been at. I just found that I was generating plenty of power at the time with them at 48 (probably should put them at 49 though).
Anyway, I'd take a serious look at power production and needs before I tilted them that steeply.
Jarhead makes a good point of build vs. buy. I came to the same conclusion a few years ago.
There are a few factors that can change the equation. If you are having it installed, buying the systems prepackaged may save you on labor. Solar installation electricians can be expensive. This is most often a factor if looking for the tax credits.
Also you will have to spend a bit of time learning about off grid components and electricity. This will be a book or two for your collection, and a few from the library on NEC guidelines.
I had a neighbor stop by on my build a little while ago. He asked if I was going to do my own PV system. I said of course. He was surprised and said "but you'll miss out on all the tax credits." I said who cares about the tax credits. He told me, "well, plenty of people." I told him that the added labor cost of a solar installer is far higher than any return on tax credits. He agreed and left. I later found out he was a solar installer.
I'm a poor truck driver. I do everything myself. I work too hard for my money to pay it to someone else if I can do it myself. fortunately (or maybe it's unfortunately) i am usually capable of most tasks some just may need some research. I have been reading for years so I have a decent base knowledge just not on specific products. I was planning to put a hydro powered generator at my current house. I have a spring fed pond that puts out a good amount of water. unfortunately I have too little head to make a system that would do much more then power a few light bulbs.
and yes Jeeps are very cool but i've spent more on them in my life then anyone ever should. lol
With hydro you would be surprised. Even if it is low output, it is constant. IIRC you are in Texas. So even if you put out a tiny 25 watts (2 cfl's) an hour that is .6 kilawatts a day 365 days a year. That is more than some solar systems on here.
DIY'er can take the tax credits on the equipment purchased. Some states, like NM, also do not charge sales taxes on equipment that is used in a solar installation, right form the PV modules down to the nuts, bolts and screws used to mount the equipment and batteries are included.
This discussion prompted me to look into the incentives since I last started this a few years ago.
It appears they changed the Federal Residential Renewable Energy Tax Credit.
It looks like it even qualifies for second homes and maybe DIY installations. I have to do more reading.
http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=US37F&re=1&ee=1
http://www.dsireusa.org/documents/Incentives/US37F1.pdf
Has anyone taken this?
Moi. On the cabin installation.
Thanks for that link Squirl. My cabin will be grid powered but I'm going to have a small solar UPS to keep the lights on when the grid goes down and that 30% will pay for the solar panel
Quote from: Squirl on September 29, 2011, 04:36:50 PM
With hydro you would be surprised. Even if it is low output, it is constant. IIRC you are in Texas. So even if you put out a tiny 25 watts (2 cfl's) an hour that is .6 kilawatts a day 365 days a year. That is more than some solar systems on here.
not EXACTLY constant. We are over 40" behind on rainfall in southeast tx. My uncles pond is over seven feet low. The lakes in my lake community are not allowing any motorized boats because the water is below the concrete skirt on the dams. My springs are strong but even they couldnt keep up and i havent had water flowing for the last month. Its quite depressing here.
Here is one thought: Schott Poly 230 watt panels are $1.64/watt. CSI panels are $1.39/watt, and falling. With the advances in micro-inverters, as well as rack systems, your average guy can start thinking about installing a grid-tie system himself (or herself). Just for fun I called a solar company here in Albuquerque and asked about the possibility of me doing the install and wiring, and them doing the final tie to the grid, and signing off on the paperwork. The guy didn't see any problems.
At $378 a panel (even less for the Chinese panel), plus $175 per panel for the inverter, the cost is $550 per panel. After adding the additional hardware, permits, and some electrical engineer labor, for about $3.5K one could install 4 panels, or about a 1KW net-meter system. No batteries required. After tax credits, net cost is ~$2K. At my usage, this would reduce my bill by ~15%. Based on the PNM plan terms, I calculated payback in 8 years.
I have seen some guys on the internet who have built small net-meter systems, and added a small bank of batteries which charge from the main system by AC charger. A bypass switch is installed which allows the panels to work stand-alone in the event of a power outage. A transfer switch is used to power the priority circuits. There is a company in Pennsylvania who has a nice niche market; power outages are more common in those areas than they are out west.
Another guy wanted to run his place off-grid totally - he just tied his Enphase system into the service panel. Since it was not connected to the grid, it simplified the process dramatically. During the day he had 120V, and used a battery charger to charge his battery bank which he used at night. It is more efficient to convert the power at the panel, and then use an AC charger to charge the batteries than it is to carry the DC power to the batteries, then use an inverter to generate 120V. The higher voltage of the grid-tie panels, in combination with the higher efficiency of the MPTT Enphase inverter, and the fact that much smaller wire can be used, makes it yet another alternative for those with small power needs (off-grid) or somebody just interested in lowering his carbon footprint, or saving a buck or two over the next 20 years.
Something else for everyone to think about...
Quote from: Native_NM on September 30, 2011, 01:23:29 AM.
Based on the PNM plan terms, I calculated payback in 8 years.
May be a better payback than most any other investment right now.
Is there a reason those csi list only on grid systems under application?
I must admit pv is the system i know the least about. My current property is so heavily wooded its not practical so i researched it much less then hydro and wind
The voltage of grid-tie panels is usually twice that of "12 volt" panels, which actually are not 12 volts. Most 12 volt panels are rated in the high teens. Under load or partial sunlight they will still put out the 14+ volts needed to charge a 12V battery.
If you use a high voltage panel with a traditional charge controller, you end up wasting a substantial portion of the watts generated. An MPPT controller allows for maximum energy harvest from the panel.
So those panels rated for 20v. With a mppt would be fine for an off grid system? The cheapest 12v panel they list is $2.53/watt
Would it have to be a 12v battery system or could you use a 24v. Araingment?
With the proper controller, grid-tie panels are a great off-grid option. If I had to have a one-panel system, I'd choose a high-voltage 240w panel and a good MPPT controller. For an off-grid system using a small battery bank, your goal is to maximize the number of amps available to pump into the batteries.
In the west, some folks report harvesting upwards of 100 amps a day at 12v from a single panel. You could run an RV indefinitely from a 2-battery system. We ran an Engel freezer on a job site, and it pulled 2.5 to 3 amps. The Engel's are expensive, but efficient. Factor in some lighting and a water pump, maybe some TV and radio, and you could live off of 100 amps a day. We are running a job site trailer on a 200 amp hour bank. Computers, laser printers, battery chargers, etc.
I think 100 amps is a stretch, though they did post the controller output, but a quick check of the math validates the numbers.
The challenge is to ensure you have enough battery capacity also. It doesn't matter if you generate 100 amps if you cant store it for later use. I created a spreadsheet that factored usage and sources by hour to ensure a given bank would cover the load. It has 24 rows (each hour) and then columns for each use and source. Sources are positive and uses negative. It assumes a fully charged system at inception. There is a cell to input max DoD, and it turns the cells yellow when the amps fall below the cutoff.
One can manage the timing of usage to balance the load. For example, if your battery bank is full and there is still sunlight, that would be a good time to use the inverter (high amps), because the system could recover before night. The goal is to maximize the timing of sources and uses.
A 24v bank would work fine, as long as you have a 24v inverter.
Let me toss this into the mix.
IMO, anyone planning an off grid system should go for a 24 VDC based system, unless it is a very small system. Twenty four volt systems can use smaller gauge wires. But to go with a 24 VDC battery bank you would need two of those modules in series, to get the voltage high enough to be able to charge 24 volts. And an MPPT charge controller is really the only way to go*.
Also think hard and long as to what amount of power will be used in the future. I haven't totaled up the values but I do know we have electrical devices in our cabin that we never dreamed of in the year we planned our place. Because the battery bank was planned to be generously over sized we have no issues with running the extras. (More lighting including exterior, blender, electric can opener, electric mattress warmer and more.)
* Lots of things to watch when planning. It's been covered here before, but the charge controller must be able to handle the highest voltage produced by the series panels PLUS a safety factor of 1.56. If the Voc of the two panels was 66.6 volts for example, the CC would need to be rated for a maximum voltage of no less than, 66.6 x 1.56 = 103.896 volts.
By "two of those moduals in series" you mean two panels correct? Not two mppt controlers
I would also have a generator for backup if i drew tbe battery banks down too much. My biggest problem.is im in south tx not far off the gulf coast. Air conditioning is mandatory, and lots of it
PV panel = PV module; somehow I prefer the term module. ???
For A/C look in mini splits. Sanyo makes some very efficient ones. They can be run from a properly designed/sized PV system. Not a small 12 volt system though.
I was already looking at them last week.probably will go that route.
Im also planning a solar hot water/radiant floor system that in the summer could be routed thru shallow wells instead for a sort of pre cooling effect
Quote from: MountainDon on September 30, 2011, 08:13:54 PM
Let me toss this into the mix.
IMO, anyone planning an off grid system should go for a 24 VDC based system, unless it is a very small system. Twenty four volt systems can use smaller gauge wires. But to go with a 24 VDC battery bank you would need two of those modules in series, to get the voltage high enough to be able to charge 24 volts. And an MPPT charge controller is really the only way to go*.
Also think hard and long as to what amount of power will be used in the future. I haven't totaled up the values but I do know we have electrical devices in our cabin that we never dreamed of in the year we planned our place. Because the battery bank was planned to be generously over sized we have no issues with running the extras. (More lighting including exterior, blender, electric can opener, electric mattress warmer and more.)
* Lots of things to watch when planning. It's been covered here before, but the charge controller must be able to handle the highest voltage produced by the series panels PLUS a safety factor of 1.56. If the Voc of the two panels was 66.6 volts for example, the CC would need to be rated for a maximum voltage of no less than, 66.6 x 1.56 = 103.896 volts.
This is good advice :) I find that I use a lot more power then even what I calculated! Just seems to be a fight really: use less....use less.....use less...but I use more anyway and watch the batteries drain down to 55% at times...and I'm not even using the freezer yet!
My calculated daily watt hour usage was 1657 with just the fridge and freezer (by calculated I mean spreadsheet) but using 1700 watt hours per day (fridge and lights only with a little toaster use) drives the batteries down to 12.2v which is about 55% of charge. So the calculator tells me I could go a few days but I find I'm going only 1.
I've not tried to run too many days without any useable sunlight but I will be trying that out in the near future as winter approaches again.
I also thought about adding two more batteries (as 10 would be better for planned usage) but I'm bumping right up against 1 year on these ones and am concerned I might be outside the window to add more...if not, then I probably ought to get FOUR more and plan on adding a 4th panel to get me up to 820 watts which in most cases will be enough for the 1020-1340AH bank (though 5 panels would be even better and might be where I go some day).
I don't think I'm too far off mind you, but I think the GCB's don't have the AH capacity they are rated for either...220ah per battery ought to do what I need in 8 batteries but I'm finding that it's more likely a dozen is required.
My plan, however, is to go to a much better battery in the future and to add more panels when I do -- but that day is hopefully 3 to 5 years off yet.
Ok, friends, I need a bit of advice on my solar setup. I've got two 200W 27V panels set up around 55 feet from the house. The way I see it, I have two choices. Build a small shed next to the panels and keep the MPPT charge controller, batteries and inverter there, then run line voltage 55ft to the house. That means building a shed, and, extending my inverter on/off switch wire to reach the house. Second possibility is run the MC4 connectors into 100ft extensions available at Sunelec. I asked the salesman if running 27V over 55-60ft is a better option given potential voltage losses. Salesman said, "why not?". Why not indeed. If that's not a problem, I could keep batteries, and all equipment in the basement meaning less expense and work. What do you guys see as the better option?
Doc
Quote from: AdironDoc on October 03, 2011, 12:18:24 PM
Ok, friends, I need a bit of advice on my solar setup. I've got two 200W 27V panels set up around 55 feet from the house. The way I see it, I have two choices. Build a small shed next to the panels and keep the MPPT charge controller, batteries and inverter there, then run line voltage 55ft to the house. That means building a shed, and, extending my inverter on/off switch wire to reach the house. Second possibility is run the MC4 connectors into 100ft extensions available at Sunelec. I asked the salesman if running 27V over 55-60ft is a better option given potential voltage losses. Salesman said, "why not?". Why not indeed. If that's not a problem, I could keep batteries, and all equipment in the basement meaning less expense and work. What do you guys see as the better option?
Doc
Put the panels in series and run them on the 10awg cables from Sunelec -- the 54vdc will be more then enough to carry the current without much loss at all (well within range) to the MPPT controller in the cabin. This is exactly what I did.
Incidentally 48vdc can run 50 feet on 10awg with <3% loss so at 54+ from 55 feet you are A OK.
As for the higher voltage, don't worry! You are using an MPPT controller and chances are if you bought a good one then it's likely to take much higher voltages and regulate them down to what is required....that's one of the benefits of using the MPPT style controller.
I'm typically running over 60vdc to my MPPT controller from my panels that are rated at 18.27v (3 in series in my case to give me almost 55vdc) and the Morningstar controller does the rest.
I like the idea of the controller, inverter sheltered in the house but I sort of don't like the idea of the batteries located there. Especially in the basement but then I am a real novice at solar. Do not claim to know anything about it. Best left to MD, Sparks and JarHead. But I have been around those huge storage batteries a lot from trucks to locomotives most of my life. I have really got a lot of respect for them, their storage potential and their gases.
Could you locate a lean to storage for them on the exterior of the cabin of out of the way?
Doc,
I am putting my off grid stuff in a separate shed for two reasons.
1. I want to have the batteries and electrical away from the house for safety/fire issues.
2. The building inspector wants me to have it away from the house for safety/fire issues.
If you have an MPPT charge controller wire them in series where ever you put the panels. I was told that even in low sunlight this makes sure your array voltage is above your battery bank voltage.
I am running over 100volts to my Morningstar and I agree with the above. Higher voltage is less line loss.
Running them in series seems a great idea to always be over the threshold voltage. Unfortunately, my Chinese controller accepts up to 40 V and has an output of 12 or 24V. I suspect 55V (2 x 27.5V) may fry it. Batteries away from the house seems a good option too because of off-gassing, etc. Someone I heard of (here on CP.com?) keeps their batts in a deck box with windowed top for warming. I do already have a 250ft coil of 12-2 UF wire. On the other hand, if I got two more panels, I'd have line voltage into the house AND a major boost to my system. A good controller costs nearly as much. This is getting interesting.
That would fry it, yes. One thing to keep in mind as well, especially in locations that experience winter low temperatures is to be absolutely certain to design for the possible voltage spikes that cold temperatures initiate. The safe thing, and the NEC thing, is to multiply the Voc (open circuit voltage, not the maximum power voltage) of the panel(s) by 1.25 and then by 1.25 again. (1.56 for those who like single steps). That will cover the coldest temperatures. I have mentioned this before but it does bear repeating. The maximum voltage rating of the charge controller must be greater than the result of that math problem.
For those who have or are considering an Outback controller they have an online tool that has temperature adjustments. Handy tool and interesting to look at even if Outback is not the unit of choice. I believe Xantrex has a similar tool.
Batteries simply need to be in an properly vented air tight enclosure if in or near the house or other outbuilding. This can be done and batteries can be in the basement. The hydrogen will rise and dissipate rapidly from a properly designed, sloped top box.
It is also key to not have any sources of possible sparks in the enclosure. No switches, no relays, no breakers or fuses. In fact no electronics at all just to protect them from battery acid fumes.
When placing batteries and inverter at a distance from the building that is being powered size the AC conductors appropriately for the highest amperage use. Depending on distances and AC amperage designed for the wires for AC may have to be about the same size as for the DC current. Run the numbers through a good voltage drop calculator.
BTW, 27 VDC at 7.5 amps on 60 feet of #10 copper wire comes out to a 4.03% voltage drop on my calculator. That's a tad high IMO.
Quote from: MountainDon on October 03, 2011, 04:57:41 PM
BTW, 27 VDC at 7.5 amps on 60 feet of #10 copper wire comes out to a 4.03% voltage drop on my calculator. That's a tad high IMO.
Thanks, Don. Now were I to house the equipment beside the panels, and run line voltage to the cabin, would the 60ft of 12-2 wire be an issue?
PV module specs please: Vmp and Imp Maximum power volts and amps.
Assuming 27 volts is Vmp, the 200 watt rating makes the Imp 7.4
60 feet, #12 copper wire = 6.35% voltage drop. Too high IMO. I try to aim at no more than 3%. Mine calculates to 1%.
OOPs I miss thought that. It's for AC, thanks Rob.
Yes the current load desired is a must know.
Quote from: AdironDoc on October 03, 2011, 08:00:09 PM
Thanks, Don. Now were I to house the equipment beside the panels, and run line voltage to the cabin, would the 60ft of 12-2 wire be an issue?
Depends on the load...
Voltage drop = current * resistance
.0016ohms/foot * 60 feet * 20 amps = 1.92 volts or about 1.6% of 120V
How much power do you need?
My calculator* indicates 60 feet, 120 VAC, 20 amps, 12 gauge copper = 4% voltage drop which is considered okay for AC circuits. (two conductors)
* EDR, http://www.edreference.com/
I'd have to do an energy analysis of all my planned items and consider the amperage if they were all to be turned on at once. Main players, a 120V pressure pump rated max 1A, 800W microwave and a refrigerator rated at 1Kw daily. Aside from that, up to ten 13W CFLs. The highest draw is at the moment the pumps start and the compressor starts, yes? Am I to calculate the flow if they all started simultaneously? That comes to around 8 amps. Add 2 amps more for assorted possibilities like clocks, radio, etc. So 10 amps over a 60 foot run of 12-2.
Quote from: MountainDon on October 03, 2011, 08:39:43 PM
My calculator* indicates 60 feet, 120 VAC, 20 amps, 12 gauge copper = 4% voltage drop which is considered okay for AC circuits. (two conductors)
* EDR, http://www.edreference.com/
I forgot to calculate for the total length of the circuit (120 ft) d* Your thing seems to be derating by ~20% as well
Grid-tie panels down to $1.25/watt. Panel is the CSI CS6P-225P 225w.
For those who were interested in my Battery High Voltage Disconnect alarms and reset on my system I did a test these last two weeks. I turned off the inverter and shut everything down so the only load on the system was a 12vdc fan in the compost unit.
And the alarm continues.
Very strange -- I have been unsuccessful in getting morning star to respond to my queries also...so they are no help at all.
Interesting...GE is going up against China:
http://finance.yahoo.com/news/GE-to-build-large-solar-panel-apf-1072600519.html?x=0&sec=topStories&pos=4&asset=&ccode=
Well at least GE is a known name, unlike the failed startups here.
I guess I wish them luck.
Quote from: Native_NM on October 13, 2011, 08:40:20 PM
Interesting...GE is going up against China:
http://finance.yahoo.com/news/GE-to-build-large-solar-panel-apf-1072600519.html?x=0&sec=topStories&pos=4&asset=&ccode=
Doubt it very much....but perhaps...just remember that GE's Jeffery Imelt is Obama's buddy and GE didn't pay a dime in corporate taxes last year...hmmmm
So fellas (and ladies), a few posts back I was waffling on whether to place a small shed beside my panels, put everything in it and run line voltage from the panels or, run 27V into the cabin and do it there. Seemed there would be much less voltage loss doing it at the panels. I've decided to run 27V over the 50ft into the basement. It will allow security for my controller, inverter, batteries etc. and whatever increase in wire gauge needed to offset voltage loss is made up by not needing to build or buy a shed.
I've used the voltage loss calculator and see the outcomes for combinations of gauges and number of conductors per phase. The question in my mind at this point is, how much loss is acceptable? At 27.5V, the difference between a 2% loss and 1.5% loss is several gauges of wire and maybe a few hundred bucks.
Chances are you'll never "see" the difference between a theoretical 1.5 or 2.0%
How many PV modules; Voc, Isc?
Has the equipment been bought yet?
Are you stuck with running the 27.t volts? Much better efficiency wise to be able to series the PV modules, but that requires matching the charge controller to the maximum voltage from the modules.
Also, if in the future you wanted/needed more power from the modules, how would that be achieved? If you go larger on the wire now, then it may be easier to add modules in parallel. ???
Thanks for the reply, Don. Panels are Sun 200W 33.2 Voc, 27.5Vmc. Everything is bought. Unfortunately, the MPPT Controller handles up to 40V so I can't run them in series. With my 2 Panels in parallel, I'll buy whatever gauge I can stuff into a 1" conduit. I was thinking to run between 2 to 4 conductors depending on price and ease of pulling. I was shooting for a 1.5% loss. 50ft run means 100ft circuit. I suppose there will always be voltage losses of some extent. How much is acceptable, I don't know.
Quote from: MountainDon on October 17, 2011, 04:46:03 PM
Chances are you'll never "see" the difference between a theoretical 1.5 or 2.0%
How many PV modules; Voc, Isc?
Has the equipment been bought yet?
Are you stuck with running the 27.t volts? Much better efficiency wise to be able to series the PV modules, but that requires matching the charge controller to the maximum voltage from the modules.
I am sure you have thought about this already but also pull in an extra 14 AWG wire or other small diameter rope for future pulling needs, identify it on both ends. Always keep a spare in the pipe!
Just curious, but have you done a solar site survey? By the looks of the picture the trees are very tall and semi close to the house. Based on my view from the photo, a roof mount would probably give you the maximum power throughout the year. Which direction is south in the photo? It looks like the spot of the proposed panels is next to the tree line.
chart for conduit capacity
http://www.belden.com/resourcecenter/tools/conduitcapacitychart/Conduit-Capacity-Chart.cfm (http://www.belden.com/resourcecenter/tools/conduitcapacitychart/Conduit-Capacity-Chart.cfm)
and an online calculator
http://www.belden.com/resourcecenter/tools/conduit-calculator.cfm (http://www.belden.com/resourcecenter/tools/conduit-calculator.cfm)
Quote from: Squirl on October 18, 2011, 08:29:37 AM
Just curious, but have you done a solar site survey? By the looks of the picture the trees are very tall and semi close to the house. Based on my view from the photo, a roof mount would probably give you the maximum power throughout the year. Which direction is south in the photo? It looks like the spot of the proposed panels is next to the tree line.
Squirl, thanks for the reply. Southern exposure is clear but gotta trim those trees back when I'm up there next. I don't want any limbs falling on the panels. I dragged the rack more or less to true south using a declination chart and propping the legs up, adjusted it to around 40 degrees. All trees in front of the panels are down from "10am to 3pm" sun, but I'll need to take some more along the creek for the later afternoon sun. I thought of roof mounting but the cabin's roofline faces southwest, and the steel roof has no pinchpoints like running seam variety. I'd need to drill and mount bonafide racks with tilts. As I've planned it, come winter, I'll just turn the clips, lift out the panels and put them in the cellar. I'll be happy with sun from 10 to 4. I'm up every other weekend, so, batteries have 12 - 14 days to charge between uses.
Tickhill, extra wire's a great suggestion. Not just for pulling, but also for power to any future sheds, outdoor needs, etc.
Start of a solar rack made of 4x4s. Faces south at 40 degrees tilt. Will be braced with turnbuckles. Firring strips on top so panels drop right into place with clips that turn over the lip of the panels.
[cool]
I was just curious. I know it has been something I have been dealing with at my site and I'm just a little south of you. In the winter the angle is at 27 degrees.
Quote from: Squirl on October 18, 2011, 08:33:02 PM
[cool]
I was just curious. I know it has been something I have been dealing with at my site and I'm just a little south of you. In the winter the angle is at 27 degrees.
Squirl, it sounds like you mean the sun is 27 degrees from the horizon? For panel rack angle, I'm using the winter formula of latitude (mine is 43) x 0.89 + 24. For me, winter setting is 62 from horizontal. Adding your solar angle from horizon to my panel angle, we have just about 90 degrees as both our angles are complementary. Makes sense.
I've actually set mine to autumn/spring as a happy medium as I don't plan on using the camp much during the winter months. Latitude x .98 -2.3 gives my current 40 degree orientation. Come summer, I'll just set the legs a bit lower and slightly loosen the turnbuckles. Magnetic declination was 13 degrees west of magnetic south, though my cellphone compass makes me wonder about it's accuracy. It's my understanding that even if we're off by a fairly wide margin, panel outputs don't suffer much?
http://www.macslab.com/optsolar.html (http://www.macslab.com/optsolar.html)
It isn't the panel angle I have to worry about, it is the trees. At the angle for the winter the tree's shadow is double its height. In addition the back part of my property is pine which don't give up their brush in the winter so no sun would get through if I put the panels to close to the trees. Each foot taller I place the panels equals 2 ft closer to the tree line I can put them.
Quote from: Squirl on October 19, 2011, 07:03:28 AM
It isn't the panel angle I have to worry about, it is the trees. At the angle for the winter the tree's shadow is double its height. In addition the back part of my property is pine which don't give up their brush in the winter so no sun would get through if I put the panels to close to the trees. Each foot taller I place the panels equals 2 ft closer to the tree line I can put them.
That's a problem that I can't imagine a solution for. It doesn't help that pine reach well over 100ft either. Can you clear a few so at least you get a few hours of peak sun? I have a wind turbine and cobbled together a 60ft mast out of galvanized pipes jointed with couplings and guyed to the ground. My turbine isn't light but with a gin pole it's not too bad to hoist. I'm just thinking, if you get a couple panels on a galvanized pole mount, say, two 10ft lengths, add a gin pole and hoisted her up and added some guy wires, would you be in full sun?
I think I found the solution so far, I just have to make sure I implement it correctly. My house is currently around 125 ft from the tree line. I also have around another 50 ft closer to the road that I can play with. If I put them up 10 ft with a large base the trees can grow to 100 ft without effecting it. Within a few years I will try and remove the trees. Pine, especially the ones I have, are generally worthless and I would rather have fruit trees anyway. Wind will be more of the primary source in the winter but because of cost and inspection issues I will probably only have solar and generator power for the first year. I just thought I would share some of my issues because it looks like you have a similar setup. How far is it to the tree line for you?
Quote from: Squirl on October 19, 2011, 10:31:32 AM
I think I found the solution so far, I just have to make sure I implement it correctly. My house is currently around 125 ft from the tree line. I also have around another 50 ft closer to the road that I can play with. If I put them up 10 ft with a large base the trees can grow to 100 ft without effecting it. Within a few years I will try and remove the trees. Pine, especially the ones I have, are generally worthless and I would rather have fruit trees anyway. Wind will be more of the primary source in the winter but because of cost and inspection issues I will probably only have solar and generator power for the first year. I just thought I would share some of my issues because it looks like you have a similar setup. How far is it to the tree line for you?
Getting your panels up 10ft shouldn't be too hard, especially with the pole mounted setups. If you were to use 10ft galvanized pipe with threaded ends, it would give you some flexibility. I'm assuming you'd cement a section into the ground at the base. If your base is a short threaded stub, add a coupling, then a 10ft length above it. In this way, you have the option of hoisting it up in the future and adding whatever length you needed. My treeline is around 130ft to the south, but as close as 60ft to the west, what you see along the creek in the photo. I'm getting full sun from 10am to 3pm. I don't know much about panel outputs vs. time of day other than solar insolation charts put me at an average of a little less than 4 hrs. That means I most want to capture 10am to 2pm.
Before digging a hole and planting a section of pipe it might be a good idea to read some of Unirac's sizing and installation information. It might also be a good idea to use a larger diameter pole than you might need for the planned current installation. A larger pipe could then be used for a future expansion. Dave Sparks who comes and contributes here uses nothing less than 6 inch pipe for that reason, IIRC. Look for used drill pipe, it can be found in many places at a fraction of the cost for new pipe. That's what I have in 4 inch, 1/4" wall, 4 1/2"OD. You don't want the wind blowing it over.
Not sure I would depend on a threaded connection. Pipe can be had in up to 20 foot lengths.
Unirac's info can be found here. (http://www.unirac.com/mounting-solutions/pv-pole-tops.php?solution=pole-mount)
There is a great sizing chart for pipes and bases and complete walkthrough guide in a free article from homepower.
http://homepower.com/view/?file=HP108_pg28_Schwartz&pdf=1
Quote from: MountainDon on October 19, 2011, 12:06:55 PM
Before digging a hole and planting a section of pipe it might be a good idea to read some of Unirac's sizing and installation information. It might also be a good idea to use a larger diameter pole than you might need for the planned current installation. A larger pipe could then be used for a future expansion. Dave Sparks who comes and contributes here uses nothing less than 6 inch pipe for that reason, IIRC. Look for used drill pipe, it can be found in many places at a fraction of the cost for new pipe. That's what I have in 4 inch, 1/4" wall, 4 1/2"OD. You don't want the wind blowing it over.
Not sure I would depend on a threaded connection. Pipe can be had in up to 20 foot lengths.
Unirac's info can be found here. (http://www.unirac.com/mounting-solutions/pv-pole-tops.php?solution=pole-mount)
Good point about oversizing, Don. Still, after seeing the pricing on official mounts for my solar panels, my jaw dropped. I looked at the actual hardware which, seemed to me, to be hugely overpriced for its simplicity. Clips and racks ended up costing more than my panels. Same was true of the wind turbine setups.
I decided a DIY approach was in order. The threaded galvanized pipes I'm using are holding nearly 100lbs at up to 50ft height. That follows the recommendations of the turbine manufacturer. The caveat is they absolutely MUST be guyed at a number of levels. Further, they must be of high schedule/wall thickness. I figure at 20ft, solar panels posts should be similarly supported at 4 cardinal points due to materials fatigue from being buffeted by winds. Turnbuckles and anchors checked frequently.
??? PV modules are presenting a much larger surface area to the wind. That was one reason I decided to go with the Unirac system. According to them is used with their recommended pole, depth, height, amount of concrete our set of panels should live through winds to at least 90 mph (because my pole os over sized for the current module array). I've recorded gusts as high as 58 mph.
Quote from: MountainDon on October 19, 2011, 01:25:17 PM
??? PV modules are presenting a much larger surface area to the wind. That was one reason I decided to go with the Unirac system.
Certainly heard good things about Unirac systems. Easy to assemble and fit like a glove. Was the setup costly?
Darn. I thought I answered this. ???
IIRC the rack I used was about $500 and the used drill pipe about $20 plus some gas that was cheaper back then. 30-40 mile drive X2.
Temperature correction.
There is a lot of literature on adjusting Voc for cold weather with charge controllers and wiring, but not on the output side. I have not seen a single sizing guide with adjustments or anything in the literature about adjustments for charge controller output watts because of temperature. I have seen the normal 1.25 safety factor adjustment for the NEC. You can seen this in the panel ratings and the NEC rating for many charge controllers. Am I right that there is no temperature adjustment needed?
Here's my take on this...
Once the charge controller has processed the incoming power and is putting it into the battery, that power is, what it is. So many volts and so many watts. Nothing more, nothing less. It doesn't matter what the temperature is to the power coming out of the charge controller. At least is what I think.
The temperature matters to the batteries mainly as a function of reducing the amount of power (watt-hours or amp-hours) that can be withdrawn from the batteries. As for charging the batteries, colder weather may be an advantage when high rates of charge may be encountered as the batteries won't get hot as fast. That is just a guess, I have nothing to back that up.
Battery capacity is reduced as the following chart indicates...
![](https://i139.photobucket.com/albums/q305/djmbucket/solar/battery_temp_corrections.jpg)
We need more rated capacity in the battery bank as the battery temperature decreases.
At about 25 degrees F the battery bank should be 25% larger to compensate for temperature losses. Or keep the batteries warm.
I was more concerned with an increase wattage from the increased voltage from the cold. Most of what I had read was that the increased voltage tends to be when there is low solar radiance and almost no amperage.
Yes. I'd think all that should be covered by using the numbers for the cold induced high voltage. Mostly that is a spike but long enough to harm the voltage sensitive parts. The highest voltages recorded remain in memory accessible to the factory service techs.
maybe someone can answer this question for me....when we went to our cabin this weekend,all my oil lamps had frozen fuel in them.If i lit one-will the glass that holds the lamp oil break?? or should i wait for the oil to unthaw??? ???
I've not had lamp oil gel or solidify but I have lit the lamp when it was in the 20's and had no issues. The olive oil in the kitchen cupboard solidify in the cold but thats never been a problem.
As far as the globe cracking it really would not do much good to light it if the fuel is jelled. What do you use for fuel? What type of lamps? Like a tables lamp with a simple wick or an Aldan? Or like a Dietz type lantern. The Dietz will take hot gases back in to the tank which causes a draw and heat up the oil some what. But if it is that cold I think I would next year look at some anti-jell like the truckers use in their diesel. However kerosene is not supposed to jell. Just doing a little quick research here and basic fuel grade kerosene does not jell till after -22 degrees. I think I would do a little research on your fuel as far as what you are using.
As far as what to do, set them some where they can gently warm and your fuel will return to normal.
Don, how are your batteries holding up to the cold? Mine are in a similar type enclosure and uninsulated. I think the cold is hitting them hard because they seem to have lower power output then in the Fall. I am thinking of putting some rigid foam around them to help hold in the heat they generate from charging.
Quote from: PorkChopsMmm on January 03, 2012, 09:26:38 AM
Don, how are your batteries holding up to the cold? Mine are in a similar type enclosure and uninsulated. I think the cold is hitting them hard because they seem to have lower power output then in the Fall. I am thinking of putting some rigid foam around them to help hold in the heat they generate from charging.
I seem to be having this problem quite a bit myself. I can get them above freezing in the day and keep them 10-12 degrees warmer then outside temps because of the porch they are in but clearly I'm losing capacity due to the cold.
I plan to insulate mine also but alas, time is something I never seem to have enough of.
Quote from: cabingal3 on December 27, 2011, 12:04:37 PM
maybe someone can answer this question for me....when we went to our cabin this weekend,all my oil lamps had frozen fuel in them.If i lit one-will the glass that holds the lamp oil break?? or should i wait for the oil to unthaw??? ???
I took a very cold lantern this weekend, poured fuel in it and lit it.
The flame is not very hot and it warms the glass up slowly. I think you would be fine with yours because you need to let the fuel thaw anyway so light the wood stove, thaw the fuel and then light the lamps :)
As the little chart above indicates there is capacity loss dur to cold temperatures. For the most part I don't notice any difference that affects our winter use. But that's why I used 12 of those batteries instead of 8. After a few years of use I'm quite certain that 8 would be sufficient for three season use; spring, summer,fall. That's pretty much what I calculated. I added 4 "extras" as I knew there would be winter loss of capacity.
I can see a lower voltage reading at the end of a typical winters day than at other times of the year. Also we don't have a full three days of autonomy in the winter, without dipping below 50%. Fortunately our winter times at the cabin seldom go more than 2 1/2 days; 2 overnites.
I tossed around the idea of insulating the batteries a lot before getting to the point of installing the PV system. Because our winter use is limited by the fact of the road being impassable once the snow gets serious I decided it would not do a lot of good. Here's my train of thought on that. When the cabin sits idle there is zero use of electricity; the inverter is shut down, there are no direct DC uses. So all that happens on a sunny day is the charge controller kicks in when the sun hits the panels hard enough. The system goes through a short bulk charge then switches to absorb for a couple hours. Then it floats until the sun goes low in the sky. The bulk period is so short there is very little heat generated. The absorb is low powered enough that again there's little heat generated. Float does nothing for heating. Time between visits is two weeks minimum. I figure that even if we left the batteries warm, by the time they went through two weeks of the above mentioned cycles there temperature would still be down to the cold ambient air temperature. Insulation only slows the transfer of heat; if there is no noticeable amount of heat to slow, the benefits of insulation are minimal to none, IMO.
Our cabin is pretty well insulated, R25 floor, R19 walls, R45 ceiling, good low-e windows. When we leave the interior and contents is likely to be 70 - 75 degrees F; sometimes we leave some fire in the firebox. Typically by the time we return the interior of the cabin is usually colder than the outside air temperature when we snow shoe up in winter. Last trip it was 40 outside and 28 inside. We have many more hours of cold than we have hours of weather warmed by the weak winter sun.
It seems to me that if my batteries were in an insulated box there would be no real operating advantage in winter. Now, if our use pattern was different, longer weekends or a week or more at a time, that would change things. Anyone living in similar conditions in a full time residence would certainly benefit from an insulated battery enclosure. In a full time occupancy it might even be a benefit to have a solar air collector heater to keep them warm. ??? But for our type of winter use and winter temperatures I'm not convinced that insulation would bring great benefits.
Anyhow that is my reasoning for our situation. Others may differ.
Don, thank you! As always a very thorough response. Looks like I need to verify my loads, insulate my batteries, and possibly double my bank (my only option at 48v). I don't think we will be back until March... That will give me the summer to get everything set up before next winter.
Don, this is why I put mine in the porch :) I can see a rise well above freezing inside the porch when the sun is out and gain about 12 degrees at the coldest part of the night/morning. I figure with good insulation I can improve the gain by reducing the loss thereby improving battery life and useability.
Every situation is different... we are very well shaded. There are enough trees that at any given moment there are more shadows than direct sun on any more or less southern exposure. great in summer, not so much in winter. It's especially bad in winter when the low angle of the sun is compunded by the trees on the south facing slope. Because of the slopeand low angle the sun must make its way through more tree tops than in summer. Once again, this is what I see, what I have, others may have different experiences.
If we used the cabin in the winter as much as we use it the rest of the year, I probably would insulate the battery box, add some more mass with solid concrete blocks or something with good mass and hookup a solar air collector from the roof. Maybe a liquid heat collector.
Cold improves battery life/longevity. Warm improves available battery capacity. Trade off.
Great thread!
I have a battery bank question. One reason standard car/marine batteries are avoided is due to their tendency to wear out quickly. Walmart has an Everstart Maxx-29 12V 125ah battery for about $75. For about $1200, you can get a 24v-1000ah. While I know batteries of this type tend to wear out in 12 months, these batteries have an 18 month free replacement warranty. Does the warranty clock reset when a replacement is given? I'm assuming it's based on the date punched on the battery, but I have never had a battery go bad in the warranty period, so I wouldn't know.
Assuming that when the battery is replaced, the warranty clock does reset, and assuming that one doesn't mind the physical labor to remove/return/replace the batteries, one could keep themselves in a constant supply of new cells.
Again, I haven't ever had to use a battery warranty, so I'm not sure how they work.
I've never had a Walmart battery warranty claim. I have had one other mainstream automotive battery replaced under warranty though. In that case the replacement battery warranty period was counted from the date of the original purchase. The original failed after 18 months, it was a free replacement and I still had up to the three year mark (from original date) for a total free replacement if the battery failed by then, plus the pro rated period out to six years. I think that was fair as I only paid for one battery. And if I was the battery manufacturer/retailer I think that is what I would do.
I sent in a request to Trojan Battery to have the warranty period clarified after a warranty replacement. When/if I get a reply I'll post it.
Similarly, but different... I buy my tires from Discount tire. I buy their tire replacement warranty for the Jeep tires. When I have a claim under the warranty I get a new tire free, but have to buy another warranty to maintain the replacement warranty. Also fair, IMO.
It would make sense that it would be from the purchase date, but I do wonder what the walmart policy is. That said, would it be good for newbie to start with car batteries with a 3 year free replacement warranty? Learning on a cheaper platform with an insurance blanket so to speak.
Quote from: mgramann on January 19, 2012, 07:24:01 PM
... would it be good for newbie to start with car batteries with a 3 year free replacement warranty? Learning on a cheaper platform with an insurance blanket so to speak.
My personal opinion is, No. Even a beginner off grid'er can have a successful experience IF they prepare properly.
What's to learn? Keep the battery fluid level up. Don't discharge the batteries too deeply. If anyone has problems with that they should probably hire the maintenance out to a third party.
The planning process begins with an honest up front assessment of the power requirements. That will determine the battery capacity required. Make that estimate for the time of year that would require the most power use; probably winter for most of us. actor in the worst case scenario for PV power production; also probably winter for most of us. Then add at least a quarter of the battery capacity for adding items that you were sure you could do without, but can't. When calculating capacity keep in mind that cold temperatures reduce available battery power. We have charts someplace here.
Most off grid system failures occur for the same reason people have financial failures. They withdraw too much power from the batteries (or checking accounts). If the PV system owner has to run the generator frequently the system is not designed right. Don't try to start with "this much", thinking you will add "that much" later. That is a guarantee for a failure, in my book, especially with batteries. Do it right and you will then have battery replacement occur pretty much about the expected end of life.
Idle thought from my fertile pesimistic imagination..... What would happen when you walk into the store with 12 bad automobile batteries and they state the warranty was void because the batteries were not used in a vehicle, or want to see the vehicles so they can test the charging system? I'm not saying they would/could do that, but I wonder what thought process the dealer/store might be going through when somebody shows up with a dozen sick batteries? Maybe that's not a worry.... I worry too much at times.
Anyhow that is my opinionated opinion. ;D
Thanks Don. FWIW I'm a worrier too, and that would be quite a scene getting them replaced :D
I will definitely be chatting with you when I decide to build a system. I have already used your spreadsheet for some initial estimates-thank you for that.
One last idea I had. This thread is full of information, but the amount is a bit overwhelming. I wonder if it would be a good idea to have a thread where members posted a quick overview of their system. Batterys, inverter, other controllers, and finally what their system runs for them. They could also comment on any changes they would make, and other contributing factors such as climate.
It would give people who are considering a system a head start, with some real world testing. To keep the thread "clean" people could PM the member for details if they think the system is similar to what they are after. As their system evolves, they could edit their posts.
I know this information is on the site, but this would put it all in a central location. An off-grid system applied library so to speak.
I have one of the wally world marine batteries for occasional use. I don't use a lot of power. 2 years and going strong . You can get years out of the batteries. It is a depth of discharge to number of recharges curve. The better batteries simply handle deeper discharges and more recharge cycles.
The better bet would be a 6v 220 amp battery, which I believe are going for around $100, but I can't seem to find any of these at the discount stores around me. They last a little longer and it is probably closer to the voltage or string you will be replacing them with. You get more amp hours for the same string. In your example you would have 8 strings of 2 batteries each. In every book, magazine, charge controller manual, and retailer I have read they suggested trying not to go over 3 strings, and the less strings the better. The more strings you go with the more the batteries get unequal charges and it can shorten the life of the whole bank. That is why they sell 2v - 1700 amp hour batteries. If it wasn't a serious concern, no one would want to deal with that much lead. While most books suggest that one string is best for charging they realize that it may be impractical for daily usage. This is because if one cell goes bad you have no battery bank at all, instead of simply operating at 50% or 66% capacity if you have 2-3 strings. I haven't seen any hard numbers on decreased life expectancy out of a large # of strings though.
Then again Trojan came out with the T-105 RE that I have seen as low as $150 with a 5 year warranty. The freight shipping is killer though.
In my experience the T105's are excellent
Batteries Plus can get them for you or golf cart places too (that's where I got mine)
I have seen web sites that give free freight to places with loading docks too
to plug Don's favorite good store Thesolarbiz -- my 1800 pounds of Surrettes cost $100 delivery to my door step, he just used a pallet cart and wheeled them into the garage-- pretty cheap, real easy
After a previous poster mentioned cycles and discharge depth, I did a quick review but didn't see what I was looking for. I wonder, what is the optimal depth of discharge for maximum life, and, do my lead-acid batteries need to be "exercised" with occasional deeper discharges? My cellphone salesman said I hurt my cp battery by not allowing a discharge before recharching it and to stop the constant charging. I'm sure lead-acid is very different. I'm about to hook up my 8 Sam's 220A 6V Ever-readys and will be using 2-200W PV's. Depending on optimal DOD, I may spring for 4 more.
Doc
Here's a graph from Trojan Battery. This is specifically for their T105RE 6 volt battery, but should be similar for others...
Notes from Trojan...
1. Shallow discharges will result in a longer battery life.
2. 50% (or less) discharges are recommended.
3. 80% discharge is the maximum safe discharge.
4. Do not fully discharge flooded batteries (80% or more). This will damage (or kill) the battery.
5. Many experts recommend operating batteries only between the 50% to 85% of full charge range. A periodic equalization charge is a must when using this practice.
6. Do not leave batteries deeply discharged for any length of time.
7. lead acid batteries do not develop a memory and need not be fully discharged before recharging.
8. Batteries should be charged after each period of use.
And a note from me: if the battery is only slightly discharged (maybe 10%) on a regular basis it should receive an equalization charge at shorter intervals. Monthly perhaps?
Quote from: AdironDoc on January 21, 2012, 12:03:08 PMMy cellphone salesman said I hurt my cp battery by not allowing a discharge before recharching it and to stop the constant charging.
I believe all cell phones use Lithium Ion batteries now. L-ion batteries are a lot like lead acid batteries in that deep discharges hurt them. They have no memory. Their life is based in part on discharge/recharge cycles. They also don't like high temperatures. It is also not good for the L=ion battery to be on charge all the time. In fact if you use a laptop. plugged in mainly, you can remove the battery and keep it warpped in plastic in the fridge and extend its life. Of course if you accidentally pull the power cord everything you were doing could be gone.
And why not toss inanother battery capacity vs temperature chart for good measure?
I have seen some different cost/benefit analysis as to best rate of depth of discharge. Some say never below 50% and 30% is optimal. Another I had read supposed there was a standard shelf life and recharge cycle to batteries and it was more cost effective to discharge 50-70% rather than over size your system since after 8 years you will be replacing them anyway.
With the fear of electromagnetic pluses either via solar or weapon delivery. Would a solar or wind off grid system be really any less susceptible to damage in reality than the norm? Also would it effect refrigerators, stoves, radios, ovens, my pickup's electronics and OH MY GOD, MY LAP TOP... Would it make sense to put all the electronics in a cellar maybe less the batteries? Not being a doomsday prophet but if something would be easily available why not?
Hey Don!
The number 9 for your Trojan list is the mechanical aspect of a battery. The ones that last really long, like 10 to 20 years, my experience has been that their daily cycles are fairly contant. One might use more energy in the summer, but the pattern over the years is fairly constant. The movement of the internals become "conditioned". This is one of the reasons new people need new batteries so often. The battery is going through so much mechanical stress that is fails.
Alot of other sins for new users are higher on your list failurewise!
Hope all is well ! Spring is coming!
I'm guessing that 4 and 6 are big offenders.
Not sure if our use pattern would be classed as constant. Over the summer it is a very constant thing. Then winter comes and it is mainly constant no use; just a daily boot up with the sun with a short bulk charge, then an absorb and the majority of the day in float, interrupted by Sat thru Monday AM a couple times of a month till May when we hit the use it almost every day summer cycle. I guess time will tell. Typical daily use runs about 20%.
Great info, Don. Thanks for taking the time to dig up the charts and post them. As the cabin shapes up, the power budget is changing. Seems each week another electrical device 'becomes necessary'. I suspect that depth of discharge, while a very important parameter, is dependent on the number of batteries used. It follows that a greater number of batteries will ostensibly lead to a longer battery life. At some point, however, it appears to make sense to use battery funds to add a 200W panel to the two others. That would lead to a lower discharge depth as well. I suspect I'm going to see how this turns out before I can judge the health of the system I've put together.
Quote from: AdironDoc on January 31, 2012, 10:54:38 PM
Seems each week another electrical device 'becomes necessary'.
Been there, done that ;D I just hope that I really I knew my wife long enough and well enough to have made the proper adjustments for excess capacity. ;) So far it looks so good... :)
Yes either more batteries as in another series string, or larger capacity batteries, like L16's.
An extra module can help by providing a more rapid recharge. How does an extra module fit in with the limits of the charge controller as to current if placed in parallel, or peak voltage if in series? An extra module may not help DOD much if the power used is mainly in late afternoon and through the evening as it happens with us. On a normal day we have excess PV capacity and can easily afford to use a small slow cooker (crock pot), even the A/C for a short time on a hot summer afternoon. In winter we help warm the bed with an electric blanket; most days are sunny and we get the power back by afternoon.
I suspect you're right, Don. I'm suffering "inflation" when it comes to things I need (or would like) to plug in. I'll put timer switches in the bathroom, basement, etc, and motion based in my hallway. Still, that paddle fan you recommended sure seems sweet :D
My controller is a cheap 60V/40A model. It won't handle the voltage of two 27.5V panels in series, but seems likely to handle 3 panels (200W each) in parallel. I'm assuming approximately 7.5A per panel at full swing into dead batteries. Like you, I expect most of my usage will be in the evenings.
This is the first time I saw off-grid panels at Costco and I thought some here might be interested. $279.99 delivered for a 100W panel.
Grape Solar 100W Off-Grid Solar Panels (http://www.costco.com/Browse/Product.aspx?Prodid=11662384&cm_mmc=BCEmail_716-_-Focus-_-11-_-MarketingItemName)
Has anyone used the new Outback Radian GS8048 inverter/charger yet? Is there any downside with the new system compared to the old Outback setup with dual inverter/chargers (for 220V)?
Only know what I have read.
First thought was, cool. It's a more cost effective package than stacking.
Second thought was, uh-oh. There goes the redundancy. If you have 2 old style for 129/240 VAC, if one dies you casn limp along on one. You won't have 240 VAC though. If you have 4 or more stacked for 120/240 VAC with increased wattage capacity and one goes out you can still work but have to watch your loads.
So what is more important? Cost savings or redundancy benefits? ???
Welding cable...and other power plans.
Any reason not to use this over the "normal" battery to inverter or battery to battery cable. For 4/0, which is what I plan to use for both battery to battery, battery to inverter, and charger to batteries,the price is 1/2 to 1/3 for the welding cable...and most of all welding cable is readily available here and any other is a real chore to find.
Inverter and charger distance to batteries is 4 feet.
Sure looks OK to me to use it, but just checking.
My system, to start...
4 12 v Marine batteries (120 AH each) in parallel to a 3,000 watt Wagen inverter. Inverter hardwired into house elec. box. Question..the inverter has a volts out read out and I wonder if that is a good (sufficient) way to tell battery discharge. At 12.1 volts, I should be at 50% and using it on the build the reading seem to be in line with what I see with the battery.
Charger..likely an Iota DLS-75.
Recharge is with 2600 watt genset hooked into house and from there to charger. Genset will also provide power to house when charging (or other times)...it is hooked into box with 8 gauge wire and running off the 240 plug.
Using a simple manual A/B switch to isolate inverter from genset when genset is providing power
Welding cable will work. It won't pass an NEC inspection as it doesn't have the required stamped approvals. But that is not an issue here.
Battery voltage is only a guide to battery state of charge. It's a very handy way to tell pretty much what is going on. The best indicator of battery charge is a hydrometer with a thermometer so the reading can be temperature corrected. Charts for that come with a good hydrometer and there are also some listed here in this topic I think. Of course if you have a sealed battery of some kind you can not use a hydrometer.
Using a hydrometer regularly and recording the reading of each cell can help detect early cell failure or deterioration. When that is found an equalization charge can be done. Unfortunately the Iota chargers don't have that ability. There are some Xantrex that do; not many. A good inverter / charger combination unit can also have equalization charging built in. I'm not familiar with the inverter you mentioned.
Any straight forward reason not to use one PV panel.
I have to bring in country...so one high capacity panel sized and weight to meet baggage is the best bet.
I am thinking about something in the 200 watt range. With some luck that can get me by day be day without a generator. I need about 500 watt hours a day....and at 70% this needs 4 hours a day which I can get 4 months of the year. This lets me cut the number of batteries I need with just a generator....I figure i can get by on one 120 AH..mostly just to store for some low wattage lights 3 hours at night.
If i get a reefer...that will all change but even at that one other panel can make it work with one more panel.
Quote from: alextrent on April 04, 2012, 06:49:22 PM
Any straight forward reason not to use one PV panel.
If one covers the requirements, why not. It's not like something that has a high failure rate and because of that you would want redundancy. IMO
So after all the whining about not being able to get stuff here, I walk into a "solar" store here ( the one and only) and see two 225 AH Trojan 105 batteries among all the other no name stuff. $105 per battery and before i can say, I will take them I get a 15% discount (no tax). A bargain at the original price.. I bought them to pick up tomorrow.
They look real...maroon..and all the labels. What is the downside...cannot ascertain date of mfg. How much can that mean? I will it have the option of bringing them back. But at this price, i guess risk is low.
I get my IOTA charger and all the cables from the States next week so i am in business for real and the marine battery and the 10 amp car charger are retired.
from Trojan...
How do you read the date codes on the batteries?
Positive Terminal- Manufacturing Date. This code indicates the actual date when mechanical assembly of the battery was completed. At this point, electrolyte has not been added to the battery and formation charging has not taken place. LETTER stands for the month and could be anything from A to L (A=January, B=February, C=March, and so on),; NUMBER stands for the date.
Negative Terminal- Shipping Date. This code indicates the month and year when the battery was shipped out of our factory. LETTER stands for the month (see below); NUMBER is the last digit of the year.
Example: A battery with "I26" stamped on the positive terminal and "J2" on the negative. "I26" means that the battery was assembled, without electrolyte, on September 26th. "J2" means that it was shipped from our factory around October of 2002.
Trojan Link, scroll to bottom (http://www.trojanbattery.com/Tech-Support/FAQ.aspx)
Thanks..
So, the missing link is how long can a battery sit on the shelf and be acceptable? Info is owhere to be found.
Trojan techies say one year from MFG date unless you know the dealer and he has charged regularly.
Good to know. Thanks
In some ways it is too bad that batteries are not shipped dry like they all were decades ago. I filled a lot of batteries working in a garage as a kid.
After they lose their charge sulfation starts setting in on the plates making it hard if not nearly impossible to get full capacity back. A PWM solar charger/regulator or desulfator unit added can help break up sulfation. Also EDTA can help to chemically desulfate them.
Considering a situation such as mine where I will be running a 50W 12V panel and hope to power an intermittent use 7.5A 12V pump at the springbox, what is the optimal site for the battery? The springbox is near the bottom of a ravine and cannot be moved. The only consistently sunny area, on the other hand is atop the hill in a clearing some 120ft away. In consideration of inevitable voltage drop, should the charge controller/battery be closer to the PV panel, closer to the pump, or in the middle? It would seem to me that a higher voltage would be better used to charge the battery, as it would require in excess of 12V to fully charge. The Shurflo motor on the other hand, may allow for a bit of drop. Is this so?
What is the rated max power amps of the PV module (Imp)?
I'm going to guess; module Vmp approx 17 VDC and Imp approx. 3 amps.
The pump is 7.5 amps at 12 VDC.
If the CC was by the batteries which were located by the pump (120 feet from the module)...
(17 VDC at 3 amps)
...for a 3% voltage drop #6 AWG wire is needed; Cu, Al would be #4
...for a 2% voltage drop #4 AWG wire is needed; Cu, Al would be #3
If the CC and batteries were by the PV module (120 feet from the pump)...
(12 VDC line voltage at 7.5 amps)
...for a 3% voltage drop #2 AWG wire is needed; Cu, Al would be 2/0
...for a 2% voltage drop 1/0 AWG wire is needed; Cu, Al would be 3/0
Depending on the CC you have you might be better off with another panel in series. Raising the volts will drop the wire size. But that's not going to work with a lot of charge controllers.
Such is the fun of long wire runs. Try my 325 foot run. That's why I run three in series for 70 to 90 volts from the modules to the distant CC.
Thanks, Don, I hadn't thought about the fact that the panel's voltage is a bit higher. The specs are:
HQRP® Solar Panel Rated Power: 50W; Maximum Power Voltage: 17.2V; Open Circuit Voltage: 21.6V; Maximum Power Current: 2.91A
I had the panel already for another project and wanted to get away with not having to buy much else. Seems your answer is clear. Park the batteries/CC near the pump. The shurflo I have is the 12 VDC, 3.0 GPM, 55 PSI, and 7.5 Amps, 4008-101-E65 3.0 Revolution. It's supposed to dry prime up to 6 feet vertically. If a proper check valve could be fool-proof and keep the pump primed, I suppose in theory I could move the pump at least 20 feet (6 feet vertical) up from the springbox without issue. I'd hate to resort to that as I planned on keeping the pump, valves, etc. tucked in under the roof of the spring-box cover.
Thanks for the breakdown.
Doc
Don,
I emailed you! Are you going to visit camp oso?
--Dave
emailed back just now.
Did anyone catch the news the week before last, about a domestic solar startup company that came up with a innovative design in panels? Don't remember the channel, but I was hoping to get the company name if any of you remember. The anchor was allowed to see basics of the design but the details were said to hush hush until August, when the patented design actually goes into production. Of note, they are using inexpensive single modules arranged in rows. Nothing fancy. Over them, what appeared to be a panel of plastic that their optical production facility originally specialized in manufacturing. They were apparently in the lens/composite industry prior to this foray. With the plastic panels deeply furrowed with what looked like embedded Fresnel ripples, sunlight in the demonstration struck the modules from almost any angle with high intensity pushing the module to produce multiples of what comparing units would be expected to turn out. The conventional panel alongside it was used to demonstrate the um..glaring difference :P
Upshot of it was that the panels cost far less than conventional to produce, take up less than half the space, and turn out 2-3x the output for a given area/footprint. Developer noted it's far less costly to push the output of existing modules using optics than to use more modules. The industry experts interviewed noted this may be the way solar panels all look down the road as a roof's worth of panels could be fit into a much smaller space without as much concern about orientation.
Any development in cost/performance is good news I suppose. Especially good to see its a domestic company. Now if only the prices on good batteries were to fall as well... d*
I have been hearing about "that" company since solar panels went to space. They have become priced reasonable but efficient in differing amounts of radiance is still for space budgets.
I think what you heard was that these panels were extremely black and worked really well in cloud light levels.
Could be. I don't remember the full story about them. I do remember the gist of the piece. As a plastics/lens manufacturer, they took cheap module strips and used a propriatary lens system produced at low cost to ramp up the power while dropping the footprint. They were confident they could beat the $/watt prices of the current Chinese manufacturers. I suppose if it's a winner we'll soon hear of it again. My main concern would be that the way the plastic lenses had troughs, they'd catch any debris landing on them and also how well plastic would hold up over the years.
I'd not heard of the report. I was going to say that I'll believe it in August when I see them. But then decided to leave it alone. Then Dave chimes in and more or less affirms my feelings... so there ya' are.... I'll wait till August. This August, let's hope. ;D
Yes! Definately August! The holy grail will be when a panel can gather energy over a day, off axis as well as tracked.
I think that my panels have been slightly exceeding the maximum amperage rating of my Chinese mppt controller but without any issues yet. It's listed at 15 max with recommendations at keeping it safely under 12. My panels should put out 200w at 27.6v but have exceeded that. I figure I've hit at least 16amps between the two of them. So here's my question. If the batteries were completely empty, I can imagine it would pull the full 16 amps. But do the batteries, which are never more than 30% discharged, really allow the panels to push the controller to anywhere near its limit?
There are two things to consider. The batteries can be full and if your loads are large, the controller will output power until it internally current limits, the panels are maxed, or the circuit breaker trips.
The second is if you have a controller of dubious design, you should conservatively current limit the beast for safety sake. You probably do not want to start a fire.
Quote from: Dave Sparks on May 24, 2012, 10:14:59 AM
There are two things to consider. The batteries can be full and if your loads are large, the controller will output power until it internally current limits, the panels are maxed, or the circuit breaker trips.
The second is if you have a controller of dubious design, you should conservatively current limit the beast for safety sake. You probably do not want to start a fire.
Noted, Dave. I just swapped it out with a Chinese 30A 1.2kw MPPT controller. Now I can add my third panel. 200W/27.6V = 7.25A. Three panels will still be well under the threshold even allowing for 20% over output. The only fires I want to start are campfires!
Doc
Best price on quality solar battery?
I'm looking for something to build a 12vdc bank in the 1200 AH range that will last a lot longer then GCB's.
Thoughts?
I'm currently looking at the Surrette S530 400ah batteries to do the job (400ah@20hrs).
Not looking to buy immediately but looking to replace the GCB's in the future and want to plan for it now (budgeting and all that).
Thanks!
Quote from: OlJarhead on June 17, 2012, 10:14:24 AM
..... last a lot longer then GCB's.
Thoughts?
That statement makes it sound like the present batteries are not performing well, maybe failing. Or is it simply that they do not have have sufficient rated capacity to do the tasks being asked of them?
Quote from: MountainDon on June 21, 2012, 01:18:39 PM
That statement makes it sound like the present batteries are not performing well, maybe failing. Or is it simply that they do not have have sufficient rated capacity to do the tasks being asked of them?
They definitely have insufficient capacity I'd say but I need to do more testing.
Life has likely been reduced (I've got to get a hydrometer this week!) due to twice draining them below 80% (actually 100% according to the meters).
I'd like a battery that should last a decade or more if possible and a capacity to run for 4 days without sun while using CFL's, the fridge etc....current usage can be 1700-1900 watt hours per day according to my charge controller and the calculator is telling me that I need up to 16 GCB's or 10 L16's (@370AH - default on spreadsheet).
I was looking at some Surrettes at 400AH (20hour rating) and I would need max 8 of them according to my load -- 1600AH -- and one more panel to keep them charged up.....I think I priced them at $2800 for 8 and they have a 7 year warranty on them.
My thought is that I need more battery bank power, can't add more batteries now since the bank is two years old (just) and the GCB's while 'ok' for me so far will eventually need to be replaced anyway. So I figure if I plan to get the bank now I can get it in the budget and acquire the batteries in less of a hurry then I might need to do in a year or two ;)
I had been looking at the Surrette, because of their excellent warrenty. I had a vendor who I trust tell me just before I ordered that he liked the Surrette warrenty but not the product. I guess they have had some unexpected failures. I went with another battery maker-- Deka... nowhere near the warrenty as the Surrette though... some other alternatives are Sun Xtender, Interstate, and Trojan. I think they all ship from the factory to ensure you are getting a fresh battery. Mine were AGM.
1200 amp hours with 215 hour GCBs would be six strings. From what I read, it would be difficult to keep those evenly charged. I have not seen any hard data on how much extra strings can decrease the longevity of the bank. The recommended maximum in most solar books and publications is three strings. That is why you see very low voltage high amperage batteries. Three sets of 400 amp hour batteries would be within most recommendations. Although the most publications recommend as little strings as possible, it is not practical to have just one. It can lead to charging difficulties if you more than one input and if you have one battery go bad, you lose all power.
If adding batteries it is also recommended to replace them all at once. The shortened life and decreased depth of the old batteries will shorten the life and performance of the new ones.
Quotecurrent usage can be 1700-1900 watt hours per day according to my charge controller
Not quite the same as actual use,as the CC amount going into the batteries is accounting for losses in the system. Meaning that CC data number is larger than the calculated, item by item x hours a day/week, calculated totals. It also is measuring the float amount of power.
With numbers like that (large) perhaps the total system needs some reassessment. Like is the electric fridge efficient enough for use with a PV system? Should the battery bank be 24 VDC? Perhaps a solar tracker is required to get more juice out of the sun hours?
The ideal battery bank would be a series string of 2 volt cells; nothing in parallel. And you buy a spare as windpower did.
I also believe that connecting the series strings to buss bars is much better than making the parallel connections with cables. OJH does have copper buss bars IIRC.
Trojan RE series also has up to a 7 year warranty too.
http://lib.store.yahoo.net/lib/wind-sun/Trojan-RE-Warranty.pdf
I don't know how it stacks up to a Surrette, who have a great reputation too.
I was looking into them because Trojan batteries have a good distribution network and I may be able to find them locally without paying for shipping.
Good points and info on the CC readings. I wasn't sure about that but it makes sense.
My neighbor has a 1000AH caterpillar battery bank and ~500watts of solar on a tracker and it seems to do the trick except in the winter where he must run a generator every weekend to get the bank back above 70%. So, my thought was that my 615 watts of solar and 880AH of batteries would at least, according to my original calcs, do the trick.
SO far, if there is sun, the batteries go back to 100% daily and I've used the system in the winter with little to no sun and the bank appears to do 'ok' in that it's still above 50% in the morning (often above 80%) but I'd planned the system to do that in 3 days not 1.
My thought is that I failed to calc based on winter numbers rather then a yearly average. Using winter numbers means the system will provide enough power in the winter and excess in the summer -- which is fine by me!
So, I'm back to the drawing board.
I'll do more research on usage to try to get the system tailored correctly but I'm pretty certain I'll need to at least bump up to 1200AH and 820watts of charging power to ensure I have enough power to use the system on cloudy winter days without worrying.
On a side note, the system isn't as bad as it might sound d* it's just that I'm a worry wart! d*
I run the fridge non-stop when I am there and last year ran it all summer (24x7) without drawing the bank down too far at all and that was before the addition of two more batteries to go from 660ah to 880ah.
I just don't think I can run both the fridge and freezer like that and want to.
Dave Sparks has one of these...
http://www.stecasolar.com/index.php?Gefriertruhe_en (http://www.stecasolar.com/index.php?Gefriertruhe_en)
Quote from: MountainDon on June 21, 2012, 03:08:41 PM
Dave Sparks has one of these...
http://www.stecasolar.com/index.php?Gefriertruhe_en (http://www.stecasolar.com/index.php?Gefriertruhe_en)
My fridge isn't a problem -- it uses less power then one might imagine. It's energy star rated and has no freezer -- I think I figured it was using 27-35 watts per hour to run...but I'd have to go back and check.
I also have a freezer that doesn't use very much either and I can run both at the same time, I just have no need. However I haven't tested the system enough yet.
As for the fridge in the link, I'd love one, but the price was too much for me when I put my system together....but again, mine does fine for what I use it for. My biggest worry, frankly, is that if I wanted to spend a few months at the cabin in the fall or spring that I'd not have enough charging power and battery power to run the system without using a generator and I hate using the genny! lol.
How about 6 of these Trojans...
![](http://eshop.thesolar.biz/mmonline/Images/TRO-50000-L16RE-2V.jpg)
http://www.trojanbatteryre.com/PDF/datasheets/L16RE2V_TrojanRE_Data_Sheets.pdf (http://www.trojanbatteryre.com/PDF/datasheets/L16RE2V_TrojanRE_Data_Sheets.pdf)
$340 each plus freight which might not be all that much. Give 'em a call.
http://store.thesolarbiz.com/online/ProductDesc.aspx?code=TRO-50000&type=0&eq=&desc=Trojan-L16RE-2V&key=it (http://store.thesolarbiz.com/online/ProductDesc.aspx?code=TRO-50000&type=0&eq=&desc=Trojan-L16RE-2V&key=it)
They are not 2 volt cells, they are 2 volt batteries; the three cells are internally connected to provide 2 volts instead of 6 volts. Not as simple as a pure 2 volt cell (you still have three cells to water in each unit...), but very cost effective for Trojans production. Six of them, nice simple with potentially neat wiring; 12 volts and 1110 amp hours @ 20 hour rate. heavy though at 120 lbs; but ya only have to move them once. Twice if you count when they get replaced some years down the road. :) With care I bet they could give you ten years easy. Wonder what Dave thinks of that? ???
This is posted in another thread, but is a separate issue. Any thoughts?
Trojan AGM 31 battery
Iota 55 AMP smart charger
So on the first go round with the new battery...after 4 hours on the charger still in the bulk stage and battery voltage at the inverter after a 3 hours off charger and no load except inverter is 12.5 V, which for AGM I read as about 75%. When I got the volt reading off the battery when first bought it was 12.3 volts (on inverter meter)...which is 50%. Sounds like something is screwed up...any ideas? Could it be my generator which is not true sine wave? I have read things about how they do not supply the right current for charging at full volume. On the other hand, Iota is one of the charger that is supposed to be able to deal with that.
I have the connections to the inverter connected to the same posts as the charger. Remain on when charging but the inverter is turned off. I assume this is not the problem as the inverter is not doing anything when off.
Is the voltage meter known to be accurate for certain?
Is it THIS (http://www.trojanbattery.com/Products/31-AGM12V.aspx) battery?
I would not vouch for the meter on the inverter. In use with my regular batteries...looked to be reading a bit low....0.4 V. This is based on the alarm going off and the shutdown which were different with when the even was to happen and the meter reading.
I am going to invest in a decent meter when in the States this week.
I ran it another 3 hours today and never go to float. Started ar 12,3 V after overnight rest and 4 hours one the charger yesterday. . Did the slow blink all the time.,..no fast. When I shut charger down and waited 2 hours I had about 12.6 5..about 65%.
The Iota instructions say to disconnect the positive battery/inverter connection before charging which i did and did not have enough time to see if that make a difference. That will be a pain but will do it if i have to to get charge.
Yes that is the exact battery.
OK. I get it ;)
I FINALLY went and picked up a Specific Gravity reader (Hygrometer? Hydrometer?) and checked my batteries.
After about 12 hours of use (arrived around 5:30PM or 6PM and checked at 7:30am) the SG showed the batteries at about 95% of charge after running the fridge all night and using lights for about 3 1/2 hours.
After 24hrs the 'Kill-a-watt' (or whatever it's called) meter I brought along showed 820 watt hours of power used AFTER the inverter.
This morning at 7:30am the batteries showed about 90% of charge (didn't get much charging done in the rain Saturday but did get some with the occasional sunny period and the MPPT controller making the best of cloudy weather).
So, perhaps I was being a bit peranoid after all. I do need to equalize the batteries (never done completely) so plan to do it next trip and take readings of the SG while doing so (Trojan has a section on doing just that).
All in all I didn't see anything way out of wack (usually I read within 0.001 between cells) until the fridge kicked on while checking this morning and readings went a little crazy -- I figure you're probably supposed to kill the inverter and charger and check then but I was in a hurry and wanted to see what two days had done.
I know my readings weren't perfect but it appears at least for now, that I'm not using those batteries as heavily as I thought I was.
Incidentally the 820watt hours used in 24hrs reflects very close to what I had down in my solar/pv spreadsheet for just lights and fridge -- I actually had the fridge running slightly more but suspect that since I keep it closed most of the time it probably uses less energy then advertised (they probably base it on more opening of the door throughout the day then I do).
Quote from: OlJarhead on June 24, 2012, 08:04:08 PM
I FINALLY went and picked up a Specific Gravity reader (Hygrometer? Hydrometer?) and checked my batteries.
:) :) [cool] [cool] c* c* 8) 8)
hy
drometer for batteries and things like wine making (different range for wine :D )
hy
grometer for relative humidity
alex
I'd get a good meter or calibrate yours against a good one.
If the charger won't go to float with that battery, put it on another good battery and see what happens there. (Jeep?) If it goes into float on the other battery then the AGM you bought would seem to have a problem.
Great idea on trying it on a known good battery
I have a ggod 1 yr. old in the jeep.
I definitely am going to invest in a meter...got a suggestion for an EZ to use one?
An auto-ranging meter is nice, no need to set the dial to the range to be measured; helps eliminate errors. Plug in probes rather than hard wired ones.
I have an Amprobe I leave at the cabin... not sure of the model nbr but I think it's a 520 or a 530 ??? I paid something like $50 a few years ago. I also have a better, older Fluke that I keep at home. The Amprobe matches the Fluke pretty much to within a couple hundredths. I think Amprobe is actually owned by Fluke.
See post 1035 for the background on this.
My reading and first call to Iota tech uncovers some strange stuff.
On stage one (bulk)...lasts for 15 minutes to 4 hours...that sounds OK,
On stage two (absorption) "Stage two: Absorption stage, will remain on for a total of 8 hours. After the 8 hours then it switches to the Float stage" So what I am reading is that this stage is on for 8 hours, no matter what the battery level is. I assume the charge rate is reduced to fit the required amps into 8 hours. In my case, this means at 50% charge when starting and stage 1 putting in about 20 amps, the charger in stage 2 is putting in the remaining 30 amps over 8 hours.....0r about 4 amps per hour.
This explains the charger staying on stage 2 even when little charge is needed and why the battery is only charged to 75% when I cut the time short.
Seems screwed up to me. i would think a "smart charger" would send in the max safe about during stage 2 and cut this time short. I believe even 15 amps in stage 2 is fine. This would mean that the battery would be charged in 3 hours not 8.
My thinking is that a single battery as I now have is the source of the problem and if I had 3 or 4 batteries and needed 200 AH, the 8 hour charge would not seem that bad??? Even then it sounds a bit weird.
Thoughts on my analysis and anything i can do. Running the genset for 8 hours to put in 50 amps is silly.
I think I have a similar issue in my trailer, the two batteries are only 160am/hour and even after 7 hours of the generator they are not full.
The charger / convertor says its 100amps.....but I'm certainly not getting those results.
I will be probably adding a decent charger from Xantrex and some solar power to do the topping up.
as I'll be going from a 160a/h to 440amp and the present charger certainly won't cope
The second reply I got from Iota kind of explains it. BTW, they reply right away and do a good job...although this answer is not what I want to hear.
It appears that for a small bank (in this case 1 battery) this is not the right charger. It likely would be for a larger bank and I will try it when I get two more batteries to bring me to 3 and330 AH total. That means at 50% charge when I crank up the generator I will need 165 amps and, simply put..... if I understand the Iota reply..... will make the charger put out more amps so the whole thing is more efficient. Right now, it does not sense a big load, so cuts back. He differentiated this Iota as a "power supply", not a "forced amp charger"...seems for me I need the latter but we shall see when i get my other batteries. I would rather sacrifice some battery life and charge faster than have to run the genset 2x as long to put in 100 amps or so.
any body got any thoughts on this...am I correct or did i misunderstand the Iota specs and what the tech guy says.
I thought this might be useful as it can be a real confuser! This bad chart on SOC and volts made me pull my hair out for a while. On the good side, caused me to do a lot of reading about batteries and charging..
Below is a note I sent to the Iota guy who I had questions to about the slow rate of charge...which turned out to be not zoo slow after all. Glad my notes were calm and nice!
I thought I would pass this on as it may help explain some of my "problem" and might be of help down the road to someone else.
I got a SOC by voltage off the net. Came from a good site with lots of detailed info. Says 75% is 12.60 and 50% is 12.30. So I am looking at my battery after 4 hours of charging and seeing 75% (12.6 v) and that is confusing and makes it look like the charger is very slow (slower than safe needs to be)..
I now see from every other SOC chart, including the one Trojan supplies for my batteries that 75% is 12.35 and 50% is 12.10...and the 12.6v that I thought was 75% is actually 90%. Everything working fine!
That info, which appears faulty is the cause of the concern about the rate of charge and my questions to you.
The other thing I found useful was that with my set up it will the me about as long to go from 90% to 100% charge as it takes me to go from 60% to 90%...so to save running the genet...I just stop at 90% and go to 100% every 10 times or so for battery health.
Have been looking into the nickle-iron batteries....They are being called a "lifetime" battery, supposed to last 25 years???? I'm in the process of getting my land excavated, tree roots dug out, going to build the one story cabin (600 SF) . I have already bought 2350 watts in panels, a Outback VFX 3624, and a Midnight 6 gang combiner box...i plan on having a solar/storage shed approx. 30' -50' from the cabin. What are some recommendations for battery bank size? I am honestly looking at the iron/nickle batteries....in the 400 Ah 24 volt (at20hr) set up...... But don't want more battery than what the panel can produce in around 4-6 hour range...i do have a 3.5K genset, and plan to find a 4-6K either propane, or diesel unit for a permanet unit...I'm at 10'000ft in S. Colorado.....supposedly real good solar expousure...Glad to see this posting area, i too believe that there needs a seperate "off grid" section.....Alot of us out here, and more everyday....and we are buying the "countryplans.com plans....rsbhunter
I think Edison developed nickle iron batteries for the early electric vehicles. That's about all I know about them though. How do their charging requirements match with lead-acid batteries?
As for the size of the battery bank that can be hard to say as there is a wide disparity in what people expect from their off grid systems. My personal experience has been that use will grow; the only question is by how much. We've been fortunate; my estimates of what battery capacity was needed has worked out well. I used the Off Grid sizing tool that is available... http://countryplans.com/smf/index.php?topic=8192.0
System failures are frequently caused by too small a battery bank, and/or too small a PV array. Be careful with the estimating of the power needs (or wants). It can be done if time is taken.
A generator can be handy but they need maintenance. I seem to run our generator mostly just to keep the engine in good shape, rust free, the fuel fresh, etc, than I actually need it for charging the batteries. We can even equalize the batteries using solar power if we plan it right.
An observation. The daytime temperatures have been reaching 88 at the cabin for a couple of weeks. It doesn't stay that high for too long; maybe 84 by noon, hits 88 between 2 and 3 PM and then falls to below 80 by 6 or 7 PM.
The battery electrolyte is now at a reasonably constant 65 F degrees. I wonder how high it will get by mid August? Nights are still cool; in the 50's.
Other than weight which in no problem for me. I like the one big battery approach. No parallel strings to worry about. All the connections for the battery are sealed so I don't have to worry about bad connections and have to be cleaning connections. When I test SOC with a hydrometer I only have one 24v battery to check not two or more strings of battery's. It takes up a smaller area than multiple battery's. And forklift battery's are designed for heavy discharge and charge in a industrial setting so in my lighter use as the heart of my solar system it should last a long time.
We also found we could put a heavy duty light dimmer switch on a 6v battery charger and charge one cell at a time since the connections between cells are accessible. Which allows us to equalize the battery by just charging the low cells. Not by trying to charge the whole battery which over charges some cells and causes sulfation in them.
We started our system with a old very used 1094lb 804 amp/hr 20hr rated battery and ran that for five years until one cell went totally bad. We are going to send it out and have a new cell put in and use it in a secondary location.
Last december we decided to get a new battery. We wanted to use up some tax credits while they are still available. And wanted a new larger battery for our main system. But I am glad we started with a used battery as it really taught us battery maintenance and care. Trying to take care of a battery that was in bad shape when we got it.
We ended up getting a 1482 lb 1182 amp/hr 20 hr rated 24v battery for $3188 delivered. And are very happy with it.
![](https://sphotos-a.xx.fbcdn.net/hphotos-ash4/429248_2468024874936_1379443770_n.jpg)
I think the prices are very comparable to the equivalent amp/hr of a multi battery system. And you don't have buying connections for between the battery's.
GB price list. GB is the only place we found the prices online.
http://gbindustrialbattery.com/Forklift_Battery_Sizes_and_Specifications_Zone15.html
A 12v 1182 amp/hr 20 hr rated 735 lb battery is $1745. But you can check the price list for other sizes.
Billy
Slow blow fuses for inverter?
Any such thing?
The ones I have now are expensive and they go quick...which is reassuring, but a bit of a lag (like 2 secs) might be useful.
Quote from: MountainDon on July 12, 2012, 09:06:39 PM
An observation. The daytime temperatures have been reaching 88 at the cabin for a couple of weeks. It doesn't stay that high for too long; maybe 84 by noon, hits 88 between 2 and 3 PM and then falls to below 80 by 6 or 7 PM.
The battery electrolyte is now at a reasonably constant 65 F degrees. I wonder how high it will get by mid August? Nights are still cool; in the 50's.
They last about 4 years in the low desert inside insulated sheds at 95F. We are lucky Don ! Thanks for the nice card!
Quote from: alextrent on July 17, 2012, 10:00:51 AM
Slow blow fuses for inverter?
Any such thing?
The ones I have now are expensive and they go quick...which is reassuring, but a bit of a lag (like 2 secs) might be useful.
There are two basic classes of fuses; Overcurrent Protection and Short Circuit Protection.
What type/class are you using? Overcurrent types will often have a built in surge capacity. Short Circuit Protection types should blow very quickly at their rated capacity.
EG: a 100 Class R amp time delay fuse may be able to handle two or three hundred amps for up to ten seconds before it blows. A class T has a very quick blow and usually a very high AIR rating. (Arc Interrupt rating). This can be important in a DC circuit as a battery can release a great deal of energy in a short time when short circuited. An AIR rating of 20,000 amps is common in class T.
If the overcurrent fuse will pass more current in a surge than the short circuit protection fuse then the short circuit fuse may blow before the overcurrent device.
Well...the adventure continues. I've always pined for more solar panels, thinking I'd like to run off them more than I run off the gens. (Duhh!) Current research seems to show that the 160/170watt 12v panels are a dying breed. Cannot seem to find even a close equivalent in the Sharp brand I currently own let alone any other brand I'm remotely familiar with.
However, in a bittersweet stroke of apparent luck, I've located some 170 watt panels...they appear to be 12v. I've always had to really stretch to understand the whole PV system, but I think these would work. I'm not wild about the brand "Jinshi" (fill in the source country blank and my personal leaning), but the fact that they even exist...and the price...so; if some more knowledgeable forum participant would like to look at these with me and respond with their wisdom/opinion, I'd be appreciative. I'd like to get 4, but with racks and shipping, likely less.
I believe I'm supposed to add PV panels that do not vary more than 10% in specifications.
The system is 12v
I have 2 Sharp 160w 12v panels up and running.
My charge controller is a Xantrex C40.
The breaker is a DC 60 amp
The inverter is a Prosine 2.0
The Jinshi panels have MC connectors, which I'm familiar with and like.
http://www.solarsystemsusa.net/solar-panels/panels/jinshi/nbj-170p/
Jinshi: Sharp
Maximum Power at STC (Pmax) 170Wp 160w
Maximum Power Voltage (Vmp) 23.6V 22.8v
Minimum Power Not listed 144w
Maximum Power Current (Imp) 7.20A 7.02A
Open-circuit Voltage (Voc) 28.5V 28.4v
Short-circuit Current (Isc) 7.70A 7.82
Module Efficiency (%) 12.9% 12.21%
Operating Temperature (℃) -40℃~+90℃ -40C - +90C
Maximum System Voltage (V) DC 1000V(TUV) / DC600V(UL) 600VDC
Maximum Rated Current Series (A) 12A Not listed
Series fuse rating Not listed 15A
Power Tolerance 0~+3% Not listed
Temperature Coefficients of Pmax (-0.45±0.05)%/℃
Temperature Coefficients of Voc (-0.35±0.02)%/℃
Temperature Coefficients of Isc (0.05±0.01) %/℃
NOTC (℃) (47±2)℃
Any brave souls who would like to chime in here?
The existing panels are connected in parallel I suppose and feed to a 12 volt battery system. So I imagine the thought is to add the new panel in parallel also. Those panels are a good match to the existing ones. Question: what will the Isc of all the panels wired together in parallel be? Will it exceed the rating of the controller. There should be a 25% safety factor between panel Isc and the controller rating. It seems to me with my rough off the top of my head math, that you can not add many panels to that controller; 2 might be pushing it. Many times when adding panels it is simplest to add a new controller and have the two run side by side. That's especially true when the panels are not well matched.
The controllers I am most familiar with also have a maximum PV wattage rating. For example at 24 volts (battery) ours can handle 1600 watts and at 12 volts only 800 watts. What's the C40?. This may be because ours is an MPPT; I don't know for certain if that is a factor with the C40. It may not be because it is simpler... max may jusy be the volts x amps compared to the unit ratings. Sorry I/m fuzzy on that/
What about batteries? Needing more? How old are the existing ones? Or is this just to increase PV capacity because you don't get enough charge in a day from the sunshine you have?
"What about batteries? Needing more? How old are the existing ones? Or is this just to increase PV capacity because you don't get enough charge in a day from the sunshine you have?"
Current system runs the house on a sunny day if I'm not working on the computer. Plus a few extra hours grace.
Talked to Xantrex a few minutes ago...OMG they are now using a foreign call center and calling themselves Schneider Electric.
Not encouraging.
Anyhow, after a bunch of verbal wrangling, I sort of got the impression that 2 more panels would be OK, but the panels I have and the ones I want (according to the call center) are all supposedly designed for a 24v system, even though the ones I own were listed for 12v systems when I bought them and I'm apparently just throttling the charging down somehow by using a 12v charge controller and system.
Yes, I would l like to go longer between generator uses. >:( Batteries are also part of the plan...I just figured one learning curve at a time....but if you think more batteries are a faster and easier answer, I'm listening.
QuoteSchneider Electric.
is a large corporation with fingers in all sorts of electrical supplies. Big as in HUGE. Global.
The panels you have are NOT for a 24 volt system. ... A 12 volt system needs panels with a minimum Vmp of around 18 volts to charge batteries. That covers some for clouds and hot weather which decrease voltage output. To charge a 12 volt battery one needs to be able to apply 14 to 15 volts. If the panels were only putting out 12 volts the batteries would not charge.
Ditto on those panels (Vmp = 23.6) on a 24 volt system. They would never charge the batteries in a 24 volt system.
MPPT comes into its own though by taking the excess volts and transforming the voltage down while increasing the amps. Your panels may waste some power but you are reasonably well covered for cloudy day performance.
If the big problem is not having sufficient PV output to recharge the last 24 hours of battery use virtually every day, then more PV panels are needed. The system should recharge fully everyday and go into float charge everyday. If it is not the batteries will be unhappy and you will be unhappy with their shortened life. A day here and there that does not result in a full charge and float cycle is not terrible. It happens to us and I can usually point a finger to the cause; clouds, I ran the air compressor or table saw quite a bit, etc. But if the failure to reach full charge and float is commonplace something should be done about that.
If your batteries are more than a year old it may not be a good idea to add batteries. Batteries all lose performance as they age. The degree of decrease varies with how they have been treated and used, average temperatures of the batteries, etc. When adding new batteries to old ones, the old ones drag down the performance of the new ones. It's a little like buying old batteries but paying for new ones.
How deep is the typical average daily discharge, as measured with a hydrometer?
"The panels you have are NOT for a 24 volt system. .. Ditto on those panels (Vmp = 23.6) on a 24 volt system. They would never charge the batteries in a 24 volt system."
Whew. I didn't think she was right, but it rattled me.
"But if the failure to reach full charge and float is commonplace something should be done about that."
They hit full charge every day...by running the gen...but it isn't cheap.
"How deep is the typical average daily discharge, as measured with a hydrometer?"
I cannot answer this as I use the readout on the Prosine 2.0 to gauge when to power up the gen again. I start with a 14.7volt battery bank readout on the Prosine, and start the gen when the battery bank readout gets to 12.3v. The inverter is set to charge the batteries any time they need to be, as well as supplying the AC into the house. There have only been a few times in the last several years that I've had the power wink out because the battery bank got too low and the gen was not on. Not enough times to cause any of the trouble you've described. The Prosine 2.0 inverter shuts down battery power at 11.9v so I think I'm staying above the "trouble" range.
I'd like to develop this system to the point that I can go 3 days or so on PV and batteries before needing the gen. I know 5 days would be better, but 3 would be a vast improvement. I know I can create 2 PV arrays...by adding another charge controller, that would eliminate any "concerns" about hooking up PVs that are not exactly the same to one controller.
I wonder if I can create a second battery bank...I'll have to explore that. This would eliminate the issue of combining older batteries with new ones. Just thinking out loud.
Quote from: considerations on September 06, 2012, 02:23:37 PM
They hit full charge every day...by running the gen...
The first thing you need is more PV capacity so the existing batteries can be recharged by solar power. For reference here's the temperature corrected state of charge chart for a 12 volt battery system. That's temperature of the battery electrolyte, not ambient air temperature.
![](https://i139.photobucket.com/albums/q305/djmbucket/solar/temp-comp-01.jpg)
Depending on temperature 11.9 could be classed as dead, as a problem. Also readings taken while in use (charge or discharge) are inaccurate. batteries should be at rest for a few hours before believing what the voltage indicates, in most cases.
Seems to me that running a second independent battery bank makes for a more difficult to manage system. But then I do not like systems that require a lot of user intervention as a normal everyday thing. So that may just be me. ... like how does one decide what to run off what? If they are interconnected at all they act as one for the most part.
"Seems to me that running a second independent battery bank makes for a more difficult to manage system."
I agree. Just seems that if one gets additional batteries, and the first bank is already several years old, and the old ones drag the new ones down, that a separate bank would be better than the combination.
"But then I do not like systems that require a lot of user intervention as a normal everyday thing."
I also have plenty to do besides fussing with Flint Light and Power. I also didn't move out here to listen to gennies humming...plus its not the cheapest option. Sunlight is free (for the time being).
In any event, after your reassurance about the PV voltage being proper for 12v, not 24, I'm going to start with at least 2 more....then study the battery situation after I get the panels up and running.
Thanks for the conversation. And I'll study the table you sent....I should learn that part of the equation before making choices about new batteries.
So all off grid experts (or more expert than I), I am wanting to start up building an off-grid system. My goal is to build slowly as money permits but be able to make monthly investments in it. I would like a working system as soon as possible. This doesn't mean large. Ultimately, I would like to run my entire place. This will take several years to build up. I would like to start moving things over to it soon though. Just so I can enjoy it :). I was thinking about buying 4 235watt Kyocera or 315 watt Kyocera panels to start. I have pretty much figured out that an MPPT charger is key. I want to be able to charge a battery bank and supplement with a generator when the sun isn't shining. I have done research over the years on this and read a lot. But, I think all of your input is better and many of you are excellent users of these systems. My ultimate system will need to be 220V. I need to run my well pump which is 3hp, 220v. Anyway, what are you thoughts on how to grow it properly?
I had two first immediate thoughts while reading your post. Number one was that you should, IMO, plan to never need to use a smelly, potentially troublesome, noisy generator. The main reason we have a generator up at our place is that I owned it long before buying the property. I run it more just to keep it in good shape and the fuel fresh than I ever need to run it for electricity. The second thought was that it is my belief that a system should ideally be sized for the use you envision and then built and put into service in one fell swoop as a "fait accompii".
for one thing, PV modules are constantly evolving, growing. That can make it difficult to get a good match when adding panels if the plan is to feed all their output to the same charge controller. An alternative would be to plan on adding a second controller when adding more PV modules. That has the benefit of redundancy.
There can be even greater problems when at some later date, say a year or more from the original installation, the desire to add more battery capacity comes up. Adding new batteries to old batteries can, more or less, simply put make the new batteries act like older batteries.
You will also have logistical problems with running a combination of grid tied and off grid. Nothing that can't be resolved, but I wonder if that is the best way?
Obviously you are presently connected to the power grid. Personally I would set money aside and save up as rapidly as I could to have sufficient funds to build the PV system once and in its more or less finalized stage. But that's just the way I would do it; in fact that was how we built our cabin including the PV system. OK, we did take out a home equity LOC when we acquired some adjacent land, but that was paid back quickly. Our PV system has no more components than we started with. Our use has grown as I was sure it would, but I managed to build in sufficient capacity to make the increase in use painless.
The current federal tax credit of 30% can help a lot with the final actual costs. It's 30%, runs through 12/31/2016 and has no maximum dollar amount. You probably knew that.
Anyhow, those are my primary thoughts on the matter. I think you will find the opinions shared by many who have been through growing a system over time. I also know that it's not always possible to do things in the ideal manner. Good luck. It is nice having a utility bill.
MountainDon, you bring up good points. Some I think I had worked through, others, not really.
Generator- ideally, you are correct. My concern here is during times of long rainy days, I may not end up with enough power to run the well pump. The generator would be to charge it up enough to do that.
Charge controller - I follow you and thought about it like this to "grow". Buy the PV modules 4 at a time and adjust the strings to compensate. For instance, 315W panels - run 2 strings of 2. When I go for the next 4, if they original aren't available, I can, I think, create 4 strings with 1 new and 1 old in each running in series. I believe that it how you would connect mismatched panels. That was a way I came up with to "grow" it. But, I could be wrong.
Batteries - I didn't think about mismatching old and new batteries. The could very well be a problem although, I suppose it could be solved by mixing them in strings like the pv panels. Wouldn't that equalize the voltages across an average rather than trying to keep a new set = to an old set. thoughts?
I would really like to grow it rather than a mass purchase..... only because I know me. If I let that money sit there too long.... I'll have another building :D
Perhaps Dave Sparks will drop by. I would trust his opinions on the panel and battery mixing. He has designed or built over 50 PV systems and does so in a manner to keep the clients happy with a minimum amount of involvement. I haven't seen him here for almost a month so maybe he will, maybe he won't. ???
I'd recommend dropping by the Outback Power Equipment forum and posing the question there. They have many experienced system builders and system users among their members and admins.
I don't have the technical abilities I'd like to have but there is something about intermixing panels and batteries that does not seem like a good thing. With widely varying age batteries in particular, I believe performance will be degraded. It may not be a great analogy but it seems to be akin to building an engine with cylinders that vary in size. ??? :-\ :-\
Out of curiosity is it to be a 24 volt system? What type of refrigeration? Do you need A/C?
I'll drop back by the Outback forum. Last time I was there it didn't seem like it was very active. I had read through a few posts and ended up going back years. I really want to go with a 48V system in the end. I prefer to spend less on copper wire if possible. The Fridge is going to be an issue as we use a lot. A/C, we really enjoy. We may end up designing the system to run almost everything except the big hogs. I had designed out a system without any change in our electricity usage. It was going to be about $98,000. :) I am not interested in spending that much... But you never know.
Originally, when I built this place, it was built ultra energy efficient. With all of the add-ons... much less so. We currently have a 3 ton main AC, and 3 medium window units. Then there is the large fridge, small fridge, deep freeze, and ice maker.. :) I love my electricity. This is why the "growth" is important... Who'd tackle a $98K system in 1 shot....
A couple thoughts, phalynx.
Three horsepower water pump is big... I'm running a 1 1/2 hp and it pulls about 12 amps from both inverters (220v) when running. I am running two 4024 Trace inverters. Add a microwave and a couple freezers running ...maybe a fridge or two and it is close to capacity.
Grow it as you need it... that is what I did. Maybe Don can post a picture so you can follow my example. :)
Here is a site that I used as well. Some pretty knowledgeable people .
http://www.otherpower.com/
Glenn,
My well guy said that I could pump with 6000 watts. Yes, that is not small but I am shooting for the new 8000watt Outback 240V inverter for the ultimate use. Another thought I had was to get a 3000 gallon tank and pump into it in 1 shot and then use a small pressure pump to provide water for the household. This would give me extra breathing room if there is an extended period of bad weather/etc.
I like the idea of a large storage tank. How much rain could you collect and store in similar tanks. Your weather blesses you with the ability to use above ground tanks all year round.?
Technically speaking, we could live off rain water. But I so love the generous amounts of great tasting well water we have. There are several people around me that live off rain water, with livestock.
MPPT chargers can change voltages for battery bank or panel expansions. Inverters cannot. Usually you can go with a stackable inverter and add a second one later, or just get the initial bank voltage you want.
Generally there are cautions about mixing new and old batteries. The old batteries will drain faster and drain the new ones faster. It shouldn't be a problem. If you battery bank is far undersized, you will use them up quickly and they will have to be replaced anyway.
Are you already on grid, and you are looking to disconnect? With that much electric usage, it sounds like it is going to be a challenge.
I am on grid. I am an electronic geek so I consume a lot... I can curb some, some I cannot. I have planned on living off the grid for about 12 years but never implemented. I am at the point now where I want to implement. I have pretty much mastered AC electrical so I figure I can rewire circuits and such to run off the grid while others, stay on the grid.
I am sure my first setup will be enough to run a few of my computers and I'll just sit there and smile at them. Then expand and add more and more.
I am building a large greenhouse as well and want to start putting that stuff on it. I have no intentions of any big lighting or anything in there, just want to play with aquaponics and such.
I figure I'll have enough small electrical items that I can power on solar in the meantime.
The MPPT charge was what I had in mind. That way, I could mix the pv panels as long as they all equaled.
Do you really need the capacity to pump all in one shot, or would pumping for say 1-3 hours daily suffice. I found with my own well application, that the difference in storage and PV capacity between my initial "one-shot" approach, and the pump a little every day approach was huge. Also, panel capacity is relativly cheap compared to batteries it seems. And like someone said earlier, you can't just add batteries willy nilly.
Another factor which seems often to be forgotten about is the cost of thick gauge cable runs between various system components. Hundreds of feet of #6 UF rated copper wire is more costly that you might assume. And those runs suck/lose energy AC or DC.
Anyway, those are two factors that tripped me up.
Hey ! back in the saddle ! Hard to give advice without data. It needs to be accurate! I have no idea how the "new" outback Radian performs in deep well situations. I only use the XW (deep wells) from Xantrex which is even better than the old SW's that Glen uses. They can surge 12,000 watts for five or ten seconds BTW. This surge ability makes the well pump and the inverter last longer because when the voltage sags the current goes up and damages equipment over time.
My experience is to ask the offgrid well driller guy's and they will tell you an XW. Many just use a generator to get data.
Outback makes great gear also and they are second to none in support. I had some issues with their equipment in deep well applications only and find the new radian a step in the right direction for surging. Only time will tell and I let others do the beta testing for deep well applications. I know what works!
So, in your opinion what is the best inverter for 4,000 watts max and general not more than 2,000. Batteries only and genset to charge. Any real disadvantages to a combination inverter/charger. 12V system. 4 100 AH batteries
There is no best ! Quality is conformance to requirements. So, it depends on quite a few requirements that I may have missed that you have posted. People who do this kind of work all have favorites from experience.
I mainly do offgrid residences and so I would never consider a 12 V inverter/charger for a client. Smaller systems and cabins may be fine for 12V systems. Good Luck!
Quote from: gringo on October 01, 2012, 12:28:16 PM
....best inverter for 4,000 watts max........ .....Batteries only and genset to charge. Any real disadvantages to a combination inverter/charger. 12V system. 4 100 AH batteries
Four 100 amp hour batteries and a 4000 watt max inverter output seem to be a mismatch, to me.
I personally really dislike running a generator so genset only seems wrong, to me. If four 100 amp-hour batteries would truly be sufficient for the use planned, then it would seem that you would not need much in the way of a PV array.A big advantage to me, with PV panels is that the system will run itself and keep the batteries charged when the place is vacant. Ours does that all year round through summer heat and winters freezing months. Not tp mention no nosiy smelly beast running.
Inverter/charger units simplify things. I can't think of any operational disadvantages, but can think of some pluses.
Well, I did overstate the wattage a bit on the max side..as but as I said generally no more than 2,000 watts is required. I figured I would oversize the inverter for the future in case I decide to go grid-like as it seems is the case for many on here. Others of us do not need all that power and do not miss it. The 2,000 watts is not continuous. I run my fridge 3 hours a day (300 watts), lights at night for 3 hours (total of 200 watts), which is the standard drill so I have plenty of power from by batteries. I run a fan once in a while when I am sweaty and the breeze is dead (400 watts) and once in a while heat water for a shower...(1,000 watts for six minutes).
So if I want to do it all and not juggle stuff on and off (which actually is easy enough to do), the 2,000 watts is my number, maybe a bit more. That is why I list that...in reality I could get by on a 1,000 easy.
I run my generator a couple of times a week to pump water to a neighbor and don't want to size up the system just to run the pump 3 hours a week. As it does that, it charges the batteries and runs my fridge. All getting the most from every gallon of gas. It is 100 feet from the house in a stone building and the exhaust goes out the back. Very little noise (the howler monkeys drown it out) and since it is maintained correctly no "dirty exhaust"
So, in spite of what you think it is far from a mismatch. It is a great little system, Suits me fine, although it may not fit your idea of one. I simple asked a simple question about thoughts on inverters...you know brand "A" over brand "B" over brand "C"...something which I though people on here with all their experience would be able to answer, but instead I got a lecture about something else.
FYI...mine is an off grid residence. Likely more than the ones you wire up for some of your clients.just not not a heavily wired one. Big is not better all over. Does not mean it is not a good fit or set up.
Quote from: gringo on October 01, 2012, 06:37:34 PM
So, in spite of what you think it is far from a mismatch. ........... ....I simple asked a simple question about thoughts on inverters...you know brand "A" over brand "B" over brand "C"...something which I though people on here with all their experience would be able to answer, but instead I got a lecture about something else.
Without knowing the details about how things are used, and all the rest of it, the mention of 4000 watts of inverter output coupled with 4 x 100 amp-hours of batteries remains a mismatch in my mind. Also, without knowing the level of expertise of the member posing the question, I do not believe it improper to question the match. Perhaps I could have gone into more detail but I thought a short answer was better than no answer. If short answers raise questions, the questions can be dealt with later. IMO.
If the response I gave sounds like a lecture it must be because of the way the recipient received it. It was not delivered as a lecture; it was and is a simple statement of a belief. Until I read the response from you and thought more about who this is, Alex I did not realize it was you, so don't feel picked upon. If the same / similar question comes up again I will respond the same.
Outback. Xantrex. Magnum Energy. Take your pick. Some will pick one over the other for a feature that appeals to them. Or as Dave stated because they are familiar with one brand more than another.
Then there's the question of square wave vs sine wave; what does one want or need? That choice can eliminate some brand names.
Point taken.
Maybe i should have just asked for brands and left out the details, which confused rather than helped.
But now I do have me brands...so all is not lost.
I have been running a Aims 5000 watt 24v power inverter for the last four years. It has been good to us and runs everything we have. Tv, fridge, lights ect. But I strongly suggest fuses on the input and output. The first one we got my brother shorted out the panel and fried it. But we sent it back and they replaced it.
I too suggest that you put a few solar panels on the battery's. I have two 110watt panels and it really helps out. I am running a 1182 amp hr forklift battery. And with the panels I run 7-8 days and only have to fire up my generator for 2-4 hrs.
This is the one I have but mine is 24v. I prefer 24v as I can run smaller cables.
http://www.theinverterstore.com/5000-watt-power-inverter.html
Here's my system the power inverter is on the wall and charge controller on the 4x4 post.
![](https://sphotos-a.xx.fbcdn.net/hphotos-ash4/429248_2468024874936_1379443770_n.jpg)
![](https://sphotos-a.xx.fbcdn.net/hphotos-ash4/419938_2473619334794_1776674071_n.jpg)
I am going to put up more panels as its really nice not to have to fire up the generator.
Billy
Yeah, I think it's time to try some panels. I have shade and lots of clouds, but hopefully can get 4 hours a day of full sun. The best place is 120 feet away so I could do 24 volt and run to the house. But as I observe the sun , looks like I get 2-3 hours on the roof right above the batteries, so I leave it at 12 volts and keep it simple and cheap and will work on 10 gauge cable for the 15 feet to the charge controller. I still will have to run the genset, but maybe once a week or less. Investing in three vs. two panels will boost me on the roof location.
My biggest problem now is it takes 3 hours on the genset to get to 85 % capacity from 50% n 400AH batteries and then 4 more to get the other 15% . IOTA says this is the way it is.
Generator powered battery chargers are most efficient at bringing the battery charge up to something like 80 - 85% of capacity. After that they use a lot of fuel to do much less at rebuilding the battery charge. PV modules with an MPPT charge controller perform excellently at charge finishing even later into the day, especially when the PV modules are connected serially.*
With that in mind it is my opinion that when one knows they are going to have to run the generator to recharge the batteries fully, the generator should be run early in the day to build the initial charge through the bulk stage. Then let the solar PV system finish off the charge.
* When the light is failing and the PV module voltage is falling (parallel connected multiple modules) to levels too low to be able to place an effective charge into the batteries, series connected modules will still have a high voltage. The MPPT controller can take that voltage and the available current and manipulate it to produce a voltage just high enough to make a charge go into the battery while it multiplies the current. Selection of the controller must be matched to the maximum possible peak voltage that the serially connected modules could produce.
That is what i need. I interpret this to mean I should runs a 24 volt system to the MPPT charge controller and let that charge the 12 V batteries...i am assuming it adjusts to 12 V from the input which is higher automatically. IF that is the case, then a lot of other times in the day with lower light I will still be charging...even more less genset use.
Quoteeven more less genset use.
Running an MPPT controller you don't need to think in terms of what volts the modules are running, as long as the Voc of the modules, series connected, is not higher than the maximum input voltage of the charge controller. The rated Voc of the modules is added, then multiplied by 1.25 and then 1.25 again (NEC formula which may be conservative). Although in the tropics that may be over cautious as you are not likely to get lows in the minus 20 or lower range. Anyhow the point is the rated Voc can easily be surpassed on cold/cool days, especially first thing in the coold/cold day as the sun hits the modules. EG: The mathematical Voc of my three modules is 3 x 36.3 = 108.9 volts. In summer I frequently see logged maximum voltages around 120 volts. In winter (below freezing as in -25 or so F) the highest I have seen is 141 volts.
The MPPT controller does a high frequency transformation of the power as it reads the incoming voltage and current and the condition of the batteries. It then adjusts the output to the best voltage and current to charge the batteries. It is sort of like getting something for free, more or less. The MPPT charge controller does do this automatically and continuously. As clouds drift past it changes to output to the optimal.
When the modules are sized correctly for the battery pack and the use and available sunshine a generator is hardly needed.
Outback power has a string sizing tool on their website. Of course it is designed for their equipment, but it may be useful to mess about with as it does have max and min temperature adjustment sliders so you can see how temperature relates. It allows selection of modules and shows the maximum number in series and parallel. Xantrex has one as well.
Changing the topic a bit. What is a best practice for over-wintering a small solar system that will not be used November - March? Should the PV be disconnected at the breaker from the charge controller/ battery, or is it ok to leave the system charging? I'm also thinking of removing the battery for the winter. Temps can get down to -20.
Here's what we do. Our cabin sits mostly un-used through the winter. Our goal is to snowshoe every other weekend from the time the snow is too deep to be able to drive up. That's usually mid December through to late March or into April. We don't always make it that often but we do make it several times at least. Because of that I wanted to leave the batteries there; I'm not about to snowshoe even one golf cart battery up and back. And I don't like oil lamps for light.
So starting with when we would leave the RV parked there all winter we've left the system active. The RV was only with a small panel good only for floating. Once the cabin PV system was up and running we did the same thing. The hardware is better and there are more batteries. In fall I make certain the batteries are fully charged and the fluid level in each cell is topped up. All DC and AC loads are disconnected (I pull the breakers whenever we leave for home.) The charge controller is left to do its thing. They have never let us down. Each and every time we return to the RV or the cabin the batteries were fully charged and waiting for use. A fully charged battery will not freeze until something like -90 F.
I also leave some partially full jugs of distilled water up there, but have never needed to add any water over the winter. With the system basically not doing much there is very little loss of water. I do top up the levels each spring and fall.
That's my system and it works for me. No guarantees expressed or implied that it will work for anyone else. But if the PV system is built with quality equipment that is installed properly... lightning protection , etc., there is a very good chance that the system will survive the winter. After all, for me at least, I have not had any summer failures either.
If the system has only a battery or two and will not be accessed at all throughout the winter then removing the batteries would be a viable option. However, then you need to keep them floating at home. I would not leave the batteries sitting in the cold without the PV system active. Even the $12 charge controller we used for the RV float worked without any interruptions.
Good information and I'm glad I asked. What I get from this is there is really no need to removed the battey for winter, just disconnect the load (easily done) and let the charge controller continue to charge and top off the battery.
I had noticed that if I go away for two weeks and have disconnected PV from the charge controller and battery, the battery charge will drop from about 14 volts to 12.6. This is a newish AGM battery, so no water needs to be added.
QuoteA fully charged battery will not freeze until something like -90 F.
I did not know that. My sense is this small system is built well enough. Grounded, lightning protected (using the Delta protector, which I want to change out with the Midnight Solar at some point). There is one problem that the buried battery box still gets too hot in the summer, and I need to build a little shed over it to keep temps down. Those high temps are going to shorten the battery life.
Quote from: hpinson on October 07, 2012, 09:41:01 AM
I did not know that. My sense is this small system is built well enough. Grounded, lightning protected (using the Delta protector, which I want to change out with the Midnight Solar at some point). There is one problem that the buried battery box still gets too hot in the summer, and I need to build a little shed over it to keep temps down. Those high temps are going to shorten the battery life.
Keep the Delta and add a midnite SP. They both have their value when it gets nasty !
"Depending on temperature 11.9 could be classed as dead, as a problem. Also readings taken while in use (charge or discharge) are inaccurate. batteries should be at rest for a few hours before believing what the voltage indicates, in most cases."
Ok Mountain Don...I've been thinking about the above statement, and now I have a question.
A reading during discharge or charge should be considered inaccurate because the batteries are in use....Would it be reasonable to assume that during discharge a battery's reading would be lower than a reading after a few hours "at rest"?
Quote from: considerations on October 24, 2012, 10:22:29 AM
Would it be reasonable to assume that during discharge a battery's reading would be lower than a reading after a few hours "at rest"?
Yes. The heavier the discharge, the greater the potential recovery. Similarly immediately after charging the battery boltage will read higher than it will after a few hours left "at rest" with no loads or further charging. That is why voltage readings can be a poor guide to the real health of a battery. And that is why anyone with flooded lead acid batteries (gold cart, L16, etc.) should own a battery hydrometer. (sorry... I "harp" on that a lot I know.)
"And that is why anyone with flooded lead acid batteries (gold cart, L16, etc.) should own a battery hydrometer. " I do...
"(sorry... I "harp" on that a lot I know.)" You do...but it is very good advice ;D.
Figured out that in the winter, with no woodstove, just the furnace, plenty of lights, computer, negligible solar panel action and after 2 loads of laundry, I used 5.34 Kwh in a 24 hour period. (At least that's what the Kill a Watt displayed) i want to go 3 days without a gen or help from the PV (as in winter). So after playing with that PV system calculator I came up with 10 L16's or equivalent. Think I'll have to save some more for that. So, since I have plenty of wood and would much rather sew than work on the computer, 10 L16's might last a little longer than 3 days. (don't worry...I set the calculator for a max 50% discharge...something new I've learned...from others, yet again :-\)
One other thought...
Not sure if you are looking into it but you might want to get the MPPT style charge controller. I apologize in advance if you are already considering that, I did not read all 44 pages of posts.
In any case, Outback makes an MPPT style charge controller. Basically, they power match your panels to the batteries for maximum output v.s. losing a lot of power due to mismatching or older style charge controllers.
I think the Power Factor is somewhere around a 93-95% efficiency and it matches various voltage output panels to each other as well. I had a system in San Felipe B.C. with a Zantrex controller which is really robust but with additional panels we were not seeing the wattage output as expected. It is not a big issue there due to no additional power needs but I am pretty sure we are losing a large amount of the potential solar output without that style of controller.
Here is a link I found that explains that type of charge controller.
http://www.windsun.com/ChargeControls/MPPT.htm
Cheers,
Roger
What are the code requirements for cable protection from the combiner box to the panels? I'm building a pole mount system and I was planning on having the combiner and dc disconnect mounted at chest level on the pole. Do I need to protect the USE-2 cable to the panels with conduit between the combiner and the panels? Or should I mount the combiner at the top of the pole where I assume it's okay to have unprotected DC cabling (but where it's harder to access the breakers)?
I am quite certain that the MC cables used to connect cables from the PV panel to the combiner box is sunlight and weather resistant. As long as the cables are fixed in place with zip ties or something similar that should satisfy the NEC and any inspector. Probably a good idea to have provision to lock up the combiner to keep curious fingers away from hot spots. I also used a self velcanizing rubber tape around each MC connection to discourage the curious from unplugging.
What Don describes is exactly what I did-- array out to combiner via zip tied MC4 cables which are rated for outdoor use. The newer combiners have some nice integrated weathertight MC4 socket connectors so tape is not needed. Plugging them in is easy but unplugging is difficult and can require a special tool. My Midnite Solar combiner is not mounted on the array pole, but on a separate post. Also, a lightning arrestor and a buried ground copper rod both off the combiner are in the mix. The combiner box with breakers is closed with a screw discouraging casual access. Not planning on inspection though, so I don't really know if this conforms to code or not. It seems safe enough though.
http://www.midnitesolar.com/productPhoto.php?product_ID=278&productCatName=PV Combiners&productCat_ID=9&sortOrder=1 (http://www.midnitesolar.com/productPhoto.php?product_ID=278&productCatName=PV%20Combiners&productCat_ID=9&sortOrder=1)
http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=23&productCatName=Surge Protection Devices (http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=23&productCatName=Surge%20Protection%20Devices)
Hey All,
what kind of meters are you using? Are they worth it?
I have a MorningStar MPPT 60A Controller and often have considered putting in a remote meter so I can see it inside the cabin (the controller is on the porch and out of site). My neighbor has a meter that gives him a %of charge remaining on the batteries which he finds useful and I wonder if I might also?
So, what are you doing? Pros Cons?
Thanks!
By remote meter do you mean,
(a) the optional Morningstar meter, or
(b) a meter like the Bogart Engineering TriMetric?
Quote from: MountainDon on March 28, 2013, 04:30:28 PM
By remote meter do you mean,
(a) the optional Morningstar meter, or
(b) a meter like the Bogart Engineering TriMetric?
Either/or -- the Bogart Engineering TriMetric looks like what I'm thinking I'd like to have though! More so then the MS model!
Well, to my mind the Morningstar doesn't offer much other than convenience for simple readings. We have an Outback Mate mainly as it is required to program the Outback Inverter. It also supplies interesting info; voltages, amps in, kWh in (CC to batteries), system high/low voltage, and so on . That info is in a 128 day log so is useful to review. Aside from programming the main thing I use it for is to check that the system goes into float mode every day. If it does not float daily, there must be a good reason like greater use or cloudy weather. That's basically all I worry about day to day. I've proven that our typical pattern of use is covered amply by the capacity of the batteries and the PV modules.
The Bogart meters are interesting and I have been tempted several times to buy one. I had originally thought I would get one but delayed the purchase, although I did include the low voltage wiring into the build just in case I wanted one. But I don't need to know the state of charge on a daily basis. If it's cloudy for several days I may use the hydrometer. Or I may just run the generator because it hasn't been run in a while.
I suppose if one is running their batteries "way down" on a regular basis one of the Bogarts could be a useful "how much is left" tool. But if that is the case perhaps the money would be better spent to go towards improving capacity?
YMMV. my 2 cents....
Hmm...good points all.
So far it appears I'm not pushing my system at all so I suppose I don't NEED one....but I'm an information glutton!
However, at $225 from the source i normally buy from I'm not so sure I need the info THAT much! ;)
Speaking of system usage etc, I got a good test this past weekend: The panels somehow tripped the breaker (only second time this has occurred) and I hadn't noticed for a day or more! Then I noticed, when showing off the system, that it wasn't charging in the full sun and was showing the charge between 80 and 90%. I checked everything over and saw the panels were kicked off so reset the breaker and everything went back to normal. I then checked the system and saw more then 24 hours without charge! lol
So there I was, using the system and not charging for at least 24 hours and still running about 85 to 90% of charge!
Gotta love that!
Trimetric Meter
http://www.bogartengineering.com/
No pros and cons....not hooked up yet...pulled the wires but did not identify which end in the power shed is the same end in the house...not sure how to be sure I hook it up the right way. The instructions warn of catastrophe if it gets hooked up backwards. growl
What's the length of wire run? Have you enough of any kind of wire, pipe, etc. to run a temporary line (through a window or whatever) to use with an ohm-meter, trying the other leads one by one?
Quote from: considerations on March 28, 2013, 08:29:20 PM
pulled the wires but did not identify which end in the power shed is the same end in the house...not sure how to be sure I hook it up the right way. The instructions warn of catastrophe if it gets hooked up backwards. growl
Use a voltmeter, if it reads (-) voltage switch the wires
Whoops, didn't mean to pull the conversation off track with my stupidity. It just put me "off" when I realized what I had [not] done. I have since acquired a volt meter...and will read those instructions as well. d*
http://www.aimscorp.net/1000_Watt_Pure_Sine_Power_Inverter_12_Volt.html
I've been thinking about buying a pure sine inverter to install on half of the cabin circuits (kitchen and bath) so we can charge things like lithium ion drills and so my wife can use her hair tools (snicker) which seem to not always work with mod sine (at least one hair iron won't work). I've been thinking that since my AIMS 2500 Modified Sine inverter has performed so well that I could get a 1k Pure sine from them (come on look at that price!!!) and split the AC panel.
Thoughts?
I'm guessing all I'd have to do would be install a second set of cables from the battery bank to the new inverter and then run a cable run from it to the panel and make sure the common bus is split left and right and then land it on the left side and the mod on the right side.
Problem: in the service panel the neutral should be bonded to the ground. Once and only once in the system. If you have two separated neutrals which are you going to bond to the ground? The bond is there for safety. I think if you made a bond from each of the separated neutral there is danger of frying something in either or both of the inverters. The electrical power of each will be out of phase and that is trouble. At least I think that will be an issue, not a licensed tech or electrical engineer.
Two panels with completely separated wiring would be safer I think. But best would be a larger sine wave inverter doing the whole thing.
Quote from: MountainDon on June 14, 2013, 10:49:18 AM
Problem: in the service panel the neutral should be bonded to the ground. Once and only once in the system. If you have two separated neutrals which are you going to bond to the ground? The bond is there for safety. I think if you made a bond from each of the separated neutral there is danger of frying something in either or both of the inverters. The electrical power of each will be out of phase and that is trouble. At least I think that will be an issue, not a licensed tech or electrical engineer.
Two panels with completely separated wiring would be safer I think. But best would be a larger sine wave inverter doing the whole thing.
I was wondering about that myself -- perhaps the 2k inverter would be better and just keep the 2.5k mod inverter as back up.
OK I'm looking at two possible inverters from AIMS. Both less expensive then any others I've found and my 2500 watt AIMS has been good to me so far.
One is a 3000 watt pure sine with no charger and 4500 watt surge, the other is a 4000 watt pure sine with 12000 watt surge and a charger.
The one with the charge will start a generator but at 10.5v on the bank and to me that's INSANE! I'd rather be able to decide when the charger circuit is kicked and that to me ought to be at 50% or 80% discharge, not 100!
So, thoughts?
Perhaps I ought to get a generator auto-start switch (Zantrex makes one but it kicks at 11.5vdc which to me is too low still) and the 3000watt inverter as that would save me the funds a 2000 or 3000 watt Honda with push button start would cost (which can be used in this fashion).
I don't have a gen that will "auto start",,,,but, I have a Magnum inverter 2012. The "Low Battery Cut Out", which is when the house winks off :-\, can be set. The default is too low like you describe, but I can set it at a reasonable level...like Mountain Don recommends, at more than 12v. Maybe Magnum has a model that would tell a gen to fire up at some (also adjustable) level. I think Redoverfarm has a gen that comes on automatically, maybe he will share if that setting is adjustable in his system.
Saw they had one actually, after my post and I was impressed that they even gave wiring diagrams for various generators. Problem is most of the less expensive ones don'thave auto chokes :(
I think I'm to need one of these puppies this winter.
Eric I do have a Magnum 4448 watt inverter/charger. In addition I have a auto/start with a BMK (Battery Monitor Kit) . I can preset my start feature with either SOC (State of charge) , Voltage or both. It has worked very well. Only downside if you can call it that is that there is a slight constant drain on the battery bank with the inverter needing power for monitoring, supply to the start battery charger on the generator and the generator controller. But even with that the generator comes on every 3-4 days for about 2 hours. The generator is a EcoGen (propane) by Generac 6000 watt. I have had excellent support by Magnum and installation was fairly easy. It was a little pricey but I feel that it was money well spent. The main reason I went with Magnum was it only required one unit to supply 240 volts which I needed for my deep well pump.
![](https://i220.photobucket.com/albums/dd161/redoverfarm/hightop/100_4683-1.jpg)
(https://s220.photobucket.com/user/redoverfarm/media/hightop/100_4683-1.jpg.html)
![](https://i220.photobucket.com/albums/dd161/redoverfarm/hightop/100_1582-1.jpg)
(https://s220.photobucket.com/user/redoverfarm/media/hightop/100_1582-1.jpg.html)
That's the generator I wanted but the price tag was quite a bit more then I'd like to pay....
For the price of the Generac I could install 1200AH of battery bank and add another solar panel and just run a generator on the weekends I'd imagine.
Quote from: OlJarhead on August 06, 2013, 11:04:54 PM
That's the generator I wanted but the price tag was quite a bit more then I'd like to pay....
For the price of the Generac I could install 1200AH of battery bank and add another solar panel and just run a generator on the weekends I'd imagine.
Once I got to checking on the Generac line I found out that this is the only generator they would warranty since it was Off Grid. The standbys were considerably cheaper but the warranty for off grid use canceled the warranty. This was the only one that was made specificly for this purpose. Standbys were $1K less. There are two standby generators near mine that have bitten the dust because of extended use as off grid. So really the extra cost is nothing compared to expensive repairs and being w/o a generator. Plus it carries a 3 year warranty where the others are only 1 year I think.
I'm starting to seriously consider this route. My wife will kill me though! d*
First order of business would be to convert to 24vdc instead of 12vdc which would just be a matter of changing cables around and switching the controller to 24v. Then replacing my AIMS inverter with a newer Pure Sine inverter/charger (aims has a 2000watt one for $919 right now and some larger ones for a little more). I'd have to add the Magnum auto gen start ($264) and generator ($3600 delivered) but for basically $5000 I'd have a backup generator capable of powering anything I'd run, a more efficient system capable of surging to 6kw and providing all the power I need, clean power at that, in the cabin and later in a shop (via gen) and I'd not have to worry about the system dying on me because I wasn't there to start the genny.
Only other thing to do would be to get a bigger propane tank installed for the generator.
Though I might also have to change out the battery bank as I do see it drop to 12.2v by morning sometimes. That only happens when the fridge is running and then it bounces back so it's not as bad as it sound (I think anyway) and SG test suggest that's just under load but when the load is gone the batteries are still around 95% cap -- unless I'm smokin' something -- anyway, I'll have to look at batteries too as I might want to do that also.
So much to do! OH and the EcoGen didn't have cold start kit last check -- I'd need that I think.
The more I think about this the more I think it's the way to go. I can get a 120 gallon tank or a 250 gallon tank (LP) delivered for FREE and only be charged $70 per year rental on it. LP right now for residential is $1.89/gallon which is at least a buck less a gallon then I pay now! Heck, that's just $189 to put 100 gallons in the tank which would last me a LONG time.
If I set the genny to come on at 12.10vdc on the battery bank then it would be at 50% of charge and would protect the system -- if the genny came on every morning I could lower that slightly since I've seen it drop there under load and I wouldn't want the genny to come on just because the fridge was running...so I could drop it to 60-80% of charge. Something I'd have to play with.
Anyway, it's a $5k ticket and that's a ton but I think it would be worth it in the long run. Only real issue is that I'm already looking at $1000 to get my water line run to the cabin and I still have to enclose the composting toilet....so much to do!
Eric here is a little something to go on. It has been a couple years so prices might have gone up a little. I might suggest that you invest in a BMK ( Battery Monitor Kit). It would take the guess work out and give the AGS a perameter to start.
Magnum MS4448PAE inverter 1 $2,160 $2,160
* 48 volts dc
* 4000 watts output
* 60-amp battery charger
Magnum MMP breaker panel 1 $550 $550
* 175-amp dc breaker
* 30-amp ac input/output/bypass breakers
Magnum MMP-MP mounting plate 1 $80 $80
Magnum ME-ARC50 advanced remote 1 $240 $240
Magnum BMK battery monitor kit 1 $150 $150
Magnum AGS - automatic generator start 1 $250 $250
Just to give you some idea. I just had my 500 gal tank filled today and it took 189 gal. The last time it was filled was last summer. But I also have a frig and hot water heater on mine. The hot water heater is just periodic but the frig stays on all summer. You might check further on your tank rental. Here if it is filled twice in one year there is no rental fee. The Ecogen only uses .85gph @50% load.
Thanks -- I'll have to look at those and see what I'll need. Hadn't thought of a panel but those costs aren't out of line and the AIMS inverter will save me $1k.
I'm looking at several things I need to do right now and the genny and start will be part of it I think.
QuoteMagnum MS4448PAE inverter 1 $2,160 $2,160
* 48 volts dc
* 4000 watts output
* 60-amp battery charger
Magnum MMP breaker panel 1 $550 $550
* 175-amp dc breaker
* 30-amp ac input/output/bypass breakers
Magnum MMP-MP mounting plate 1 $80 $80
Magnum ME-ARC50 advanced remote 1 $240 $240
Magnum BMK battery monitor kit 1 $150 $150
Magnum AGS - automatic generator start 1 $250 $250
I have the Midnight Solar MNDC breaker panel (I think the 250amp breaker) with lightening protector and breakers (60a I think but I planned on switching one to an 80a which I have but didn't install yet).
Likely I'll go with AIMS 24v 3000 watt Inverter/Charger with 60A charger it runs at 88% nominal efficiency and line mode is 95% with 10% THD (seems a little high but then for nearly half the price I can't complain)
I won't need a battery monitor as I can connect my PC to the charge controller so will be able to see what's going on that way without much trouble. These days I just look now and again though I might like an indoor battery meter just so I can see what the bank is doing without looking at the PC or the box. Need to look into that and see if it's worth going that route or just using Morningstars.
The wife approved the ECOGEN (whoohoo!) so I'll get the Magnum Auto start kit for it and set that at 12.1vdc/24.2vdc with hopes that it won't start the genny daily there! I want to be sure the bank isn't abused though and if the genny has to run a LOT then I'll have a good excuse to upgrade the panels and battery bank :) and with running 24v I could crank up the panel wattage and battery bank without worry :)
My neighbor uses a 1000AH cat battery with about 500watts of panels on a tracker (so equal to maybe 625max) and it stays above 70% charge during the week. Then he runs his genny on weekends to top off the tank so to speak, and to run washers and dryers etc. I may be able to do the same until I get a bigger system.
Only reason I recommended the BMK is that it will start/stop your generator without you being there. At least that is the way that I have mine set up.
Quote from: Redoverfarm on August 08, 2013, 12:01:43 PM
Only reason I recommended the BMK is that it will start/stop your generator without you being there. At least that is the way that I have mine set up.
That's what Magnum ME-AGS-S does -- the BMK I think only works with their inverter whereas their auto start works off bank voltage only. The AIMS inverter will sense the incoming generator power (AC) and transfer to it for the cabin power and charge the batteries. When the genny cuts out after two hours (assuming the bank is back up to acceptable level) then the inverter will transfer back with a 10msec transfer time which is usually enough to prevent even a computer from dropping :)\
QuoteThe ME-AGS-S is the 'standalone' version of Magnum Energy's Automatic Generator Start (AGS) controllers.
This auto generator start controller can automatically start your generator based on battery voltage or high temperature. Adjustable settings include: run time, start volts DC, start temp, quiet time, and 24 hour clock.
http://www.firemountainsolar.com/manufacturer/kohler/kohler-8-5-res-residential-backup-generator/
Anyone know anything about these off Grid Kholer generators? I've got pricing on an 8.5kw LP off grid genny set up just like the generac but not as quiet (65db vs 52db) that puts it about $600 less after shipping etc.
Quote from: OlJarhead on August 08, 2013, 05:52:38 PM
.... an 8.5kw LP off grid genny set up just like the generac but not as quiet (65db vs 52db) that puts it about $600 less after shipping etc.
I have heard John's Generac run.
I have a generator that purportedly has a dB rating of 65 - 68.
I
much prefer the quieter one; Generac with average half load dB of 52. That is much like a little Honda EU1000!
I place a premium on quiet; worth it to me.
Quote from: MountainDon on August 08, 2013, 06:01:40 PM
I have heard John's Generac run.
I have a generator that purportedly has a dB rating of 65 - 68.
I much prefer the quieter one; Generac with average half load dB of 52. That is much like a little Honda EU1000!
I place a premium on quiet; worth it to me.
Good point -- and something I've been thinking about too.
I've used Generac before and it does have a good warranty (2000 hrs or 3 years) but seeing the price on the Kholer which is also a good name and being $600 cheaper for 8.5kw vs 6kw of the Generac and I have to wonder if it isn't just that much more worth looking at.
Guess I need to hear one run!
Reviews seem to suggest folks are very happy with the Generac and the sound level is often described as Don does which makes me think for an off-grid unit it would be better. I might ignore the $600 difference and go with it anyway.
Next question: what 24v to 12v converter do you use? I see Samlex makes one (SDC-23 20 Amp 24v DC to 12v DC Converter) but I've also seen some very small ones out there too.
I'll need one to run 2 small 12vdc fans (120mm fans used for composting toilet vent and an insulated duct to draw air to same), a 12vdc ceiling fan and a car stereo.
Thanks!
see this link... (http://countryplans.com/smf/index.php?topic=2335.msg65662#msg65662)
Solar Converters was the brand. Not sure if they make them any more.
I chose bigger than needed and am glad as I since added another occasional use item.
Spendy little buggers ???
I've sent a note out to two suppliers, one whom I deal with a lot and another I'm likely to deal with soon ;)
Just read a review of the Kholer by someone who sells them and I have to say that it steered me RIGHT BACK to the Generac!
QuoteFor years we were able to offer the Kohler models that did everything listed above with great success. Unfortunatley Kohler (and all other manufacturers) have discontinued production of models that worked great for off grid use and have instead focused on making residential grid backup models that need 24/7 utility power to run the controller and only get used occasionally when the grid goes out. While the current Kohler models we offer are not ideal in some ways due to the high speed 3600RPM, two cylinder air cooled engine, continous power use even when off to run it's controller which will drain it's starting battery in less than a week if not accounted for and less efficient operation when running they DO have some very positive attributes. Two wire remote/auto start is standard, the sizes available are ideal for battery charging, LP fuel use, and they do have a warranty for off grid use. The Kohler 8.5RES and 14RES are very similar in price to a Honda 6500 but have a weatherproof enclosure, simple two wire auto start and LP fuel.
Looking at the Generac it runs at 2600RPM so a little lower, is much quieter and has a 3 Year/2000 Hour Limited Warranty (much better then Kholer). Not sure how many watts the controller uses and it does have a 2.5amp trickle charger so that's 300watts which seems like a LOT (maybe it's me but a 300watt appliance running full time on a small off-grid solar power system seems a but much...what am I missing?
Anyway, I'm thinking the Generac is likely where I am going despite the $600 increase in price -- my wife would prefer the lower priced model but I just think we'll be happier with the Generac
I too have heard John's Generac run and inside the cabin you hardly can hear it. The company I work for sells Siemens generators which are Generac with a different label. They are now offering a 5 year warranty. It may not apply to the off grid model but worth looking into.
John Raab? Or another John! lol Wasn't sure who Don meant -- or is Redoverfarm also a John?
Looked at some options and decided that if I get the job we might not use cash for the genny since CC companies are begging us to get another card (we generally pay them off before interest is charged and then close them! lol they don't like that but keep offering it to us). We figure since we'll be saving rent (if I took a job anywhere else I'd pay rent) the savings more then covers the cost of the generac.
One of my challenges now is to figure out how much propane I'll need. I'll be running the genny quite a bit in the winter since the battery bank is a little small for what I want to do and then I'll also be running an 8000btu heater like MountainDon's to keep the composter room warm. My thought there is to super insulate the room and the duct coming from the wood stove so that it won't require that much heat to keep above 50 degrees. I plan to build with 2x6 walls but after reading (a long time ago) about CoyoteRidge (I think it was anyway) with his double 2x4 walls I'm thinking a 2x6 R21 outer wall with a 2x4 R13 inner wall and an R30 roof and well insulated dict from the wood stove pushing warm air into the compost room and I ought not to run the propane heater that much -- maybe only once or twice a nice/day.
So with that, plus an 18000 btu heater of the same kind inside the cabin to keep it warm when I'm not there, the genny, cook stove and instant on hot water and, well, I'm not sure if a 250 gallon tank will be enough.
Quote from: OlJarhead on August 10, 2013, 11:07:49 AM
is Redoverfarm also a John?
Yes
And that is a *huge* difference in SPL between those generators, the Kohler will "seem" to be more than twice as loud as the Generac and you will spend years regretting not spending the few bucks extra for the quieter model. As always YMMV
Shopping is so much fun..its the installation that tests the ol body.
Not power but I saw some solar hot water panels for $50 today on CL.
Gotta admit that $50 got my attention! Wonder if I could use those? Problem I see is that I don't want to run a pump to push the water up into them on the roof and while passive should work with gravity fed system that's above the panels I'm just not sure.
Perhaps I could run the hot water lines into the panels and then into the instant on HW heater and reduce how much propane I use making water hot?
Anyone used these things?
OK I'm fighting with this: 2000 watt inverter with 6000 watt surge and 30A charger or 4000 watt inverter with 12k surge and 50A charger?
I think the 4k Inverter would be better because it's bigger and when it comes to power it seems better to error on the side of caution but I'm not sure I'd need it as the biggest load I have now is a toaster I don't use and in the future will be a 1k or lower MW Oven.
Thoughts?
Quote from: OlJarhead on August 27, 2013, 09:46:31 AM
OK I'm fighting with this: 2000 watt inverter with 6000 watt surge and 30A charger or 4000 watt inverter with 12k surge and 50A charger?
Everything else being equal; depends.
One reason I went with 3500 watts was the experience of using inverter power in the RV. The inverter used was not large enough to permit simultaneous operation of some of appliances. So most of the time we are using just a fraction of the available inverter power. Perhaps not the most efficient inverter operation. ??? But using anything around the cabin requires no thought about what else might be on or what else might come on.
Depends on the user and user's family.
Thanks Don -- now another problem has cropped up: Transfer Switch Ratings vs Generator power output???
I was told that the generator's 50A @ 120v was higher then the 30A transfer switch on the 2000 watt inverter and possibly more then the 4000 watt inverter. A 6000 watt inverter charger has a 65A (waiting on final word) transfer switch and 85A charger but is really WELL over what I think I'd need.
Waiting on them to call me back.
http://www.theinverterstore.com/4000-watt-pure-sine-inverter-charger-24-volt.html#
Got my answer :) AIMS is FAST!
The Tech explained that their Transfer Switched are rated at 240v so no problem using the Generac 6kw with them but he recommended the 4000watt inverter primarily because it's capacity to charge the batteries and provide the full 4kw when hooked up to the generac.
he also agreed that the Magnum Auto Gen Start was the better way to go.
Eric not to steer you either way but I feel you will not regret going a little larger on the inverter. Who knows what additions you will add in the future as far a electrical needs. There are a couple things about my system (non solar) that I guess I need to toot my horn. Once I got the system set up correctly I just monitor things and it does the rest.
Here is the outfit that worked my details and I ultimately bought from their company on my Magnum products. Was the best price I had gotten and Kent Osterberg was super knowledgable.
http://www.bluemountainsolar.com/
Magnum support has been outstanding.
This was sent to me by Bob Cramer one of the system designers/ Big Wig at Generac.
"The drawings you are pulling off the web may be old and the wrong ones for the generators you are buying. The proper generator for off-grid living is the Generac EcoGen unit. It is designed for off-grid installations, comes with a 3 year warranty, has 500 hour service intervals, reduced noise, reduced fuel consumption and is 120v factory wire with the ability to be 240 converted.
With that being said, before we launched the EcoGen generator I had engineering incorporate a 2 wire start feature into the HSB 2008 and 2010 controller. One controller uses pin 17 and 18 and the other uses 21 and 22. The older 8kw and Core unit do not have 2 wire start capability so they cannot be used in this type of installation. When I get the serial number of the unit you are using I will send you the retrofit kit and you will be able to make the change. We record the serial number and match it with the registration information and not the system that the unit has NO warranty because of the application it is being used in."
The BMK in my opinion is the way to go. Not only does it monitor the voltage it also monitors the SOC (State of Charge). I have my AGS set to start both ways as a fail safe. One just a tad lower than the other.
Thanks. The Magnum BMK battery monitor kit when I first looked at it I thought was for the Magnum's only. Wasn't until after buying a Bogart Engineering Trimetric Battery Meter Kit that I realized the BMK was about the same thing.
That being said I've probably gone a little overboard as I ordered all of these:
Bogart Engineering Trimetric Battery Meter Kit
Remote Control for AIMS Power Low Frequency Inverters
ME-AGS-S Auto Gen Start
Solar Converters Step Down Voltage Converter - Model PPT12/24-20/R12
AIMS 4000 Watt 24 volt Low Frequency Inverter Charger
Now I'm about to order the Generac too :)
So I'll have remotes for the Inverter and the batteries as well as the Auto Gen Start and I might even order one for the MPPT Controller too ;)
Stick in a CD player and some speakers and I'll have one heck of an entertainment center! lol
I guess I'm too late for this question?
Do the AIMS inverter/chargers have a search mode? And what is the power draw in search?
Search can save a lot of battery power when nothing in the cabin is actually consuming power, but you want to be able to have something work the moment it is turned on. If there is no search function then the inverter has to be on and in idle mode.
I've seen some large inverters that draw up to 5 amps (at 24 VDC) when in idle; up to 2 amps in search..
Our Outback draws 20 watts (0.8 amps) in idle and only 6 watts (0.25 amp) when in search. If the system has an Outback charge controller then the remote (Mate) can be used with both the CC and the inverter/charger.
QuoteIdle Consumption with Power Saver Mode ON: <1.88 amps DC depending on search mode
Quote
4000 watt low frequency inverter
12000 watt surge for 20 seconds 300% surge capability
Terminal Block
GFCI outlet
Marine Coated and Protected
Multi Stage Smart charger 40 Amp
remote panel available
auto frequency
10msec typical transfer time
optional 25W power save mode
7 battery type settings for charger
I wanted an outback or a magnum but honestly AIMS has treated me well and the cost savings over the others was enough to make me stay with them.
Hi Folks
After a bit of an extended absence I am happy to be back on the forum.
I am looking to replace my rubbish Xantrex Freedom HF1800 watt inverter /charger. It worked great when it worked. Unfortunately it's only 3 years old and on a cold winter's night roughly 16 months ago the charger shorted its board and now unfortunately the inverter portion for no apparent reason has stopped working all together. Turns out these new inverters from Xantrex are china made, I guess I should not be surprised as its hard to find ones that are not. After reading the last few pages of this thread I have had a look the Aims inverter chargers as they sound attractive but after reading many of the online manuals they mostly appear to be made either in Korea or China. Now I have my fair share of Chinese consumer goods, which some have represented good buys but I am very leary about going down this road again. I have also heard suggestions from Midnite folks( may be former employee sour grapes) that although products like Outback are assembled in the USA its unclear if they don't source come their components from elsewhere. Soo, long story short I am looking for an off grid 3-4kw 48 volt low freq sine inverter setup. What manufacturers should I be looking at from a reliability perspective( i.e, I want more than 3 years service)? confused? I am sorry upfront if this stirs up some sort of ford vs chevy( or china vs the world :) debate, That truly is not my intention.
Thank you
Quote from: upa on August 28, 2013, 08:15:32 AM
Hi Folks
After a bit of an extended absence I am happy to be back on the forum.
I am looking to replace my rubbish Xantrex Freedom HF1800 watt inverter /charger. It worked great when it worked. Unfortunately it's only 3 years old and on a cold winter's night roughly 16 months ago the charger shorted its board and now unfortunately the inverter portion for no apparent reason has stopped working all together. Turns out these new inverters from Xantrex are china made, I guess I should not be surprised as its hard to find ones that are not. After reading the last few pages of this thread I have had a look the Aims inverter chargers as they sound attractive but after reading many of the online manuals they mostly appear to be made either in Korea or China. Now I have my fair share of Chinese consumer goods, which some have represented good buys but I am very leary about going down this road again. I have also heard suggestions from Midnite folks( may be former employee sour grapes) that although products like Outback are assembled in the USA its unclear if they don't source come their components from elsewhere. Soo, long story short I am looking for an off grid 3-4kw 48 volt low freq sine inverter setup. What manufacturers should I be looking at from a reliability perspective( i.e, I want more than 3 years service)? confused? I am sorry upfront if this stirs up some sort of ford vs chevy( or china vs the world :) debate, That truly is not my intention.
Thank you
Might check on previous post in this section. As for me I have a 48 volt system and am satisfied with Magnum products. Here is what I have.
http://countryplans.com/smf/index.php?topic=6059.msg172189#msg172189
Apollo, Magnum, Outback, Schneider/Xantrex XW series.
And if you have a charge controller by one of those it would be nice to have the same brand as usually you can then integrate the two with one remote.
Quote from: OlJarhead on August 27, 2013, 03:12:56 PM
I wanted an outback or a magnum but honestly AIMS has treated me well and the cost savings over the others was enough to make me stay with them.
To clarify this the Magnum I found in the same power output range was $2 vs the AIMS at $1.3k
That $700 difference was the cost of my concrete ;)
Quote from: MountainDon on August 28, 2013, 08:58:33 AM
Apollo, Magnum, Outback, Schneider/Xantrex XW series.
And if you have a charge controller by one of those it would be nice to have the same brand as usually you can then integrate the two with one remote.
Thank you for the kind suggestions, gentlemen, very much appreciated. I am in a fortunate position where I can start all over, so am not tied to one manufacturer based on old equipment. My original setup was a good learning platform. No major regrets and the remnants of the old equipment will be put into some form of back up use. Its interesting how things have changed over the last 3 years. After briefly looking online It looks like fully assembled systems such as the outback power one, or magnum/midnite epanel setups are not any more expensive than the original component cost. It kind of looks like what happened to computers, it appears to be getting to the point that it might make more sense to buy a fully assembled system vs building it yourself. Not to mention I am floored how inexpensive solar panels have become. I can remember when I thought 500 watts solar array would be the most I could ever use(afford), now I am think 2-4 kw would be nice and relatively affordable. Only rub I see is that an appropriately sized 48v battery is still quite spendy
OK, lots of reading today, my head is hurting. I believe I have a solar plan, please critique it as you see fit.
I think I have it narrowed down to an Outback system. Magnum came in a very close second, I love the fact midnite makes a prewired epanel system with their classic controller and the magnum 4048 inverter but I really do not need the dual phase feature on the inverter and its pricing locally or shipped from the states is coming in significantly more (~ 1K) than similar spec outback. I actually think the magnum may be a better product with its superior power corrected charger and less fussy rc-50 control/display unit but I am not sure its a $1000 better. If I was still living in the states it would be a different call as it is only about $300 difference in the US but I am getting nailed hard with shipping, brokering and exchange. Apollo seems cool but it appears their customer service reputation is a bit lacking compared to the other bigger players. Schneider/Xantrax XW series look very worthy but frankly they are tainted in my eyes with my past experience despite the fact that I really do appreciate their lower end consumer grade items are an apple to oranges comparison to the XW series
So it looks like I am looking at an Outback FP1-2 prewired AC and DC boxes with 120Vac Bypass, vfx3648 inverter, flexmate 80 Amp charge controller, MATE3, HUB4,
flexnet DC, appropriate breakers(175 amp DC breaker , 80 amp DC charge controller breaker and a 60amp AC interlock) and integrated surge protector for both ac/ dc sides. PV would be a 2.8kw array consisting of ten Canadian Solar(made in Ontario, Canada but the cells are quite very likely from China) 280 watt gen 2 -polycrystalline panels( good deal at 89 cents a watt) Vmp 35.6 Imp 7.86 Voc 44.2 , 2 panels per series in 5 parallel runs on a raised and yet to be built ground mount likely set at a winter(snow shedding) /summer compromise of 45 degrees- MC4 connectors, 10 gauge extensions to a max of 25 feet , running through a midnight PV combiner with five 15 amp DC amp breakers, delta surge arrestor, 4 gauge wire running from the combiner ~ 20 feet to charge controller in my "power shed" where the inverter and batteries will live. I think I can get a good deal locally on t105s, so the 48 volt bank will likely be 225 amp to start or eight 6V cells wired in series (4-0 gauge inter connection and inverter cables)with option to parallel another string for 450 amp/hr total. Based on my math the 2.8 kw array should have no problem with either configuration supplying a C/5 to c/10 charge rate. Currently my load requirements with electric fridge and other assorted loads at the cabin are at a minimum of 1.8 kw/day and I can easily see 3kw being used without much effort. With my winter insolation at 1.9 hours but not accounting for efficiency losses I think I may squeeze by ;), now summer insolation is 4.2 hours and I may be even able to run my 5500 watt window a/c for a few hours during the day at peak array production if required- sweet. Most importantly I am really looking to give my poor Yamaha 2000 inverter genny a break(I put 1200 hours on her in the last couple of years)good times. Oh, I also have a larger manual start gas generator that can supply nearly 25 amps a/c at 120v if the bank needs a top up on cloudy stretch. I would love an auto start but can't seem to justify another capable generator at this point. I am hoping I won't need it too much.
Did I miss anything in my plan? flaws with my thinking?
The Outback looks like a good way to go.
But I wonder if you should reconsider the golf cart Trojans? I keyed in on the phrase "to start" that you used when you mentioned the T-105's. Give consideration to one of the L-16's, like the Trojan 6V 420AH Battery L16P AC. I believe in the long run they may last you longer as well as provide more capacity in reserve. Just a thought.
An alternative would be Rolls Surette. You might even consider the Rolls Surette 2 volt cells and going 24 Volts instead of 48. Nothing better than an all series battery bank. Just more thoughts.
Thanks Don, I figured the battery was my weak link. The reason I am leaning towards the Trojans is that I already have 4 relatively new 6 volt units and the upgrade with 4 more units or 225 total amps would be only be around $500 or 12 more (450 amp total) at $1200 vs $4000 for surrettes. Main reason I am even considering the 48 volt system is to keep my parallel connections to a minimum. I am done playing around with large 12 volt parallel banks, they are just an exercise in frustration. I have maximally priority budgeted for the inverter/array and the less so for an optimal battery bank . Unfortunately this where I have to financially draw my line. My reasoning is even if I murder my bank in a couple of years the worst I will be out is $500-1200 and I may very well be in a better position financially to consider a larger capacity or surrette battery at that point. I hope that makes sense
Budgets are a part of the decision making. Hopefully the old batteries are in good enough shape as to minimize any bad effects on the new ones ability to act like new ones. Best of luck!
Quote from: MountainDon on August 29, 2013, 07:19:11 PM
Budgets are a part of the decision making. Hopefully the old batteries are in good enough shape as to minimize any bad effects on the new ones ability to act like new ones. Best of luck!
As usual you are the voice of reason(thank you), I am going to check out larger capacity and better quality options at a couple of dealers tomorrow. Otherwise, I pulled the trigger today on the outback system and PV array. I am still trying calm myself about the boat load of money I just spent. Regardless, should have them in the next couple of weeks and now I get to also stress if I can get them up before the weather gets miserable. I am not entirely sure why I can't do these things at the beginning of summer d*
Quote from: OlJarhead on August 28, 2013, 09:46:19 AM
To clarify this the Magnum I found in the same power output range was $2 vs the AIMS at $1.3k
That $700 difference was the cost of my concrete ;)
Back to generators...
The one thing I would comment on is do you need 240vac? Do you have 240V loads? You could cut the cost down by just buying a 2KW or 3KW Honda EU series inverter based generator and having it modified for propane. You will get very long life and even less noise than the Generac or Kohler.
Only the 3KW Honda will autostart. The EU6500i Honda would be over the price of the units you mentioned but just about the best built for long propane hours offgrid.
More solar and a larger bank? Definitely my choice. Good Luck!
Well got the ground mount finished, mounted the panels (total 2.8 KW) and wired them all to the PV combiner (2 panels in series and then paralleled). Still have to trench about 40 feet (double what I originally thought) and lay the 6 gauge wire( 4 gauge was overkill as 6 still provided less than 3% voltage loss) to the shed that is going to house the PV controller, inverter and 48 volt battery bank. Still waiting for the inverter and have to make up my battery interconnect cables but I am feeling more confident that I can flip the switch before the weather becomes too cold.
Hard to tell by the picture but those panels are 3.25 x 6.5 ft each and weigh around 50 pounds , they are very certainly awkward to handle at height especially when your doing this on your own, man I feel sore today :D
Finally after a rather longer than anticipated wait from my vendor my preconfigured Outback system arrived. Since I had all my PV, AC and battery bank wiring done well in advance I think it took me less than an hour to mount this 110 pound board, make final hooks up and do the pre energization check. Despite the wait I am glad I got the preconfigured system as it had all the appropriate breakers, wiring to meet code requirements. All the components were seamlessly integrated and the package was uber easy to install. The cost was the same as buying the individual components but overall it was a huge time and aggravation saver to have the factory assemble it for me. Unfortunately when I "flipped" the switch (it was actually around 10 breakers :D) it was a little anticlimactic as I had solid rain yesterday so I had to fire up the little Yamaha generator to provide the new bank's first charge and equalization. Even with the solid overcast yesterday the poly panels still managed to produce 200 watts per hour with the available ambient light.
I am impressed so far, ran all my typical household loads overnight including fridge, propane furnace( it ran frequently as it was cold last night), lighting, sat box TV it was all so seamless like grid power. The battery monitor reported 84% state of charge this morning not bad at a reported bank temperature of 5 degrees Celsius, pretty much in line with what I calculated it should be. The mate 3 controller is a little intimidating at first but as you look at it closer you realize its interface is relatively simple but provides a tremendous amount of control and information(PV controller, inverter, and flexnet battery monitor all under one roof). I still think I like Magnum's interface better from an ease of use(the menu selection rotary dial is superior to outback's overly sensitive solid state touch dial)and aesthetic ( about half the size of the outback) perspective but I think the Outback interface is much more richer as a data logger( can Ethernet directly to notebook, via SD card or wireless LAN) and overall options control.
[cool] [cool]
I don't think anyone else has mentioned this...
Home Depot sells 120 VAC Cree LED bulbs in equivalent 40 and 60 watt sizes; 450 & 800 lumens. (actual power use 6 and 9.5 watt). The 9.5 watt (60) come in daylight and warm white. $14 each or a six pack online for $78.
We now have four at the cabin in the most used lights. They are very omnidirectional and bright enough to be useful. They are also dimmable. In spring I intend to install a couple of the R30 reflector lamps along the exterior wall from cabin to shed.
http://www.homedepot.com/s/cree?NCNI-5
Questions for you solar guys out there. First a bit of background for those who don't know. We have been off grid for going on six years. Have a large 12 volt bank, a bit over 4,000 AH. Maybe 5,000 I can't remember off the top of my head. Also our bank consists of a mix of AGM 2 and 12 volt batteries. Our batteries can be rewired in 24 volt but not 48 volt due to limited two volt. For all these years we have been recharging our bank with a gas charger. Now looking into improving our solar system. I've been looking at the equipment and amazed how much prices have come down in five years. We are also here in VA where there are only 3-4 solar hours a day. We also have a 5000 watt modified sine inverter. I can not afford to build the whole system at once so I would like to start adding things we can build with.
First question am I understanding correctly that higher voltage systems (dc volts) are better? Are there any good pure sine inverters that are switchable for input voltages? Also looking at panels and charge controllers. I noticed that Midnite makes a switchable controller that could work for us. But it will only handle 4 250w panels @ 12v but goes up to 15 250 w panels at 48 v. Does anyone make one that will handle more panels at 12 v and still switch to higher voltages?
I know there are lots more questions but this will help get me started. What I would like to do is add 1-3 kw of good panels and a charge controller to what we now have then add more and better equipment as we can afford it. Anything we buy for our system from this point forward I want to be high quality. Unlike the thousand I threw away on those Harbor Freight panels a few years ago. I know from reading here many don't agree with this plan but its what our income will allow. One good point is the more we build our system the more it will save on power bill (gas). So our system should be able to grow faster as it also starts saving us money.
Opinions on equipment brands would be welcome too.
Here is a system about like I would want to end up with. In a dream world.
http://www.wholesalesolar.com/solarpowersystems/workshop-8-off-grid-solar-power-system.html
If any of you can help THANKS.
Larry
A World Away
QuoteFirst question am I understanding correctly that higher voltage systems (dc volts) are better?
Higher DC voltages can occur in two areas; the PV array and the battery bank.
@ the PV array higher voltages are good when longer distances between panels and the charge controller must be used. Series connecting the panels = higher voltages and that = being able to use smaller wires compared to parallel connecting the panels.
@ the battery bank the higher voltages also reduce wire sizes to the inverter. More important IMO, is that the CC can handle more total PV array watts as the battery (system) voltage increases, as you noticed. Basically going from 12 to 24 volts doubles the wattage the CC can handle; same with the change from 24 to 48 volts. Outback, Xantrex XW and Midnight all have CC that can be used with higher voltage battery banks. Various models can also handle higher input voltages than others.
Higher system volts are also superior as that reduces the number of parallel battery strings. It is best if all the batteries can be connected in series to make 24 or 48 or whatever higher voltages. IE: Eight - 6 volt batteries in series for 48 volts is much better than the eight batteries in two series strings of 24 volts, and then the series in parallel. Hope that comes through clear.
BUT having a mix of batteries types, voltages and amp-hour capacities is not ideal. When the battery capacities are unequal some will be overcharged and others undercharged. However I understand the financial aspects you have to deal with. For now selecting a good CC and buying some PV panels sounds like a great idea, even with limited sun hours. The PV panels are THE solar item that has dropped precipitously in price. Other stuff not so.
NO, I have never seen an inverter that has an input voltage selector. Good charge controllers OTOH auto select the battery voltage and can operate over quite a range. Just carefully read the specs. I favor Outback but that is mostly because that is what I have. I also like the Midnight and XW series when I read about them. When I bought I got better pricing on the Outback. It is nice to have same brand CC and inverter as then the units can be tied together and share data.
That's a HUGE battery bank to me! But then I'm in a small off-grid cabin and live alone so perhaps I need less ;)
I started with a 12 system with 880AH (after adding 220AH in the first year) and a 2500watt MS inverter and MorningStar MPPT controller (which is switchable from 12 to 24 or 48v with dip switches like most others) but through research (mostly from guys like Don on this site) I opted to switch to 24v and bought an AIMS 4000watt Pure Sine inverter/charger (about $1200) and found 4 more batteries of the same age, type and size to add to the bank).
I know have a 24v system with 660AH of battery bank (1320 if configured as 12v but I'm no longer using 12v) and during the winter only get 2-3 hours of charging (trees are my biggest issue and I think with a couple removed I can get 3 hours for a little longer but by mid-December I'm sure I'll be lucky to get two hours) from my 615watt solar array (non-tracking). Because of this limited winter charging I installed Generac's EcoGen 6kw off-grid generator and I LOVE it!
With my inverter/charger set to run about 85% (it is adjustable) I charged my bank up in two hours :)
I've also installed a TriMetric battery monitor (loving that too) and will be installing Magnum's AutoGen Start switch tomorrow as well as a 24-12v step down converter tomorrow (for fans and car stereo).
I found that with bigger better inverters the power usage without a load went down and the efficiency went up and while I could have gone with a Magnum/Xantrex/Outback inverter/charger to get a little more efficiency I'm pretty happy with my AIMS and the money it saved me.
As for upgrading your system I'd seriously look at going to 24v at least and getting a new inverter charger and charge controller but of course, it all costs money right?
We used to say in racing it isn't the cubic inches, it's the cubic dollars that wins the race....perhaps that can be used in solar power off-grid systems too? lol
Wow! Upa that looks pretty nice!
Quote from: BiggKidd on November 09, 2013, 09:37:44 AM
Have a large 12 volt bank, a bit over 4,000 AH.
How are you counting those amps and hours Larry? That does seem like a lot; are you calculating watt-hours? Watt-hours is probably the best way to calculate theoretical capacity. For example...
We have twelve 6 volt 210 amp-hour batteries. Three series strings of four batteries with the series strings parallel connected.
One serial string = 24 volts and 210 amp-hours.
Three strings x 210 = 630 amp-hours at 24 volts.
610 x 24 volts = 14640 watt-hours
I saw a comment on AIMS and that they might be made outside of the USA but I believe they are actually made in Reno NV. I know at one time anyway, they were made in the USA (AIMS stands for American Inverter Manufacturers -- or something close to that.
Admittedly I cannot find a statement by them that all their inverters are US made so perhaps they aren't but I like the fact that a guy started making them in his garage in Reno and today big companies and organizations are using them (I believe I saw that NASA was using AIMS inverters).
I don't think they are as good as Outback or other big players becuase I've seen the efficiency ratings of those and I think they appear better then AIMS but the $800-$1000 higher pricetag will keep me in AIMS for a while ;)
Quote from: MountainDon on November 09, 2013, 11:31:42 PM
How are you counting those amps and hours Larry? That does seem like a lot; are you calculating watt-hours? Watt-hours is probably the best way to calculate theoretical capacity. For example...
We have twelve 6 volt 210 amp-hour batteries. Three series strings of four batteries with the series strings parallel connected.
One serial string = 24 volts and 210 amp-hours.
Three strings x 210 = 630 amp-hours at 24 volts.
610 x 24 volts = 14640 watt-hours
Curious, are you still running those GCB's Don? I was wondering if you went to L16's or something but then seeing the AH ratings made me pause and think maybe youre still getting good use out of those GCB's? GIves me hope if you are!
Thanks Guys
Yes Don I understand about series / parallel. You know it is a large bank, we have run over two weeks without a recharge before when the charger broke. Yes the mix of batteries isn't a good idea but since they were free...........................
With plans to upgrade in the works I thank you all for the information. Currently looking at several makes of panels think I will try to get a few in the next month. Since it looks like 4 is all the CC will handle @ 12 v I am leaning toward the renogy 300w polycrystalline . That would be a good start I would think. IDK
The amp hours are from the lables on the batteries. Sixteen at 134 AH each 12 volt and 12 at 1,100 amp hours each 2 volt. All are AGM batteries a friend who works in a backup power supply co. got me.
Thank You All
Larry
Check out the panels at sunelec.com as they tend to have some GREAT deals. I've purchased 4 from them and am very happy with the panels and the price.
Guys I also have seven more 134 AH 12 volt batteries that are being equalized they were in the string until earlier this year when Carl gave me 12 more to replace a few that had gone bad after five years of hard use. In five years I had five of sixteen go bad. Since he gave me 12 more I put them all in removing the worst ones. Since they were still "good" I set them up to equalize. They have since evened back out and appear ok. I may switch them out with the other old batteries and equalize those.
Did I mess up by assuming that adding the label amp hours was the actual amp hours of the batteries?
Ok I will check them out.
Thanks again
Larry
When I get back home I can get pictures of the labels on the batteries.
Larry
Oljarhead,
I looked at those panels, they don't give much info. :-\ Take a look at these renogy panels here.
https://www.renogy-store.com/300-Watt-Solar-Panel-p/rng-300p.htm
Thanks
Larry
thats a great deal!
BiggKidd... the amp-hour rating that is the important one for off grid use is the 20 hour rate. Some batteries are rated at longer or shorter times, such as 100 hour or 5 hour. Hundred hour ratings are higher than the 20 hour. Our batteries are 210 amp-hours at the 20 hour rate.
Oljarhead... same batteries we placed into service summer 2009. Plates viewed through the fillers appear the same as when installed, FWIW. Performance is much the same now as then too. Water them twice a year and maybe equalize three times a year, IIRC ??? I'd have to look at the log book but that is in the battery enclosure. And I'm not there.
Installed and set up my TriMetric meter today and after fully charging the bank it read 101% of charge.
THen after 4 hours of running the cabin (watching TV etc) I see it's reading 94% of charge. I was happy to see this until I saw the voltage was showing 2.4v which according to Trojan is only 60% of charge.
I'll have to shut down for the night soon so it will be interesting to see if the batteries increase a little in voltage but I'm a little confused by the 94% right now as it would seem that's not accurate unless I'm not understanding the way it calculates the percentage of charge.
Any ideas?
Quote from: MountainDon on November 10, 2013, 12:56:17 AM
BiggKidd... the amp-hour rating that is the important one for off grid use is the 20 hour rate. Some batteries are rated at longer or shorter times, such as 100 hour or 5 hour. Hundred hour ratings are higher than the 20 hour. Our batteries are 210 amp-hours at the 20 hour rate.
Oljarhead... same batteries we placed into service summer 2009. Plates viewed through the fillers appear the same as when installed, FWIW. Performance is much the same now as then too. Water them twice a year and maybe equalize three times a year, IIRC ??? I'd have to look at the log book but that is in the battery enclosure. And I'm not there.
That's great! I've abused mine more then you but it gives me some hope that they might last another year or more...I might not have to buy the new batteries next year and that would be a big savings....but see my post on the TriMetric because if it's wrong then I can't see living with this small bank that long. I need to run the calculator again with better data that I now can gather from the meter as that would help me understand the capacity I think.
sorry I seem to have fallen asleep in the middle of this. :-[ Long day and another today, can't wait to get back home. Don I'm pretty sure that is the 20 hour rate. But I'll check.
Thanks
Larry
Hi Guys,
Could I get you to look at these panels and give me an opinion? http://www.civicsolar.com/product/et-solar-et-p672300ww-300-watt-solar-panel and heres a link to the others I am looking at. https://www.renogy-store.com/300-Watt-Solar-Panel-p/rng-300p.htm
Thanks. BTW those batteries are at the 20 hour rate. Just about ready to order 4 panels and the midnite 150 controler. Do I need a combiner box for this? I figure this will be a good first step.
Thanks
Larry
Well it turns out the civic solar is out of stock. Renogy on the other hand has the 300 w panels and offers free shipping. So unless I find a reason not to go with them I think thats what I'll order. Still looking for the best price on the midnite solar classic 150. Civic solar has a decent price but wonder if they have it in stock?
Larry
Do you all use combiner boxes on your systems? How about breakers / fuses on the in / out charging? Finding out there is a lot more to solar than what it took to hook up my harbor freight panels! My DC stuff now has no breakers or fuses. When I was running 12V in the house that had a fuse but since we went all 120 AC haven't used any DC fuses.
Thanks
Larry
Either of those panels appear okay.
Combiner: They are handy things when it comes to connecting panels together to transmit the power run to the CC. It is possible to cobble something together using off the shelf electrical service panels, etc. The BIG thing to remember is devices like breakers, switches, disconnects, etc. that are made for use with AC current are usually not usable for DC current. Usually. AC current as it's name indicates alternates directions. Every time it changes direction the current drops to zero as it heads in the other direction. That makes interrupting AC current much easier than DC. Using an AC disconnect on DC will sooner or later reult in the contacts being burned, maybe even welded together.
In case you are not aware DC can create flame arcs if the current is sufficient. Pulling a DC fuse to disconnect an active set of panels for example, can result in getting burned and/or starting a fire. So be careful if making something up from parts off the shelf.
OTOH, Square D QO and QOC breakers can be used on low voltage DC circuits; 12 or 24. Nothing higher.
There are also breakers available from golf cart parts that can handle high amperage and high voltage DC loads. Solarseller.com has assorted DC rated breakers.
Breakers / Fuses: Devices like breakers and fuses must be rated for DC to be safe on DC. The aforementioned Square D items may not have the DC approval labeled on them but they are okay. But because they may not be stamped for DC an inspector may not pass them.
I like having a suitably sized breaker just before the input connection (from PV) on a CC as well as just after the output connection (before batteries). Suitable means, on a 24 VDC system the breaker voltage should be 37-38 volts or more. The amperage should be equal to the maximum of the PV output or the CC output.
A breaker in the positive line to the inverter is good as is a Type T fuse right at the battery positive. Yes, both; the type T fuse is for catastrophic shorts and the breaker can be used as a disconnect. Many DC breakers are rated for disconnect use; check ther specs before purchase.
Usually equipment made for DC use is much more expensive than for AC use. They need much heavier contacts and not so many are made as AC ones.
Hope that helps.
The Midnight Solar DC combiners are reasonably priced and have a cutout for their nice MNSPD-600 lightning arrestor.
http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=9&productCatName=Combiners
Prewired with DC breakers and MC4 connectors (nice) here:
http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=35&productCatName=Combiners - Pre-Wired (http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=35&productCatName=Combiners%20-%20Pre-Wired)
Thank you again Don.
Yes when I was using 12v water pump etc I did have a fuse or fuses inline. Since we got away from 12v stuff I haven't. All of our power does run through a standard breaker box. Yes your answer was very good and concise. The midnite combiner box is what I have been looking at. I am trying to make sure anything I buy at this point can also be used when I switch to a 48v inverter, magna sine 4448. I think I only have one last question for you guys and I'll be ready to order. What amp breakers do I need for running two of the renogy 300 W panels in series then in parallel with two more. Nope just realized two more questions. Can I run just one set of 10 awg cables from the four panels to the combiner (less than 100')? Do you mount the combiner closest to the panels or the Charge controller?
hpinson, I like that prewired box but with the amp limit I think I will have to go larger.
Thank you all for taking the time to answer my questions it is a huge help!!!
Larry
QuoteWhat amp breakers do I need for running two of the renogy 300 W panels in series then in parallel with two more
Look at the specs... Short- Circuit Current (Isc) = 8.56A. The panels in series still produce a max of 8.56 amps but their maximum voltage output is doubled; that is the Open - Circuit Voltage (Voc) 46.12V X 2 = 92.24.
The two series strings in parallel will double the maximum amps; Short- Circuit Current (Isc) 8.56A X 2 = 17.12 amps maximum. The voltage max stays the same, 92.24.
Round 17.12 amps up; 20 amps would be a good breaker size. The voltage rating of the breaker should be the max Voc, 92.24 x 1.25 x 1.25 = 144.125 VDC. So 150 - 165 volts would do. That voltage is very close to the maximum the Midnight 150 can handle.
~~~~~~
QuoteCan I run just one set of 10 awg cables from the four panels to the combiner (less than 100')? Do you mount the combiner closest to the panels or the Charge controller?
Combiner is placed close to the panels, that saves wire. There would be two series wired sets that complete their parallel connection in the combiner. Then one pair (positive and negative) that go from the combiner to the charge controller, with the positive passing through a breaker/disconnect before the charge controller IF the distance from the combiner to the CC is too great to make it convenient to just rely on the breaker disconnect at the combiner.
10 AWG is fine for the usual distances from panels to combiner.
What would the distance from combiner to CC be? I can run my calculator to see what wiring sizes would be best.
Don,
Thank You I had come up with 20 amp. But didn't have the formula to back it up, just seat of the pants reckoning. I am not sure on the distances yet watching the sun as the winter progresses to get the best location. It will be mid dec. before everything is delivered and ready to mount. It will be less than 100 ft though, may be as little as fifteen. If I could go five hundred the panels would go on top of the hill. I am sure more trees will have to come down. Its a good thing too. I know people who have no trees and hate it. I have to many trees, but still love them. Just thinning some for other projects. :) Boy its nice getting answers that make since. The people who are in solar sales need classes I think. Most of the techs likely know their stuff but the sales staff ..................................
You all have a nice night.
Larry
FYI, with 4 panels as described, in series/parallel
maximum voltage drop of 2%, #4 awg = 145 feet
maximum voltage drop of 3%, #4 awg = 218 feet
maximum voltage drop of 2%, #6 awg = 92 feet
maximum voltage drop of 3%, #6 awg = 136 feet
maximum voltage drop of 2%, #8 awg = 58 feet
maximum voltage drop of 3%, #8 awg = 87 feet
maximum voltage drop of 2%, #10 awg = 37 feet
maximum voltage drop of 3%, #10 awg = 55 feet
maximum voltage drop of 2%, #12 awg = 23 feet
maximum voltage drop of 3%, #12 awg = 35 feet
G/L
Don thats some great info. Thank you. I will likely use 10 awg even if its a bit of overkill going less than 30 ft which looks like my distance. Now wholesale solar is trying to work up a better price on their panels since I told them last night I was planning to go with the renogy panels. d*
Can't wait to see what they come up with.
Larry
Guys,
I bit the bullet today and ordered 4 of those Renogy 300w panels. After I go by the bank tomorrow I will order the classic 150 and breakers etc. This should be a fair start to our adventure in real solar power.
Thanks to all who helped with my questions.
Larry
Finally got all my stuff ordered. After the bank shut my card down thinking it was fraud. [cool] At least they are watching out for the customer.
Don,
I was hoping to barrow some more of your fountain of knowledge. :) Trying to make sure we can use all the same stuff once we switch to 48 v and more panels. Also just really realized just how big this bank of panels is going to end up. [shocked] What is the formula for figuring wire size. I would like to be able to continue using the same wire when we switch to 48 volts I am thinking we will end up maxing out with panels on each controller. But I am not sure at this time how many amps thats going to be. So many numbers!
The midnite 150 controller looks to be most effecent (sp) around 70-100 volts going in. So should we keep them in pairs or step up to sets of three in series for a 48 volt system?
UGG Old dog new tricks! d*
Larry
QuoteWhat is the formula for figuring wire size.
Not a formula exactly, but a calculator. The one I use is an electrical design program on my computer. There are some online ones. Here's two...
1. http://www.nooutage.com/vdrop.htm
2. http://www.windsun.com/Hardware/Voltage_Calc.htm
As current flows along longer and longer wires there is more drop in the voltage measured at the far end. Ideally we'd keep that to 2 or 3% maximum; less is best. When figuring for wires from PV panels to the CC use the Vmp voltage figure and the Imp maximum power amperes.
On selecting a charge controller. Maybe you are aware already, but be sure to allow for the cold weather voltage spikes that occur with PV panels. There should be a safety factor. The best / safest method is to use the Voc figure for the panels. If 2 panels are in series multiply the Voc by 2. Then multiply the Voc total by 1.25 and multiply by 1.25 again. The result should be lower than the maximum input voltage for the CC being looked at.
The amps should of course be under the CC max amps rating. Same for the wattage.
Also as for how many panels in series.... from a post above....
The panels in series still produce a max of 8.56 amps but their maximum voltage output is doubled; that is the Open - Circuit Voltage (Voc) 46.12V X 2 = 92.24. take that 92.24 x 1.25 x a.25 and we get 144 volts. That is close to but still under the 150 max volts for the MN150. So stop at 2 panels in series. Series groups can be wired in parallel; 2, 4, ... panels. But I did not check the wattage limit so check that. This is why MidNight makes the 200 ans 250 models.
Midnight has a online sizing tool...
http://www.midnitesolar.com/sizingTool/index.php
Thanks Don,
Midnite also states in their owners manual that they produce more watts at lower incoming voltages. It looks like 70-100 volts is best through out their chargers. I need to find the manual again and link it. The salesman kept saying to put three in series but that doesn't fly. I think the reason most go with the higher voltage units is because of the distances involved. Thanks for the links, I will save them. You know I am not a well educated person but seem fairly lucky a grasping most of this stuff.
http://www.midnitesolar.com/pdfs/classicManual.pdf
Copied from page 11 of the linked manual.
For example: if you are using a Classic 250 and 48v battery bank, the maximum continuous output power based
on 25 degree C ambient is 55 amps when using a PV array that yields a Maximum Power Voltage of 180 volts. The
same set up using a bit higher voltage modules that result in a 200V Maximum Power voltage will result in only 53
amps. Although 55 to 53 amps is not a significant change, it does give you the idea that all things being equal, lower
voltages are a bit more efficient.
I tried to copy the graph but it wouldn't work, pages 10 and 11.
Larry
Here's a link to midnite solar string sizing guide.
http://www.wholesalesolar.com/products.folder/controller-folder/MidniteClassicChargeController.html#MidNiteClassicStringSizingTool
Larry
Using the data sheet here :
https://www.renogy-store.com/300-Watt-Solar-Panel-p/rng-300p.htm
for the panels and the string size here :
http://www.wholesalesolar.com/products.folder/controller-folder/MidniteClassicChargeController.html#MidNiteClassicStringSizingTool
for the controller If I plugged all the numbers in right then 16 panels 8 parallel strings of 2 @ 48 volts battery bank should give me the best bang for the buck. Would you agree?
Thanks
Larry
using a low temperature of -22 F and a high of 104 F that seems to work on a 150. I'd say good!
Thanks Don,
It has never gotten that cold here and we have seldom seen 104 either. Thanks for double checking my numbers. [cool]
Amazingly the panels have already shipped.
Did you see what I was talking about the lower voltage for the incoming PV? When figuring wire size what voltage do I use for the PV? Its seems like a dumb question but . I'm thinking 75 volts since if I understand this correctly the mppt is going to try and hold the panels at the optimum charging level. Jeez there's still so much I am not sure of.
I also think you for taking the time to share your vast solar knowledge.
Larry
Quote from: BiggKidd on November 14, 2013, 12:28:52 PM
Trying to make sure we can use all the same stuff once we switch to 48 v and more panels. Also just really realized just how big this bank of panels is going to end up. [shocked] What is the formula for figuring wire size. I would like to be able to continue using the same wire when we switch to 48 volts I am thinking we will end up maxing out with panels on each controller. But I am not sure at this time how many amps thats going to be.
I am away for a few days and the conversation picks up again, how exciting :D Larry if you are planning to upgrade to a 48v system in the future, now is an excellent time to consider your wiring infrastructure as presumably you are going to bury your 30ft run from the PV combiner to the CC and nobody likes to dig wire trenches more than they have to. While the suggested 10 gauge run would be sufficient for the four 300 watt panels in the suggested series /parallel runs it won't be sufficient for 12 panels(3600 watts) assuming you wanted to max out your single 80 amp CC at 48 volts in the future. You are going to be pumping out much more amps(~ 50)and at that distance and assuming 2 panels in series x 6 paralleled runs your going to need at least 6 gauge wire(2.4% voltage line loss).
Incidentally the following pdf http://lib.store.yahoo.net/lib/wind-sun/PV-NEC-V-193.pdf (http://lib.store.yahoo.net/lib/wind-sun/PV-NEC-V-193.pdf)is an excellent primer on the topic, it will likely answer most of your questions
I suggest that using the Vmp voltage would be about right as would be using the Imp current.
upa makes a good point about sizing the longer runs of wire to be suitable for the future expansion.
The paper upa pointed to is good. Wiles, the author is an expert in the field of PV and the electrical code. He's been involved in PV for many years.
Thanks Upa , Don,
Had to go out of town should be back home sunday night or monday. Yes I surely want to be able to use the wire once I make the switch to 48V. Now that I have had time to sit back and think about how big this is going to turn out looks like I'll have to move some (most) things. Including the battery building. Still thinking about the best way to go.
More tomorrow or monday.
Larry
The folks at Midnight Solar are super smart and helpful. I called them anytime I needed help with sizing breakers, decifering wiring diagrams, wire sizes, as nauseum. They did not laugh or get irritated, not once. They are super....I say if you are not absolutely sure. Just call them...it is actually fun to has a conversation and hang up knowing what is required. I would have been much more uncertain about my system expansion this summer without them.
Just got tracking info for everything I ordered. According to what they sent everything will be here by friday. [cool] When I ordered I got the impression it would be well in to december before everything got here.
Oh lord I hate mondays, on sunday I take my MS medicine mondays feel like the flu. >:( To make it worse my girls went to their moms this weekend first time all year and came home with ..................................... The stomach FLU !
Hey its november and she got them for the first time in a year and brings them home sick. >:( >:( >:(
As to installing the panels, I really didn't think this out to well. I just didn't do the math. d* Putting up the first four panels is no problem just requires a bit of prep work. Its the other 36 planned panels that are causing a problem. The panels roughly measure 40" x 76" x 2" so 40" times 40 panels = one looooooong rack. We are in a small clearing in the middle of the woods. Now taking out trees has always been part of the plan but not that many right away. We are also near the bottom of a hill. So you can imagine the corner I have painted myself into. Another problem I am having is getting a true compass reading. Since my battery bank seems to throw a pretty good magnetic field.
The biggest problem with taking out the trees is I am not ready to process these. I have been gathering up parts to make a bandsaw mill but haven't started building it yet. A lot of these trees are ones I am planning to use to build a log house. It will be roughly five years before I am ready to start on the "big house" which is also going up on top of the same hill. Five, six, seven hundred feet away.
So to make a long story short I think I will place these four panels on a pole mount. That of course means having to move them later. Surely could use some ideas.
Think I need to start my own thread so I don't junk this one up with my ineptitude.
Larry
Quote from: OlJarhead on November 10, 2013, 12:57:33 AM
Installed and set up my TriMetric meter today and after fully charging the bank it read 101% of charge.
THen after 4 hours of running the cabin (watching TV etc) I see it's reading 94% of charge. I was happy to see this until I saw the voltage was showing 2.4v which according to Trojan is only 60% of charge.
I'll have to shut down for the night soon so it will be interesting to see if the batteries increase a little in voltage but I'm a little confused by the 94% right now as it would seem that's not accurate unless I'm not understanding the way it calculates the percentage of charge.
Any ideas?
If I read you battery specs correctly you have around 15kw of stored potential in your 24v battery bank and your trimetric is saying you used 900 watts over 4 hours watching TV , sounds reasonable vs the 6000 watts based on voltage measurement only. I suspect the trimetric measurement via shunt is very accurate at measuring power coming in and out. Basing SOC on voltage alone is not so accurate. Keep in mind that Trojan's SOC table with open circuit voltage values assumes the batteries have been resting for at least 6 hours and it is also meant to be referenced with specific gravity measurement. If your temperature compensated hydrometer readings are ok, go with what your trimetric says if not, one or more of your cells could be on their way out and they may be dragging the good cells to a dysfunctional level.
Good post Upa an I agree with what you surmize though need to correct the numbers. My bank is 12 220AH 2-GCS Golf Cart Batteries in a 24v series/parallel configuration so I've actually only got 660AH of capacity assuming the batteries are still capable of producing max power after 3 years of use and abuse.
Having said that, though, I'm starting to realize a couple things:
1. Setting the TriMetric meter at 660AH may not be accurate since the batteries are often listed at 210AH as well. I may change to 630AH to see what it does then.
2. With the Freezer no longer running I see the generator no longer runs daily. It ran the 14th and the 16th and may run today but it's possible it won't if the sun comes out nice and strong.
3. Battery bank read 25.1v when I arrived around 6PM last night and drew down to 24.6/24.5 by the time I went to bed around 9PM (I was watching TV). This morning some 8 hrs later the batteries were at 24.6/24.5 still. Clearly leaving the inverter in sleep mode and only running the fridge and composter fan uses very little power and I should no longer have to worry about leaving for weekends etc. but more interestingly was the battery bank reading because it demonstrates that just because a voltage is recorded does not mean that you have a specific percentage remaining on the batteries. It takes more factors in order to determine that and there's a lesson there.
Oh and yes, the TriMetric meter has leads that run to both sides of the shunt as well as the battery bank (one side).
I suspect you are very under panelled for the size of battery bank and it is more apparent now that the sun is less seasonally helpful :(. I think I read somewhere your array was 600 watts, which with some quick math and assuming optimal conditions would only provide a 2-3% charge rate on a 660 amp/hr 24 volt bank. That would explain why your generator is starting up every day especially with the presence of a refrigeration load. Generally a c/10 or 10% charge rate is more desirable in a balanced system and this would probably represent a 2400 watt array. I think even doubling your array to 1200 watts would help quite abit, likely borderline in the depths of winter but likely ok in summer. If you have any money left in your budget I would look at more panels since they are fairly inexpensive at the moment.
In this case the system was build as a 12v system with 660AH at 12v and 615watts of solar at about 60v (MPPT controller), then I added 2 more batteries to take the bank to 880AH and the panels were doing fine there but when I converted to 24v I also added 4 more batteries taking me to 660AH (would have been 1320@12vdc) and really need another panel.
At the moment the fridge isn't an issue and the usage I have is working out nicely. It was the addition of the freezer that caused the headache as it was just a little too much with me also running lights and the TV etc.
So, today when I left the bank was at 24.4vdc and the sun likely brought it back up enough to last another day ;) The gen hasn't run since Saturday now and while it may run tonight when I get in and start watching TV it also may not.
So I think I'm ok now but if I want to run the freezer again I'll need more solar charging and likely a new bank of batteries with a little more capacity.
Thats Great,
Any day (s) without the genset running are good days. [cool]
PS My panels just got delivered.
Hi again fellow CPR'ers. I am now living full time in my off grid home and have a few questions for the experts. We have finally completed most of the work required to prepare for a Northern Minnesota winter so now I can work on a few pressing but non critical issues. POWER!! We have been running two generators for 100% of our power needs. A 2K Champion inverter is our primary source 90% and a Champion 9K fills in the balance. I have them wired to two different panels with a transfer switch connecting them. That way I can continually run the house off the 2K, fire up the 9K when we need to run the well pump and shut it back down. If we want to run the entire house off the 9K to run the microwave, hairdryer and other high wattage devices we just flip the transfer switch.
My question REFRIGERATION! Until now we have simply used coolers, yes coolers for a family of 6! My wife has been very patient but is ready for a real fridge. We had a small fridge but it was too much of a load on the 2K genny with everything else. I want to try two things. Since it is 7 degrees outside right now I want to cut a hole in the top and run a 1.5 PVC fresh air intake into the fridge, this should help substantially through March to reduce the electrical load. Secondly, I want to setup solar dedicated to the fridge. How do I calculate my needs for both PV collection and battery storage? I would also like to change the compressor to a Danfoss BD35F.
Thoughts?
Thanks in advance-Jon
I don't think the piece of pvc pipe will have a great effect unless the air exchange is fan driven. No proof, just a thought.
Solar for fridge. You have to start with the fridge and the power it consumes to work and give satisfactory results. The Danfoss would be a good compressor for a 12 to 24 VDC system. Would the BD35 have the capacity for the size of fridge you have in mind? I know they have programming that is used to suit them best to various configurations.
If I was going to the trouble of adapting a Danfoss I would also investigate how easy/difficult it would be to have the waste heat from the compressor stay in the house in cool weather but be vented outside in warm weather. We do that with a conventional refrigerator and it does make a noticeable difference in both winter and summer.
So anyhow once you know the watt-hours the fridge will use in a 24 hour period you can calculate the battery capacity. Keep in mind batteries are less efficient in the cold, how many days of cloudy weather you want to cover and the maximum depth of discharge on the batteries.
Once the battery bank size is known, with the local good sun hours known the size of the PV array can be calculated. Other variables such as choosing a MPPT charge controller over a PWM type have to be looked at and possibly matched to the specs of PV panels used.
But start with the watt hours of power needed.
Don- Im not sure how much effect the cold air intake will have either to be exact. I though about wiring a dc computer fan to a small pv panel to run during the day. Just based on my experience living in Minnesota I know cold air rushes in like a waterfall though an opening. I was just installing a fresh air intake for my Lopi Endeavor and when the 3" line was laying on the floor it felt like it was being forced in by a blower.
Im not sure about the effectiveness of the Danfoss BD35F, I just thought it would make sense if I had a dedicated panel and battery bank for the fridge to convert to DC and drop the inverter from the system. I dont even have the fridge yet, so once I buy one and know the draw I will start there.
I am going to run a propane fridge at my cabin.
No worrying about running my batteries down and the things will run a long time off a 100# tank. ;)
Propane fridges are another option. Ours does work well. When we bought it PV panels cost double what they do today. The propane fridge costs a little more today, but then batteries also cost a wee bit more today.
The Danfoss compressor sure is efficient and I like them.
The regular home refrigerator can be had in some fairly efficient models for much less than a propane fridge of equal size. But you have to run AC.
Several different ways to go... personally if I was doing the fridge thing all over today I lean heavily towards more PV and batteries and a regular residential refrigerator. Although it would also then be nice to have an auto start generator setup to cover things just in case the weather went solar crappy for a week.
I use a Danby fridge with no freezer. IT uses less energy and I have the option of running a freezer if I really need one (in my thread I mention that I've turned mine off so I don't really need it and it takes too much power to run).
IN the future I'll get a bigger battery bank and more panels and run the freezer too.
I think I am going to start with an older used fridge. That way if I cut a hole in it to pipe in the 5 degree air from outside all winter and it is not successful I am not really out much. I just cannot justify an LP unit. I think I would rather spend the money on an efficient standard unit and pv system for it.
Yes any day the gen doesn't run is a good day! Specially when the heaters are running!
Got this from Bogart:
QuoteHello again, Erik
Your're reading the percent right. But keep in mind that battery companies estimate the "capacity" of their batteries higher than is realistic. So 91% may be optimistic. The main value of this is that from one day to the next you can see your relative battery usage. And yes, voltage is a very poor guide to how full batteries are-- except when they are very full-- or very empty.
Also, I wouuldn't worry about getting the exact capacity entered in the meter-- the really useful part of the percent is to be able to compare your relative usage, (as I said). If you usually get down to 85% or so (say) and then one day it goes down to 70%, that tells you that you are about twice as far down as you were before.
As to voltage for turning on generator-- probably 23.8 could be reasonable. Even this might be a little early if you voltage was lower because of a high load you just had.
But when you get down to about 22.5 volts, then the volts number becomes significant to tell you that you are really low on power. Above 24V voltage is a very poor guide.
So I think setting the bank to 630 might be more realistic and I did this. I've got the switch set to 23.8v as a safe bet but I might lower it to 23.5v to see how that works out.
On a side note the boys were using the skill saw this past weekend when the gen wasn't running and the inverter didn't care one bit ;) The cabin was powered easily as well as the saw so I'm pretty happy with my 4k inverter now :)
Finally got my 4 little panels up today.
![](https://i129.photobucket.com/albums/p213/biggkidds/DSCN0034_zps93bf5492.jpg)
(https://s129.photobucket.com/user/biggkidds/media/DSCN0034_zps93bf5492.jpg.html)
A slow start to going solar with only 1200 watts. I also have six of the HF 45w kits that we have had a few years now.
Now I am still waiting on the combiner box to show up then I can hook it all together. I was able to keep some of the tilt adjustable I can adjust between 35 and 55 degrees. The tall front posts do create a small bit of shading but I think (hope) its worth it. In the picture the panels are at 51 degrees.
Larry
There are many things that we take for granted when we live connected to the power grid. One is the maintenance of the batteries in out motorcycles, ATV's etc. If the ATV or whatever gets taken back to where the grid is available connecting to a charger of some kind requires little thought. There have been 2 off grid approaches I have used; taking the battery home over winter and using a small PV panel to maintain the charge. Taking the battery home is a pita. falling tree branches do bad things to small pv panels.
We have an Outback charge controller. They have an auxiliary function. One of the options on the AUX menu is called float. When the main battery bank has gone through the bulk and absorb stages it goes into float charge. With the float function engaged a device can be switched on. I chose to have the float function activate a solid state relay switch.
The SSR switch is connected to the on-off remote on the Outback inverter. So when the CC goes into float the inverter is switched on. We make sure that when we leave all lights, fans, pumps, etc are all turned off.
This time of year when the cabin is left unoccupied the charge system goes through a brief daily bulk charge, a one hour absorb charge and then into float. On an average day float lasts for 3 hours, maybe 3.5 hours.
In the barn I leave a 2 amp battery charger connected to the ATV battery. It is plugged into a timer that is plugged into 120 VAC power. When the CC is asleep, in bulk or in absorb the timer and battery charger are off. When the CC is in float the timer is running. When the timer clicks into "on" mode the battery charger begins to charge the battery. It is set to allow battery charging for 2 hours every 12 hours of float time; 2 hours every 3 to 4 days.
I hooked it up November first. So far it has worked well. We went up just after C-mas. The ATV cranked over and started on one tap of the start button. Left disconnected overnight the voltage in the AM was 12.65; full.
It works for me and beats dragging the battery home. Plus the SSR came out of a surplus box.
I have long resisted the urge to buy a battery monitor for the cabin PV system. Partly out of my own parsimonious nature and partly because sp gr readings are a very accurate method of telling not only battery state of charge but the health of individual cells. However, now because of a top from one of the members here, I now have an Outback Flexnet DC (http://www.outbackpower.com/outback-products/communications/item/flexnet-dc) and I got it at a very good price. The ebay vendor (http://www.ebay.com/itm/New-Outback-Flexnet-FN-DC-Advanced-DC-System-Monitor-FLEXware-/380804633505?pt=LH_DefaultDomain_0&hash=item58a9b993a1) has one left although for a slightly higher price than what I paid.
When I get it installed and hooked up I'll report back. Use requires an Outback Mate which I have had since the system was placed into service.
It comes with the needed twisted pair wires and a Cat5 cable. In addition it does require at least one 500 amp shunt.
My system has only been up a couple of months but I am really starting to warm up to the flexnet monitor's utility. I have to admit I was a little skeptical initially on how useful it would be and I don't think it will entirely replace periodic checks of specific gravity, but on the whole it seems like a reasonably accurate measure of the energy that comes in and out of the battery. The connected mate can report all sorts of useful information from SOC to specific real time/historical amp/wattage draw and replacement. What I probably like most is that on the mate 3 the battery health can also be simply represented by just 3 brightly colored LEDs that you can clearly see from across the house(now that is mounted in the dining room not the power shed). This is brilliant for my wife who could care less what an amp is but has no problem appreciating green is good, yellow is caution(less than 80% SOC) and if she sees red she needs to get my attention :)
Funny that you mention that. I tend to use mine more as a voltage meter then a % of charge meter though I do look at that too. Now that I have it though, and understand what I'm looking at a little more I really like having it. I must also admit that I love the Magnum auto start switch too@! Specially since I can dial it up or down depending on my needs or time of day.
For example, when I know the load will be light and I'll be away I tend to set it at 23.0vdc which is about 80% on the % meter (really depends on loads and use ove a period of time and not specifically the voltage itself) whereas when I know the load will be heavier and I'll be using a lot of power in the evenings I set the switch to start at 23.5 to 23.8vdc and make sure the generator will come on to run it's 5 hours when I'm using the most power. That way if the sun didn't come out and the batteries are around 24.2vdc when I arrive at the cabin the generator will kick on shortly after I fire up my network and/or TV and will power the cabin while giving the batteries a good charge.
One thing I also do is set my inverter to sleep mode when I am gone. I love this feature because it kicks the usage down to between 5 and 20 watts and only kicks on to full power when something like the refrigerator needs it. This can make the differnce between the generator running daily on cloudy days (or every other day) to not running at all for a week.
QuoteI also do is set my inverter to sleep mode when I am gone.
Why only when you are away? Just curious. ??? We leave the inverter in search mode all the time so it sleeps when not needed. That amounts to most of the daylight hours of any typical day at the cabin.
Quote from: MountainDon on January 13, 2014, 02:34:59 PM
Why only when you are away? Just curious. ??? We leave the inverter in search mode all the time so it sleeps when not needed. That amounts to most of the daylight hours of any typical day at the cabin.
Because if it's in sleep mode the answering machine won't kick it on when someone tries to call me when I'm out working around the place (and have no cell coverage)...I discovered that the answering machine doesn't draw enough wattage to cause the inverter to 'wake up' so I miss calls and messages if I don't have it on when I am not there.
On the otherhand I flip it to sleep at night and when I am away.
This summer I needed to replace a DC motor speed control for our RCH ceiling fan due to a lightning hit. They now sell at about $100.
I found a speed control on ebay (http://www.ebay.com/itm/400623785332?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) for less than $8. The catch... ships from China and will not fit inside a std wall box. I took a chance and risked a total of $7.41 including shipping. Price today may be a little more.
Obtaining a working model was a bit of a task. The first one arrived with a really cold solder joint; a MOSFET was loose on the board. They shipped a replacement @ n/c. Each shipment was slooow; about 20 days from China. The second arrived with the srew that hold a heatsink to the MOSFET cross threaded and loose. The third one was the charm and arrived in great shape. I connected it to the fan Friday night. It works fine. The speed is adjustable from just above stall to full speed. It just looks funky.
The bonus is the other two controls also work after I re-soldered the one and found a tiny screw to repair the other.
The amount of time it took was a disappointment, but their customer service was good enough for the price paid.
When I get around to it I'll see how they work as a dimmer for 12 VDC LED's.
I chose this one because of the high frequency. There are lower frequency ones that are a little cheaper but there is a chance of hearing a buzz. Oh... in my application it also ran very cool as well as quiet.
:( I am not satisfied with this forum...
spammers usually are
Quote from: shohel1000 on September 24, 2014, 08:12:41 AM
:( I am not satisfied with this forum...
Strange post and it is not even a full moon........ Another group I follow went in the toilet this week. Attacked by four or five most likely one that is trying to bust it up.... Doing a great job of it.....
You Administrators do a remarkable job with this group. We have had our issues but pretty dog gone good info at the grass roots level.
Quote from: rick91351 on September 24, 2014, 10:06:05 AM
Strange post and it is not even a full moon........ Another group I follow went in the toilet this week. Attacked by four or five most likely one that is trying to bust it up.... Doing a great job of it.....
You Administrators do a remarkable job with this group. We have had our issues but pretty dog gone good info at the grass roots level.
And John also for selecting therm ! Where has Glen gone or has he found a full time job?
It's been a long time since I posted anything new to this topic.
Today I want to mention something new in the battery world. Lithium ferrous phosphate batteries, or LFP, also known as LifePO4 batteries. Note there are other lithium based battery technologies out there. LifePO4 are the safest... no bursting into flames like those on the Boeing Dreamliner.
They have great promise. They do not sulfate when left in a partial state of charge for example. They can also be severely damaged with improper charging or discharging. There is a whole lot of partially correct information out there. I've been looking at LFP for a few months and it has been a confusing time. I found one of the better, if not the very best, articles on this battery technology on another forum.
If interested in new stuff like batteries go have a read over here... (http://www.pbase.com/mainecruising/lifepo4_on_boats) That's page one.
Thanks Don, my GCB's are getting old (and abused) but sill holding out after 4 years of heavy use and I'm thinking next year I'll get a new battery bank (and double the capacity).
On a side note I finally sorted my charge controllers 'state of charge' light issue. Somehow 'd missed one dip switch and got it sorted today :)
Now I just need to survive another winter but I'm in pretty good shape I think.
I've been giving a lot of thought to my problem of trying to find some A-205-fa3 solar panels which appears to be pretty much impossible these days. You see I have three of these panels and could really use 4 or 5 of them but finding an 11.15IMP panel these days is nearly impossible (if not impossible) so I've been thinking that instead of going out and buying ANOTHER charge controller and 1000 watts of panels (or less) I might just bite the bullet and buy enough panels to get to around 1000 watts and under 150vmp and swapping out the panels.
Then I'd still have the current 615 watts of panels for another year when I can justify spending another $600+ on a controller for them and either using on another cabin or adding to my system to increase it's charging capacity.
Today's prices are pretty low and it looks like I can add 900-1000 watts of panels for under $1k which would get my charging up to what I need in the short term (since my 615 watts isn't really enough for my current needs (no pun intended)).
THoughts? IDeas?
I could use a few of those fa3 class panels as well, as we want to build a small 12V solar generator. Any idea why they are so hard to come by lately? My guess is that the panel industry is mainly producing for the rooftop grid-ties, and 12 volt is not used much now in those installations. Not much demand?
I think it's a combination of: Most people want higher wattage and higher voltage panels now so supply and demand is dictating the industry (i.e. you see a lot of 300+ watt panels in 24-48v now and few 12v.
Most systems you see being built today are 48v systems so all the professional shops are selling panels to suit.
In a way it's almost like the computer industry a decade or two ago with panels constantly increasing their capacity. You see few 200 watt panels (if any) but tons of 300 and higher...heck I think I saw some in the 390watt range recently!
I'd love a few of those frankly but the voltage was too high for my controller (max 150v)
The cost per watt is usually much higher on the so-called 12 volt panels. Unless one only needs a couple of panels I believe it is better to buy the larger wattage, higher voltage panels. Especially is the plan includes an MPPT controller anyhow.
Our GC-s's have been in service now for 64 months. For the most part they still perform very well. Two cells lag behind the others a little (lower sp gr) but the occasional equalization brings them back to being very close. I hope they go another couple years. At that time the LFP's (lithium ferrous phosphate) might be lower priced than today. There are some nice advantages but LFP also bring their own quirks along. Little, if any, room for overcharge / discharge errors. And the biggest bugaboo I see right now, other than initial $$ outlay, is cold weather. They do perform better than FLA in discharge mode, but they should never be charged below freezing. In many situations that will not be a factor, but in our case where the batteries will sit in an unheated space for weeks in winter, that is an issue.
...............
link to story (http://www.renewableenergyworld.com/rea/blog/post/2014/11/europe-is-still-1-in-relative-solar-energy-production?cmpid=rss)
linky (http://myemail.constantcontact.com/5--Off-Sale-for-one-week-starting-on-Black-Friday.html?soid=1102554981384&aid=tlSN284o4t0)
Grrrr....
After much debate, research, more debate and a call from SolarWorld I think I've gone about this wrong.
I can get away with 740AH of capacity on my battery bank, though it would be a bit small but with an average of 4.7hrs of sunlight at my location (the engineer at SolarWorld gave me that from a 40yr database he has) I would need 3.9hrs of charging (after bulk) to get the 740AH bank back to 100% after use. He's telling me to do that I need 6 280watt panels and another MPPT controller and this would leave my generator for only when it was absolutely needed. He's telling me that I never fully charged the GCB's on solar because my 605watt array just wasn't enough to do it and eventually they just wore out (sulfated etc). This would mean a $5000 build to add the 6 280watt panels, 8 batteries and an outback MPPT controller not to mention racking, wiring etc.
So what went from a $2500 +/- battery bank purchase has gone to double that to try to get enough solar to charge the bank enough that it will last a long time. He also told me that he's seen well maintained GCB's run 8 to 10 years (interesting).
So, what to do???
I might be able to swing the $5k but it will be a serious downer since I hadn't planned on it at all and don't really want to finance anything. Let's hope the biz has done well enough that I'll get a bonus big enough to cover that much cost.
I've been messing with the calculator a lot lately and plan to run these through it to see what it tells me but man I really didn't want to have to buy 6 new solar panels let alone a controller at the same time I bought the batteries.
If I input a fairly abusive power usage at the cabin I can use about 140AH in a day (TV, Internet, Fridge, Lights etc based on winter use not summer use) so by setting my autonomy to 1 day I'll need 8 L16's at 370AH ea for a 740AH 24vdc bank. I set it to 1 as the only time I'd actually be in that position is in the 4 months of low sun usage and during that time I'll mostly NOT use even half of the 140AH (more often than not I'll only use that 3 to 4 days out of every 2 to 3 weeks). So 740AH should be find since I do have a genny to back things up when the sun decides not to show up or I abuse the power. I just have to set the genny to run at a higher voltage to ensure the system doesn't drop below 20% DoD.
Next, if I put in 4.7hrs of ave sun (thank you SolarWorld) and I put in the 280watt panels (9.07Imp) it shows 4 of them not the 6 he calculated though I think his calculation was based on having to recharge the 740AH completed (maybe?). This does not include the 3 205 watt panels (11.07Imp) I already have so perhaps 3 of the 280 watt panels coupled with my 3 205's and I might be just fine. After all that will give me ~1445watts of solar charging which is more than double what I have now. I'm no expert but my 605watts maintained my GCB's pretty well when I wasn't abusing the system.
Price drops down to $3150 which s a lot easier to swallow.
So knowing what I've written here what are your thoughts?
The plot thickens! I used altestore's calculator to 'build' a system using my PV spreadsheet calculator to see what the difference was. Using 3380 watt hours per day, 24v system 2 days autonomy, 40F min temp it shows a 843AH battery bank then using 4.7hrs of ave sun I would need 935watts of charging and recommended 4 280watt panels for 1120watts.
This makes me think that going with 740AH and 1400+ watts of solar I should be good to go really.
QuoteNote: All calculations assume only a 50% discharge to your batteries to optimize battery life.
I'm seeing this a lot.
Question: To recover 140AH in a battery bank am I right in assuming:
1. That if I am charging with 11 amps at 54 volts and the MPPT controller reduces the volts to 30v that I'm then going to be charging at ~20amps?
2. If I am charging with 20amps from the MPPT controller I'd need 7 hours to charge 140AH?
3. If the above is correct to recover 140AH in 4 hours of sunlight I'd need 35amps of charging?
4. If the above is correct then by adding 4 300 watt panels with 8amps the MPPT controller would convert the 152volts (4 panels at 36v ea in series) to 30v and 40amps and would charge the 140AH in 3.5 hours?
Finally with the above can I assume that the 20amps from the first set of panels (3 205 watt 11.3imp panels in series) plus the second set of panels (300 watts 36v 8imp in series) 40amps the two working together would charge at 60amp and complete the charge in just over 2hrs?
What I am trying to do is determine exactly what I need to charge up my 740AH battery bank (when I get it and install it) with solar and 3 to 5 hours of sun (ave is 4.7 hrs).
I also want to make sure I understand what my generator needs to be set to to ensure a complete charge after a day or two without much solar. The inverter has a 50amp charger so I'm under the belief that if set at 100% of charger capacity it would take 2.8hrs to recover the 140AH of usage.
I'm using 140AH as it's the most I'd use in a day based on current calculations.
Any response appreciated.
QuoteCurrent Boost
Under most conditions, TrakStar TM MPPT technology will "boost" the solar charge current. For
example, a system may have 36 Amps of solar current flowing into the TS-MPPT and 44 Amps
of charge current flowing out to the battery. The TriStar MPPT 150V does not create current!
Rest assured that the power into the TriStar MPPT 150V is the same as the power out of the
TriStar MPPT 150V. Since power is the product of voltage and current (Volts x Amps), the follow-
ing is true*:
(1) Power Into the TriStar MPPT 150V = Power Out of the TriStar MPPT 150V
(2) Volts In x Amps In = Volts Out x Amps Out
* assuming 100% efficiency. Losses in wiring and conversion exist
That is from the Morningstar site on MPPT controllers so a quick calculation suggests the following:
3 panels of 205 watts @ 11.27Imp @ 18.2v in series will give 615 watts @ 11.27Imp @ 54.6v and when converted by the controller to 29.4v to charge a 24v bank will give 20.9Imp and 615watts (power in equals power out) if I understand the above correctly.
Quote from: OlJarhead on January 20, 2015, 11:18:20 AM
Question: To recover 140AH in a battery bank am I right in assuming:
1. 2. 3.
In a theoretical, 100% efficient world, Yes. Here on earth with the equipment and materials we have, No.
(a) Batteries will not charge at a constant rate from start to finish. As they become closer to full the amp rate will taper off.
(b)There will be some charging loss due to battery inefficiency as well as some loss as charge controllers are also not 100% efficient. As well, the greater the difference between the incoming PV voltage and the outgoing charge to battery voltage, the less efficient the CC is.
(c) The closer you can get the amps into battery current to be C/10 of the AH capacity the better off it will be. If too high amps then more energy is wasted in making heat which in turn will cause electrolyte loss to a greater degree. Too low an amp input and the time for a charge gets to be longer than the sun will be up.
Potential issue with scenario 4. The Voc voltage is too high for the commonplace 150 volt MPPT charge controllers. Midnite does have models with 200 and 250 volt limits that would be suitable.
Regarding the two strings of PV; old and new. Pardon me if I missed it but is the plan to use two charge controllers, one for each string, or to route all the PV through the one charge controller? Knowing the Vmp, Imp and Voc ratings of the two different panels would help in figuring how well they will play together.
The info from Morningstar is fine as far as it goes, but they do state in the last line that the example is for 100% efficiency. So the power out is = to the power in less the internal losses. I can always feel the loss with our CC's as they are almost always warmer to the touch than the surrounding materials.
My plan is to add a second string of panels (4x310watts) and a second controller (Outback Flexmax 80). If the Flexmax 80 can only take up to 145vdc input then I can make the array a series parallel system with two panels in series parallel to two more panels in series giving me ~72vdc input. Which will be fine with 10awg cables from 50 feet away.
QuoteWatts 310
Cells 72
Panel Vmp 35.80
Panel Imp 8.68
Panel Voc 45.42
Panel Isc 8.99
That's the new panels I'm looking at but frankly it will depend on who has stock etc when it comes time to buy.
What is 'c/10'? Capacity of battery bank divided by 10? If so I'd need to add 6 of the 310watt panels instead which would give me about 60Amps of solar charging on that array which, when added to the 20amps on the old array minus varius efficiency factors should work out nicely if I understand you correctly.
Another thing I've been contemplating: 740AH of battery cap would mean I'd have to run my generator 3 hrs every day if there is no sun at all and I use 140AH of electricity in the cabin. Thus on full usage I'd run as much as 90hrs in a month on the genny using approx 45 gallons of propane.
On the other hand if I had 1110AH battery cap and allowed it to run for 1.5 days without sun/gen I'd have to run my generator for a total of 4 3/4 hrs for a total of 95hrs per month using 47.5 gallons of propane.
My point? and these are rough calcs only, but with only 50amps of max charging capacity and a max timer of 5 hrs on the auto gen start I can run the genny daily for 3 hrs to give me 150amps of charging roughly vs running it every 1.5 days for nearly 5 hours to get the 220amps I'd need if I used 140ah in 24hrs. In other words, I'd have to actually run the gen longer despite not needing it as often.
Seems to me without a much bigger charger on the inverter I'm better off having a smaller bank with lots of solar and limiting use on cloudy days. Make sense?
QuoteWhat is 'c/10'? Capacity of battery bank divided by 10?
Yes; with the result being the number of amps that would be near to ideal for charging the batteries, nless the battery manufacturer recommends something different. You can usually charge at that rate and be safe and as quick as possible w/o overheating.
?? If the present charge controller could handle the watts from the new PV array how about buying a Midnite Solar Kid for the old set? The Kid can handle 150 volts maximum, 30 amps output to batteries and with a 24 volt battery up to around 850 watts of panels. Actually Midnite states up to around 1000 watts of panels for a 24 volt system would be a good match. That is because for most of the day the panels will not be producing the rated watt output. So for a short time (noonish) a good CC can handle the excess wattage. It does mean the output would be limited to the max rating; 30 amps on The Kid. Just food for thought as it is <$300 (NAWS (http://www.solar-electric.com/inverters-controllers-accessories/chco/misoclchco/midnite-solar-kid-mppt-charge-controller/midnite-solar-kid-mppt-solar-charge-controller.html)). We have one now; since lightning strike.
Regarding the panel watts and C/10 thing... Systems can also work / live, with having a lesser output from the PV. Ours, for example. But that is because we have more battery than we really need. I overdid the battery capacity. Right now if I was re-doing the batteries I would have either 8 GC-2 or maybe 4 L-16. But one disadvantage to the L16's for us, would be that tall case batteries should really have a higher amp charge to guarantee better mixing of the electrolyte from gassing.
QuoteIf the Flexmax 80 can only take up to 145vdc input then I can make the array a series parallel system with two panels in series parallel to two more panels in series giving me ~72vdc input. Which will be fine with 10awg cables from 50 feet away.
Yes, that would be about a 3& maximum voltage drop at 72 volts and 18 amps. That's workable.
Never been really happy with the MorningStar MPPT controller or their support so I'd rather relegate it to 2nd fiddle ;)
I'm currently running 12 GCB's but as mentioned in my cabin thread pretty much smoked them this winter :( Oopsie. SO I'm working working working the PV Calc tool to come up with something I can live with and am fairly certain 740AH of L16's is going to do the trick. Of course, from the above you're suggesting I have 74Amps of charging but I think I can do well with the 60Amps, after all I have both the autogen start and don't spend as much time up there in the winter anymore so likely will get a lot more sun then not. In the summer I can see good charging from early in the morning (7-9 is a trickle but it comes on hard before 10am and runs very very strong past 3pm...usually I use less power than is floating by the sun until the night starts to come on.
I just thought I'd toss the lower cost option of the Kid in there. :) I do like the Outback equipment. I especially like it when one of their inverter/chargers is a part of the system as it can all be tied together with a Mate. But if there is no other OB equipment in the system there is also the choice of the Midnite Classic. Both MN and OB are better than MS. FWIW, the MN software is a little more aggressive than the OB. I notice that the MN wakes up earlier than the OB ever did. Not that it produces much power at 8 AM, but it is on the job early. Also FWIW, the OB founders/engineers are the folks who started and now run MN.
Interesting, looks kinda like the OB too. The FlexMax 80 is a couple hundred less than the MN Classic by looking at MN's site but that might just be retail.
Quote from: rio on June 05, 2015, 04:07:51 AM
Off-grid throws away 30% or more of your solar power in charging/discharging losses as shown to the right. Further, battery systems throw away another 50% of your annual incoming solar power because the battery can't save the excess power in summer for use in the winter when you need it . 8)
Point being? In many of the cases here 'off-grid' means we're too far from any grid to even consider grid tie systems...we're off the grid in more ways than just a cable ;)
Quote from: OlJarhead on June 05, 2015, 12:09:55 PM
Point being? In many of the cases here 'off-grid' means we're too far from any grid to even consider grid tie systems...we're off the grid in more ways than just a cable ;)
Some of us are even off the map. Hope you are doing well and hey Don! I have been lurking incognito! Friday!!!
Quote from: Dave Sparks on June 05, 2015, 02:38:00 PM
Some of us are even off the map. Hope you are doing well and hey Don! I have been lurking incognito! Friday!!!
Glad to see you post Dave.... thought maybe the killy-wiggles might have toted you off... ;)
Quote from: OlJarhead on June 05, 2015, 12:09:55 PM
Point being? In many of the cases here 'off-grid' means we're too far from any grid to even consider grid tie systems...we're off the grid in more ways than just a cable ;)
Yep!!!
My place is 15 miles from the grid. ;)
Some of us are still kickin' here ;) Glad to see you're still with us :)
Sometimes life catches up and this last month they found out that I was overdue. One of my neighbors got sick and my old grey male feral cat got sick. Then the replacement cat would not play well with the senior outdoor cat.
My wife is always saying stay away from any hospital. She has a ton of nursing behind her developing that sentiment. She likes this quote as far as medical things go.
There are two dangers that arise form being ill informed.
One is that you will do something stupid.
The other is you won't realize what you have done! William F Sharpe
So this month we are going stay under the radar and work outside on the house. Having avoided the big killy wiggles last month (thx rick) and looking for the marine half of the family camping out here for a Canadian whiskey taste test soon. Might even have time to finally hire John and get a real architect to make our boxey place have some curves.
How many of you folks really chose to be away from the power lines? I know we did and recommend it! c*
c*
Most of my goal for wanting to build is to be away from those nasty lines.
I don't want to hear or see anything electric... the most I can stand is a fridge by necessity (solar and battery, propane) and LED lights.
Maybe a pump... but even there I might go manual.
Quote from: Dave Sparks on June 07, 2015, 03:39:40 PM
So this month we are going stay under the radar and work outside on the house. Having avoided the big killy wiggles last month (thx rick)
Not a problem Dave... Really don't know what one is but my buddy the ex 'lectrition now coffee house owner use to talk about them. Sort of guess I would figure whatever it is when I run into one.... Sort of like Olympia Beer and their artesians. Knew sooner or later knew was going to see one so I quit.... COLD TURKEY..... Yeppers c*
My father would poor out all the beer I put in the refrigerator unless it was his Olympia brand. I think that may be a willy nilly.
Quote from: OlJarhead on June 05, 2015, 12:09:55 PM
Point being? In many of the cases here 'off-grid' means we're too far from any grid to even consider grid tie systems...we're off the grid in more ways than just a cable ;)
OP post removed as pointless. FWIW, it was posted from Mohali, Punjab, India
Quote from: Dave Sparks on June 07, 2015, 03:39:40 PM
How many of you folks really chose to be away from the power lines? I know we did and recommend it! c*
c*
We did not choose to be away from the power lines as a prerequisite to buying the property. However, even with the lightning damage last year, I am happy with the choice. A monthly power bill for when we are not even there would start to add up after this length of time. No grid tie net metering available there either. With a small increase in PV capacity I am now reasonably confident we could go with a new small electric (Energy Star) refrigerator in place of the 8 cu ft propane burner fridge.
When you start shopping for an electric frige check the access for cleaning the coils underneath. Some are so tight that there is not a vacuum attachment made that will get in there. In that case you have to use a spray coil cleaner and hope that it does not react poorly with the coils or damage your flooring. Nice to bask in the glow of an electric LED light. You will be living the high life! Hope you all have a safe fire season. We call it the mean season.
I love our LED's! That is all we have now. I made a set of strip lights at the kitchen counter. Direct China import, run on DC avoiding the inverter as there was DC present for the water pressure pump. I could get rid of one of the parallel strings of batteries we use so little power now. The inverter on idle uses as much or maybe more than our normal complement of a couple of LED's for reading at night. But we do have a bigger TV now... 40" LED.
Quote from: Dave Sparks on June 13, 2015, 09:42:51 AM
Hope you all have a safe fire season. We call it the mean season.
We have had one of the wettest months of May on record. :) Many years we have campfire restrictions by Memorial Day. Not this year. Grasses are growing well. That may be bad news later if or when it gets dry. But the ground and ground cover that is usually quite dry already is moist at present.
I meant the propane reefer being replaced with an electric will allow you to bask in the LED light of the fridge. It's a man thing......
We have a new plane flying for Cal fire this summer. It is an old P3 Navy 4 engine prop that was a submarine killer. It can really fly low & slow over our roof. Much better sound levels than the DC-10 that ran full power when at low altitude. Better hold off on losing batteries until you get the electric fridge.
I have a retro fitted LED light in the Servel fridge.
Runs off the solar batteries now instead of D-cells. 8)
Wow you are really living! d* we just used a flash light back in the day. Say hi to Karen!
PV panel output voltage drops as the panel heats up. A panel laid flat or nearly flat on a roof will run at a higher temperature than a panel mounted so air can freely move around it, like on a pole top mount.
Conversely, as a panel is cooled, as on a -20 degree day, it's output voltage rises. Cold weather performance is enhanced. This is good as cold weather usually means shorter days, fewer hours of sunshine. That won;t make up for the greater number of hours os summer sunshine, but it helps. <removed unrelated ad - moderator>
Hi folks. I'm looking for a quick sanity check. I'm considering living in a small cabin in northern Wisconsin with no access to grid power. Could I buy a solar system that might keep the wife reasonable happy for $5,000 to $7,000? It would need to provide power for lights, clothes washer, freezer, refrigerator, laptop, stereo, tv, and various other small appliances/electronics. I have some light electrical experience but have never worked with solar. I'm willing to research/learn and do the work myself. Is this anywhere close to realistic or a recipe for divorce.
Thanks
Yes, no, maybe.
There is a calculator here that will help but you must really look at what you need vs what you want and how many amps you'll use in a day etc etc. If you went with 48v system and GCB's you'd be looking at 16 batteries (~$1500) to give you 440AH@48v and you'd need about 10 panels of about 8amp ea (Sunelec that would run about $3300) an Aims inverter ($1500), say another $600 or so for a controller and then you need cables, breakers, etc etc....that would be twice the system I'm running now and I'm just scratching the surface so I guess you could say a tentative yes provided you spent some time figuring out how much power you will use exactly.
And don't forget the backup generator (in my case the Eco Gen ran about $3500)
Quoteclothes washer, freezer, refrigerator
How new or old are the appliances? Recent high efficiency appliances would be necessary or at least highly recommended to go 100% solar powered.
No range was mentioned. Probably because a propane range would be planned? That is good as cooking on an electric range doesn't work too well with solar power and batteries. However, there is a gotcha. The vast majority (99% ? ) of gas ranges sold in the USA require AC power to operate the oven, even if the oven is gas fueled. The vast majority of ranges, all the common names, use a heater bar or glow plug for the oven gas burner. IIRC they consume 400 watts IIRC, possibly more, and are on the full time the oven is turned on. Chances are excellent that if the range has electronic ignition for the stove top burners it has a glow bar / plug for the oven. There are some ranges made w/o the oven burner heater bar; Peerless Premier is the name that comes to mind. Or you look for an old range that has pilot lights for the burners and the oven, like we did. That has the downside of gas waste and the heat from a continually burning set of pilots.
No mention of space heating or cooling. Standard air conditioners are another bottleneck off grid. There are some highly efficient mini splits with amazing SEER ratings. Quite usable off grid. Can be used for heat in winter too.
Once past those hurdles it gets easier. LED lighting saves a lot of energy. Ditto on modern LED TV's. On TV's and things with remote controls... they all consume power when sitting idle, waiting for a command from the remote to be turned on. A solution to that is to unplug the unit, or to use a switched outlet. That works good. Be aware that some TV's lose their settings when the power is turned off. We returned a TV that returned to the setup screen every time power was interrupted because of that. I don't know how many have that issue.
So,... start with power needs estimate. A good estimate. That will help to determine the capacity of the battery bank required. That in turn helps to size the balance of the system.
If this is your full time residence remember you own the power company. If something happens, and things do happen, you are the service department. Because of that I recommend using top quality name brand equipment. There are many brands out there. Only two manufacturers that I am aware of make complete systems; Outback and Schneider. Keeping to one of those for the charge controller and inverter allows meters and controls that unite the system. The parts work together. I recommend giving serious thought to that. Those brands will raise the price, but also raises the reliability level. If struck by lightning, for example, an Outback inverter / charger can be repaired in the field by installing new circuit boards.
How much good sunshine does your area get? Especially in winter. I am spoiled by the sunny skies of the SW USA.
Can it be done for 5 - 7K? ??? I am doubtful, buy not certain how much more. Depends on the power capacity you need to make everyone there happy.
Oh, then there is a well pump. Most of the time, unless you are going to collect rainfall. How deep are wells in the area? Deeper = more power to lift the water.
An alternative to doing all your own research and design is to hire a competent designer / installer. We have a member here who does exactly that. Dave Sparks. He won't come out and advertise himself here, but I have no qualms about referring him. Email him (offgridsolar@sti.net) if you want. He will give you an honest response. I would trust him to design a system for myself or any of my friends or relatives.
Thanks Don ! I just finished one for this really beautiful Log cabin. The owner who had been running a Diesel for 20 years got tired of the maintenance. He did not want solar because he said he won't live that long. So one route to keep cost down is a battery based inverter / charger. With a 3 hour daily generator run time and once a week a 5+ hour run even Wisconsin is doable.
All of the guy's questions here need an answer and you can always add the solar later. Unlike where Don lives you will always need a good generator. I hope this helps you and there is a link to my web page over there somewhere if you need to do this soon! Is today the Equinox?
d* I have a friend in WV who has a generator based system as Dave described. Member Redoverfarm. :) He uses a Magnum inverter / charger along with a propane fueled Generac generator. Single string series, 48 volt battery bank. Runs a well pump too.
Thanks for the replies. That's exactly the feedback I was looking for although not the answer I had hoped. I'm hesitant to spend too much more because I don't think I'd get it back if we ever needed to sell. Wisconsin is not very remote (at least compared to places out west) so buyers can find something relatively close by to almost anywhere with grid power. This place is a 700 sqft unfinished cabin. No drywall inside so wiring would be easier. No appliances yet so I'd be starting from scratch. Don't need AC up here. There are a few hot days but we do without it where we live now. My plan was to heat primarily with wood and use propane as a backup. The well is about 50 ft deep. I'm not in love with the generator idea because of the increased dependence on fossil fuels. Even though I love the location maybe I'd be wiser to keep looking.
have a stream on your property?
http://www.powerspout.com/
Quote from: cbc58 on September 22, 2015, 08:53:23 AM
have a stream on your property?
http://www.powerspout.com/
No stream. It is adjacent to a river but it gets quite cold up here (-30) so I would guess that things might freeze up. It's also pretty low gradient.
Consider moving to the Southwest US if you do not want to use a generator. It really make sense if that is important to you. Pick a place in the foothills somewhere with 15" of rain or more, a blue oak woodland or similar, and property that is wide open to the sun or on the right side of the mountain.
Quote from: Dave Sparks on September 22, 2015, 09:55:11 AM
Consider moving to the Southwest US if you do not want to use a generator. It really make sense if that is important to you. Pick a place in the foothills somewhere with 15" of rain or more, a blue oak woodland or similar, and property that is wide open to the sun or on the right side of the mountain.
I lived in central Arizona and northern New Mexico for a few years each. Liked both areas, especially New Mexico. Loved the mountains and the huge swaths of public land. The downsides I noticed were expensive land, particularly if water was available, and struggling schools in more rural areas. I've got a young child so that limits the places I can consider. I'm not opposed to having a generator as a backup. I just wouldn't want to rely on it constantly.
Yes, we love our sunshine! :) And very little snow to shovel. Mostly I don't.
Quote from: MountainDon on September 22, 2015, 01:25:03 PM
Yes, we love our sunshine! :) And very little snow to shovel. Mostly I don't.
Up here in the great white north we just look at it as our gym routine. ;) Me thinks your missing out on a great deal! rofl
Quote from: MountainDon on September 22, 2015, 01:25:03 PM
Yes, we love our sunshine! :) And very little snow to shovel. Mostly I don't.
By the way when it does stop snowing we do have brilliant sunshine 8) in between snow storms and snow squalls........
I lived in the great white frozen north for most of the first 38 years, 10 months, 29 days of my life. Latitude 49.8994° N.
I think I have the best deal where I am now. Latitude 35.2861° N 1010 miles further south ;D
The northern place actually has more days rated as sunny (316) than where we are now (278). However, the days down here have more hours of sunshine, and less difference between hours of summer and winter sunshine. Back north the winter cold combined with the short days get to be a real drag. At least for me.
Quote from: MountainDon on September 22, 2015, 02:18:57 PM
I lived in the great white frozen north for most of the first 38 years, 10 months, 29 days of my life. Latitude 49.8994° N.
I think I have the best deal where I am now. Latitude 35.2861° N 1010 miles further south ;D
The northern place actually has more days rated as sunny (316) than where we are now (278). However, the days down here have more hours of sunshine, and less difference between hours of summer and winter sunshine. Back north the winter cold combined with the short days get to be a real drag. At least for me.
We are not very far from the 45th so I understand completely the short day cycle but so love the long day thing..... One reason I wanted to move to the mountains was the lack of inversion (fog), Boise valley can get bad - very bad and dreary especially on those really short day light days.
61 degrees and got 4 inches of snow last night. Temp is 42 and sunny now!
It seems as though the amounts of snow vary widely from year to year here in Canada. This year we got a few inches and then it rains. Right across Canada it has been quite warm but extremely gloomy this winter so far, so there has been little to no snow on the ground.
Btw, I crunched the numbers for power use again on an off-grid solar system. It's hard for me to live on anything less than about 4000 watts a day and to go off-grid the costs with no generator seem exorbitant and the project exceedingly large. Depressing.
Living off grid really does mean giving up a lot of power hungry items or learning to use them sparingly when the gen is running. Unless of course you have a ton of money to spend ;)
I think it's more about independence and sustainability vs cost savings.
4 KwH a day is not bad for use. That's about a third of what we use at home and about 3 times as much as we use at our cabin. Calls for a healthy sized battery bank though.
4KWH is what most offgrid homes use when conserving in my opinion. Cabins a little less. Hard to do this up north without lot's of generator use. The other way to bring this number down is a propane refrigerator or something that gets away from an electric refrigerator cycling. I have a client in Alaska doing this with 12 KW of solar and very little generator use. Anything can be done if the strategy is right.
Yes, the more you can reduce your electrical dependence the easier it will be to run off grid mostly solar.
I'm planning to run propane fridge, stove, wall heater and main heat will be a Wiseway pellet stove.
Pretty much the biggest electrical draws will be my espresso machine and microwave.
Lighting is going to be 100% LED as well.
TV and SAT dish are the only other real draws on the system.
Can't miss my hockey games just because I'm in the bush now can I? ;D
Plan on vacuuming?
Water Well pump?
I thought I was ahead of the consumption when I installed a Grundfos 240v pump which is a slow start using 9.8 amps. No one ever mentioned that to attain that 9.8 amps of AC it would take 31 amps of DC. Biggest consumption is the flush toilet. If I could just convince the ladies to hit the woods. Nope not going to happen. ;)
Quote from: Redoverfarm on December 10, 2015, 01:02:19 PM
Water Well pump?
I thought I was ahead of the consumption when I installed a Grundfos 240v pump which is a slow start using 9.8 amps. No one ever mentioned that to attain that 9.8 amps of AC it would take 31 amps of DC. Biggest consumption is the flush toilet. If I could just convince the ladies to hit the woods. Nope not going to happen. ;)
If it's yellow let it mellow if it's brown flush it down.
Something that could help some with the power use would be a dual flush mechanism; low volume for #1 and higher volume for #2. We have a couple of the kits sold by MJSI (http://www.gomjsi.com/products/dual-flush-converters/) in our 2 toilets. The volume is user adjustable. We have one with the button and one with the lever control. The lever type requires less finger force that the button. But the button best suited the one tank with a side mount control. With the current model (with a green inner flush "cable") it is possible to change from one type to the other. Ours (with a blue "cable") can not have the handles switched. We use less water since installing them. We've had them since June 2012 and they continue to function with no attention needed.
Don both of the toilets are dual flush low consumption. Now whether the guest know to use them accordingly I am not sure. Just one of those things I will have to live with until later. ;D
Quote from: Redoverfarm on December 10, 2015, 01:02:19 PM
Water Well pump?
I thought I was ahead of the consumption when I installed a Grundfos 240v pump which is a slow start using 9.8 amps. No one ever mentioned that to attain that 9.8 amps of AC it would take 31 amps of DC. Biggest consumption is the flush toilet. If I could just convince the ladies to hit the woods. Nope not going to happen. ;)
Use a 25+ gallon pressure tank, a pressure switch and you can flush most of the night without cycling the grundfos.
Yep got that and it works fine for the family. But there is several occasions when there is 20-25 people there and the tank doesn't have enough capacity to keep up. But w/o an extremely large storage capacity it can not be helped.
![](https://i220.photobucket.com/albums/dd161/redoverfarm/hightop/100_4683-1.jpg)
(https://s220.photobucket.com/user/redoverfarm/media/hightop/100_4683-1.jpg.html)
A couples sizes up on the pressure tank in my opinion, but with that many people....
Low flush composter works for me but I never have more than 8 or 10 people and that's rare. Then an outhouse will do the trick which we also have ;)
Our property is essentially one big hill, which drops 500' from the top down to the water. We have cleared several acres at the top, and will have a barn there, but do not want our house up there. The house will be part way down the hill (200'?), on a relatively flat area closer to the water. The kids want cabins right down by the water.
Since the hill slopes down to the north and east, the top is really the only area where we can get direct sunshine for most of the day. That means that the solar panels will be at the top of the hill. How should we deal with having the majority of our consumption (the house) being a couple hundred feet from the panels? Higher voltage means smaller wires, so I expect that we will run as high a voltage as reasonable to be able reduce wire costs. This will probably be standard 120/240 AC, but I welcome any feedback to suggest other options.
Worse yet, the cabins will be several hundred feet farther from the panels. I expect that I could have an additional battery bank near the cabins and charge them via AC at relatively low current, so that their local batteries can provide or augment their needs, and so reduce the wire size for that long distance. Is this feasible? Are there reasonable options?
1. House a couple hundred feet from the PV array.... It makes sense to me to series connect PV panels and run higher voltage DC to the cabin where the charge controller and batteries are located. That is what we did, for a 325 foot distance. In general select a solar charge controller that can handle at least 150 volts DC input like the Outback FM. Midnight has some that handle 200 and 250 volts, Morningstar has one that does 600 volts as does Schneider in the Conext SW series. Magnum offers one that is rated for 200 volts. Some of those are quite expensive.
Keep in mind that when you series connect PV panels to raise the voltage, the charge controller loses some efficiency in dropping the high output to 24 or 48 volts for the battery. However, with a wire run of a couple hundred feet that is probably a good trade off, IMO.
Also keep in mind you are building a system; PV panels, charge controller, batteries, inverter. When the equipment is all from the same family they can communicate with each other. One remote can function with the CC and the inverter.
Have you determined the probable daily consumption? That determines battery bank capacity which then allows calculation for PV capacity, charge controller. Consumption also determines inverter size of course.
2. A further 200 to 300 feet from house to a cabin or two.... How much power capacity will be needed for a cabin or two? Need a good estimate on that too. On first thought it would seem that running 240 VAC from house to cabin might be the best. ??? Then split that 240 AC in a service panel to have the usual twin 120 VAC setup. But I am out of my comfort zone on what is best for that.
Will you require 240 AC for the house? Like for a well pump or whatever?
As for having a second "cabin" battery bank and charging that with an AC supply, seems like there would be a lot of total loses with all the DC to AC, and AC to DC and back again if the cabin is to use AC power for lights, etc.
No power grid available?
Anyhow that's thoughts off the top of my head... need more capacity required numbers to get more helpful.
2 final notes: 1.... regarding series connecting panels for a high voltage DC run... The coldest possible temperatures need to be factored in as cold raises the voltage output of a PV panel. Just thought I'd mention as I have no idea of your knowledge level. All the major charge controller players have online string size and charge controller calculators. 2.... lightning is very destructive if it strikes an array. I'd recommend giving protection a lot of thought, especially with a hill top array. Been there, had that done to us.....
Why not put everything in the barn up on the hill and run AC own to the houses? You can run AC a lot further without much loss.
For the distances being discussed, say a maximum of 500 feet from top to bottom, there is very little difference between AC and DC transmission losses. It is mainly a question of volts and amps. AC does have the advantage of lower cost disconnects and fusing compared to DC. It could be worth a look at it.
A detailed look at what the actual AC and DC loads in the house and the cabins needs to be done before any real planning on one system vs another, IMO.
Quote from: MountainDon on January 10, 2016, 11:05:02 AM
For the distances being discussed, say a maximum of 500 feet from top to bottom, there is very little difference between AC and DC transmission losses. It is mainly a question of volts and amps. AC does have the advantage of lower cost disconnects and fusing compared to DC. It could be worth a look at it.
A detailed look at what the actual AC and DC loads in the house and the cabins needs to be done before any real planning on one system vs another, IMO.
Totally agree and even longer distances than 500 feet. Much better to keep all the electronics and batteries close to the house and run DC the distance. Run the DC at 300 to 400DC mppt and live the good life! I do this as much as possible for my 85 offgrid homes.
First, thank you for the replies. The internet is full of information, but these few paragraphs here have given me more insight than many hours of online searching and reading.
We will need 240 at the barn and possibly at the house. Occasional tools usage at the barn, and possible well usage near the house. Well is actually TBD. A local well company said wells in that area are generally about 500' and $10,000. Our nearest neighbor collects water into a cistern from 2 year-round springs, and said he has found at least one spring on our hill which may be a better option than the well. I will verify necessity for a well.
I have done some power estimates using our home as the example, and will grab actual info from our next bills. We are terribly wasteful in our current (pun intended) power usage, with AC, 2 refrigerators, 1 large freezer, incandescent bulbs everywhere, several TVs always waiting for input from a remote, etc. Our youngest children have been (almost) gone for several months, and we already see that our electricity needs will shrink drastically. One of the refrigerators will go, and the freezer can shrink by 1/2. The AC will morph into mini-splits, and whatever TV we keep will probably get turned OFF when not in use. We will not have natural gas in Tennessee, however, so may use electricity to replace some of our current gas usage.
We will not have a grid connection. We are about 3500 feet from the pavement and nearest power line. Our nearest neighbor was told it would be over $20,000 for them to get power brought in, and they are less than half that distance. $30,000 - $40,000 for us to run power lines through a forest full of line-breaking limbs seems a poor investment.
The cabins ( 3 @ 16' x 24' ) will each have lights, a small fridge, and a microwave. Probably also a TV for DVDs and video games. Propane for cooking, heat and water heating. I expect no AC. Water will be piped in from uphill, with pressure regulated at the cabins.
As I get better usage numbers I can better size the system, but am hoping to determine how to do it, then later figure out how big. FWIW, the property is at about 36.45 degrees north latitude. Again, thanks for the feedback.
Quote from: Dave Sparks on January 10, 2016, 02:26:56 PM
Totally agree and even longer distances than 500 feet. Much better to keep all the electronics and batteries close to the house and run DC the distance. Run the DC at 300 to 400DC mppt and live the good life!
I had to ponder this for a bit, but think I get it. The high voltage DC reduces voltage drop because there is less current than at a lower voltage. Any voltage drop from transmission losses will be between the panels and the house (batteries, electronics). The controller will convert this DC (at whatever voltage) to the appropriate voltage for charging the batteries, and the inverter can then provide AC at full voltage without the line drop. If converted to AC at the panels, the AC voltage at the house could drop considerably.
Transmission losses still exist, but do not affect the AC voltage at the house.
A possible downside would be more expensive high-voltage DC switches and breakers?
Thank you.
Well, voltage drop is voltage drop, AC or DC is for our purposes the same. It does take DC rated switches and other components.
But yes the high voltage will mean less current and so there will be less loss or drop. And the best part is # 8 or so wire for a 5,000 watt solar system.
You are right the new roof solar converts the DC at the panel and makes it simple for residential as there is not a DC run. I dislike them because in hot climates electronics on a roof is just against everything I know.
The cost difference is small for DC rated components, especially if you are my client....Drop me a line or go to my webpage
Shameless plug but actually a very good deal for anyone who can do the basic handyman skills of installing solar. All the other things I help with are on my webpage!
FWIW, I believe you can trust Dave and what he says.
Quote from: Dave Sparks on January 21, 2016, 03:23:03 PM
Well, voltage drop is voltage drop, AC or DC
Thank you for the reply, Dave. And yes, Don, Dave seems to really know his stuff. I am glad I asked my questions during one of Dave's "very active" phases. : - )
It seems to me, though, that having the long run be DC between the panels and the controller and batteries would be better regarding the drop. The voltage drop will happen there, but the controller will then correct it to the proper charging voltage for the batteries, and full converted AC voltage will be available at the house.
If The AC was converted at the panels then sent the 300-400 feet to the house, the voltage drop would mean that AC house voltage would be lower.
The drop still happens, but the house voltage is good. If converted at the panels house voltage is reduced.
Don, I am still really happy about the LG linear fridge compressors you pointed me at. That was the last load in an offgrid home that had a surge with it off my list.
Not because of the surge load on the inverter but alot of ambiance is lost when a dimmer for lighting has a slight flicker from the fridge cycling.
I have had to run two lighting circuits for a few clients who had this way up on their list. I did agree with them also!
I have to put a word in here about used forklift batteries..... Super.
So much better than the old L16's I have been using. I got one from my brother years ago and rejuvenated it.. bypassed one bad cell and charged it up. It was a 36volt that fell off a scrap trailer breaking a couple cells. I found 24volts in line that were good and tapped into them then later had to take one cell out and hook to one of the spare cells that were good.
They are gigantic 2 volt cells with a lot of capacity. Makes me think one would be ahead to just buy a forklift battery new rather than spend tons of money over the years replacing so many L16's or golf cart batteries. :)
Hey Glen,
I have your phone number you left a few weeks ago. Glad you are back in the county!
The problem with forklift batteries is they are too heavy to easily move around. Someone like you no problem.
The other problem they have for Offgrid is they are designed to be deeply cycled and charged for 16 hours or so. They work an 8 hour shift and charge for 16. People do use them offgrid but they really need to know what they are doing or they end up with problems long term.
I pretty much use the 2V 1,100 AH L16 and get 10 years or 5 if the client does not follow the rules.
With the newest battery technology hanging on the wall, like the Samsung Lithium Ion NMC cells there are some nice things ahead if they can make them safe enough for your home.
I am hoping to get another couple years out of the golf cart batteries at our cabin, then see what the market has to offer in lithium batteries. Our GC-2's were put into service 7/2009; 81 months ago. They don't get used every day though; good / bad. Or maybe just do another set of GC-2's, though I like the apparent ability of the LFP batteries to be stored at partial charge over many months.
There is alot to like about the Lions but there are some spectacular U-tubes about how they fail. I think I would rather have lightning! ;)
But they can be done right! One of the challenges for someone who sells them is that they become HAZ MAT when on the shelves for more than 6 months.
But they're not HAZ MAT after being installed for more than 6 months? ;D
I haven't looked for any youtube video fails... are they LFP or some other Lion? I have seen a couple of cylindrical 3.7 volt cell fires; INR or ICR. LFP is supposed to be safer?
I can't say what I think yet because of an NDA. But, there is no rush to know this yet as none of the biggies are selling them yet.
I am talking the biggies, the Schneider's and the Outbacks.
Whenever you can tell whatever, I'll be interested. :) I would like to see one or both of those biggies do something in the lithium battery field. Too many small, unknown names saying lithium is the best thing since sliced bread.
Next year! [cool]
Quote from: old_guy on January 21, 2016, 08:26:34 PM
Thank you for the reply, Dave. And yes, Don, Dave seems to really know his stuff. I am glad I asked my questions during one of Dave's "very active" phases. : - )
It seems to me, though, that having the long run be DC between the panels and the controller and batteries would be better regarding the drop. The voltage drop will happen there, but the controller will then correct it to the proper charging voltage for the batteries, and full converted AC voltage will be available at the house.
If The AC was converted at the panels then sent the 300-400 feet to the house, the voltage drop would mean that AC house voltage would be lower.
The drop still happens, but the house voltage is good. If converted at the panels house voltage is reduced.
What should be considered is overall "power" (wattage drop), vs only voltage (given a load - there is no current without a load of some sort).
AC is always used to transmit power over long distances because it is easy to step down (decrease voltage, increase current capacity) and up with a transformer. DC is not so easy (transformers don't work on DC). Most of the "step down" and "step up" conversions for DC create more loss than the transmission line itself. You can convert AC into DC fairly simply with a rectifier, but the opposite isn't as simple or efficient. So once you have DC, you better off leaving it as DC as well as at the same voltage.
As far as transmission loss goes it is about voltage vs. current. Higher voltage and less current is always better (given the same total wattage). It can be explained mathematically with ohms law, and there are plenty of sources out there if you're curious about the equations.
The bottom line - If you increase the voltage, and therefore drop the current you end up with less overall resistance and therefor power loss (because calculating resistance is based on the relationship of voltage and current). Since it is easier to step down AC voltage, you're better off leaving it as AC for as far as you need until you convert it to DC. Once power makes it to it's destination as AC, you can step the voltage down with a transformer, then convert it to DC via a rectifier (if DC is your end goal).
I'll qualify this by saying I'm not exactly sure what we're doing with the panels, but this is what I know about line transmission.
Quote from: MTScott on April 25, 2016, 12:58:06 PM
What should be considered is overall "power" (wattage drop), vs only voltage (given a load - there is no current without a load of some sort).
AC is always used to transmit power over long distances because it is easy to step down (decrease voltage, increase current capacity) and up with a transformer. DC is not so easy (transformers don't work on DC). Most of the "step down" and "step up" conversions for DC create more loss than the transmission line itself. You can convert AC into DC fairly simply with a rectifier, but the opposite isn't as simple or efficient. So once you have DC, you better off leaving it as DC as well as at the same voltage.
As far as transmission loss goes it is about voltage vs. current. Higher voltage and less current is always better (given the same total wattage). It can be explained mathematically with ohms law, and there are plenty of sources out there if you're curious about the equations.
What makes you think that we do not consider overall power offgrid? What makes you think we are stepping up DC offgrid?
what makes you think that AC is always used over long distance? What is long distance to you?
What makes you think transmission loss is only about voltage and current?
You make good points but the word always is wrong because there are"always" other strategies that you may not be considering.
The bottom line - If you increase the voltage, and therefore drop the current you end up with less overall resistance and therefor power loss (because calculating resistance is based on the relationship of voltage and current). Since it is easier to step down AC voltage, you're better off leaving it as AC for as far as you need until you convert it to DC. Once power makes it to it's destination as AC, you can step the voltage down with a transformer, then convert it to DC via a rectifier (if DC is your end goal).
I'll qualify this by saying I'm not exactly sure what we're doing with the panels, but this is what I know about line transmission. I understand that you do not understand the solar panels ;) ;) --Dave
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Quote from: Dave Sparks on April 25, 2016, 02:09:46 PM
What makes you think that we do not consider overall power offgrid? What makes you think we are stepping up DC offgrid?
what makes you think that AC is always used over long distance? What is long distance to you?
What makes you think transmission loss is only about voltage and current?
You make good points but the word always is off because there are"always" other strategies that you may not be considering.
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Eh, some of my posts sound better in my head before I type them. Always was strong - a poor choice I'll admit. Maybe "usually" is a better term. That is usually what you see with high power lines. That's also why I put my last statement in there - I'm not exactly sure what you guys are working with, so it may not apply.
I was really just relaying some theory. No I don't believe that transmission loss is "only" about voltage and current, but if ALL all other things are equal (same wire, distance, load, environment, etc..), modifying the voltage and current during transmission can change the overall power loss. If power loss over the a long distance "is" a concern, then efficiency could be gained if it is possible to transmit at a higher voltage, and the same will be true for DC or AC. As a basic example, ff a guy started with 120V AC, but wanted 12V DC in the end, I would expect that transmitting at 120V would be more efficient rather than converting to 12V first, then transmitting. That is all I was saying, and it may not apply here. How long is long enough to make it worth doing? That I'm not sure on, but it probably could be calculated.
DC does have its advantages over AC in transmission as well, but modifying DC voltage has losses. If a guy is starting with AC at the source, then he could maybe take advantage of long distance transmission efficiency by adding transformers. ..maybe. I'm sure there are diminishing returns for both cost, and efficiency.
So, you're absolutely right, there is no "always" better solution. I was just throwing more ideas in the hat.
With a PV system we have DC first at the panels. At the other end we more than likely want to be using 120 VAC, not DC, or at least not much DC.
When I ran the numbers for our system, with a 325 foot distance between the PV and the cabin, it did not save me anything on wire to run AC the longer distance. Our plan was to use about 650 watts of panels. That was 2009; at today's prices I would do more. Three panels in series meant about 90+ volts and 8 amps of DC traversing 325 feet. At the cabin the uses included a few kitchen appliances with large but short duration current flows. Microwave of almost 10 amps, toaster, coffee maker, etc. As well some lights, a stereo, a TV.
To send the AC power the same distance still required about the size wires as running DC, and keeping voltage drops at maximum amps low enough.. In part this was because I did not want to build a system that required thinking whether or not one electrical device or another could be used. We lived like that in the RV for years and we frequently caused an overload and an inverter shutdown. Running the AC wires the distance meant having the wires large enough to carry 20+ amps the distance. The DC system I envisioned pushed less than 8 amps and that only a peak power.
Not to mention the fact that I like the idea of the batteries and inverter in place at the cabin and not 325 feet away, down a slope that drops 120+ feet in elevation.
Quote from: MountainDon on April 25, 2016, 04:30:18 PM
...Not to mention the fact that I like the idea of the batteries and inverter in place at the cabin and not 325 feet away...
Unless one of the batteries shorts out and catches on fire. ;)
Quote from: Adam Roby on April 25, 2016, 05:00:55 PM
Unless one of the batteries shorts out and catches on fire. ;)
In my experience with 87 offgrid homes the real danger of something "catching on fire" as you say is when the equipment is far away and less likely to be noticed. Batteries are protected by fuses or breakers and fire is extremely rare and non existent (so far) for the systems I design. The most likely failure mode is a dead battery or poor battery performance. This happens every 5 to 10 years or so and can go longer if one is lucky and does the maintenance.
In the Boeing 787 Dreamliner's first year of service, at least four aircraft suffered from electrical system problems stemming from its lithium-ion batteries. Although teething problems are common within the first year of a new aircraft design's life, after a number of incidents including an electrical fire aboard an All Nippon Airways 787, and a similar fire found by maintenance workers on a landed Japan Airlines 787 at Boston's Logan International Airport, the United States Federal Aviation Administration (FAA) ordered a review into the design and manufacture of the Boeing 787 Dreamliner, following five incidents in five days involving the aircraft, mostly involved with problems with the batteries and electrical systems. This was followed with a full grounding of the entire Boeing 787 fleet, the first such grounding since that of the McDonnell Douglas DC-10 in 1979.[1] The plane has had two major battery thermal runaway events in 52,000 flight hours, which was substantially less than the 10 million flight hours predicted by Boeing, neither of which were contained in a safe manner.[2]
The National Transportation Safety Board released a report on December 1, 2014, and assigned blame to several groups:[3]
GS Yuasa of Japan, for battery manufacturing methods that could introduce defects not caught by inspection
Boeing's engineers, who failed to consider and test for worst-case battery failures
The Federal Aviation Administration, who failed to recognize the potential hazard and did not require proper tests as part of its certification process
I was just petting the cat backwards... for fun.
Quote from: Dave Sparks on April 21, 2016, 04:13:56 PM
Hey Glen,
I have your phone number you left a few weeks ago. Glad you are back in the county!
The problem with forklift batteries is they are too heavy to easily move around. Someone like you no problem.
The other problem they have for Offgrid is they are designed to be deeply cycled and charged for 16 hours or so. They work an 8 hour shift and charge for 16. People do use them offgrid but they really need to know what they are doing or they end up with problems long term.
I pretty much use the 2V 1,100 AH L16 and get 10 years or 5 if the client does not follow the rules.
With the newest battery technology hanging on the wall, like the Samsung Lithium Ion NMC cells there are some nice things ahead if they can make them safe enough for your home.
Thanks, Dave... I guess I am kinda special. You are correct, it hasn't moved from the place I set it about 5 years ago, but it did end my problems with the L16's. Guess I should cut them out of the mix now....Getting to the age where one year or 5 feels about the same... but all in all doing super great. :)
So busy lately I have 16 things waiting ahead of every one I get done.... but batteries is not generally one of them now.
For my panels now, I am generally running around 100vdc to the MPPT controller and letting it handle the stepdown to 24VDC of my 2 4024 Trace inverters piggybacked for 240v. It got me down to reasonable size wiring without major voltage drop... I try to get 500 watts or so of similar panels to run from one controller. 2 controllers are bigger. I have 6 controllers charging the forklift battery. They are all reasonably happy. I have somewhere around 5000 watts of panels.
Of course I run by rule of thumb.... not engineered stuff like our pro, Dave does. I don't generally have any major fires unless my welding lead moves when I'm charging the forklift battery.... :) Do as Dave says... don't do as I do. [ouch]
Nice Glen d* There are many ways to do all of this and I think I learned the most from my sailboat when it did not sink!
We always planned on ditching her if we got in a jam in some nasty ocean storm out near the Galapagos, or somewhere...
Ended up the 3rd best day in my life when I still had and sold her :)
Thanks for the vote of confidence Dave... I think.... ???
Not only a vote from me but I printed a few extras because it is an election year :(
We all know the vote is not legitimate... it is controlled by the computer programmers of the PTB (otherwise, how could there be more votes than people? ).... But it does do it's part in the pacification of the masses... makes them feel they actually had a say and slightly responsible if things go wrong at a later date... :)
Oh I love military industrial complex rule... [ouch]
My Bergey wind generator failed about 8 years after I put it up.
that was about 6 years ago I think.... I had Myanmar friends here the last couple weeks learning welding, and they wanted to help me repair it so we took it down to check it out.
![](https://scontent-sjc2-1.xx.fbcdn.net/v/t1.0-9/13260078_10209891766753069_9117532449030404198_n.jpg?oh=3607d30e7277e744a42aa2d203ff1b9a&oe=57DD3FF4)
We found the slip ring brushes had broken a spring so I fabricated one from a spring clip and ordered a new set of 2 (4 brushes on 2 holders) after we put it back up with the Mariposa rigged ones installed.
We used my Harbor Freight remote controlled winch to lower and raise it.
![](https://scontent-sjc2-1.xx.fbcdn.net/v/t1.0-9/13230130_10209891758392860_7022891077581709687_n.jpg?oh=a94abb482d9aa047ed6089f05299714e&oe=57D22DB2)
The guys did most of the work transferring the cables to the Gin Pole and back.
![](https://scontent-sjc2-1.xx.fbcdn.net/v/t1.0-9/13256061_10209891758672867_5721449478221900176_n.jpg?oh=d40fd7006959ab131363fcc8fc932413&oe=57D4D17A)
My wife and Kho Lar are electrical engineers. Saw Tun was a mechanic in Ship Yards. Looks like I have enough qualified help.... :)
![](https://scontent-sjc2-1.xx.fbcdn.net/v/l/t1.0-9/13233145_10209891766073052_4637743322233536194_n.jpg?oh=ab02f5e3577375ba70834fee8cbcfc58&oe=579AA600)
It's up and running awaiting the delivery of the brushes and rubber bushing nuts for the Nacelle. :)
Very nice Glen ! Good to have a crew and even nicer at happy hour!
I miss the boys . They passed their welding certification tests and went back home to Florida.
I think the Mariposa rigged brushes are failing now as I am not getting full power on the wind generator but I kind of expected it anyway. Original design is quite poor with a single wire spring holding the brushes to the slip ring. The new ones will be here soon and Moehnin and I can drop the tower ourselves now that some of the tree interference has been removed. I think I can manage with only one electrical engineer, or maybe I can call Dave in a pinch if I need 2..... ???
We need to check out that happy hour one of these days, Dave. :)
$100 worth of wind generator parts arrived today. :) Time to take it down again.
![](https://scontent-sjc2-1.xx.fbcdn.net/v/t1.0-9/13254021_10209946266875538_1565163125584503608_n.jpg?oh=d6afe1584eafb10df2cddd894d84e381&oe=57E7092D)
Some day.... [ouch]
Well, cool.... [cool]
The wind generator was putting out 15 amps the other night so I guess the brushes are currently OK. Don't have to take it down yet. That is about 360 watts when we normally would not have any solar power... there is one advantage of having a wind generator also. :)
Looking forward to next month when the 97 year old leaves for 3 months! Will call you then Captain Glen!
I guess you could come over and help me weed wack or cut oak :)
Looking forward to seeing you Dave... Weed Wack.... Cut Oak.... two of my favorite things... yes... you and I could do that while the girls enjoy happy hour... I'll bring over my new (used) DR self propelled Weed Wacker and a couple chain saws... [chainsaw]
Still got some vibration in that chainsaw....
If this is not OK to post some used gear you guy's can delete this. Cleaning the garage out....
SW + 2524 Xantrex Inv/Chg 10 years old in excellent condition used for 3 years. $800
6" pole mount - The pole mount can be expanded for more solar. Mount is adjustable and made by Direct power and water. Model TPM2H $200. You can text the phone, e-mail, or voice. 209 813 0060
2" gasoline powered water pump - DuroMax XP652WP 2-Inch Intake 7 HP OHV 4-Cycle 158-Gallon-Per-Minute Gas-Powered Portable Water. Used for 10 hours and oil was changed. Runs well. replaced with electric pump. $160
A bunch of Outback MX-60's in unknown condition (probably need fans only) make offer
Solar hot water drainback tank (heat exchanger) New $200
It's an old chainsaw, Dave. I always buy used. [chainsaw]
I have no problem with posting some solar bargains here for the members. You are not a commercial company ..... besides I have bought bargain items from you myself. The controllers I assume are 60 amps at up to 150 VDC input? and variable charge voltage output?
If anyone else has a problem with this they can let us know. :)
YES ! No fan convection cooled 140VDC working and 150 Max @ 60 ADC.They will current limit above 60ADC.
Great, thanks for the info. If I get rich I may check back but... don't wait for me..... We are pretty good right now. :)
After the initial questionable start, the brush repair we did on the wind generator seems to have smoothed out and the generator is daily adding around 15 amps of power a couple times per day as temperatures change in the valley and microclimate winds go by. Saving the new parts until needed. :)
Glen, Thanks for hooking me up with Matt (whitlock). He got some great equipment and I have some pocket change.
It was great seeing him again! We live so close and he (and you) were such a big help in the Telegraph fire. Fun stories and serious adrenaline.
We are taking the 97 year old to here summer home for three months soon. I will call!
How is Matt & Don'ya?
He seems fine and knows so much about the gold mining here. I heard her name but now I can't remember it either. :o
My pleasure Dave. I thought he could use a bargain or two. Matt and Donya were doing pretty good, Don. He sometimes gets a bit of back trouble... just don't make the young guys like they used to. :)
We try to look out for each other a bit up here in the hills.
Fires and mining... always exciting. [ouch]
Looking forward to hearing from you, Dave. :)
Say Hi to them.
Did the mining museum close as was scheduled to happen a few years back?
Yes and no on the Cal mining museum. It did close after it was robbed of 2 million. I think it was 4 guys with crowbars. They did not get any of the really historic gold.
The Fricot 13 Lb gold rock was safe, but they got enough. They melted it down and I think all of them were caught in a couple years or so.
Museum is open now and probably a little better secured now d*
Will say Hi Don.
Yes... the museum is open again now. Quite a fiasco out here in the wild wild west... I think the closing thing was a ploy to squeeze more money out of the public or something.
Just took our two Myanmar/Florida visitors through the museum a month or so ago. Pretty decent displays again. I wish the old model moll was in operating condition yet. It was cute to watch the things in it working. :)
A couple of weeks ago I noticed the blue indicator LED's on one of the Midnite Solar SPD's was not illuminated when it should have been. FYI, the SPD is a surge protection device that can suppress power surges caused by nearby lightning strikes. They can not protect against a direct strike. Everytime they suppress a surge they wear out to some degree. The Midnite SPD's have LED's that remain lit when power is present and when they are functional.
So anyhow, back to the story... The SPD at the top of the hill was the one I noticed being non illuminated. I hiked the 325 feet down to the solar array. The SPD down there was non illuminated as well. As a double check I removed them and connected them directly to the batteries. Both remianed non illuminated.
I got out my spares (2 DC and 1 AC version are kept as spares). I installed both DC spares, one at each end of the power wires from PV and uphill to the cabin and the charge controller. Both set of LED's illuminated brightly as they should. Just as a side note, the SPD's on the AC circuit side were working fine.
**** Midnite covers lightning hits under warranty.**** Just a $20 UPS cost to send them to Midnite. I got an RMA# and shipped them off to Midnite for refurbishing. They pay the return shipping. When they return them they will be the spares until next time.
We've been in away most of the time since that and I left the cabin system PV array to CC lines disconnected as we are getting into lightning season. I have a pole 12 feet from the cabin where the underground PV feed comes up to a Midnite box with a MNEPV breaker. I pull the breaker to disconnect power to the CC and then disconnect/remove the cable that runs from the box to the cabin and the CC; remove the connection at the box. Then I roll up the cable and place it in the enclosure that holds the CC. I hope that 12 foot jump to the cabin is too much for lightning to jump. The ground wire from the SPD at the boxes connect to a grid of copper clad ground rods and a copper sheet ground plate.
This works for short absences as we do not have any electrical devices that need to run when we are absent. When we are at the cabin, June through August I disconnect the PV when I hear thunder in the area. It is a bit of a bother, but less bother than replacing the arm's length list of electronics that were toasted.
.... in case anyone is interested... if you are in a locale that receives lightning you should be interested. :) Relacing things like CC, invertes, etc can be not only tedious, but expensive.
Good advice Don ! I just worked on a system that an overflowing toilet drained in the power system. There was the smell of burnt electronics and a little something extra :P
Can anyone suggest a retailer that has a good mix of customer support for a self install and good pricing? Starting to think about my system again. Its basically going to be a stationary RV setup, but I'd like the option to run some power tools at times. Loads would be water pumping from cistern (6ft of head, will use an 4.4 gal precharged pressure tank), on demand propane water heating, maybe a fan for a propane heater, 3 way dometic fridge, LED lighting, cell phone charging. Weekend use except for a couple extended stays as time allows. Good all day southen exposure on the ky/ohio border. I already own a honda eu6500is generator. I'd probably pay to oversize the system some.
NAWS (https://www.solar-electric.com/)
I've had good price and service from NAWS as well.
I'm really agonizing over which midsize charge controller to use. Anyone have any experience with the Morningstar PS, Morningstar Tristar, Midnight the kid, BlueSky SB, or Outback Flexmax 60? Listed in no particular order. I've been working with NAWS to size my system, and am coming up with a 12v 220 amp hour battery bank and 3 or 4 Kyocera 150 watt panels.
My cabin is weekend use, and theft is a (small) fear, so for both reasons, I'm trying not to have thousands of dollars in equipment sitting out there.
I have the Morningstar TriStar MPPT controller and while it works I've never been happy with it or their support. My next will be an Outback.
I have used the FM60 and the Kid. Both work well.
Will there be an inverter? One thing I like when there is also an inverter is to keep the CC and inverter the same brand and networked together. You can do that with Outback, but not most of the others. Xantrex has some that interconnect or network. Another nice thing about the Outback inverters is the built in charger which can have its charge profile tailored to suit the generator used, if there will be a generator.
If you are in a lightning prone area also invest in good suppressors like the Midnite SPD's. Maybe look into an air terminal and ground plates/rods array as well if lightning is likely.
I'm kind of up in the air on an inverter. With 2 6v 220 amp hour batteries it doesn't seem like it makes sense to try to power much AC stuff. I go back and forth on it. I already own a EU6500is generator, so it would be nice to have a quality inverter charger to maintain the batteries, but I worry that it will also lead others (cough, wife, cough) to be tempted to run loads the bank can't handle. So I have been considering the idea of just using the generator when I need to run something on AC.
Been testing a very nice 300vdc CC from "begins with an O and ends with a K" Out very soon!
Cool.
I'm still holding my breath waiting for "new" LiFePo4 news.
I'm still liking my used forklift battery with multiple gigantic 2 volt cells to make 24 volts. We used it hard this summer always using more power than we had panels, but it is back up to full charge since I quit running the 1.5 horsepower pump 1 1/2 hours per day or so. Now only 15 minutes per day and acid shows full charge on hydrometer. :)
Glen brings up a very good point that I can tie into Don and his curiosity of using Li-ion for offgrid. I will load a file her but it has always been a pain for me do this on this forum so I often don't. Not a big deal for me either way being a user of google photos.
One thing the chart shows is how well lead acid does with big loads like Glen is talking about. 1.5 HP.
The other thing I can say for anyone really wanting go this route is they need to be using a 48V inverter as there will be few choices at 24V nominal.
They probably will need an inverter that can have firmware updated at your site to be safely using this very new tech in an offgrid home.
It will be very expensive at first compared to 2V large capacity lead acid. I would guess prices getting better in 2018.
It is promising as anyone who picked up a Li-ion drill and been able to leave it dead for a month or more with a smile after charging knows.
I ended up going with a self selected setup that I got from Northern Arizona Wind & Sun. Its a Kyocera 150 watt panel, a Morningstar ProStar 30 PWM controller and a midnight babybox with midnight breakers. I bought a 30 foot MC 4 cable that I cut in half. I unded up having to upgrade the controller so I could be over $500 and get free shipping. At lrast this way I can add another panel if I ever want to. Below is a picture of my setup. I decided to affix some cable with anderson connectors permanantly to my battery compartment so I can easily connect and disconnect. The cable is incredible stuff it is the size of 12 guage but the strands are so fine with so much surface area that it is rated for 60 Amps. The Anderson connectors I used ate rated for 45 amps. I'm going to mount all this either inside a pelican case or just on a nice piece of furnature grade plywood cut down to size with a handle routed into it.
![](https://i801.photobucket.com/albums/yy300/Mike_1894/20161118_113244_zpstncvg09n.jpg)
(https://s801.photobucket.com/user/Mike_1894/media/20161118_113244_zpstncvg09n.jpg.html)
![](https://i801.photobucket.com/albums/yy300/Mike_1894/Mobile%20Uploads/IMG_20161112_084215_zpsjwvpww5z.jpg)
(https://s801.photobucket.com/user/Mike_1894/media/Mobile%20Uploads/IMG_20161112_084215_zpsjwvpww5z.jpg.html)
There we go, went faster than I thought.
![](https://i801.photobucket.com/albums/yy300/Mike_1894/20161118_130728_zps3prw8tgu.jpg)
(https://s801.photobucket.com/user/Mike_1894/media/20161118_130728_zps3prw8tgu.jpg.html)
[cool] I like Casita trailers.. :)
Has anyone looked into the Powerwall 2 that Tesla is supposedly going to start selling?
Kind of skeptical of the company, and not really a fan of how they market themselves.
It says 14kw and a built in inverter - which must be a high quality pure sine wave. $5500 for the battery+inverter and I believe it said something like $1600 for the installation - I don't know if this is labor + what kind of charging they are implying - I'm guessing grid tied?
Anyway, I mainly bring it up because $5500 for 14kw of AC in lithium ion batteries and a pure sine wave inverter seems like a pretty drastic price drop from what I was seeing a few years ago. I think that this is roughly equal to 26 golf cart batteries? Someone might need to check my math there. $2600 of golf cart batteries that will last 7 years at most vs lithium ion which includes a 10 year warranty and aren't those expected life spans closer to 20-25 years?
Other advantages, there is no venting necessary or wiring all the batteries, much less space taken up.
May not make a big difference for a full time off grid set up, but as these lithium ion prices come down it seems possible to create a backup system that includes solar and wind in addition to a generator.
Side note
Tesla batteries in their cars are simply Panasonic computer batteries that are wired together in a special way. I had looked into this at one point because Panasonic stock may be a steal right now if Tesla's meteoric rise is sustainable.
I think they're going to keep going up.
They just purchased Solar City so they can produce their solar roofing shingles.
They say their new shingles will not cost much more than a regular shingle job (after factoring in useful life, energy savings etc.) but turn your entire roof into solar panels but it just looks like a regular roof.
Tesla is even powering a whole island!!!
http://www.theverge.com/2016/11/22/13712750/tesla-microgrid-tau-samoa (http://www.theverge.com/2016/11/22/13712750/tesla-microgrid-tau-samoa)
Quote from: DaveOrr on December 01, 2016, 10:05:16 PM
They say their new shingles will not cost much more than a regular shingle job (after factoring in useful life, energy savings etc.) but turn your entire roof into solar panels but it just looks like a regular roof.
I think that needs some more checking into. I believe the comparison to "regular" roofing was not to our nearly ubiquitous asphalt shingles but to more expensive tile roofs which the tesla solar roof looks like. Tesla pictures 4 types and all appear lsimilar in appearance to 4 different tile or slate roofs. Don't believe the $$ comparison is to ashphalt shingles until you see the actual product pricing and what instakllation requirements are. Just my skepticism showing through....
Quote from: MountainDon on December 01, 2016, 11:22:29 PM
I think that needs some more checking into. I believe the comparison to "regular" roofing was not to our nearly ubiquitous asphalt shingles but to more expensive tile roofs which the tesla solar roof looks like. Tesla pictures 4 types and all appear lsimilar in appearance to 4 different tile or slate roofs. Don't believe the $$ comparison is to ashphalt shingles until you see the actual product pricing and what instakllation requirements are. Just my skepticism showing through....
Actually it was to asphalt but they factor in the longevity of the roof, the payback over their life etc.
Initial outlay is 3.5 times the cost of regular shingles. But regular shingles would need replacement 3 times during the life of Teslas roof.
So they say.
The whole thought of connecting all those very low voltage panels in series is not something anyone living offgrid would want to do no matter how the connection is made.
If you live on the grid it is nothing but money that you are risking with schemes like that. They say the connection method is easy and it will last. Offgrid in some of the places I go there are very few people to help you and so the owner must make servieable and intelligent choices.
When the fire people rate that kind of roof and it gets tested over time by early adopters, I might think about it for a barn roof offgrid. Certainly not the roof of an offgrid home.
That's a really good point. Serial connection of all those little panels, and exposure to extreme heat and cold over time with corresponding expansion and contraction and corrosion. It makes me think of a long string of Christmas lights where one goes out. How do you identify and replace?
Quote from: Dave Sparks on December 08, 2016, 12:29:16 PM
The whole thought of connecting all those very low voltage panels in series is not something anyone living offgrid would want to do no matter how the connection is made.
If you live on the grid it is nothing but money that you are risking with schemes like that. They say the connection method is easy and it will last..... Offgrid in some of the places I go there are very few people to help you and so the owner must make serviceable and intelligent choices. It is just too easy now to use (10) 45V solar panels in series and have zero problems for 30+ years.
Imagine having strings with 80+ panels in series :(
Imagine having to find the bad panel?
When the fire people rate that kind of roof and it gets tested over time by early adopters, and the loss of efficiency of not having cool air under the panel, I might think about it for a barn roof offgrid. Certainly not the roof of an offgrid home.
These solar tiles have been around(other companies) for 10 years now and none of them have been good for a typical home. Maybe someone will do this right because it does make sense for grid-tied solar, I just would not hold my breath!
Hey Dave,
I see that you have a lot of experience with tracking mounts. I have a couple basic questions about them. I've done some reading on them and like some of the benefits they bring to the table. I'm starting to think about my cabin system which I will probably be ready for in late summer. 1) Do you use mostly single axis passive trackers like the zomeworks? How does tracking impact this general rule of thumb when sizing panels to a bank (Bank AH) x charging volts x1/.77x8-15%. Meaning since you're tracking, should you design to less array size? Last question, would it be poor design to have 2 panels on a tracker and two panels fixed to a roof?
My hypothetical system would kind of be in a funny spot. On the small side, but really close to needing a bigger charge controller than the more affordable 30amp controllers or upping battery bank voltage to 24 and using a step down.
While we wait for Dave I read somewhere, long ago mind you, that solar trackers add only about 25% to production and cost more than adding more panels. When looking at my system I was able to buy 6 new panels for the price of a solar tracker.
Doing it yourself is different if you have the wherewithal.
Trackers are still very nice when you want to operate something like a mini split for A/C or heat. Early AM can be enough to get the SOC up and then in the afternoon there are hours of power for the mini split or whatever.
What happened to the home-built tracker that Glenn made?
I don't have any intention to run a mini split or AC, but I'm enticed by tracking because of my experience with my smaller portable single panel system. Being able to tilt my panel towards the sun at 8:30 AM in November and start getting juice was eye opening. The difficult to quantify benefits of less severe discharge depths on batteries have to be pretty significant.
http://www.sunfolding.com/
The home built tracker I made... Well, it did work, but using junk materials caused it to be a bit untrustworthy. Dave Sparks told me that with the low cost of panels now, it makes more sense to just add panels in the direction you need to add power in, such as morning or afternoon. :) I agree.
Passive tracking like Glen spoke of (an east and west facing array) is an easy way to get long hours of power without using the battery and less time using the battery. This can really help if you have the loads. This is really for people living in a home full time who have cooling loads in summer and fortuanate enough to live in a place that they may not need a generator for winter. Unless your cabin is going to become a place where you live I would think that you are overthinking this. ::)
I have never liked the Zome Tracking system and always use Wattsun (Array technology). I am a dealer and get wholesale pricing for my clients. The Horizontal linear axis tracker I use holds about 4,500 watts of solar and I doubt anyone could build it themself and have reliability for decades.
Some large homes need two of these. I hope this helps!
Quote from: flyingvan on December 23, 2016, 02:32:29 PM
http://www.sunfolding.com/
Any info on these? I had sent e-mail to them 6 months ago and never heard back. Looks like Utilty tracking which can very rarely make sense for Offgrid costwise. When I saw Al Gore on their web page I thought that was why I never heard back. Maybe I was wrong......
There is an installation using a bunch of these (http://arraytechinc.com/duratrack-da-tracker/) that I pass on the way to Los Alamos. It is interesting to see them at different times of the day and year. Every so often one of them loses track.
No, no further info. My sense is it's past the idea stage and got enough funding to be developed into a concept.
When there is price and availability info, and an installation manual, then we can talk about field testing. The commercial/utility trackers are extremely reliable at this date and so half of the bragging on their website is not really accurate. If I hear anything I will let you know. If I can link this below it will show one of the 4,500 watttrackers I use. Delivered anywhere in the US continent for less than 3K$ and the same concept (HZLA) as the start-up you linked. They have been in Don's state since the early 80's. The link Don posted is not really how people do this anymore. I never used those Don because there was more to go wrong with a DA tracker. Anything outdoors with lightning can fail and Array Tek has been great with parts. I always say if a tracker fails, you have a fixed mount array until you fix it. None of mine have failed except a lightning strike that needed a new PCB.
The HZLA does not need the installer to use a ladder and in commercial apps a pile driver installs the mounting poles. The dual axis tracker does have a 40% harvest gain over the 25% for the HZLA. These harvests are for a grid-tie application. For offgrid it is the hours of additional power we care about because we rarely use all that is available. Once our battery is charged there is alot of unused energy left unused on the offgrid "table". This is often compensated for in winter d*
http://arraytechinc.com/duratrack-hzla-residential/
Solar panels on roof or on ground ?
Our first structure will be a gambrel roof barn. Current plan is for the ridge to run almost N-S. That could change.
The lower half of the gambrel roof is very steep. Below it will be a shed roof, 3-12 or 4-12 pitch. If I rotate the barn so the ridge runs E-W, would it make sense to put the solar panels on the steep barn roof, or does it make more sense to keep the panels near the ground for safe accessibility.
Hoping to learn from others' experience.
Thanks.
I prefer on the roof out of harms way. If you wire them decently you don't have to do much other than clean the dust off once in a while. Maybe a good spray nozzle on a hose could take care of that. If you have plenty of room, the ground is not bad either. Up to what seems best for you. I'm short on space so, roof it is. :)
IMO, if you have ground space, stay off the roof. Easier, safer, fewer roof penetrations...
Thanks. I think we will leave the barn orientation as planned, and put the panels on the ground. We have room, I also dislike roof penetrations, and I am getting into the brittle phase of life. We will have a couple dormers on the roof, and they also would have added complexity to putting panels up there.
Really appreciate the feedback.
A good plumber can also minimize the roof penetrations if the roof slope is high. I got ours down to one 3" pipe for the whole house.
Glen, you don't have ground space? Where did you move? The ground is always best unless you are worried about theft and that is less of a concern with lower panel prices.
I have ground space but it is on steep slopes ...yes, Ideal for the needed angle for southern exposure, but... it is quite a ways for me to get wires back to the power center, I don't want to put conduit and the trees are not spaced right for me to string wires through. :)
If I put it on the roof I don't have to worry about driving into it with a tractor or Bobcat, it is close to the batteries and inverter, and I keep my open spaces flexible for whatever I may change my mind to. [ouch]
Not to mention you are a tad closer to the sun! ;)
Hey, I can always use an extra few watts a day. :)
Just making sure that you have not changed too much. :o How do you like KRYZ ?
Same old me, Dave. Doing what I can to get by. :)
KRYZ.... what a fitting name for a Mariposa station. Actually I hadn't heard of it before you mentioned it. ???
What do you think of it? I downloaded the app so I can check it out a bit.
By the way, going to daylight savings time really helped. I got enough extra solar I don't have to kick the generator on now. Maybe we should lobby to keep it year around. :) :D :D :D :D
We like KRYZ alot and it is good for the town. We also stream the jazz station from
http://player.capradio.org/player.aspx?stationid=2
As for saving daylight, I am all for it........
I'll have to try to listen to KRYZ a bit more if I can get the volume high enough to hear it over the voices in my head. :)
Quote from: glenn kangiser on April 03, 2017, 11:23:52 PM
I'll have to try to listen to KRYZ a bit more if I can get the volume high enough to hear it over the voices in my head. :)
Is that the Alien thing or the Politic thing? We can add on to the Fruits and Nut state the sanctuary state pretty soon. That ought to help fix the roads in our county right?
Well, Dave. No hope for the voices I think. As for the roads, I see they just added another 12 cents per gallon for them to steal from us, and misappropriate with all of the rest of the money they already have that isn't being used to fix the roads.
Note that the road repairs already done were done by printed money for the recovery act by the feds after the bankers ripped us off and made our real estate not worth anything so they could buy it back for half price.
They felt so bad they about us having nothing that they thought they should print money (increasing inflation) to repair the roads and add the high speed rail to nowhere so they could give us enough work to build up our savings so they can pull another scam on us in a few more years after our savings are built back up.
Next they will charge us for stopping the spraying of spreading chemtrails blocking our sunlight if we want to use our solar off grid power. :)
Kind of Knarly last night with the lightning. 87 inches of rain, need any water? Darn, here it comes again more rain. I better go and see if the road is still there ;) Nice that the sun charged the batteries this AM, did not expect that break in the Wx.
We also had plenty of rain. The battery has been doing pretty good with a bit of boost from the wind generator. I don't think it is working 100 percent. I need to pull it down again and put the new brushes in. :) A bit of snow mixed with the rain here today.
Quote from: Dave Sparks on April 08, 2017, 02:59:06 PM
Kind of Knarly last night with the lightning. 87 inches of rain, need any water? Darn, here it comes again more rain. I better go and see if the road is still there ;) Nice that the sun charged the batteries this AM, did not expect that break in the Wx.
Planet is pretty messed up. We had some record rainfall last week with 3 1/2 inches... did you say 87 inches in a day? That sounds biblical!
Maybe 87 inches for the year... About double our normal. Dave will have to buy more water storage tanks to keep it all. :)
Nah, 87 inches season to date! Glen and I would be building docks if that was in a day! :P
I need more tanks at 15 inches of rain. Got to test that two years ago. The key to being in the cat-bird seat for most anyone harvesting rain is getting that inch in May. We usually do but....
It can be a pain trying to stay topped off with some room to capture until that last rain in May.
Nice thing to think- If we had to build docks, we would be a couple of very few inhabitants in California. :) ....... on the other hand.. ???
If the flatlanders were able to live through it, they'd be climbing these mountains like rats abandoning a sinking ship.... yep, 87 inches for the year is enough for me. :)
Don,
Hang tuff with the fire! Did you see the simplyphi batteries in the Wind Sun Store. Still pricey but 24V option is there.
I'm still having great service from my road kill, chopped up , bypassed, recharged used forklift battery... the one my brother found along the road. It gets a bit short in the winter when I have to kick the generator in once in a while as usual, but never a problem when there is plenty of sun. It holds well overnight with plenty to spare.
We are not especially careful about power either. :)
Quote from: Dave Sparks on June 19, 2017, 09:11:50 AM
Don,
Did you see the simplyphi batteries in the Wind Sun Store. Still pricey but 24V option is there.
No I had not seen those. Thanks for pointing them out. Maybe time next year or the year after. The golf cart batteries still work quite well. ;D Not bad at all for batteries that were made June '09.
I see those Simplyphi batteries are made in California too.
I believe the Simphi cells are Chinese. I was hoping to get them to let Schneider Solar or Outback Power get access to the BMS and extract internal Soc, current in/out and State of life but not getting much interest from them.
It is very nice to know how much is in the bank after an all night run of cooling and the 10 KWH LG Chem is perfect for us.
Knowing State of Life really makes the unknown a much more useful and accurate tool for planning. I expect these to last 15 years or more from the data I have seen. [cool]
100F + today, again... drink some water with the Beer and Limes Glen c*
Well they sure aren't giving them away!!!!
The 3.4 is $5,400 Canadian!!!!! ???
It all will come down but the early adopters need to pay in first :P
Were using lemons Dave but missing the beer....makes me fall asleep.
Lemons sliced and steeped in hot water with the peel, keep the old blood pressure down though. :)
Posted about this in my cabin build but thought to ask here":
What are your thoughts about putting the inverter, and possibly the charge controllers inside the cabin vs in the porch with the batteries?
I can order more flexible cables to make that happen and am thinking it might be a good way to get the electronics away from the batteries though it poses some issues (like not being able to turn on power until I am inside the cabin vs just entering the porch and flicking it on.
https://www.delcity.net/store/100A-MiniBus-Common/p_807936.h_807937
What do you think of using a bus like this to provide 12vdc power to multiple devices? I have a 24v to 12v converter that I use to power a 12v ceiling fan, some 12v fans in the composter room and my car stereo. Today I just wire nut everything to the output (12v) on the converter but I'm looking for a clean way to provide power and thought that I could two of these to provide + and - connections to each device.
With two buses I could land the fans etc on each buss and then provide the power connections to the buss frm the converter. Should be a cleaner way to do this and allow me some more connections.
Thoughts? Any suggestions? Truth is I was looking for a toggle gang switch I could provide power to on one side and then multiple toggles for each item (so I could then just turn them on or off).
Quote from: OlJarhead on September 28, 2017, 09:45:22 AM
What are your thoughts about putting the inverter, and possibly the charge controllers inside the cabin vs in the porch with the batteries?
Electronics last longer when subjected to less extreme temperature shifts and fewer of them. So, inside where it is warmer and more constant is probably better. Sometimes there are other factors in play that make having either outside easier/better/convenient.... Just watch the wire sizing
Quote from: OlJarhead on September 28, 2017, 09:59:55 AM
What do you think of using a bus like this to provide 12vdc power to multiple devices?
A buss in a box makes adding and troubleshooting nicer / easier and looks better. Maybe even safer rather than having wire nutted connections scattered all over. A fuse or DC breaker box with positive and negative buss bars would be the ultimate DC distribution. I've seen some BlueSea products that look good.
Was looking at some blue sea stuff today. Not sure I want the LED's but otherwise they look nicely put together and are likely the choice I plan to make.
LED's use almost no power. The idle or standby power consumption of the rest of the electronics use vastly larger amounts. Even bright indicator, pilot light, LED's use maybe 20 - 25 mA.
Quote from: OlJarhead on September 28, 2017, 09:59:55 AM
https://www.delcity.net/store/100A-MiniBus-Common/p_807936.h_807937
What do you think of using a bus like this to provide 12vdc power to multiple devices? I have a 24v to 12v converter that I use to power a 12v ceiling fan, some 12v fans in the composter room and my car stereo. Today I just wire nut everything to the output (12v) on the converter but I'm looking for a clean way to provide power and thought that I could two of these to provide + and - connections to each device.
With two buses I could land the fans etc on each buss and then provide the power connections to the buss frm the converter. Should be a cleaner way to do this and allow me some more connections.
Thoughts? Any suggestions? Truth is I was looking for a toggle gang switch I could provide power to on one side and then multiple toggles for each item (so I could then just turn them on or off).
How are you fusing the devices on your 12V systems?
I'm planning to use a low voltage DC breaker panel.
Blue Sea Systems makes some nice ones and they even make custom ones.
The only bus I'll need is a ground(12V-) one as the breaker panels have an internal 12V+ bus connecting to the breakers.
Went with the blue sea stuff. basically the blue sea panel for switching and fusing and a blue sea buss for grounds.
Hmmmm........ok first 3 panels are up and wanted to get at least two more up before leaving this weekend but it's been snowing so that aint happening. I thought perhaps I could get some equipment installed but my idea of putting it inside isn't working too well either. So that leaves me back to putting it in the porch which I was trying to avoid.
Next issue was that I realized two of the 3 DC breaker placements on the Midnite Solar 250A Disconnect box were taken up (one for PV in and one for Controller out) leaving only one remaining spot for the new controller out breaker.....I could leave the combiner breakers as my only breaker in the mix on the Outback Controller but am not sure I like that idea so I'm trying to figure out how to now install a 4th breaker in this box. There is an opening at the rear up top that looks like a plate can be installed there, perhaps for installing more breakers and I'm hoping that is the case becuase I'd rather not have to buy more boxes. As it is now I have two Midnite Solar PV combiner boxes and the Midnite Solar DC Disconnect box.
This month marks the 100th month (8 years, 4 months) that our golf cart batteries have been in service. :) They still attain full charge after a normal days sunshine and after a normal previous day and nights use. A few cells in the grouping of 12 batteries have to struggle some to reach "full" sp. gr. readings but they do come along. We are happy! ;D
Midnight solar sent me the plate for the 2nd opening in the DC Breaker box so I am set there. Just need to get the breaker for the solar panels and then I can get back to setting up the new panels. I have 4 up but it's snowed a bunch up there so I am uncertain if I will get the next 3 panels up. I could use the three I have in series but the voltage will be close to the max (something like 118-120 in series so when it gets cold that will go up and could approach the max which I think is 150vdc). Or I can just use two and cap off the 3rd until I can get a 4th (or all) panel up.
I can't quite wrap my head around amp hours...
If I have four 6v 200 amp hour batteries, do I have 800 amp hours of storage regardless if they are wired at 12 or 24 volts?
If the batteries are all in series for 24 volts, then you have 200 amp-hours at 24 volts.
If the batteries are wired in two series pairs to provide 12 volts per series pair and then those are connected in parallel, then you have 400 amp hours at 12 volts.
Perhaps it would be easier to think in terms of watt hours? In both of the above cases the total energy is the same.
24 volts x 200 amo-hours = 4800 watt-hours. Similarly 12 volts x 400 amp-hours = 4800 watt hours.
Assuming all batteries are the same, when batteries are in series we add the volts up but retain the same amp-hour rating as a single battery. When batteries are in parallel we add the amp-hours but retain the same voltage as a single battery. If the batteries are in a combination of series and parallel perform one step at a time. Each series set and each parallel set must be the same. . EG, first add the volts of one series string to get the volts, then add the amp-hours of the parallel sets to get the AH capacity.
Amp-hours printed on a battery applies to one one battery; connect more batteries in series or parallel and you must apply the information given above to get the total energy.
Hope that helps.
Thanks Don...Yes watt hours does make more sense. I was worried that by going higher voltage I was somehow getting less storage capacity.
sent you a PM beavers
Just saw that the U.S. will be imposing a 30% tariff on imported solar panels. I saw mention that the tariff begins in June, 2018, but have also seen that it begins immediately. It continues for four years. First year, 30%. 2nd year 25%. 3rd year 20%. 4th year 15%.
If you buy solar panels that are made outside of China, like the USA, there is no Tariff ;)
Some of the absolute best panels in the world are made outside China. Sunpower, Mission, Prism, Panasonic USA, and quite a few others.
Some US companies Like Suniva are gone because they could not compete with Chinese sponsored dumping into this market.
I won't even go into what a hassle it is to troubleshoot a bad solar panel that should have lasted over 25 years. Not to mention that Chinese companies often go out of business by changing their name so warranty is a joke.
Trying not to sound opinionated :P
So it is only Chinese panels? I read that it was any not manufactured in the U.S., but did not do enough checking to verify.
American manufacturers should be able to compete in a fair marketplace, but no one can compete against government supported dumping.
It will be interesting to see how this shakes out. Thank you for he info.
Not to mention our government giving a 30% tax credit for a US install of panels from a country that is playing dirty. Pretty crazy!
Tariffs are usually never good things so hopefully this will go the right way.
Suniva filed for Chapter 11 bankruptcy protection in April 2017 and has since awaited a decision from the Section 201 trade case before determining its going concern value, according to sister publication Debtwire. Suniva previously merged with Chinese producer Shungfeng International Clean Energy in October 2015, but nevertheless blamed its insolvency on "steep price competition" from Chinese solar imports, according to a Debtwire report.
SolarWorld filed for insolvency proceedings in Bonn, Germany, in May 2017, while its US operations remained unscathed. In a response to Trump's ruling this week, SolarWorld USA CEO Juergen Stein thanked Trump and said, "we are still reviewing these remedies, and are hopeful they will be enough to address the import surge and to rebuild solar manufacturing in the US."
It's my understanding that the tariffs are on all imported solar panels not just the ones from China. I also read somewhere that the thin-film type panels are exempt from tariffs.
The Trump administration issued a decision on a high-profile trade case, imposing 30% tariffs on imported crystalline silicon photovoltaic modules and cells. The first 2.5 GW of cell imports of every year are excluded, according to the press release, which offered no details on whether or not some countries are exempt from the tariffs. Implementation starts in 15 days.
The tariffs will decline in 5% increments over a four-year span, ending at 15% by 2022. The decision draws from one of the three separate recommendations issued by the U.S. International Trade Commission last year in a rare Section 201 of the Trade Act of 1974 proceeding, and excludes a floor price and quotas recommended by two United States-based solar manufacturers last year.
According to GTM Research, a 30% tariff pencils out to roughly $0.10-$0.15/watt, which could reduce utility-scale solar installations by 9%. Trump's decision will likely mean the demise of the petitioners, Suniva and SolarWorld. Both companies told Utility Dive that without their proposed duties, which are markedly higher than the final decision, they would likely fold. However, these tariffs would benefit domestic thin film manufacturer First Solar, who came out in support of tariffs last year.
I'm in the very early stages of figuring out a small off grid system for my cabin. Just like always money is tight d*
I would like to start small and build the system so it can be added onto in the future. My question is what parts of the system should I invest in first? I'm thinking a good charge controller and inverter? Then adding additional batteries and panels down the road. Any other tips for building an easily expandable system?
I'm still working on calculating all my loads...but it won't be a lot. Planning on propane for the fridge and no washer or dryer right now. So mainly looking at lights, microwave, fans in the summer, stereo (no TV), and charging laptops/phones.
Quote from: Dave Sparks on January 26, 2018, 11:48:29 AM
If you buy solar panels that are made outside of China, like the USA, there is no Tariff ;)
I read that even US built panels use Chinese made cells, so even "US panels" would still be subject to the tariff. Is that correct?
Quote from: Beavers on January 29, 2018, 09:56:28 AM
I'm in the very early stages of figuring out a small off grid system for my cabin. Just like always money is tight d*
I would like to start small and build the system so it can be added onto in the future. My question is what parts of the system should I invest in first? I'm thinking a good charge controller and inverter? Then adding additional batteries and panels down the road. Any other tips for building an easily expandable system?
I'm still working on calculating all my loads...but it won't be a lot. Planning on propane for the fridge and no washer or dryer right now. So mainly looking at lights, microwave, fans in the summer, stereo (no TV), and charging laptops/phones.
Batteries should be added in the first year or so of the originals at most. So bear that in mind.
To me a good charge controller and Inverter/charger are a good start. I found they were the things I upgraded fairly quickly.
You can start small on panels depending on what you are doing but know that you may not be able to find the same panels later so may end up with two charge controllers and arrays.
I stated with 3 205w 12v panels, a PCM controller, 2500 watt modified sine wave inverter and 55amp 12v charger with 6 batteries. Today I have those panels plus 6 305 watt 24v panels, a Morningstar MPPT controller, Outback Flexmax controller, 4000watt pure sign wave inverter charger and 24w to 12v converter as well as a 6kw genset with Magnum Research Auto Gen Start switch....and 12 batteries instead of 6!!!
Quote from: Beavers on January 29, 2018, 09:58:31 AM
I read that even US built panels use Chinese made cells, so even "US panels" would still be subject to the tariff. Is that correct?
No, that is not true! US made panels are mostly made here. Many times US cells are sent to china to keep the price low and claim that they are mostly made here. This has been going on long before the current president made more changes. It is convoluted! I would not worry about it either and ignore all the hype.
Is your cabin going to be anything more than a place where you spend very little time?
I would stick with one brand of equipment to make it easy and informative for you and other users of the power system.
Here is a link of a large system but is has all the data that one would need. The percentage of charge, temp, voltage, loads and if there was a generator hook up it would show also. Outback and Schneider are similar and can get out to the web and be monitored anywhere in the world.
https://photos.google.com/share/AF1QipOgnmWeNVSyRaxa_K8_EBtE6L5rOuvpNgiU1ATXyTlrJbmVEfZp00mNowopQbi0Hw/photo/AF1QipN1R-2MwZW5Dz7_hi8e1Q66QSYgqgp1e7FUoP2-?key=Y0dDeTlVbmV5ZmhJV3B6Z3ZKNjZ6ZmU5WnhCUkV3
Thanks for the info guys.
We will eventually be living full time in the cabin.
I've been looking at backwoods solar and northern Arizona wind and sun. Any other good recommendations for online sources?
Allow me to quote a system! Take a look at my website on the left! I offer all the offgrid support and that is not just the power!
I would personally trust Dave to design a system for myself. He knows solar. FYI, he encourages clients to learn as much as they can and perform installations if they can.
Sorry Dave I didn't know you were a solar designer. I'm more of a DIY type of person. I've got a lot of reading yet to do, but I am really enjoying learning about solar.
No need to be sorry! Thanks Don for the kind words! I basically charge a fee for the design and a fee for the equipment at excellent wholesale prices from my 2 suppliers. If you buy the equipment you get the installation advice for handyman skill level DIY. We have been Offgrid for 26 years now. I would not know how to write a check to a Utility ;)
Hey Beavers,
I made a video on designing a small entry level system it might be of help. It's kind of targeted towards the Casita Group I participate in (but they banned it, goes against Renogy kit group think) but regardless I think its helpful. There is one small error that is not really discussed in the video but it's the pinned comment. I should have posted it here first I was basically begging for tech editors 2 weeks ago when I was building it. *edit, I was just able to sweet talk my way into unbanning it.
https://youtu.be/BxWXhVnAkBM
[cool] We have a Brat on our trailer. It hangs,well is bolted with security head machine screws, to the rear by the spare tire.I painted it to match the trailer so it is very unobtrusive. Works like a champ! I'm sure Amazon sells a lot of those Renogy kits though. :(
Glad to to hear you like your Brat, that has always been one that intrigued me. I would love to be able to go out and buy one of everything.
Am I reading this chart right? I have an 1800 watt continuous rated generator. Should I be ok running the 55 amp charger with this generator?
![](https://images2.imgbox.com/c8/ba/o9xYxf3n_o.png)
(http://imgbox.com/o9xYxf3n)
Maybe someone else will chime in but my answer would be NO. I have a 3000 watt Honda and it only has a 30 amp breaker.
I have an Iota DLS-55.
I have a Honda EU2000i.
They get along okay. The maximum inrush current is a rather brief spike. That does not seem to be a bother; yes the Honda feels it but never sounds too unhappy. When charging the Honda might run at full throttle for a while but I don't usually let the batteries get under 1/3 full so the charger doesn't usually pump maximum amps anyhow. That has been my experience.
Iota does make a charger that has better PF (Power factor = efficiency), no inrush to speak of at all. I haven't looked lately but IIRC they introduced it a few years ago ... might only have been a 24 volt model... at the time I was looking for 24 volt so that is what I remember. Many chargers have a poor PF because most manufacturers believe you are going to plug into mains power, not a generator. Better PF can be expensive though.
Thanks Don.
I just got a Ryobi inverter generator. I can't believe how quiet it is compared to my bigger Champion generator. I really like the Bluetooth and app for it. Its nice to be able to see the load, fuel level and turn off the generator remotely. [cool]
https://www.homedepot.com/p/Ryobi-Bluetooth-2-300-Watt-Super-Quiet-Gasoline-Powered-Digital-Inverter-Generator-RYI2300BTA/300347426
Quote from: Redoverfarm on March 19, 2018, 10:42:48 AM
Maybe someone else will chime in but my answer would be NO. I have a 3000 watt Honda and it only has a 30 amp breaker.
John, I think you are mixing the AC amps and the charger DC amps. As Don said it will be fine and nice that the bluetooth is adding value and modernizing the venerable Honda.
If it would start it, and output 240Vac, and run from propane I could sell dozens of them ;)
Quote from: Dave Sparks
If it would start it, and output 240Vac, and run from propane I could sell dozens of them ;)
/quote]
That would be a nice generator!
![](https://images2.imgbox.com/95/61/YLTmWiX0_o.jpg)
(http://imgbox.com/YLTmWiX0)
Anyone see any potential problems with my wiring? Where do I ground this?
Is the generator used as a portable device? No permanent connection between it and the battery charger?
Is the generator output also connected to any cabin wiring, service panel, etc?
Is the power output from the inverter used directly via plugging into the inverter AC outputs? Or does it feed into a service panel of any sort?
Looks like maybe a 12 volt battery system? The distance between batteries and charger and batteries to inverter would be less than 10 feet? #4 AWG wire would be more than adequate.
No PV panels? No charge controller?
The fuses should not be in the same enclosure as the batteries just in case one blows when hydrogen is present in a combustible mix, unless the fuses are fully encased to keep the arcing within a shell. A fast-acting class T fuse is best for use in a DC line connected to a battery bank. They can be mounted directly to a battery or in a case. Others may have to be mounted in a case to contain arcing. Fuses / breakers must be rated for DC use when used in DC circuit.
The generator will pretty much permanent in an enclosure. Battery charger is an Iota plugged into the generator. No hard wiring of the generator to the cabin.
For now I will be plugging into the inverter to run a fan and charage phones. When I get a bigger inverter it will be connected to a service panel.
Yes 12 volt system...battery bank is four 6v golf cart batteries. Will be 5 foot from batteries to inverter.
No pv panels or charge controller yet.
I got class RK5 time delay dual element (FLNR 50) 125V DC fuses. Will those work?
Thanks for the help!
Generator. Used as described it more or less is much like using a portable generator on a job site to power tools. According to OHSA regs that does not need a ground to earth.
Inverter. Used as described it would be as intended, more or less a portable device. No need to have an earth ground. Things change when a service panel is introduced though.
House wiring, done according to code, has a bond of the neutral and ground at one place in the system. That is usually a green screw that bonds, or connects, the ground and neutral within the service panel. If you connect a MSW inverter to such a system, the MSW inverter will be toasted, the magic smoke is released and the MSW inverter is no good anymore. It seems odd to me but any MSW inverter I have checked out has 60 volts between ground wire and neutral and 60 volts between hot and ground. Add those up and you have 120 VAC. But introduce a N-G bond and you produce smoke. PSW, pure sine wave, inverters designed for hard wiring should not have an internal bond and should be okay wired to the typical bonded service panel. I don't know about PSW inverters with built-in outlets. ???
Small portable generators with built-in outlets, often have the neutral conductor bonded to the generator frame, which equates to a neutral-ground bond. In that case, when the generator is connected to a service panel there should NOT be a bond in the panel. My Honda EU2000i is one w/o the internal bond. But the Honda EB200 does have a N-G bond. It can get confusing.
Fuses. I'm not familiar with the ones you mentioned. The idea of the fuse is to protect the wiring, not the charger or inverter. A lead acid battery can supply thousands of amps with a short circuit. If the time delay is too long the wiring could be damaged. Time delays are most often designed for use with circuits that power motors that may have a large startup surge, then fall to normal ranges. So I can't say those are good or not.
The NEC used to exempt 12 volt systems from needing a ground to earth; higher voltages required an earth ground of the battery / DC negative.
Once PV panels are installed that has some rules too. PV systems are now supposed to have a GFP (ground fault protector). And with panels the lightning issue can become a serious concern and will need protective devices and good grounding.
I am not an electrician so take what I stated above as a place to start your own research from.
Thanks Don.
My Ryobi generator has a "neutral floating" ground lug on the front. I should probably start with reading the manual to see what it says. d*
I double checked the specs on my fuses. I got them from AltE it says they are good for inverters up to 700 watts so I think I'm good there.
My electrical knowledge is very little. One of the big reasons I'm starting with such a small system. I'll definitely continue reading up and learning more.
Is there a solar charge controller? I probably missed this as it is changing before my eyes d*
Nope. No solar yet. I'm a total electrical novice...so I'm starting very basic and slowly working my way into things.
In July of 2009 we installed golf cart batteries (12 - 6 volt in a series/parallel 24-volt arrangement) for the then new solar electric system. Today I replaced them. Not bad; 9 years service.
Last year I had noticed some of the cells were not coming up to the full charge specific gravity reading (1.265)as quickly as the others, no matter what I did. In fact, some cells would never make it past 1.225. This spring water use went way up on about 10-12 cells. Yesterday it was obvious most of the batteries had reached the end of their useful life. Several cells had very low sp. gr. and no volts. That resulted in cooking away the water in one series string during our three week absence to Canada.
Over the years we have actually reduced the amount of energy we use at the cabin. No more TV; we use a laptop with a TV tuner whenever we want to watch something. LED lights have supplanted the CFL lights. I think 8 batteries will be more than ample for our needs.
I wanted lithium-ion, but stayed with the tried and true, familiar flooded lead-acid. Considerably less out of pocket, even with the liklihood of longer service life and much reduced maintenance.
Good to hear MD! :)
Only 8? For the cost (to me anyway) I'd keep the 12 because it gives you longer discharge time to 20% DoD without sunlight which means more days in the winter to not worry :) but you know what you are doing, it was just something I've pondered since I use more power than you. Just posted some on my setup in my thread, but in short I use about 50AH to even 55AH overnight so without sun I can use more than 20% of my 660AH bank in one full day (or darn close to it but I can conserve more if need be and get by for about 36hrs on 20%) so my bank is a tad small but I'm upping to charging power by several factors which I think will reduce gen use.
Hey Don, Did you use the costco golf batts? I recently did for a friend as they are easy to get and pretty cheap. We had to go to 2 different costcos to get the same date code.
Fires....
We have 4 people staying here who were evacuated/lost power and they go home today :) The town has placed dumpsters everywhere as all of the food is spoiled. Yuk in 100F heat.. Not good times :'(
This has been going on for 15 days/50K acres but we had little wind. The Carr fire in Redding has done 80K acres in 3 days because of the 70 mph winds. 7 people dead and 35K evacuated. Quite few homes burnt.
We never planned for any help in a fire and designed for it. We use to load the truck in case we decided to leave but have stopped doing that as it is more dangerous on the roads with all of the dead bark beetle ponderosa. Nasty business. Still Love it here but some big changes are coming or the whole west is in trouble.
Hi Dave, glad to hear you are still safe.
Batteries: I used Sam's Club as the clubs near me carry GC-2 batteries and the Costco's do not. Go figure? I got lucky and found a shelf full of same batch batteries.
Fires: We are very happy that the FS began some very serious thinning around us a few years ago. Google Earth/Maps now has recent images that clearly show the vastly reduced tree density. That should help a lot if, or should that be "when" another fire comes too close. Between the FS contractor thinning and the wildfires (3) that have been close in the past few years I am hopeful. A nephew used to live in Redding. Real bad there.
We have had maybe an inch and a half of rain quite recently :)
Rain ! Maybe in October... Day 22 tomorrow of being indoors much more than I like. Smoke on the Water :P
The new rainfall amount for the Jemez is now 4.21" of rain since July 17 ;D
However, most of northern NM is still in what is called an "exceptional drought" :(
OK, I have been pondering something of late: When you are at your cabin using power in an off-grid scenario as I am it seems to make sense to have the charge controller (s) go into absorb long enough to push the total Amp Hours used since fully charged back into the bank before going into float. If in my case you tend to use between 45 and 65AH overnight it stands to reason that Absorb, if pushing 40amps into the bank, should run for about 1 1/2 hours (maybe more?). Once Absorb has run long enough to put the bank back to 100% (by the meter not SG) then it makes sense to have it float as long as possible as this will provide power during the day to run various items (fridge, fans, radios etc) while maintaining the bank until the sun goes down so you have full capacity before the night starts -- right?
OK so now here is the real question (though the above poses some too): What about when you leave the cabin and the system will be sitting dormant for some time? For example, my system only really uses about 1 or 2 amp hours overnight when I am not there and the inverter is off. I run two computer fans in the back composter / water entrance room and a bilge fan/blower for the solar heater. Even if I used a total of 6AH overnight (close to 1% DoD) the system doesn't really need to Absorb for so long -- at least to my thinking. Wouldn't it be better to drop Absorb to a shorter period and extend float?
The Morning Star controller can provide 16amps at full sun on the old panels and allows me to set float as well as aborb extension times but the Outback does not (I am actually disappointment in the Outback a little because of this), So, would it make sense to only use the smaller bank when I am not at the cabin? To run a diversion load with the Outback which has 6 305w 8amp panels running to it that really aren't needed when I am not there?
Or, would it make more sense to leave the inverter on to maintain the generator battery and draw a small load overnight (I'd have to do the math but I'm guessing 25AH or less) just so the bank is being used? The problem, of course, with this is when the clouds and snow come and there is no solar charging for days and days. In that case the generator will run often or I'll have to disconnect the system when the time comes (which could be any week now).
Just looking for some ideas and thoughts on this.
Oh and here is what I am running now:
Array one: 3 205w 12v panels in series feeding a Morningstar MPPT charge controller. Max battery charging about 16.5amps @ 29.6vdc -- pretty much infinity adjustable for Absorb and Float times.
Array two: 6 305w 24v panels in series parallel (two panels in series, 3 sets in parallel) feeding an Outback Flexmax 80 charge controller. Max charging should be over 40amps but I've not seen it do that yet and need to calc (which I've done but not sure where it's hidden).
Battery bank is 12 GCB's from Costco providing 660AH @24vdc
Inverter is Aims 4000w pure with 55amp charger
Magnum Research Autogen switch (max volt start point is 24v and max run time is 5 hrs)
Generac EcoGen 6kw
I've had similar thoughts recently.
I've also read that absorb should be longer than you'd think, but would be limited in solar applications by day length.
Some CCs adjust Absorb time based on how much the battery was discharged. The Morningstar will allow an absorb extend based on the low voltage the night before, right? There might be an option in there....Do a short absorb unless the battery was discharged below X, and then add 2 hours then?
Other CCs have the ability to adjust absorb based on the ending amps.....Morningstar doesn't do this IIRC, but I think Midnite has the option on some controllers. Not sure about Outback. But that might be another solution, absorb being based on end amps (Because the amps taper at absorb voltage as the battery gets closer to 100%). This would accommodate for use or lack thereof overnight, having a short absorb time when you're not there.
Not sure which Outback you have, but it looks like some of them DO have the end amp option: http://outbackpower.com/forum/viewtopic.php?f=29&t=7116
Hmm, good discussion on this very issue here: https://forum.solar-electric.com/discussion/14196/optimal-absorption-time-good-bad-wasted-effort
Also, I can't think of any reason you'd NOT want the batteries to float until sundown once absorb is completed.....
Thanks or the replies.
The MS does allow absorb extension based on voltage settings so I could set absorb to go to any additional length of time based on voltage. This is 'ok' since voltage on the string doesn't really represent SOC since under a load the voltage drops and then rebounds after the load is off. This is why the battery folks say not to bother using SG readings unless you've allowed the batteries to rest at least 12hrs but 24 preferred.
I could set the MS to run a short absorb and extend at say some voltage that represents 80% SOC perhaps. But I can float the MS all day too so really, leaving it at 1.5hrs Absorb and float for 3+ should use all sun.
The problem I see is that the Out back only allows an adjustment to absorb time. So I can set that to absorb for 1.5 hrs (which is about right under use) and shut off at 0amps (batteries are charged) but with the MS sending amps also this might confuse the OB and I can't set it to float longer than 1 hr
Quote from: MountainDon on August 03, 2018, 03:58:06 PM
The new rainfall amount for the Jemez is now 4.21" of rain since July 17 ;D
However, most of northern NM is still in what is called an "exceptional drought" :(
If I had a way to send you some rain I would. We are getting close to 50" this year. Glad it wasn't snow . That would be close to 50 feet. :(
We are having some rain now and on-off over the past couple of weeks. Could still use some more.
So Outback responded with "there is no way to change the float time on our controller".
??? ??? Not sure why you would do this and must admit, I'm regretting my decision to move to Outback at this point. My Morningstar is far more flexible.
Who is telling you that you can't use a hydrometer?
I think you are mixing up resting voltage? SG can be measured anytime!
SG is the one strength of this slowly fading technology with quite a few weaknesses these days.
Not that I can't, that it doesn't mean much unless the batteries are at rest long enough. Other than making sure they are all about the same SG reading.
For sp gr they don't need to be rested. Perhaps the sp gr readings should not be taken when being rapidly charged or discharged so to minimize gassing and the possibility of bubbles adhering to the float.
Perhaps the confusion on my part is that Trojan told me to not take the SG readings unless the batteries had been at rest for at least 12hrs because they would not represent a true reading. Meaning that under a charge or load the SG reading isn't the same as under rest.
Same with looking at voltages to decide a SOC. The voltage under load does not represent the SOG vs the voltage at rest does
Just because someone tells you something???
Due diligence is required.
Sorry, but SG can accurately measure state of charge, anytime! Even with bubbles there are ways to get a good reading. Been doing this a few weeks ;)
I run into this sometimes with Outback, Schneider, Midnite etc. There are new people who really are not up to speed (especially in Support) and you can get information that is "not quite right". You can digest it faster if it is from Engineering, most of the time....
New system build
I am new here and am working on setting up a small solar system to run my deep water well off of in the event of power outage on my small homestead which my area is known to have from time to time. A few years ago we had a pretty heavy ice storm and power was out for about 2 weeks. The people who lived in this home built house said they melted ice sickles for drinking water. My wife said she did not want to go through that so we installed a 22KW generac so we would have power.
I have been sitting on four brand new Renogy 300 watt solar panels for about 5 years (still in the box) and we have decided after watching our electric bill continue to rise month after month to set them up. I bought these panels to use on an off-grid cabin that I own in the mountains but never installed them because there is a theft problem there and I'm afraid they will be stolen. I have been using a EU2000 generator to recharge a 12 volt battery bank there for the last 3 or 4 years and it has worked great considering I'm not up there very often.
I was helped by @MtnDon (Thank you again @MtnDon!) on another site 4 years ago to design the solar plan for that location so I now am pulling out the plan and readjusting it to set up a small non- grid tied system here on our small homestead to run the well if need be but also maybe when not using it for the well to run a fridge or some outbuilding lights etc. and cut back on our grid use.
Here is what I own so far: Four 300 watt Renogy solar panels, one Midnite Kidd charge controller and I also have about 100 feet of copper 2AWG wire I bought from a contractor who had left overs from a job.
I have found a dealer who is offering me a great price on eight Trojan T105 batteries for $116 a piece ( which I think is a great price) and I'm looking at a AIMS 6000 watt pure sine wave inverter. 110/220 output ( this is changeable for sure) What I'm trying to figure out is do I run this in 24 volt or 48 volt? My distance from panels to Kidd will be about 20 to 30 feet. The distance from my controller and panels to well is about 50 feet.
My well pump is 230 volt and I can not find any info on what the startup draw is or the running draw. I guess after searching around for info that a 4000 watt or 6000 watt Inverter/charger should handle the pump.
Any ideas from you who are experienced would be greatly appreciated. Other places I have mentioned this system at have really pushed the Lithium Ion batteries at me and I know that I can not afford to go there even though I would love some so maybe we can avoid that discussion if possible.
We hope to be able to double the panels and the batteries after this system is up and running so information on how to keep this system under it's limits so we can would also be great!
Here are the specs for my panels:
Maximum Power a t S T C ( P m a x ) 300W
Optimum Operating Voltage (Vmp) 37.46 V
Optimum Operating Current (Imp) 8.01 A
Open-Circuit Voltage (Voc) 46.12 V
Short-Circuit Current (Isc) 8.56 A
Hi. Too bad there is too much theft risk to install those panels at your cabin. Our system has worked well for about ten years now,with the exception of the lightning strike. :o
Yes, lithium batteries have advantages over lead acid. If the lithium batteries do last at least as long as the
manufacturers and sellers claim, they can even save money in the long term, even with the big initial expenditure. Flooded lead acid batteries like the T105 do have one nice thing... the ability to take sp gr readings of each cell. That can tell you exactly what the condition of the cells is. I keep a log book of the readings of each cell. Lithium have to be charged when the battery is above 32 F. Not a big deal but in my case, I will have to do something about that when I change to lithium. But that is a few years off as I just put new lead-acid into service this summer.
If your plan is to have the solar and batteries as a backup to operate the well pump as well as use solar power "to run a fridge or some outbuilding lights etc. and cut back on our grid use", those items will need to be separated from the other grid-tied circuits. There can not be any way the power grid and power from a generator or inverter can be "mixed".
AC power has a sine wave. Viewed on an oscilloscope good AC power is represented by a wave ...
![](https://images2.imgbox.com/f1/de/GU59hKes_o.jpg)
Simply put the peak and valleys of two AC sources to be combined must be matched, otherwise, damage is going to occur to at least some of the equipment. Your equipment or the power company equipment. When generators that are designed to be parallel connected the engine speed, the waveform, the voltage is all matched. If the voltage is off a bit between the two sources damage can occur. Same with inverters, some are are designed to be parallel connected, many are not. The ones that can be paralleled will sync the waveform, etc. None of those can easily be sync'd to the power company system as far as I know. The inverters and other equipment used in a grid tied solar system are designed to be compatible. The power company will have a list of approved equipment. The AIMS are almost certainly not on the list.
So, if a portion of your home is grid-tied and a section is not, you would need to totally separate the non grid powered fridge or whatever circuit from the grid powered balance of the system.
Or you make a proper grid-tied connection between your solar panel system and grid approved inverter and use the grid as a battery. This needs to be coordinated with the power company and all equipment approved and the installation inspected. FWIW, most grid-tie systems don't have any batteries, but backup batteries may be included with proper design, approval and proper automatic safeguards to keep your power completely separated from the grid when the grid loses power. Many people hire this out but with guidance, a DIY person can do it. Member Dave Sparks (https://countryplans.com/smf/index.php?action=profile;u=4301)can help with system design and equipment purchase. Dave charges a fee for his services and really knowsHis contact emailis on his website. his off-grid power. (http://members.sti.net/offgridsolar/)
There is a very real danger to power company workers if a non-authorized power source like a generator or solar inverter system is supplying power into a power grid that is not powered by the grid system.
Another member here has a standby, automatic start generator, that will take over and supply power to the home when the grid goes down. It has automatic controls to maintain isolation from the grid.
We reduced our power company bill by replacing the old furnace, the old A/C and the appliances and old electronic gear over several years time, as well as changing every light bulb to an LED. Our power company has a three-tiered rate system as many do. We seldom ever get into the second tier and never into the third and most expensive tier. We have lower total power use/costs than even some of our neighbors who opted for a solar lease or power purchase agreement. Of course, we also go dark if the grid fails, but in our area, the grid has been very reliable. If it wasn't I would probably go with a good generator system running off propane or natural gas.
I hope you find all that useful. More questions welcomed.
Yes, that is a shameless plug for Dave, and no, I do not consider this spam as we know Dave to be qualified and honest.
MtnDon, I had planned to pull any circuits that I run on this solar system away from the grid and keep this system off the grid completely. The location I have chosen for the panels and the electronics and batteries is very close to the panel that my well and outbuildings that I want to run on this system so it would be pretty easy to just install a breaker panel and rewire these circuits directly to this off grid panel.
Here is the old design that you worked up for me back in 2014:
---------------------------------------------------------------
Here's a thought that works with 1 Kid charge controller
4 of the 300 watt panels; 2 series strings of 2 panels each and those series strings connected in parallel
48 volt battery bank
buy 2 more of those batteries; 2 series strings of 4 each, connected in parallel
Then when those 12 volt batteries die buy some real RE batteries (like L-16's) or at least golf cart batteries
MtnDon
Member # Posted: 15 Sep 2014 18:22 - Edited by: MtnDon
Reply Quote
That has the Kid working at half capacity (amps) more or less. Better than working close to the maximum, as far as theory goes. It also cuts the parallel batteries down to only 2 deep; much better than as is now.
If those batteries are about 115 amp hours each then you would have 115 x 2 = 230 AH @ 48 volts = 11040 watt hours. At 50% max discharge = about 5 Kw usable power.
230 AH would be served well with a 20-25 amp charge input. The 4 panels on the Kid would supply 21 amps at 57.6 volts (equiv to 14.4 on a 12 volt battery). Just about ideal for charging.
Now find a 48 VDC inverter.
----------------------------------------------
So here is my plan, tell me if I have this right.
I will lay everything out the same as above except rather than the 12 volt trolling motor batteries I plan to buy 8 of the Trojan T105s (225AH) and wire them the same in two series strings of 4 batteries each and then connect those strings together parallel. (6v x 4=24 volt series strings x2) This should be a 24 volt setup instead of the 48 volt but should make 10800 watt hours which is very close to your original design that you did for me in 2014.
225AH x 2 = 450 AH @ 24 volts = 10800 watt hours. At 50% max discharge, This should still be about 5 Kw usable power. Hopefully my math is correct.
Unless I'm better off wiring all 8 batteries parallel for a 48 volt system. I do plan on adding 8 more batteries and 4 more panels at a later date but it will probably be awhile to come up with the funds.
Correct me if I'm wrong please.
Then I'm looking at this Inverter/charger as a possibility:
https://theinverterstore.com/product/6000-watt-pure-sine-inverter-charger/
---------------------------------------------------------
6000 WATT PURE SINE INVERTER CHARGER 24Vdc / 240Vac INPUT TO 120/ 240Vac SPLIT PHASE OUTPUT
6000 Watt, 18,000 Watt surge, 24 Vdc, 120 & 240 Vac, Inverter, Charger & Transfer Switch. 50 amps @ 120 Vac. Input charger 240 Vac.
This AIMS Power Low Frequency 6000 Watt 24-volt Split Phase Power Inverter Charger is not your average every-day power inverter. What you see here is our top-of-the-line power inverter, built for the purpose of running your whole house (smaller home), business office or large RV. This inverter charger is perfect for your off Grid system or for use as an emergency backup supply.
Split Phase Power Inverter
The 110/220 split phase inverter is capable of producing 2 legs of 110v, making this inverter perfect for home and shop applications with a 220 panel in place.
However, the inverter can utilize grid-power to charge the batteries and send the power out to your application using the built-in 85 amp charger. If the grid power is lost, this inverter is equipped with a seamless transition transfer switch, becoming a true UPS (Uninterruptable Power Supply) when you need it in emergency situations and natural disasters (battery required).
This inverter charger has an on optional LCD remote showing you of any abnormalities on all parts of the system, giving you ample time to fix the issue and exactly where to look. This inverter charger also comes with an Auto Generator Start mode that can tell a generator to start up and begin providing charge to the batteries (through a separate charger on 120v gensets) or providing power to the home.
Need to use this in a different country or with 50hz electronics? This whole house inverter comes with Auto Frequency Detection software, providing you with the correct power frequency on either 50hz or 60hz.
Am I better off with a 48 volt bank?
So 8 batteries in parallel because I'm going to add another string later on?
Is 2 strings of 8 batteries better than 4 strings of 4 batteries?
Or will my charge rate be insufficient? In hind sight looking at the numbers I think it will be insufficient.
Sorry about all the different posts. Just trying to figure out all of this as I wait for your vast knowledge on the subject...LOL. I'm learning as I go and want to get it right. I sure don't want to ruin my batteries from an insufficient charge rate or order the wrong inverter or some other issue that I have wrong.
Sorry, I'm not ignoring you but have found myself in the middle of some neighbors with frozen pipes and a leak or two.
I didn't think you were... no problem at all. I'm busy with livestock myself! LOL
225AH x 2 = 450 AH @ 24 volts = 10800 watt hours.
or 225AH @48 volts =10800 watt hours
Wouldn't the charge rate of 21 amps at 57.6 volts be better suited for the 48 volt system @ 225AH rather than the 24 volt system recieving 21 amps at 57.6 volts for 450AH?
The only question is ...Is an 8 string of six volt batteries better than two strings of 4 batteries? Of course if I expand into double the solar panels and double the batteries I would be looking at two strings of 8 batteries or four strings of 4 batteries.
Seems like the 8 battery string would be better and the charge rate better suited for the 48 volt battery bank.
A series string of those T105 batteries is better than having the same number of T105's in two series-parallel strings.
The panels you have work out well to charge the 48 volt battery bank with a KID MPPT controller. MN has a string sizing tool (http://www.midnitesolar.com/sizingTool_kid/) for checking that.
If the same 2S 2P configuration of solar panels was tried on a 24 volt battery bank, the KID will be overpowered with too many watts. 24 volts won't work. If you wanted more panels you would also need another controller as with the 4 panels in 2S 2P it is at about 75% of capacity. Or buy a larger capacity controller.
I have no idea how much surge capacity you will need to start that well pump. No easy way as far as I know for determining that. It would sort of be a shame to have to get a huge inverter only to cover the pump surge. But maybe unavoidable unless you can fund a new low surge well pump. There are some you could run right off the panels without any inverter.
As for running other household items as long as they are completely on their own system so your system cannot power up a dead grid you should be fine. How old is the fridge you might power? If it is anywhere near time to replace it you could buy an inverter compressor fridge and not have any startup surge there either. LG and Samsung sell some fridges like that. Often it is hard to find what tech the compressor uses when looking at fridges or the spec pages. Those new compressors all have a 10 year warranty on the compressor so that can help weed out the old style compressors. Some of those compressors are also known as linear compressors. No surge, virtually silent, I really like them. With a new well pump and fridge the inverter could be made much smaller. Just a thought.
Thanks MtnDon. BTW, I traveled near the mountains where you live a few years back on a run to pick someone up in Oregon from Central Texas. Beautiful country for sure!
I am planning to put my 24 VDC solar system together this year. Up until now I have been running 12 V LEDs and my water pump off a single deep cycle battery charged by one of my solar panels. I had planned to do a 12 V system, but the more I read and understand, a 24 V system would work better and give me more options in the future. I have two 250 watt solar panels and am using a Trace MPPT charge controller. The Tracer will handle the 2 panels hooked up in series. I plan to purchase an Outback FM 80 charge controller so I can add more solar panels in the future. I'm thinking of buying a 24 V Samlex 2000 watt PSW inverter for AC power. I'll use a 24 V to 12 V converter to drop down the DC for my 12 V lights and pump.
This is a sketch of what I am currently thinking of.
![](https://i.imgur.com/M28SlTJ.jpg)
All comments or suggestions are welcome. I have to read up some more on lightning protection.
One question I have is about tying a 24 V battery charger into the system. Do I need to disconnect the charge controller when I am charging the batteries with a battery charger? I have read that it is not necessary to disconnect it, but I'm not sure if charge controllers have circuitry to prevent back feeding power or not. I know some inverters come with integral battery chargers but I would prefer to have them separate.
Thanks.
Dave
Re: 14x32 in NH Lakes Region
Some quick comments and questions....
It is advised to put a breaker in the + line from PV panels to the charge controller; close to the controller. This makes it easier for setting up the CC. The procedure is to first connect the CC to the batteries. The CC usually ID's the system voltage. Then, once that is set the input from the panels is connected. A breaker makes it easier than connecting wires to terminal lugs, IMO.
The MN surge suppressor needs a good ground to earth. That is best achieved with two earthing points about 16 to 20 feet apart and joined to each other by a single continuous ground wire that also connects to the MN-SPD ground.
It is also a good idea, IMO, to use another MN-SPD on the AC circuits side. I like the MN-SPD a lot. They have a warranty and they honor their warranty. We have had to replace them a couple of times as we are in a lightning prone area.
Re the grounding rods: the NEC calls for no more than 25 ohms resistance. To measure that you need two grounds in the earth. Disconnect the ground wire that runs between them and measure the ohms between rods. You should have less than 25 ohms. The lightning folks I have dealt with recommend 10 ohms, or less.
Ifyou have much lightning activity you may also want a separate lightning rod and grounds system.
Batteries? What kind and what AH capacity? Lead-acid? Flooded or sealed batteries? You may be able to make a better battery bank by going to 6 volt or even 2 volt batteries and having a single string of them in series to make 24 volts.
We have a Samlex inverter as a backup spare. We have been lightning struck. I like a combination inverter/charger best of all as they have a better charger builtin than most of the stand alone chargers out there. The Outback, for example, can have the maximum charge rate programmed. If starting a charge off the generator their inverter/charger will ramp up to the preset maximum rather than slamming the generator with a full power surge demand.
Having the CC and the inverter/charger both by Outback also lets you use a Mate to tie everything together with cat5 cables and set and read data inside. If you have not looked at that you should before you buy the hardware. Yes, it will cost more but I do love our system.
Do you have inspections to meet? The Samlex inverter is NOT meant for hard wired use. If you need to pass an NEC inspection the Samlex will not work. If you have no inspections and go ahead and use an inverter with receptacles built in be aware that those types of inverters usually have an internal bond between the neutral and ground outputs. Therefore do NOT implement the service panel bond that is normal in a residential AC service panel. Having a panel neutral-ground bond with AC coming from receptacle outputs on an inverter will burn out components in the inverter... release the magic smoke. Complete toast.
There were some significant changes made to the NEC a couple of years ago. I have to admit I am NOT conversant in the changes. Some or all, of the changes were to protect first responders in emergency situations. Sorry, but I am not certain of what the changes entail for an off grid system. It may be more to do with grid tied systems and may be only with roof mounted panels. ??? Maybe Dave Sparks will comment.
We also use a Samlex 24to12 converter to run a few small 12 volt items.
Thank you for the comments MountainDon.
I don't have to do any electrical inspections in my town. That is one of the reasons I bought the property. I only needed my septic system inspected and need to call in the fire chief to look at my wood stove installation. That said, I want to do my electrical safely, so I don't burn the cabin down!
I am planning on four 12 volt flooded lead acid marine deep cycle batteries. They are 115 amp hours and I can get them for about $110 each. I know that 6 volt fork lift batteries would probably be better, but I will need a learning curve for taking care of my batteries and I would rather start out with cheaper ones and then move to better ones when I am more experienced.
I will look more into combined inverters / battery chargers. I see your point about charging the batteries gracefully instead of slamming them with max amps right away. I do need to stay under $1000 for my inverter, so the top of the line is out of my budget.
I will definitely put a switch between my panels and the charge controller.
Thanks for the lightning / surge suppressor info and especially the grounding info. I need to bone up on grounding. I have a metal roof on the cabin which will be higher than the panels; I don't know what is more likely to get struck first. I am surrounded by tall trees as well.
I'll keep everyone posted on my progress.
Thanks,
Dave
QuoteI am planning on four 12 volt flooded lead acid marine deep cycle batteries. They are 115 amp hours and I can get them for about $110 each.
Do you belong to Costco or Samsclub?
For $90 to $100 each (where I live) I can usually get a 6 volt golf cart battery with about 210 to 220 AH capacity per battery in that price range. Four of them in series gives you pretty much the same capacity at 24 volts that you would have with 4 of those 12 volt batteries in a series-parallel configuration. The golf cart type batteries have thicker lead plates than any 12 volt battery sold as a marine or RV battery. That makes them better for the deeper discharges you are likely to use in an off grid system. Some Walmarts will have golf cart batteries in stock as well. Less money, better battery and the all series is better for the batteries. Try to avoid parallel batteries if at all possible. There will also be a core charge but that should be the same for a 6 volt golf cart battery as for a 12 volt marine/ rv or auto battery. Last year the core charge here was $12 IIRC, though it might be $15 now. You get that back when you trade the old one in for a new one.
Along with the flooded batteries buy a good hydrometer and a notebook to log the specific gravities. The Hydrovolt battery hydrometer seems to work well and compensates for temperature. They are German and I noticed a while back that Midnite seems to have bought the rights for the USA. Rinse with distilled water after use is a good idea with any hydrometer. Also one of the battery water dispensers you can find at NAPA, and other auto parts stores. Even Amazon. They make filling easy as they have an autostop device.
Lightning? There seems to be no rhyme or reason to how it strikes. It goes sideways as well as up or down. A higher metal roof is no guarantee of anything, IMO. We had burn marks around the eves as well as lower down the slope at the array. Virtually everything with a silicon chip blew, except for a $59 microwave. Can't figure that one out; it has digital touchpad controls and we still use it. Circuit breakers on the DC PV lines were blown apart. One of the GFCI's ceased working. The more or less center pine in a cluster of four 75 foot pines had spiral lightning tracks and died; the others are still fine.
QuoteI will look more into combined inverters / battery chargers. I see your point about charging the batteries gracefully instead of slamming them with max amps right away.
My meaning was more that the gentle ramp up eliminates the start up surge a conventional charger has. No surge is easier on the generator.
..... 4 of the 6 volt GC batteries have half the number of cells, compared to a 4 x 12 volt bank.
Don is correct about the golf cart batteries rather than the deep cycle batteries. Marine/auto Deep cycle batteries become toast in a very short time. I also like the Costco GC batteries.
Now I have gone to a $4000 875 amp @ 6 hour forklift battery with tubular plates.....​Very satisfied with it. The manufacturer is in San Leandro near one of our jobs and he sets them up special for solar customers with float caps to see the levels instantly.
Costco GC's are hard to beat. For an emergency temporary repair, I use them for places that are at lights out. Keeps them off the genset until they decide what is next.
I saw few offgrid lights out this summer during the Ferguson fire. How did you do Glen during that nasty 6 weeks?
Still finding limes for the Pacificos? :)
Yes, we belong to Costco. I looked on their website and they sell 6 volt Interstate GC batteries with 225 amp capacity. I'll take a look this weekend and see what the prices are. I assume they are around $100 each. Now I understand that the GC batteries in series would be only half the number of cells to take care of as opposed to the 12 volt battery setup I sketched. Thanks for the tips!
I started looking at 24 volt inverters / chargers. I can't afford the high end ones like Outback and Magnum, so I looked at the AIMS 2000 watt which costs about $650. The remote switch/panel is another $100. I was reading the manual and it said I would need a generator with 150% capacity of the inverter. So I think that would be a 3000 watt generator I have a Champion 1500 watt generator; I like the size - I can carry it around myself and don't want to buy a bigger one just to run an inverter/charter. I could buy a separate 24 volt charger and run it off my current generator. I'll keep looking.
Dave
Well, Dave, I thought you would never ask... I was getting frozen steaks out of my freezer for a barbecue on the day all of those people on that reliable grid power were having a free dump day to dump all of their thawed frozen goods.
...​and to think that the lady at the county building department told me it was against the law (really) for me to consider living off grid if it was available from the local power company. Off grid was just too unreliable....​Oh, and 2008 telegraph fire, I did the same thing....
Well, ok, it did go out on the local fire department radio that there was a crazy guy at my house with guns and a tractor. I don't recall meeting him, but the sheriff's and fire chiefs sure showed me a lot of respect when they saw I was serious about not leaving....
Limes and Pacifico's...... Sounds good. 😊
For the poster, if this is for the long haul, you may find that using cheaper equipment, only saves cash the first time you buy it... Do it right and buy equipment that will supported. I only use Schneider and Outback but now that Magnum makes a cc they are on the list. Stay with the same brand and you can get site data over the internet if that is important. You may find later that it is.
Well Glenn how did you do with the smoke? I went to a few offgrid places that were evaporative cooled and it was smoke city indoors. The mini-split is a godsend for that and in the past I always sized offgrid for winter and it now pays off for producing power on a really smokey summer days 8)
When we built the same lady, I think :P told us we could build an offgrid home but we could not live in it.
I bet they do not push the utility so much with their recent fire history :-\
We always keep a few limes for you here! FRIDAY
Thanks Dave.
During the worst of the smoke we were working away from home. San Leandro I think. We were home on some mildly smokey days. A friend working for the fires said if the fuel supplier would quit selling the CDF diesel to restart the fire it would have went out. During the smokiest days they could hardly get it to relight.
Yes, that is true. If it goes out too fast they will not get as much funding next time, and many areas had not burned in years so this was their opportunity to burn it un interrupted by the tree huggers. As you know, years of forest mismanagement under Governor Moonbeam and friends have created many unsafe areas.
Keep the limes ready and hopefully we get a Friday off some day soon. Yes, we are self employed, and can take off anytime we like.... But our customers must come first so if they need us we work, even putting off our trips to Myanmar to see family.
Don't get me started on tree hugging and refilling the Ocean ???
Ingrid retired last year and I am 1/4 time at Offgrid Solar so let us know. Looking forward to meeting her!
18K gallons full from the 20+ inches of rain so we will have ice with those limes ;D
Sounds good Dave. Maybe in a few weeks we will get a Friday off... Not sure. Supposed to start a new project in Richmond. Doing a bit of educational and shelter assistance for kids and underprivileged in USA, Myanmar, Africa and Bhutan so we need to stay busy. 😊
Quote from: Dave Sparks on January 26, 2019, 05:05:42 PM
18K gallons full from the 20+ inches of rain...
Woo-hoo!!!
Hey Dave, I have to guess that you are topping off all of your tanks this weekend.
We finally finished nearly all of our last job in San Leandro except the last 4 stairways they are not ready for, due to weather of course. 😊
Its been too quiet for a while here on countryplans. A good time for me talk about solar.
We started building in NE Tennessee in July of 2017. We got the walls framed and partially sheathed, and the roof sheathed and covered with underlayment, before that winter. Wall sheathing completed, some windows in, half the building wrapped, and metal on the roof in 2018. We now have stairs to the second floor and most of the windows in. We hope to get the siding on this year and begin moving in next summer.
It is over 1.5 miles of gravel road from the house to the pavement and power lines. A mile of that is on an easement along the property line between 2 neighbors, the remainder through our own land. The power company wants $7/ft to bring in power. So, $55,000 PLUS purchasing easement(s) from the neighbors, and clearing those easements, to get power brought in. Brought in through the forest, where every breeze blows down a limb. Uh, no thanks.
We got serious about solar this spring. I had read everything I could find for a very long time, and learned a lot, but was very aware that there was much more to know. I sent an email to our Dave Sparks, got a quick reply, and soon found myself telling him "let's do this!",
Our Tennessee location has its challenges. We are on top of the hill, but in what is basically a notch in the forest. Tall trees on the east and west sides of our clearing, as well as neighboring hills, block both early and late sun. With clear info on our site Dave helped us find a good panel configuration and array locations, and he determined good electronics to support it.
I spent 3 weeks there in July, installing a water system, receiving the shipments of solar equipment, and starting the solar install. We installed and wired up the electronics and the batteries, built the ground mount for some of the panels, and ran the wires from array to house. As always, I needed one more day, and did not get the panels installed. My son and neighbor continued working on it and, 2 days later, sent me a photo of the readout showing we were generating almost 2900 watts. Woo-Hoo!
The system is 48 volts (batteries), with 27 310-watt panels planned (only 9 installed so far). We planned to have 24 2-volt batteries, but the distributor could not meet his delivery promises, so we are temporarily using 8 6-volt 210 Amp-Hr golf cart batteries.
With just 1/3 of our panels installed, and using batteries with only 1/5 the planned capacity, the solar has changed everything. We can run a huge 120V window A/C, an old full-sized refrigerator, all the lights and stuff we could want, and still charge the batteries to float every day. We must turn off the A/C as soon as the sun gets too low or it will deplete the batteries.
And QUIET, without the generator running. We had been using about 10 gallons of gasoline in the generator every day before turning on the solar. I just spent a week there and did not use even the 5 gallons in the generator fuel tank. What little I did use was only because I had left the AC running too long after sunset and wanted to top up the batteries.
I started frequenting CountryPlans years ago for the building info, and have learned and applied much from here. The OFF GRID POWER thread became more important as I was ramping up our solar plans, and Dave was a welcome bonus. I am retiring next summer and moving then to our Tennessee home. Thanks to everyone here for your help along the way.
I'm happy to hear you hooked up with Dave. He knows his stuff and is good to work with. Solar sure beats gasoline any day. ;D
I thought this tutorial very interesting: DIY 12v 100Ah LiFePO4 Solar Battery for $555
https://youtu.be/vTFLuKjvUQw
Nice video and it does show the pricing is still not there for LFP. Consider you can buy a similar battery at costco for less than $100 and have a warranty.
The costco battery may not last as long but who knows how long this DIY will last. Also how good will this be if overcharged or discharged since there do not appear to be any specs.
I've seen a couple other videos from that guy. Pretty good. One thing that I noted that made me wonder though was how he used two band clamps (hose clamps) to hold the cells together. He mentioned that prismatic LFP cells can swell. The packs I have seen sold by companies that sell batteries assembled from prismatic cells all used metal plates that were then held by band clamps or some other sort of straps. From what I understand these cells can develop quite a "bow" under some conditions if not properly restrained. Makes me wonder if his method is too much of a shortcut?
![](https://images2.imgbox.com/b5/2c/MnwDy6GU_o.jpg)
Some of the prismatic cells are now made using aluminum outer cases instead of the plastic. FYI, those appear to be CALB cells; one of the big names in Chinese LFP. (CALB = Chinese aircraft lithium battery)
He mentioned having had problems with BMS units that did not work. Someone I know in CO built himself a similar LFP battery for his travel trailer. He bought the cells and a BMS from a stateside seller. The first BMS he received along with the cells did not work right out of the box. He got a replacement sent quickly at no charge. But that was disconcerting. His system does incorporate a couple of large HD disconnect solenoids that are controlled by the low and high voltage sensors.
Overcharge can kill LFP much quicker and with greater finality than lead-acid. Must admit that lead acid are very forgiving compared to litium.
I'm going to keep watching what is happening in the lithium battery field. I got new lead-acid batteries last year and am good for a few years. The one thing I like the best about LFP is they can sit for months on end in a partial charge state, not being used, not being charged, and not be damaged.
A downside is they are so much lighter they are more likely to be stolen than lead-acid.
I think something better will come out. IBM has patents on a new type of cell that will not use the expensive heavy metals.
To me the major downside of LFP is you can't charge them below 32. Well, you can once :(
Might try and wake up this thread.... ???
Dear wife and I are getting serious about the get-away cabin and I'm now pricing a solar installation. One problem I have is realistically estimating our energy needs. Right now we are at two extremes: our house in Anchorage uses upwards of 30 kWhr per day in the winter. Much less in the summer, although we heat with natural gas. When at the cabin our current uses is probably in the single digits of watt-hours per day. Definitely under 100, but all we do is run a few headlamps and two CPAP machines. I can only guess what our needs will be when we have the cabin completed and spend months at a time there.
Based on my guesses I've gotten a quote for a 1300 W array @ 24V with a 4000 watt inverter. Four 415 A-hr Rolls batteries at 6V. I'm thinking this is overkill (not a bad thing) but I have no clue by how much.
Does anyone have a system that reports their daily energy use? if so, what numbers do you see and for what sort of appliances?
I'm becoming more informed, and realizing the more I learn the less I know! ???
I'm looking at a fairly small array, four to six 60-cell panels most likely. I want to do a top of pole mount, but one thing I am running into is the challenge of sinking a deep enough hole to properly anchor a 4" pole. My calculations show I need to get the hole down to seven feet, but the best I can muster with my hand-operated power auger is about four to four and a half feet. That's barely adequate for a two-panel topper, so maybe the solution is to have two or three poles.
Any other ideas for how to mount six panels?
Quote from: ChugiakTinkerer on January 21, 2021, 07:00:16 PM
Might try and wake up this thread.... ???
Does anyone have a system that reports their daily energy use? if so, what numbers do you see and for what sort of appliances?
I use a Trimetric 2030 to monitor battery juice. Been happy with it to give me live updates on current draw, or daily battery AH.
I also use a Kill-A-Watt for 120V devices. $20-30 for one, and they work awesome for watt draw and totalizing watt hours over time. They do NOT do well at high currents for long periods. (I'd not put 1000W through one for a long period of time.) Seems the fuse is a bit undersized. But for seeing how much your CPAP uses overnight, that'd be perfect.
Also, my Morningstar Prostar charge controller gives me the daily AH put into the batteries. And a downloadable history. So I can average out my sun hours over time for my location, or see the worst day, or how low my battery voltage got overnight, etc.
Quote from: ChugiakTinkerer on February 14, 2021, 11:21:52 PM
Any other ideas for how to mount six panels?
I had the same thoughts as I was designing my bigger/permanent system, before I opted to go on the grid.
I was going to do a wood-post mount system. But I didn't need much height, just the right location. Like a few 4x4s or 4x6s and some crossmembers to hold the panels.
I have a small three panel pole top array we installed in 2009. I hand dug a hole with shovel and a post hole digger ( clamshell type) to get to the 5 feet I wanted. Lots of concrete at the bottom for the 4" drill pipe post.
I think if I was needing another for more panels I might think of using 6" pipe. That gives room to grow the panels sizes in the future.
Do you need much elevation to get above snow? I wanted 4 feet to clear any possible worst case snow fall. If not for the snow I would build a near ground level rack myself.
Remember to protect it well against lightning strikes. The Midnite SPD's are excellent when coupled with a good grounding (earthing) system.
Keeping clear of snow is my only need for clearance. Unless I need to worry about a moose scraping his antlers on it.
A ground mount may be the trick. But that will still need to be anchored to the ground in some fashion.
My location is 62.4 degrees north latitude. My initial thought was to mount with that angle of tilt from horizontal. According to the PVWatts calculator I can squeeze out an extra 5% of output by keeping the panels at 45 degree tilt in the summer and 90 degrees in the winter. That has the added bonus of keeping snow from accumulating on the array. Changing the tilt angle twice a year would be no big deal.
I've been playing with the PVWatts to see how beneficial it would be to increase the panel size. There's a big return going from 1.3 kW to 1.54 kW, it drops generator usage by tens of hours each year. That assumes of course that I have accurately predicted what our occupancy and power load will be. So maybe it's a phantom, but it certainly appears that paying for more panel area/output up front is a lot cheaper than paying for fuel and oil to run the generator year after year.
Also looking at bifacial panels. With such high albedo for half the year it seems like a no-brainer.
Been pretty busy from the wildfires last year. I may have missed a few happy hours here...... Hey Don!
The history of bifacial is while they are beautiful and make sense, they are prone to leaking water in the back as the seals are small to let the light in. If you buy them, make sure you can get warranty. You may need it!
Below is a link to what I use to monitor clients and make adjustments anywhere there is cell or internet. It sends me alarms/warnings if I want them.
https://photos.google.com/photo/AF1QipMAjVuFzZ3vtUp5neK25EyEO5FJa-0Cx211cYXC
Quote from: Dave Sparks on March 04, 2021, 10:56:11 AM
Been pretty busy from the wildfires last year. I may have missed a few happy hours here...... Hey Don!
The history of bifacial is while they are beautiful and make sense, they are prone to leaking water in the back as the seals are small to let the light in. If you buy them, make sure you can get warranty. You may need it!
Below is a link to what I use to monitor clients and make adjustments anywhere there is cell or internet. It sends me alarms/warnings if I want them.
https://photos.google.com/photo/AF1QipMAjVuFzZ3vtUp5neK25EyEO5FJa-0Cx211cYXC
Thanks Dave, good to know.
I put my 50% down yesterday, for a 24V system with four Canadian Solar 375W bifacial panels. I'll be sure to monitor the seals and hang on tight to my warranty paperwork.
Quote from: Dave Sparks on March 04, 2021, 10:56:11 AM
https://photos.google.com/photo/AF1QipMAjVuFzZ3vtUp5neK25EyEO5FJa-0Cx211cYXC
Gives me an error, 404.....
Quote from: MountainDon on March 04, 2021, 10:00:49 PM
Gives me an error, 404.....
I may have not turned the sharing on. Try this one.
https://photos.app.goo.gl/f3xJfJqQ4d6zEuKV9
That worked. Cool tech. [cool]
Hoping for a good spring and summer, but we haven't had enough moisture to really make that a certainty.
I know what you mean Don. Snow pack is 2/3 normal and even worse in the southern sierra. Below is a link to some pix I am getting from the utility camera's that are all new this last year. I think they know fire season is going to get worse before it gets better. The state is doing a better job in dealing with forestry issues. In the past it was do nothing and blame it all on climate change. The politics do not matter when half of the state is on fire. The towers in the pix are what I monitor/adjust in the previous monitor link. Hope you and Kathy are doing well ! We got shot with moderna on friday. Crossing fingers ;)
https://photos.app.goo.gl/5cb1FzLkAa22UGpB8
I think it is too late for that :)
[moderator note: this comment was in response to a deleted spam post]
I would guess that [spammer name removed] is a potential spammer.
[moderator note: this comment was in response to a deleted spam post]
Well I don't need off grid power, but for some reason I punched in my info on tesla's website. I can't believe this price.. unfortunately they don't serve my area.
After tax credits $4k installed?!?! I would have thought if I bought materials and did everything myself, then whatever professional requirements for the grid/battery tie safety it would have been closer to 20-25k.
People will spend more than $4k on just a generator!
My off-grid power setup is running about 20k and that is with me doing all the installation. The solar panels and battery bank aren't cheap, but they do bring the cost per kWh down considerably compared to using just the generator. Granted, I'm amortizing the costs over thirty years and I may not even be alive long enough to see all those savings.
The Tesla estimate hides a lot of details in that little asterisk. Anyone who would buy a system based on that estimate is deserving of all the surprises they get.
A question for those who have roof mounted solar panels. Do you have metal or shingles? If metal what kind of mounting rails did you use? Ease of installation?
We did pole mount. I have seen metal roofs with panels but have no idea what most have used. There is one guy near us with a standing seam roof and he used some special mounts that secure to the standing seams. Your roof is the typical panels that overlap, like ours, IIRC.
I have been looking at some. Most have short pedestals a couple inches that the rails mount to which allow the rails to clear the ridges of the metal panels. Just thought I would throw this out in hopes someone would have a recommendation of type or brand.
Quote from: MountainDon on April 21, 2021, 05:40:59 PM
We did pole mount. I have seen metal roofs with panels but have no idea what most have used. There is one guy near us with a standing seam roof and he used some special mounts that secure to the standing seams. Your roof is the typical panels that overlap, like ours, IIRC.
I do not like using a Home roof but have used these on barn. S5 for standing seam metal. Sorry this is late! Busy with fire season and another bad drought.
https://s-5.com/products/solar-racking-systems/
Dave thanks for the link.
https://www.youtube.com/watch?v=cHNELRnJ_4Y
Please pass the salt? Battery?
If this turns out true I'll be all over it! :D
Anyone have experience with the Jackery Portable Power Station?
Thought about going this route for the CPAP machine. Specifically on recharging.
How long does it take to recharge with the power station's solar panels vs recharging from power source?
Searched forum and found no other mention of this product. Certainly not trying give any push towards this item. Have not purchased it.
Thanks
I have a question on grounding the neutral wire in a CB panel.
I plan on finally hooking up my 2,000 watt PSW inverter this spring. I will connect it to a standard 6 circuit AC electrical panel box. I only plan on using 3 of the circuits. I understand in normal grid tied main panels, the common leg is also connected to ground inside the panel to create an effective ground fault current path. On sub panels this is not necessary. Would there be any difference when using an inverter as the source of electrical input? Should I treat this the same as a main panel and bond the ground and neutral busses together?
Thanks for any thoughts.
Dave
It depends on whether or not the inverter has a bonded neutral or a floating neutral. If it has a bonded neutral then there should not be a second bond in the service panel. You can use one of these 3 led testers (https://www.homedepot.com/p/Klein-Tools-GFCI-Tester-RT210/206517824) to check... Plug the tester into the inverter receptacle and see if the 2 "correct" lights illuminate. That would mean the inverter has a bonded neutral. That tester can also be used on a generator test and of course your home.
The service panel usually has a green screw inserted into the neutral buss, which will connect to the ground thru the metal case. Remove it to remove the neutral bonding; insert to bond.
I have seen an inverter be ruined by connection to a system with a service panel neutral bond.
Quote from: Hunterscabin on January 29, 2023, 03:48:04 PMAnyone have experience with the Jackery Portable Power Station?
Thought about going this route for the CPAP machine. Specifically on recharging.
How long does it take to recharge with the power station's solar panels vs recharging from power source?
Searched forum and found no other mention of this product. Certainly not trying give any push towards this item. Have not purchased it.
Thanks
Sorry I missed this!
YES! I use a Jackery 550 for my CPAP and can leave the heat on without issue. It runs about 10% or less of reserve power when using the 12v adapter. We have Roof Top Tent on my Jeep and I use the Jackery for my CPAP and my wife uses it for her hair irons etc and we recharge it on the 12v socket at the back of the jeep when traveling.
What's everyone's thoughts on increasing my 660AH 24vdc battery bank without drastically increasing the cost?
Don't want to add more batteries (Have 12 GCB's now @220AH ea) nor weight (816lbs now) but could use more AH's of course.
Lithium seems too much $$$ and needs to be warm to charge (not gonna charge em at 0F for example)....AGM's also seem pretty spendy (I may go that rought) but I can afford more than the $105ea for GCB's at Costco that are 210AH (used to have the 220's but they moved down to 210s for some reason).
Thanks in advance.
Quote from: MountainDon on February 02, 2023, 08:23:24 PMIt depends on whether or not the inverter has a bonded neutral or a floating neutral. If it has a bonded neutral then there should not be a second bond in the service panel. You can use one of these 3 led testers (https://www.homedepot.com/p/Klein-Tools-GFCI-Tester-RT210/206517824) to check... Plug the tester into the inverter receptacle and see if the 2 "correct" lights illuminate. That would mean the inverter has a bonded neutral. That tester can also be used on a generator test and of course your home.
The service panel usually has a green screw inserted into the neutral buss, which will connect to the ground thru the metal case. Remove it to remove the neutral bonding; insert to bond.
I have seen an inverter be ruined by connection to a system with a service panel neutral bond.
Hi Don,
Thank you for the information on bonding and the testers
I looked in my Samlex user manual and it says the neutral is internally bonded to the metal chassis of the inverter. The inverter has an internal GFCI which monitors the current flow. (When in doubt, read the manual !) From the manual:
"The AC output of this inverter is available through a NEMA5-20R Self Monitoring GFCI Duplex Receptacle. The Neutral slot of this receptacle (longer rectangular slot) is internally bonded to the metal chassis of the inverter.
GFCI Tripping and Reset: If there is a leakage of 5 to 6mA due to ground fault on the load side or there is a Neutral to Ground bond on the load side, the GFCI will trip.
Caution: Do not feed the output from the GFCI receptacle to a Panel Board / Load Center where the Neutral is bonded to the Earth Ground. This will trip the GFCI."
I will definitely pick up one of those testers to double check my wiring.
Thanks again,
Dave
Quote from: OlJarhead on February 05, 2023, 12:27:32 PMWhat's everyone's thoughts on increasing my 660AH 24vdc battery bank without drastically increasing the cost?
Don't want to add more batteries (Have 12 GCB's now @220AH ea) nor weight (816lbs now) but could use more AH's of course.
Lithium seems too much $$$ and needs to be warm to charge (not gonna charge em at 0F for example)....AGM's also seem pretty spendy (I may go that rought) but I can afford more than the $105ea for GCB's at Costco that are 210AH (used to have the 220's but they moved down to 210s for some reason).
Thanks in advance.
Cheap bastard that I am, I went with GCB's. I asked my Jeep mechanic and he got them for me at wholesale. I bought 4 Interstate GCB's 224 AH for $132 ea, with $20 core charge, 58 lbs each. I think that was 3 years ago. I hope the prices have not increased too much because I am thinking of buying another 4 of the GCB's.
Dave
Costco tends be lower. 8 years ago I bought my 220ah GCBs at $89ea plus core....they now have 210ah GCBs ar $105ea
But I want more reserve...even 59AH more would be better...235s give me 45AH more at 24v so I'm looking at those but if I could bump that another 50 plus without spending $10k I'd do it
Quote from: DavidRaftery on February 06, 2023, 11:35:53 AMCaution: Do not feed the output from the GFCI receptacle to a Panel Board / Load Center where the Neutral is bonded to the Earth Ground. This will trip the GFCI."
That's good. Some inverters simply go "Phffft" and stop working forever.
Simpliphi PHI-3.8-24-M 3.8kWh 24 Volt Lithium Ferro Phosphate Battery With Metal Case | NAZ Solar Electric (solar-electric.com) (https://www.solar-electric.com/simpliphi-phi-3.8-24-60-m-lithium-ferro-phosphate-battery-with-metal-case.html?msclkid=7126a24ace401ab4edc8c1a7b90bb310&utm_source=bing&utm_medium=cpc&utm_campaign=Shopping%20-%20All)
Looking at this has me thinking.
Since it's rated at 10,000 cycles at 80%DoD if I read that right it would mean it can take a 75AH draw regularly without issue...right? I mean, I usually see about 45-65AH overnight from last solar charging to first solar or roughly 5%-10% of my 660AH bank (which I realize is a little undersized, but I've protected it for 8 years and it's still actually doing well after the last fiasco and only drawing down to 24v under load in the cold - freezing after 8hrs without a charge).
Anyway, if I understand correctly the above Lithium option, though a lot smaller, and double cost, might actually work since there isn't an issue drawing it down even more.
Of course, there is the issue of keeping it above freezing....but maybe I can set a charge controller to NOT charge under 32F???
I have both the Morningstar MPPT45 and the Outback Flex (60 I think)....and plenty of solar with the 9 panels I have...just wondering if maybe this is an option.
Thoughts?
A friend here used BattleBorn lithium batteries in their cabin. They had no devices that would draw power when they were absent so they were able to simply pull the charge and discharge breakers to Off and leave things, usually with somewhere between 60 to 80% charge. They moved the batteries into a corner inside the cabin so they would get warmed up to above freezing before flipping the charge breakers on after arriving. That would be my plan whenever we change.
But I seem to recall you need to leave a fan running when away. That complicates things. As far as I know, there is no low-temperature cutoff setting in a Flexmax charge controller unless something new has been added. I think I have seen that some built-into-the-battery BMS systems have a low-temp cutoff, but am not certain nor any idea which it might be.
Ya that's my concern. I think since they can draw down a lot more than GCB's it might be fine to use a much smaller bank like this one but I do need to leave fans on in the back room to circulate the heat and keep the composter from freezing.
I suppose I could just let it freeze in the winter but that can be a problem as well (pipes freezing up) resulting in the walk of shame to the outhouse in sub freezing temps and a foot or two of snow.
If I could keep these above freezing it wouldn't be an issue and I can certainly get them there during the day when the suns out, but can't do it otherwise...unless...
You know, I have that heated back room, I could put them in there if they aren't too big...hmmm....means changing things like putting the inverter back there too but it might be worth it.
What do you think about the AH rating vs GCB's?
I was doing some simple math and I think this one 86lb battery will provide more usable power and last longer than my GCB's -- like more than twice as long) and I can keep it in the room in the back where it will remain 50F or more year round.
If I moved the inverter back there as well, I have a remote switch I can put in the porch to turn on the power...I'd just have to run the charge controller and cables to the back room.
Might motivate me to put a good door on the back room and finish it too :D and give me a LOT more room in my porch as well :D
I agree with your assessment of what lithium battery capacity could be used. The greater usable capacity of the lithium means less required total capacity when compared to flooded lead-acid batteries. We use fewer kWh of power on an average day so I believe we can get away with about half that capacity. Now I am torn between going to lithium immediately or working out the present GC-2s for another couple of years.
I will have to move them inside the cabin which will mean relocating the inverter as well and routing new cables from the CC. Doing that will also mean the entire large exterior battery enclosure can be repurposed. So bonus #1.
Bonus #2 comes in the form of lithium recharging faster from the same size PV array as the lithium cells have lower internal resistance. Bonus #3 = no more watering. :)
Just be sure that the battery can discharge at the rate you need for the length of time you want. That may influence the choice of one battery or two smaller capacity in parallel.
Hi Guy's ! Been some time. The other problem with Lithium is that you do have recharge them ! When going from an old lead acid that has lost capacity, the extra capacity of being able to go down to 10% Soc with lithium, will take more solar or gen run time.
Not a good thing to find out in Winter Offgrid, especially if you are not close loop charging the LFP.
Close loop is where you save the charge time Roger?
Don, what ever happened to Glen the moderator? Hope you and Karen are Peachy!
Thanks guys -- I received an email from a sales rep that said I'd need THREE of those LiPo batteries. What the??? d*
Not much point then.
But he basically said with my battery bank he'd recommend going to 50% of that (so 330AH) and then seemed to have math that said 450AH of LiPo equaled 330AH of Lead....ah...no.
But didn't seem to get that I'd only be using about 40% of the AH cap on the battery when I'm at the cabin nightly (and that's likely spring and fall vs summer when I have a lot more solar production)....at about 40% nightly I can't see why I'd need THREE $2500 batteries.....
What am I missing? Seems to me ONE of those 24v 150AH batteries should be all I need if I'm only using a max of around 60AH between sundown and sunup....specially when I set my genset to run at 24vdc under load to prevent dropping very far (lol I know, that's probably way higher than most but I don't want to replace batteries lol).
24V 3x MULE - LiFePO4 - 360Ah - 9kWh - BigBattery.com (https://bigbattery.com/products/24v-3x-mule-lifepo4-360ah-9kwh/?utm_source=Website&utm_medium=LearnMore&utm_campaign=Analyst&utm_id=ButtonsCamp)
$3400 for this bank of 3 120AH batteries giving 360AH of Capacity of LiPo backup which HAS to be better than 660AH of lead ;)
I received a reply back on the SimpliFi's and it was the draw each battery can handle vs the AH rating. So yes, I'd be fine with just one batter as long as I didn't draw more than an inverter capable of around 1500 watts.
Chatted with a sales rep on the Big Battery store batts above and he agreed those would do what I needed and then some. So I may go with the https://bigbattery.com/products/24v-3x-mule-lifepo4-360ah-9kwh/?utm_source=Website&utm_medium=LearnMore&utm_campaign=Analyst&utm_id=ButtonsCamp setup.
I figure it will be a little heavy getting them into the back room and I'll have to do some changes but I'll end up with MORE capacity not less (I know it sounds nuts) and no more watering, worrying lol...just have to make sure they cant be killed but it sounds like they have a cut off to protect them.
The only problem with these is I was just told they only have 3000 to 5000 life cycles but then I was told that is at 'normal usage' lol -- come on folks. I schooled the salesman. He then said that was at 100% DoD.
Since I'm running more like 15 to 20% DoD I'd get 20+ years out of them. ???
If so I'm doing it.
Quote from: OlJarhead on February 22, 2023, 12:00:44 PMI received a reply back on the SimpliFi's and it was the draw each battery can handle vs the AH rating. So yes, I'd be fine with just one batter as long as I didn't draw more than an inverter capable of around 1500 watts.
Yeah, I was thinking it must be the continuous discharge rate. We don't use more than about 1200 at any one time if we pay attention to what we are doing.
I've not heard of 'BigBattery".
Quote from: Dave Sparks on February 21, 2023, 01:49:56 PMDon, what ever happened to Glen the moderator? Hope you and Karen are Peachy!
I haven't seen Glenn here for quite a while. I do see he did log in about a week ago. He is still around; he has a presence on facebook.
Karen and I are fine. We are waiting for it to stop snowing and begin melting in the mountains. We have had more snow up there than any year in the past 5 or so for certain. The snow is welcome, we just don't bother trying to access the cabin and may not until sometime in April. Then we have several bags of assorted seeds to sow. A mixture of annual and perennial grasses were donated by state and national reclamation agencies.
At first I thought Big Battery was just the store but it appears they are a US company and make the batteries in the US.
https://bigbattery.com/business-to-business/
Amazon has a Chinese 24v100AH LiPo4 battery for under $700...so I suppose I could get 3 of those for $2100 but the 10 year warranty and US support for the Big Batteries seems like it might be safer ;)
I'm almost 100% committed :D I need to make plans to finish the super insulated room and move at least the Inverter to there as well but the Charge Controllers may remain where they are...I'm just not sure!!! I could move them I guess and it would only add about 18 feet to the runs from the combiner boxes so I'm thinking that would be ok because I'm running over 60vdc at that point anyway.
And if I put the combiners and inverter in with the batteries in the back room (and secure it with a well secured steel door) it would be VERY HARD for a crack head to break in and take it all vs what I have today.
So, I'm 'this close' to going with LiPo! Have the $$$ on hand too.
What am I missing? What should I consider? Any other battery suggestions?
Quote from: OlJarhead on February 24, 2023, 08:11:35 AMBig Battery ... ...it appears they are a US company and make the batteries in the US.
Well, that is something. So all we need to do is hope they remain in business for at least as long as the warranty period. It is tempting to go for the lower-priced unit from Amazon but then we get into more questions about who is behind them, and what's inside the box. It is sometimes hard to really know what the best choice is. The $700 "looks" like a deal.
Quote from: OlJarhead on February 24, 2023, 08:11:35 AM...if I put the combiners and inverter in with the batteries in the back room (and secure it with a well secured steel door) it would be VERY HARD for a crack head to break in and take it all vs what I have today.
Not to rain too hard on your parade, but when I built our cabin I thought the same about the steel door, 1" deadbolt, etc. Now I think that works best in town where there are neighbors close by and the noise of breaking in might also be a deterrent. The 2 brothers who broke into our cabin were drug users. There were no neighbors around. They had to work very hard to breach the door, but they did. Cabin, shed and barn. I ended up needing to replace the steel door and the frame on the cabin and make "make-do" repairs on the barn and shed doors. The new door has no fancy locks, just enough to keep out an honest person. I did have the satisfaction of seeing the two big bootprints on the door that likely happened before they resorted to the 6-foot steel digging bar and deforming the door and splitting the frame all to hell.
It sucks when we have to be so concerned about thefts. Back in my youth, I don't think the doors on the farmhouse were ever locked. The keys were always in the truck.
Good point. Perhaps just the one I made, with insulation as planned and insurance ;) If I can get it.
There is a guy on youtube that tears apart a lot of the foreign made batteries, I can't recall his name but his videos are very informational. Some batteries are definitely better than others but its probably worth checking out if your considering it. Unfortunately I don't have any experience to offer.
Thanks.
I'm now very seriously looking at ordering the LiPo4 batteries and storing until I am ready for them as I'll need to do some work first.
With inflation and the fact they can come with a charger etc I'm thinking I could charge them up and store them fir the few months until the room is ready.
Then I'll sell the GCBs for cheap as they do have some life in them still.
I see Amazon has several different brand names of what appear to be the same 24V 100AH LiFePO4 batteries. None that I looked over made any mention of a low-temperature cutoff being included. High temp yes. That is sort of too bad, though I believe Victron has a low-temperature cutoff device available. Not sure how much it costs.
BigBattery mentions Over/Under Temperature Protections, but I didn't see any specs on that. But I didn't look too hard either.
I'm interested in what you do.
24V Battery Lithium 120Ah 3 kWh LiFePO4 LFP Residential Solar Trailer Cabin Boat (batteryevo.com) (https://batteryevo.com/24v-battery-lithium-120ah-3-kwh-lifepo4-lfp-residential-solar-trailer-cabin-boat/)
I'm also looking at these now ;)
They are pretty much the same as the Big Battery ones I think. Seems like the price comes from recycling cells that weren't used previously or not used enough to reduce life cycles.
The cells are from China, the batteries assembled and tested here.
One way or another, I've committed to doing this NOW (like to get in before they go up in price like everything else does lol).
Just trying to get the best one I can with support etc.
I plan to get with the charger and parallel bus so I can charge them and leave them in the shop before use :D I think that will motivate me :D ;D
On the amazon ones I kept seeing reviews that made me pause ;) You have to hunt for them as they show the top ones up front but when it came to support it seemed like you had to talk to China....and getting a refund might not happen if something goes wrong.
Also, the US stores seem to all offer affiliate programs which could be nice.
I found the guy I was watching on youtube. If you are interested in a specific battery he may have torn one down. I don't know anything about him but I do enjoy his videos.
DIY Solar Power with Will Prowse
I've made a decision (unless I find a better deal while I wait for them to come in stock)....
I'm going with the BigBattery ones. They are NEW cells, 10 year warranty and 3000-5000 life cycles at 100%DoD according to them vs recycled batteries, 3 year warranty and 4000 life cycles at the other place. Pricing is almost the same.
So I'll order the 360AH bank which will give me 288AH of useable backup (80% DoD) without much worry which is more than 3 days of backup before I hit 80%. Vs the 2 days I had to get to 20% DoD on my FLA GCB's.
Basically now I can go 4 days without solar vs 2 days before.
Only thing I need to sort is when to make the genny come on which I'm guessing might be around 50%DoD instead of 20% like do now (actually probably more like 10%)...I'll have to see a voltage curve but I suspect I'll run the generator a lot less now.
Need LiPo4 Batteries?! Check this out: 24V Battery Lithium 120Ah 3 kWh LiFePO4 LFP Residential Solar Trailer Cabin Boat (batteryevo.com) (https://batteryevo.com/24v-battery-lithium-120ah-3-kwh-lifepo4-lfp-residential-solar-trailer-cabin-boat/)
At checkout put in the Coupon Code of OldJarhead and you'll get 10% off!
I haven't announced this ANYWHERE else yet but do plan to do a video soon with the announcement to let everyone know.
I also see the price of these is down a little to $995ea so you'll get $99.50 off EACH battery if you buy these but the code is good for ANYTHING on the site.
Hope that helps someone :D
One thing I need to find is a voltage guide to SOC levels for LiPo....anyone have a good source?
Quote from: OlJarhead on March 15, 2023, 04:42:09 PMOne thing I need to find is a voltage guide to SOC levels for LiPo....anyone have a good source?
Rather than referring to these as LiPo I believe you should be using the term LiFePO4, as LiPo can refer to a type that has a nominal voltage of 3.7 volts and is not the same chemistry as LiFePO4.
I understand SOC to mean "state of charge", correct? Voltage is not a very good guide to SOC for any lithium-based rechargeable cells and batteries unless a very accurate voltage meter is used. They do not drop voltage as much as lead acid. Being off by 0.1 volt makes a bigger difference than with lead-acid cells and batteries.
I've seen a few tables but I can't say one is better than any other. I don't know where the data is coming from as they mostly all seem to have the same anomalies that I figure are coming from rounding off voltages to a tenth of a volt.
Interesting! I always learn here :D
The controllers on the batteries only show DC Volts and Amps so it's hard to know where they are. Currently they show 26.7v and I have a charger which is set to charge at 28v I believe (need to double check that).
I know the shut off is set between 20-21v so I can assume that's 100%DoD but was hoping they would have some kind of ramp that would give me an idea of where they are now.
I was told not to store them more than 3 months without charging them but I also read somewhere not to store them at 100% SoC.
???
Quote from: OlJarhead on March 15, 2023, 06:24:43 PMI also read somewhere not to store them at 100% SoC.
???
I believe the voltage for a planned storage period with LiFePO4 should be 3.3 to 3.4 volts per cell.
I'll have to see how many cells there are and get the charge voltage right. I have the PDF somewhere at home ;) Time to get them up to speed on charge I think.
I've learned that I just need the three batteries to be within 1v of each other which they are now after some charging. it's clear though, that the BOM's decide when they are full or not and shut off any incoming charge to stop them from overcharging.
Also, for now, I've decided to install them where the old FLA's are for now to get them in use sooner. Then I can spend the time needed to get the back room ready.
BOM's BMS :D
I believe that voltage should be more in the neighborhood of 0.1 volt between 12 volt batteries connected in parallel, not 1.0 volt. However, I have read other opinions that 0.2 volts to 0.3 volts difference is okay too.
A small voltage difference between lithium cells and batteries is a greater difference in total charge or energy, than what we are used to with lead-acid.
What they are saying is that it must be within 1v before connecting. Not sure why it doesn't need to be closer...maybe something to do with getting them balanced after connecting?
Or maybe he said 1V but meant .1V...hmmm
I guess we can't go too wrong by following what the seller states.
QuoteI just need to confirm that my voltage between 3 Mules I will be running in parallel should be within 1v of each other?
Is that correct? Bascially one is at 27.5v one is 28v and one is 27.7v
Dylan 11:06 AM
Yes that is correct
I'd decided to double check with tech support on my 3 LiFePo4 batteries. and the above is what I got back.
Also, they have a button to turn them 'on' or 'off' in the front so all three will need to be 'on' whenever in use which for me will be all the time.
[cool]
OH man I LOVE my new batteries! I'll report more on them later but just know that I now see the light!!!
Woot!
[cool]
I have replaced my GC-2 golf cart batteries, too.
I went with SOK LiFePO4. They have a 24 volt 100 amp-hr battery. Their case is steel and the top is held on with 12 screws. It is serviceable if ever needed. The BMS is built in and has low and high temperature disconnect. Also a low voltage disconnect. 55 lbs. 7 year warranty. $1011 delivered, each.
I ordered 2. One is lost in shipping though. I have charged it to 90% at home with my faithful Iota DLS27-25 charger that I bought back when I put the original system together. All I needed was the new IQ4 Lifepo plugin module. $20. There is a bluetooth app for monitoring. The second will be paralleled when it comes.
I installed the one battery today and reprogrammed the Midnite Solar Kid controller. It works fine. I may move them inside. There is a suitable space inside the other side of the wall where the battery cabinet is located. Two 30 to 36" cables should work. Then the existing cabinet can be repurposed for storage.
After removing the old lead-acid batteries I washed the battery cabinet out with some baking soda and water to neutralize whatever acid was present. It bubbled a little. The 5 year old GC-2's are being donated; 4 to each of two young neighbors.
A very nice bonus that comes with LFP batteries is the faster charge. Less internal battery resistance = faster charging grom the same PV array and charge controller.
very nice....
Cool! I'm finding that the 240AH I am using of my 360 (still gotta balance that last one) is MORE than the 660ah I had before by a long shot :D and I can see much better performance this winter when there is less sun which means less generator run time :D
I'm stoked! Heck, I need to get back up and work on that soon!
Today is very cloudy. We've not seen blue shy since yesterday. For a few hours early this morning we were in a cloud. (8800 ft altitude).
The LFP lithium battery is recharging. Not real fast but much better than the lead-acid batteries would do under similar conditions.
Nice! I do find they recharge much faster!
If you go with lower charge rates, this increases charge time, and if you have batteries in parallel, having a bit higher rate gives you more time for the absorb cycle to balance the bank, especially if it's an open-loop comms system. If open-loop and you have 2, 3, or 4 parallel strings, the longer 30-60 mins absorb timers allow for better balancing between the parallel strings. Might be a good thing to shut down a string or 2 of PV once in a while for better balance.
Sorry to hear about Glen. Appreciate the update Don.
Quote from: Dave Sparks on August 27, 2023, 01:37:32 PM If you go with lower charge rates, this increases charge time, and if you have batteries in parallel, having a bit higher rate gives you more time for the absorb cycle to balance the bank, especially if it's an open-loop comms system. If open-loop and you have 2, 3, or 4 parallel strings, the longer 30-60 mins absorb timers allow for better balancing between the parallel strings. Might be a good thing to shut down a string or 2 of PV once in a while for better balance.
Sorry to hear about Glen. Appreciate the update Don.
Hmmm.....
So the batt co tells me to set the Charge Controllers at a specific voltage with no absorb or float time difference (same voltages) because the BOM's manage the batteries anyway.
I'm not sure, and will find out next week I think, but I'm thinking my batteries are finally balanced as I saw them all accepting almost the same amperages when I kicked on my generator though they were not the same and that confused me.
I need to hook up my LiFePo4 battery charger so I can use it separately and disco the batteries so I can see if they are, indeed balanced and if not, charge up the 1 or 2 that aren't.
I'm running 3 24v batteries in parallel (FYI)
This is probably not an original thought, but has any system of multiple batteries been hooked up .. not in hard-wired parallel .. but in parallel only in orientation, and by using switching relays .. only one battery is in circuit at a time? By proper measurements and controlling, all batteries would see similar loading and charging. An additional up front investment, but it works around the problem of batteries not matching exactly .. at least, I would think.
The missing second battery of mine never showed up. The tracking number shows it should be in a shipping terminal but it evaporated or something. In the interim I have been using the one and have been quite pleased with its performance. For the time being I have asked the seller to refund the cost of the missing battery and they agreed.
One battery, no parallel connections, is very nicely simple. So far we have never discharged to less than 78% charge left. That is partly due to the ability of the LFP battery to recharge after the noontime power use to be fully charged again by dinner time. It also helps that we now have a longer exposure to sunshine than before. A small silver lining from the wildfire destruction of so many 70 foot pine trees.
Batteries in parallel are, I believe, vastly superior to those in series. Sitting idle they should, in theory, self equalize to the same voltage. The BMS in each battery should, in theory, match each cell in the battery to within very small variation. The cells in our 1 battery are extremely close in voltage, measured in hundredths of a volt. My memory is not as good as it once was and the log is at the cabin and I am not.
If the less sunny parts of the year prove to make a second battery useful I will add a second. But we don't snowshoe in, in winter anymore and our power use has diminished with led this and that. So, we shall see.
Don, are your batteries in a warm environment? Have heaters?
I'm in a bit of a panic as Big Battery told me to get my batteries into a warmer space ASAP as we're likely going to see minus temps at the cabin later this week (as in two days)....seems anything below 23F isn't good for them but if they are warmed to over freezing that day they should be fine...but if they aren't and they drop even colder I'm told they could be damaged (cell damage) and after $3600 investment I'm going to be driving back shortly to move them into the back room!!!
Our SOK battery is inside the cabin, but unheated when we are absent.
The spec sheet for my SOK battery states that it can be...
... stored -22F to 95 F
... discharged -4 F to 140 F
... charged between 32 and 113 F
So I hope SOK is correct on that. Their temperatures pretty much match the data I collected before buying the SOK. I had been considering building the battery myself with LFP prismatic cells (the rectangular things) and a BMS board. Building a case for them and so on. I collected data on three different name brands of cells.
We seldom see any temperatures below zero or over 95 F.
Best of luck
Interesting.
I had conflicting information on mine as it states they can discharge down to -22F but storage is +23F
When I asked about this I was told they can discharge much lower than storage temps but it isn't always good and the cells can get damaged at those low temps.
Here's what BigBattery says about mine:
Turns out that is an error -- it should be -4 not -22