OFF GRID POWER; various thoughts on...

Started by MountainDon, January 13, 2009, 02:18:39 AM

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glenn kangiser

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.
"Always work from the general to the specific." J. Raabe

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Tickhill

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
"You will find the key to success under the alarm Glock"  Ben Franklin
Forget it Ben, just remember, the check comes at the first of the month and it's not your fault, your a victim.

Pray while there is still time


glenn kangiser

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.
"Always work from the general to the specific." J. Raabe

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Tickhill

Thought I would post a picture of the SUN SL-3024 inverter/charger. Mounted in vertical position.

"You will find the key to success under the alarm Glock"  Ben Franklin
Forget it Ben, just remember, the check comes at the first of the month and it's not your fault, your a victim.

Pray while there is still time

glenn kangiser

Thanks, Tickhill.  Much fancier than I expected.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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AdironDoc

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

glenn kangiser

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.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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MountainDon

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.

Just because something has been done and has not failed, doesn't mean it is good design.

AdironDoc

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


MountainDon

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.
Just because something has been done and has not failed, doesn't mean it is good design.

AdironDoc

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

glenn kangiser

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
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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Tickhill

Dad and I got the 3 SUN HS-190-RL panels mounted and they really woke the batteries up! I have included some pictures showing the panels, also the new Tyco solklamp ground clamps for PV and the Outback FM60 in action.
I used an existing 3" rigid conduit and Unistrut for my mounting framework. Will bury conduit and run 8 AWG wires from shop to panels, only about 25' away.
Blessings











"You will find the key to success under the alarm Glock"  Ben Franklin
Forget it Ben, just remember, the check comes at the first of the month and it's not your fault, your a victim.

Pray while there is still time

glenn kangiser

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.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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Tickhill

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.
"You will find the key to success under the alarm Glock"  Ben Franklin
Forget it Ben, just remember, the check comes at the first of the month and it's not your fault, your a victim.

Pray while there is still time

Windpower

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)

Often, our ignorance is not as great as our reluctance to act on what we know.

glenn kangiser

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]
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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Windpower

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

Often, our ignorance is not as great as our reluctance to act on what we know.

glenn kangiser

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.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

Tickhill

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.
"You will find the key to success under the alarm Glock"  Ben Franklin
Forget it Ben, just remember, the check comes at the first of the month and it's not your fault, your a victim.

Pray while there is still time


glenn kangiser

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.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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uncle

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

glenn kangiser

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.  :)
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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uncle


MountainDon

#599
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.



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.
Just because something has been done and has not failed, doesn't mean it is good design.