OFF GRID POWER; various thoughts on...

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

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upa

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

upa

#1151
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?


MountainDon

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

upa

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

MountainDon

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


upa

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*

Dave Sparks

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!


"we go where the power lines don't"

upa

#1157
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


upa

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.


MountainDon

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

MountainDon

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

BiggKidd

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
A hard life only makes you stronger.

Larry

MountainDon

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.

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

OlJarhead

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



MountainDon

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



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

OlJarhead

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 ;)

OlJarhead

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!

BiggKidd

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   
A hard life only makes you stronger.

Larry

OlJarhead

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.


BiggKidd

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
A hard life only makes you stronger.

Larry

BiggKidd

When I get back home I can get pictures of the labels on the batteries.

Larry
A hard life only makes you stronger.

Larry

BiggKidd

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
A hard life only makes you stronger.

Larry


MountainDon

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