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Small Cabin Forum / Off-Grid Living / Location of charge controller, inverter, batteries and solar panels?
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scrimshaw
Member
# Posted: 14 Jul 2009 14:09
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I think I'm ready to make my purchase of a solar system. I'm probably going to go with an 80 watt solar panel, 1000w inverter, 15 amp charge controller and 2 AGM 12V batteries.

I've got my cabin wired with four receptacles, 5 indoor lights, and 4 outdoor lights, or thereabouts and plan on using the low watt fluorescent bulbs to reduce energy output. I also want to intall an engery efficient ceiling fan (found on that produced only 37 watts).

I've got all my wired receptabcles and lights going to a circuit breaker that a friend helped me with. We also have an 8 foot grounding rod.

My solar panel will be about 125 yards away and we're planning trenching the cable to the cabin.

Questions:
Do the batteries, inverter and charge controller go inside the cabin or where should I put those? How does the solar panel connect to the circuit breaker? What do you all store the batteries in?

Thanks,
Eric

CabinBuilder
Admin
# Posted: 14 Jul 2009 17:23
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Quoting: scrimshaw
My solar panel will be about 125 yards away

There will be some voltage drop over that distance.
See Voltage Drop Calculator.

Keep in mind that inverter consumes power even when idle - you should keep it off when not using.

soundandfurycabin
Member
# Posted: 14 Jul 2009 23:39
Reply 


Yeah, the distance is a big issue. I think you'd have to keep your batteries and inverter at the panel location, then run 120V AC to your cabin. Otherwise you'll have to pay a fortune for the cable. Try out the nifty calculator CabinBuilder posted, and keep in mind that you should keep the voltage drop under about 3%.

scrimshaw
Member
# Posted: 15 Jul 2009 07:53
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How do I store the inverter and batteries at the panel keeping them from the elements?

Vince P
Member
# Posted: 15 Jul 2009 08:09 - Edited by: Vince P
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Quoting: scrimshaw
How do I store the inverter and batteries at the panel keeping them from the elements?

I keep my batteries and inverter under the floor joists of the cabin. I hard wired a switch to the inverter from the inside of the cabin, so I can simply "flip the switch" to turn on power.
Next to the switch, I have two charge controllers and a voltmeter that I wired to the batteries in order to monitor voltage.
Hope that helps.
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IMGP5160.JPG


Anonymous
# Posted: 15 Jul 2009 16:37
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You could build an insulated box out of exterior-grade plywood or just buy a large rubbermaid type of container or a deck box to put them in. This is the largest I've found:

http://www.canadiantire.ca/AST/browse/2/OutdoorLiving/3/OutdoorStorage/DeckBoxesBench es/PRDOVR~0600258P/Outstanding%2BSolutions%2BBasic%2BDeck%2BBox.jsp

scrimshaw
Member
# Posted: 16 Jul 2009 07:57
Reply 


Vince, I like your idea of running under the floor boards, I had the same idea but the electrician I am working with wasn't too excited about the idea as he said it might start a fire? Is this that dangerous of a setup or should I be OK? I could atleast build a box for it under the floors to contain the batteries and still keep them underneath. Thanks,
Eric

lamar5292
Member
# Posted: 26 Sep 2009 01:59
Reply 


You can put inverter inside but fan makes noise and they will last longer if kept cool.

I store my controler and inverter outside on porch protected from weather.

Batteries must be kept outside and I use a heavy wooden box which will not deteriorate from acid like metal will.

Batteries should be kept warm in winter and cool in summer for longer life. I insulate the box in winter and it is kept shaded in summer.

LaMar

Moontreeranch
Member
# Posted: 3 Oct 2009 12:35
Reply 


I plan on building a "dinette" sitting area that can be converted to a bed...got a good deal on some RV salvage cushions. my plan is to house all of the electrical components under one of the benches. I plan to use sealed AGM so off gassing will not be an issue. A Divider will keep the disconnects /breaker, charge controller / inverter from the battery side. If necessary I can vent the controls side to the interior. Our passive Solar design should temper the extremes when we are not there.

Anonymous
# Posted: 26 Oct 2009 11:35
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You can also see the basic Cabin Solar Guide here as well.

Bobjr59
Member
# Posted: 9 Aug 2010 13:19
Reply 


as far as storage for the setup goes I like this one
Suncast Storage Bench, Taupe
Product #60-0236-6 just follow the link from above and look for this product #60-0236-6

Bobjr59
Member
# Posted: 9 Aug 2010 13:21
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lamar5292 I enjoyed your book thank you for giving me some great ideals

munkyfst
Member
# Posted: 26 Sep 2010 01:25
Reply 


You are right about the fire hazard, I've seen batteries "slag" themselves without warning, bith in aircraft and in vehicles, I would NEVER trust them under the floor boards. ever!

DeZal
Member
# Posted: 9 Oct 2013 11:58
Reply 


I'm building a yurt. I live in Maine (gets cold). I am constructing an off grid solar power system. I have a few Questions:
1. Which batteries are best for this purpose?
2. What is the best storage? Inside/Outside; insulated/vented? Location/distance?
thanks!

Dillio187
Member
# Posted: 9 Oct 2013 12:06 - Edited by: Dillio187
Reply 


1. for most off-grid systems, your standard flooded lead acid (FLA)
battery is your best bet. This includes golf cart batteries or off-grid type batteries like Trojan's and Surrettes. Do not use car batteries or Marine batteries, they are not designed for the repeated deep cycling of a solar energy system.

2. I disagree with the older posts above about keeping your batteries outside. In the winter, they will get very cold and cold batteries can lose up to half of their capacity. In the summer, they will get hot which also shortens their life. I keep my batteries inside, and if venting them is of concern, put them in a box with a vent outside. Honestly unless you have a HUGE battery bank in a very small space, I wouldn't even worry about the miniscule amount of hydrogen created, but that's just me.

I live in Minnesota so obviously it gets cold as hell here. I have built a few systems each way, and now my own two systems both have their batteries inside for the reasons I mentioned above.

Truecabin
Member
# Posted: 9 Oct 2013 12:29 - Edited by: Truecabin
Reply 


if you put batteries outside in the cold you need to buy more battery capacity as Dillio said maybe twice as many batteries
if you want to buy less batteries cuz they are $300 a pair then you have to keep them in a warmer place usually this means or give up interior space for your batteries

keeping them inside doesnt always help if your cabin is cold when you are away
if your cabin is heated full time inside is good then

dont assume your batteries will warm up they will be cold for days or a week its the same as if they were outsid except they are inside using up your space

im thinking of a small cabin that doesnt have extra space
i think i will someday make an underground battery storage so they dont get colder than the ground temp

either way it costs you but think about it if you have more batteries then when its not cold you have 2x the capacity

toyota_mdt_tech
Member
# Posted: 9 Oct 2013 12:42
Reply 


Quoting: scrimshaw
My solar panel will be about 125 yards away and we're planning trenching the cable to the cabin



Can you make the system at the panels a 24V or a 36V system, then drop it down at the cabin to 12V? I say this because if you double the voltage, you can get away with half the wiring size. In your case, it would be like doubling the wire size to compensate for the 12V system, or tripling it (36V) then drop it down to 12V at the cabin. Do you plan on having the batteries near the solar panels or at the cabin?

Truecabin
Member
# Posted: 9 Oct 2013 13:52
Reply 


scrimshaw question is from 2009

power would be wasted to drop higher dc to 12v
and that special component would cost more than big cables i dont know if anyone does this because its just wasting power
your better off just wasting the power in a small cable and simpler too

once you go 24,36,48v then you have to convert to ac to do everything which isnt all bad but no more 12v and there is waste in the inverter that has to run fulltime so then you need bigger panels too and the inverter is expensive too
you cant beat the low watts of 12v led lights if you want your system to be small and low cost
you will get the best bang for the buck with 12v led lights then just run a small inverter only when you need 120vac

creeky
Member
# Posted: 10 Oct 2013 08:34
Reply 


most mppt solar controllers will convert high voltage to low. you will lose some power. my morningstar manual shows about a 4% loss from 96 to 12v. Less with lower voltages.

Truecabin
Member
# Posted: 10 Oct 2013 14:01
Reply 


mppt good info, thx! 4% is not so much when panels are $1 a watt

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