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rockies
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# Posted: 27 Mar 2016 06:15pm
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I've seen a lot of threads about designing the solar panel and battery system but nothing on how to properly store it. I understand that the batteries have to be kept warm but there should be outside air allowed in to prevent a buildup of off gassing from the batteries. Can the system be housed inside the cabin or is a special "lean-to" style shed attached to the outside better? Should they be kept in a separate out-building away from the cabin? What is needed to properly house the system?
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Nate R
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# Posted: 27 Mar 2016 07:45pm
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From what I've learned in teh RV world, seems that unless you use AGM batteries, flooded batteries ideally should have a way to vent outside, and hydrogen gas rises, so there should be a vent at the top of whatever the batteries are in. Plenty of people keep them inside with no venting.......the risk of explosion IS pretty low. But if nothing else, keeping the acidic fumes off of surrounding things is probably a good idea.
My plan is to keep the battery inside a structure, but in a separate box with outside venting. I'm not sure there's a "best" answer as far as separate shed, etc.
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Clipper
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# Posted: 27 Mar 2016 11:50pm
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If using flooded batteries they should be vented. If stored inside they should be in an enclosure and vented to the outside, preferably by way of DC vent fan.
if stored outside they should be sheltered from the weather. The concern over freezing is mitigated by ensuring that the batteries are maintained at full charge every few days as it will never get too cold to freeze a fully charged battery, even in Canada.
I chose to locate my solar components and batteries outside my cabin as I need all the space that i can get inside. I insulated and vented my battery box. works great.
Component shed and battery box
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battery box
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creeky
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# Posted: 28 Mar 2016 12:59pm
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First: Lithium are the only batteries to consider for full time off grid.
Your climate is all. Lithium batteries should not be charged below 0C or 32F. This is not a problem as lithium does not off gas and can be stored in a closet in the home. The small size and weight greatly ease installation and there is no maintenance. You would want to keep the batteries isolated in a locked box to avoid accidents.
In a very cold climate, such as mine:
My lithium battery pack (coming soon) will have 4-6" of polyiso insulation wrapped around them. With one wall easily removed for summer cooling.
For winter heat, as my batteries are in a separate unheated building, I am installing a mat style heater hooked to an arduino controller. When the temp of the batteries reaches 5C the arduino will turn on the mat heater for a brief period.
It will also record a variety of heat and power use stats, but that's another story.
Clippers got a nice box there.
As mentioned: among the poor performance characteristics of lead acid batteries: the off gassing issue. The batteries must be in a vented box. The fumes can damage wiring, electrical equipment etc. You do not want the fumes in your home. Period.
AGM batteries are only suitable for those with deep pockets and intermittent use. The low lifespan and high cost aren't suitable to off grid life. A lithium pack would weigh less, take up less space and cost far less amortized.
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Bret
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# Posted: 29 Mar 2016 07:36am - Edited by: Bret
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Hey Creeky, did you decide which lithiums you are buying?
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creeky
Member
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# Posted: 29 Mar 2016 10:37am
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I think so. 400 amp from LongPower. I like the winstons... but $$$.
Still. Might cave and spend the extra money for a Balqon pack.
My plan is to do 2P4S (probably in 2 stages). Or two parallel banks of 4 serial batteries. With BMS.
For those who are interested. I've seen 100 amp cells for 80-90 bucks US on ebay.
The "miniBMS" recommended by the company in BC. less than 200 after you put all the bits together. Or around 300 if you add in a "fuel gauge".
there are fuel gauges for lithium on ebay for 40 bucks out of china. cheaper BMS as well.
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