Batteries -winter

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System
System Posts: 2,511 admin
in Solar Beginners Corner #1
I have lead acid batteries -8.

What is the best thing to do in the winter with them other than lugging them home?

I have not installed the system yet.

I can 1. put them in the bunky in an insulated box - but gets cold up there -20c

2. put them in the cottage which is log with no heat.

3. put them in the cottage walkout basement.

PV panels will be on the bunky which is 50' from the cottage - also where the generator is.

Should I shut the system down completely for the winter?

Please help.

Jerry
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Batteries -winter

    Charged batteries are in no danger of freezing. Leave them tied to the charge controller & PV's and they'll be 'happy' all winter. Make sure your panels are at the proper angle for Winter in your area. Disconnect the Inverter so there is no load drawing. A proper Charge Controller will keep them properly charged even with the limited light of Winter.

    -20 isn't so bad; it gets to -40 in the Cariboo and my batteries survive. :D
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,440 admin
    #3
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    Re: Batteries -winter

    You might place a smaller panel on the south wall of the building (above the drifts) and run your controller from it. How long would roof mounted panels stay snowed over in the winter for your area? If you mount your panels near 90 degrees (vertical) and they are above the ground/snow level--then they will probably shed snow when it warms up a bit in between storms (but vertical panels on a roof may be more obvious to vandals/thieves).

    Batteries "like" cold weather in that they age slower and have lower self discharge. Just make sure they are near 100% charged before you leave for the winter.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #4
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    Re: Batteries -winter

    Leave them connected to the CC. Make sure they are full of water, kill all the potential loads and you will be fine. A fully charged battery won't free at least until near -60. 1/2 charged will be fine at -20C. I have two panels hinged on the wall so that when I leave for a bit in the winter they don't ever get any snow on them. Even at a less than perfect angle, even a single ~60 watt panel is enough to keep a 250 ah battery bank in float over the winter as long as they start out charged and there is no loading.

    Tony
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  • bryanl
    bryanl Solar Expert Posts: 175 ✭✭✭✭✭
    #5
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    Re: Batteries -winter

    It might also be worth looking into a desulfating type battery maintainer. For instance, BatteryMinder(tm) makes a charge controller that uses the technique described in HomePower magazine a decade ago. There are others that do a similar 'pulse' charge or modulated current and others that use timed charge bumps.

    You want to keep your batteries at top charge (without electrolyte losing overcharge) and you want to avoid electrolyte stratification type effects for best battery life.
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  • bobdog
    bobdog Solar Expert Posts: 192 ✭✭
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    Re: Batteries -winter

    I leave my batteries in the Gila wilderness for up to 5 months. I fully charge them before our last trip in and then set the CC to equalize for gel cells. This way it will keep them from stratifying, but not over charge to the point of fluid loss. Obviously by not being able to get to them for months, I can't rightly top them off. So, water loss is a big deal. So far, whether I'm right or wrong, it has worked.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Batteries -winter
    bobdog wrote: »
    I leave my batteries in the Gila wilderness for up to 5 months. I fully charge them before our last trip in and then set the CC to equalize for gel cells. This way it will keep them from stratifying, but not over charge to the point of fluid loss. Obviously by not being able to get to them for months, I can't rightly top them off. So, water loss is a big deal. So far, whether I'm right or wrong, it has worked.

    Equalize for gel cells? :confused:

    We may have a terminology conflict here. I hope so, anyway.

    As far as I know, you don't equalize gel cells and they don't stratify.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,440 admin
    #8
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    Re: Batteries -winter

    I think he is setting the charge controller to "Gel Equalize" setting--which typically is zero equalization. I am guessing this is a flooded cell bank (talks about water levels and stratification--which are not typically gell/agm issues).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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