Winterizing Solar Cabin

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ramloui
ramloui Solar Expert Posts: 109 ✭✭
in Off Grid Solar & Battery Systems #1
Hello everyone! I'm new to this forum and very excited about the depth of knowledge I can tap!!
I have just acquired a cabin in a remote area on the noth shore of the St-Laurence river in Quebec, Canada, and I would love to install a solar electric system to run a few lights, water pump and the coffee maker.

My question is about what to do when I shut down and winterize the cabin between October and April. I'm especially concerned with the batteries. How well (od bad) will they do? Would disconnecting all the loads and leaving the PVs connected be enough? I'm thinking that if the PVs are almost vertical, then the snow would fall off and the little sunlight they can catch will keep the batteries charged so they will not freeze. Does that make sense?

Thanks for all your input!!

Louis.
Off-grid cabin in northern Quebec: 6 x 250 W Conergy panels, FM80, 4 x 6V CR430 in series (24V nominal), Magnum MS4024-PAE
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Winterizing Solar Cabin

    Welcome to the forum. Bienvenue sur la forum. :D

    You are correct in your assumptions. Speaking from the experience of the Cariboo where Winters are -40, charged batteries do not freeze. So all you have to do is keep them charged.

    The first step is to disconnect all loads when leaving for Winter. Leave the charge controller and solar panels connected.
    The second step is to tilt the panels up! If you check the "ideal" PV angle for your area in Winter you'll see it's much more vertical than for Summer. You can put the panels right up to vertical, eliminating any possibility of snow build-up. Mine are at 72 degrees which does the same thing. Some people will added a small amount of vertical panel with just enough capacity to keep the batteries ahead of self-discharge. This is particularly useful if changing the angle of the main array is difficult or you might find yourself unable to return in time to make the adjustment.
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  • Coach Dad
    Coach Dad Solar Expert Posts: 154 ✭✭
    #3
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    Re: Winterizing Solar Cabin

    Welcome to the exciting world of Solar Electric....

    I believe that fully charged batteries will not freeze under most situations.

    I built an insulated battery box for my batteries. It contains vent holes at the upper front and lower rear for air movement AND it has a removable lid that can be changed between Summer and Winter. The summer lid is a piece of lattice covered with a bug screen which allows FULL ventilation. The Winter lid is a solid piece of insulated plywood. The box is NOT fully sealed as I mentioned that it has vent holes on the top and bottom. I used 1 inch rigid insulation on all sides.

    Yes... Adjusting the PV angle to vertical is also a good idea.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #4
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    Re: Winterizing Solar Cabin

    A fully changed FLA battery won't freeze until well below -40. I have several applications where the batteries sit over the winter with just the PV, and they are always fully charged in the spring.

    Make sure you water the batteries before leaving, and turn off any auto eq function on a charge controller. Turn off th eloads, dues properly and you will be fine.

    Tony
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #5
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    Re: Winterizing Solar Cabin

    Living in NE Nova Scotia, I definitely get the best overall winter results with my panels vertical. Of course I tilt them back for summer, but in winter, there is NO snow collecting on them and the little extra power I might get from having them slightly tilted up for max ideal harvest, is far more than made up for by not having to deal with trying to keep them cleaned off, the extra light reflected off the snow covered ground, and not having to deal with lost production while waiting for the sun to melt off the snow. I've done it both ways, and for where I live, vertical is overall, by far the best!
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #6
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    Re: Winterizing Solar Cabin

    I too have remote site panels mounted vertically in the winter, for the reasons Wayne suggests. You don't need to be concerned with "full production" in the winter, as all you are doing is looking for float production.

    Tony
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  • ramloui
    ramloui Solar Expert Posts: 109 ✭✭
    #7
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    Re: Winterizing Solar Cabin

    Thanks guys for the quick response!!
    Leaving the batteries where they are will be the best solution because I do not have anywhere to put them at home other than the living room (the wife will complain for sure) and they are quite heavy.

    I will have to figure out a practical way to tilt the panels because my plan is to put them up a TV tower.

    Cheers!
    Louis
    Sometime soon I will also have a description of my system below my name like you guys;)
    Off-grid cabin in northern Quebec: 6 x 250 W Conergy panels, FM80, 4 x 6V CR430 in series (24V nominal), Magnum MS4024-PAE
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #8
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    Re: Winterizing Solar Cabin
    ramloui wrote: »

    I will have to figure out a practical way to tilt the panels because my plan is to put them up a TV tower.

    Cheers!
    On the TV tower just for Winter? If so, keep in mind that if you're not going to be using power from the batteries over winter, there is no need to have all you're panels connected, and therefore no need to mount them all on the tower for winter. You really don't need much to keep up with the normal self discharge, and the fewer panels (barn doors in a wind storm) on the tower, the less likely is the tower to blow over.
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  • ramloui
    ramloui Solar Expert Posts: 109 ✭✭
    #9
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    Re: Winterizing Solar Cabin

    I understand what you are saying about the tower blowing in the wind. It's just that I have the tower and I thought it would be discourage thieves to climb up there to steal the panels while I'm not there.

    Cheers.
    Off-grid cabin in northern Quebec: 6 x 250 W Conergy panels, FM80, 4 x 6V CR430 in series (24V nominal), Magnum MS4024-PAE
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #10
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    Re: Winterizing Solar Cabin

    If people are going to steal them, they are going to steel them. Mount them with tamper proof hardware if you can, or pull a piece of aircraft cable between them if you ar that worried.

    Quite frankly that is what we buy insurance for.

    Tony
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #11
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    Re: Winterizing Solar Cabin

    Might be easier - and more secure - to go with Cariboocoot's suggestion to leave out just enough PV to maintain the charge. If you have (let's say) 8 panels but 2 will maintain float, then just leave up 2 for the winter.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,457 admin
    #12
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    Re: Winterizing Solar Cabin

    A 1% rate of charge over the winter should keep an already charged, battery bank fully charged without loads (vs 5% to 13% rate of charge for "real" usage).

    So, you can reduce your risk over the winter from theft. Worst case, cold batteries have very low self discharge. Even a 1% "stealth panel" on the south side of the cabin may be enough to keep them charged (at least when the snow is not drifting--not that I know anything about snow).

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