Cottage owners are faced with a number of choices when it comes to the expensive batteries of their off-grid power system: Take them home and put them on a trickle charger? Leave them at the cottage? If the latter, should they be disconnected? Or not?

Batteries are expensive items and you want to get the maximum life out of them. It is important to take good care of your batteries! To those that do not want to take their batteries home I tell them they have two options:

The first option is to make sure the batteries are fully charged, to a full 100%, and disconnect EVERYTHING (charge controller, inverter, etc.). Fully charged batteries only freeze at -65C and they are quite happy to sit for 4 or 5 months, it doesn’t do anything to them, as long as they were 100% full when you left them. The cold actually helps slowing down the chemical processes and self-discharge.

The other option, if you have solar panels at an angle where they will be free of snow at least a few times during winter, is to disconnect all but the charge controller. That way they’ll be kept charged over the winter. If the panels are at a shallow angle and will be snow covered for the next 4 months there’s no point going this route, it is better in that case to just disconnect everything as mentioned above.

We have had some customers use a smaller solar panel (100W or so) mounted completely vertical on a south-facing wall with its own small charge controller. They leave that connected during winter to keep the batteries charged (and they disconnect everything else). That too is an excellent way to get batteries through the winter.

If you do leave the charge controller connected, make sure there are NO additional loads. It is really important that those batteries sit to as close as 100% charge as possible. That is what makes them endure without damage, and it makes them frost-proof (a fully-discharged battery is pure water, that freezes at 0C!).

And Now For Something Completely Different…

We recently added “wish lists” the Web site. You can now create lists of parts for your projects, without actually having to place them in your virtual shopping cart. If you are not logged in with an account you have just one (unnamed) wish list that is cleared after 30 days, if you have an account on the site and log in you can have as many wish lists as you want, and you can give them meaningful names.

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