Battery Care

[Bill McAlpine]

I'm setting up a small system for a shed (600 W) and have a few questions.

1. The shed won't be used in the winter. Should I bring the two 6 volts batteries inside for the winter ?
2. Does a battery box for 2 batteries still need venting - active or passive ?
3. If I bring the batteries inside for winter, should I keep them topped up with a car battery charger?

Thanks
Bill

[Joe Blake]

Hi Bill, and welcome to the forum. Probably the first thing for us to know is your location and just how severe are the winters there? eg does it snow?

[Bill McAlpine]

I'm in Bancroft Ontario. -30 Celsius (-22 Fahrenheit) not uncommon in winter.

[Rob Beckers]

Hi Bill,

I've written a little article about cottages, batteries, and what to do in winter: https://www.solacity.com/what-to-do-with-batteries-over-the-winter/
This is something that comes up frequently with our customers.

The long and short is that fully charged batteries only freeze below -65C. So you can put them away and leave them (outside), as long as they are fully charged when you put them away. They're happy to sit for 4 months or so, no problem (the chemistry slows down as well, including self-discharge, at the low temperatures).

Battery boxes should have some venting (for regular flooded batteries, no venting needed for AGMs). It's not that the batteries go bad, or there's a risk of explosion, but the battery tops tend to get very, very grimy if there is no venting at all. If your battery box is outside in a shed all that's required is a couple of 1/2" holes on the left/right of the box, at about terminal height, just so some air can move through.

Hope this helps!

-RoB-