Q: I have heard that keeping rechargeable batteries in the cold is damaging to them. My shop is only heated in the cold months when I am doing a project.
Should I continue to bring the batteries and chargers in, or can I keep them in the cold and continue to charge them?
A: The recommended temperature range for charging rechargeable power tool battery packs is typically between 40°and 105° Fahrenheit. Attempting to charge a pack that’s hotter or colder than this can disturb the chemical reaction inside the battery’s cells and permanently reduce the pack’s performance and runtime. As I’m sure that Utah winters commonly dip down into the low 30s, you definitely don’t want to recharge your packs when the mercury drops down this low. Further, for optimum performance it’s best not to store batteries in places where the temperature dips below 40° F.
To avoid the hassle of lugging your packs between your house and shop during the winter, try keeping them in the shop in an insulated container, like a foam ice chest, fitted with a heating pad (the kind you’d use to ease a sore back). Set the pad to its lowest heat setting.
If you do end up with a cold battery pack, all you have to do is warm it up before you recharge it. Once the temperature of the internal cells is in the recommended operating zone, the battery should perform up to par, regardless of the outside temperature.