There's plenty of info on the web about how easy it is to destroy your tools' batteries if you try to recharge them below the freezing point. If you keep them in an unheated shop or garage, you need to bring them inside and warm them to above 32F before you charge them. You can use them in the cold, although they'll put out less power, but don't charge them in the cold. Here's one site for an example:
LITHIUM BATTERIESYou can use your cell phone at 0 but warm it up before you charge it. If you have a power pack, keep in an inside pocket for a while before you use it. That also applies to your GPS, camera, and whatever other electronics you carry around in cold weather.
Then it comes to lithium batteries in EV's and hybrids and your lithium starting and RV batteries. From what I've read (I'm no electrical engineer), car makers haven't kept up with the needs of EV owners and the batteries are prone to cold weather problems (the liberals don't tell you about those, do they?). There are a few batteries out there with internal heaters to keep them above freezing. Of course that reduces the power available for driving.
It pays to do some reading on recharging lithiums. There's no end to what's on the web about it and lots of is conflicting and confusing.
