I was wondering what are the best rechargeable battery solutions for working in low temperature environments, ie. from -20 to -10 Celsius degrees. From what I have figured out, Li-ion batteries cannot be charged at temperatures lower than 0 Celsius degree. Lead acid batteries can be charged from -20, degrees but they are big, dont offer high capacity and cannot have many discharge cycles. I was wondering what would be the best solution here? I have heard that there are battery packs that provide heating coating that one can power up in order to heat the battery, but was not able to find any. I would appreciate all hints and help.
Lead acid (or gel or AGM), but only discharge/use 20 % of capacity to avoid freezing approaching -40 °C. i.e. go into winter with fully charged batteries.
Liquid NiCad can go to about -50 °C.
At Dome A and similar bury the primary spiral lithium batteries > 3 m to avoid winter temperatures (balmy -63 °C as opposed to below -80 °C on the surface). Run on them all winter, and have 3 x solar panels spaces 120 °C for all day solar operation when the summer sun is out to save the batteries.