Maybe not the right time of year for a question like this, but hard to wait a few months for answer that's been on my mind for some time already
I have been riding a Bafang BBSHD throughout last winter commuting 45km each day, lowest temp about -7 deg C. The battery has been charged indoors both home and at work, so when I started riding, the battery was warm and stayed at a good temp the whole way, because of the large current draw from BBSHD. Now I have built a larger battery that doesn't need recharging at work, and is permanently mounted to bike, so indoor charging is not possible anymore. So now I want to clarify the following.
If I start in the morning with a charged battery that has been in the shed during the night, it will be cold, but heat up rather quickly when riding because of large (initial) internal resistance when cold. At work it will also get cold, so when I head back I will have the same situation, loosing some capacity to heat up battery. Since battery is warm when I get home, my plan is to hook it up to charger ASAP, and then the current from the charger will keep both the charger (Satiator 5Amp charge) and battery at a good temp, even if shed temp is below 0 deg C. In that way I avoid charging a cold battery, which I know can damage it, and it will be full for the next day.
Does this sound like a good plan, or will it cause reduced life cycle of battery? The biggest question is probably what is the lowest internal temperature of a battery pack one can start riding without causing significant reduction of battery life (standing for 7-8h at work outdoors the battery internal temp will maybe approach outside temp, but maybe not if I insulate it somewhat?). Active heating before riding is not an option, as I will need current from battery to do so.
Any opinions and preferably experiences on this issue? I've tried to search for this case, but haven't found a thread that covers it completely