I built myself an e-bike from a kit bought on Amazon. It works great but I have a question regarding batteries for which I can't find an answer online.
I found a great deal on 4.4 Ah (36V) batteries usually for small electric scooters. Since 4.4 Ah is not enough (same with their max current of 16 A), I put 2 packs in parallel. I am aware that there are drawbacks, that my batteries won't last as many cycles as one 8.8 Ah pack but for the price I got them, I simply don't care.
I hooked them up after equalizing their voltages and charge them up in parallel. There is no problem with that. I eventually reach 41.8 V and batteries don't get hot at all while charging.
My question is about discharging. Whenever I reach my destination, one of the two batteries (always the same) is hot to the touch (not burning, simply hot) while the other one isn't. Why is that?