I built two 12V LiFePo4 battery backs with preassembled 3.6v 100ah packs from battery hookup using their recommended BMS. I connected 4 packs in parallel without BMS and top balanced them with a power supply. I did that with each set of 4. Then I assembled them into individual 12v packs with their own BMS. I put the packs in series to power a 24V trolling motor. For most part they perform well. However, I have noticed since I installed them and connected them to NOCO Genius 10X3 12V charger, one pack never gets up to the same voltage as the other. Twice now, when they have been left on the charger for an extended time, maybe two weeks or so without use, the battery that never gets up to the same voltage drops to 5V like the BMS is shutting it off. The other battery operates as expected. Is this a balance issue or something? I’m charging them with their own banks from the charger but they are still connected in series while charging. I pulled out the battery in question and each of the 4 packs in there were 3.4Vs as if they had drained and the BMS cut them off. Am I doing something wrong? Should have a different setup maybe just make a single 24V pack with 1 8s bms? Thanks for any help you may have.
