With modern 18650 cells almost without fail, every problem with your battery which is NOT caused by improper mounting and physical damage to the battery is going to be the BMS. The BMS handles the charging and discharging of your pack making sure that there are no problems with any of the cell groupings. When a cell stops working and the voltages are too high or too low it will shut down power on the entire pack. For whatever reason BMS’s can become flakey and every problem I’ve had with my packs could be traced back to a problem with the BMS. A ‘leaky’ BMS will slowly drain down one or more of the cells in the grouping causing the entire pack to be out of sync. If it drains the power on a cell grouping down too low then the pack will not work and you’ll have to remove the dead cells as shown in this article. The problem is if you replace the cell groupings without replacing the BMS the problem will just occur again. This article will go into troubleshooting faulty BMS’s and how to replace them in about the amount of time it takes you to swap out a flat tire. Did you know Americans spend more time doing their taxes every year than having sex? I think we have our priorities way o...