AltLiving said:Has anyone else had an issue with these cells failing (seemingly random)? I think my issue may have come from not having all of my 22s pack in the holders, as I have not had issues with any other packs I have made with these cells. I am using a 200 amp ANT bms so I know they are not getting overcharged or over discharged(I never charge them past 4.1 volts per cell or discharge the below 2.6 volts). And I live in the states in the southeast, so they haven't ever been cold and the bms keeps them from getting hot. I have had 6 cells fail in the last 3 weeks. No visible damage to the cells(like punctures or crushed cells or tabs blown apart lol). Cells are kapton taped for compression, and to keep the tabs from shorting. They are then surrounded by a layer of foam to prevent any impact or shorting inside my bomber frame. Any ideas, because I am running out of spare cells and ideas myself? Any help would be greatly appreciated. Gonna remove all the cells holders today and somehow install the pack to a secure position in the frame....somehow. still coming up with that plan.
No. I have never had a cell fail or drop below .1V balance. I've bult 3 12S packs and one 3S4P pack.
Your cells are failing because you discharge too low. Is your BMS set for 3.2V LiFePo4 (Lithium Iron Phosphate) discharge cutoff??
FYI 2.6V IS WAY TOO LOW and will damage cells. Never go below 3.0V. I try not to discharge below 3.3V. And like you, I charge to 4.1V.