This is very interesting as I have had 2 UP5000 batteries (out of a 5 stack) replaced in 18 months because of high voltage alarms. Batteries were also updated to latest firmware 2.19 or 2.20 (firmware also increases 0.5C to 0.9C) and it did not help in my case, unless there is another firmware update that I'm unaware of. The scenario I encountered on both batteries was one cell not reaching target voltage of approx 3.45v (averaging 3.3v) and another cell on the same battery hitting the 3.65v threshold which my 15KVA Quattro recognised as high voltage cutting the battery from charging several times before eventually sort of balancing with highest cell reported at 3.53v and lowest at 3.45v. All suggested methods of balancing were tried prior and after the firmware upgrade with no resolution.
