February 11, 20233 yr Having issues with one battery, No. 5 in pictures ICC. For some reason this battery appears to go flat from around 40% as seen in the dip in the attached graph, the graph is showing the entire stack of batteries. They all charge up to 100% again, and all, including No.5 discharge evenly until the 40%odd then it goes down to 2%. I have 7 x US2000 connected to 2 Axpert. This No. 5 battery is around 4 years old and been fine till now
February 12, 20233 yr Author With batteryview I get one cell 3.009V when flat. After charging and no error showing all voltages show balanced and correct Does this indicate a faulty cell?
February 12, 20233 yr Author OK, definitely faulty cell. Removed battery from the stack, and properly swollen.
February 13, 20233 yr For interest, what was the Axpert voltage setpoint to charge the batteries to? Bulk/float charge voltage?
February 13, 20233 yr Author 33 minutes ago, 0012 said: For interest, what was the Axpert voltage setpoint to charge the batteries to? Bulk/float charge voltage? Bulk 53.2V float 53V
February 14, 20233 yr 16 hours ago, Colin said: Bulk 53.2V float 53V Thanks. That is according to Pylontech's datasheet. Interestingly, Victron override this to 52.4V. When Victron detect it's a Pylontech connected, it automatically disregards the BMS's charge voltage limit of 53.2V and institutes its own limit of 52.4V https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom
February 14, 20233 yr I don't know whether the 53.2V has anything to do with the swollen cells. However, it may be worth considering the 52.4V limit going forward? Even at 52.4V the SOC still reaches 100% on all batts.
February 21, 20233 yr Author Battery view confirms that there was overcharge current on this battery. Also was overvoltage up to 54V on some of the other batteries. Surely this means BMS faulty as the batteries not charging equally? I am suspecting it may even be reporting incorrect values? My charge voltage was set to 53.2V, I have reduced it to 52.4V as advised and in case batteryview was correct, however reading with a Megger brand multimeter, I get a reading of at least 0.5V lower than the reading reported in ICC (which I assume is from the BMS?), so I am suspicious of the records from Batteryview Any assistance would be appreciated, don't want the expense of another battery failure
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