I've had a slight niggle with my battery, it's been working fine but the batteries have very slowly gone out of balance by 150 mV between the highest and the lowest. The net result of this is apparent loss of capacity, during discharge the lowest voltage battery trips the BMS which switches the battery off from the inverter, during charging the highest voltage battery stops the charge when it hits maximum voltage.
The solution is this:-
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This is a smart active balancer by NEEY. It can handle up to 24 cells and is easily configured by it's APP. It monitors all of cells and will balance them within preset voltages. It discharges the highest voltage cell and charges the lowest voltage cell until all of the cells are within 'x' mV of each other. My cells were 154mV between highest and lowest 90 minutes ago (charging from Solar ATM), I enabled the active balancer with a 4 amp balance current the cells are now 30mV between highest and lowest.
Installation was easy, setup straight forward and it seems to work very efficiently. Unlike many balancers, this unit will still do the full 4 amps with just the smallest of variations eg 5mV.
Available from Aliexpress circa £80 - bargain in my book.