Hi,
I have made a 3S BMS board (imitation of the bq40z60 EVM board, all parts same) and used well. Recently I noticed that once the discharge stopped at the CUV threshold, the 3S battery pack voltage drops day by day 33.7mV; each cell voltage decreases evenly. (The board causes this problem. Not connected cell voltage remains almost forever.) At this rate, I worry that over one month later the pack would be inoperable permanently.
I suspect the leakage path as the following picture (the DSG FET symbol is incorrect); pack(+) --> CHG FET diode forward --> DSG FET diode reverse leakage --> BUCK low-side FET diode reverse leakage --> GND & pack(-)
Is this scenario possible?
Thanks,
Joshua Kim
