In a
battery pack manager that manages series-connected rechargeable unit cells, a
cell equalizer equalizes the
cell voltages by individually discharging the unit cells according to deviations from reference voltages. An
overcharge / overdischarge
detector detects an
overcharge and an overdischarge state of each unit
cell. An inhibit circuit prevents the cell
equalizer from discharging the unit cells when the
overcharge / overdischarge
detector is activated to reduce the
cell voltage variability, which would otherwise occur as a result of interference from the overcharge / overdischarge
detector, so that the overcharge / overdischarge states of all unit cells can be determined with precision. Connecting lines of the unit cells are monitored to detect a line-
cut. The inhibit circuit further inhibits the cell
equalizer when the connecting lines are being monitored to reduce the
cell voltage variability, which would otherwise occur as a result of interference from the line-
cut detection, so that false line-
cut detection is avoided.