Battery pack manager

An apparatus for lessening variations in a state of charge (SOC) or remaining capacity of a battery pack. The battery pack is made up of a plurality of blocks, and slave units are provided for the respective blocks. Terminal voltages of the blocks are detected and supplied to a master unit. Variations arise in a state of charge or remaining capacity of the respective blocks for reasons of differences among the slave units in terms of electric power consumption. The master unit controls deactivation timing of the respective slave units incidental to turning off of a vehicle ignition according to the variations in the state of charge of the respective blocks. The deactivation timing is delayed much longer with an increase in the state of charge, thereby equalizing the state of charge or the remaining capacity.