Battery control apparatus and power supply system

A power supply system comprising:

• a first storage battery that includes a plurality of battery cells;
• a cell monitoring apparatus that is connected to each battery cell of the first storage battery and detects a voltage of each battery cell;
• and
• a battery control apparatus to which power is supplied from a second storage battery other than the first storage battery, the battery control apparatus calculating a residual capacity of the first storage battery based on a charge-discharge current during charge-discharge to an electrical apparatus that is connected to the first storage battery, wherein
• the first storage battery is connected to the cell monitoring apparatus and the battery control apparatus via a resistor that is provided on a conduction path that branches off from an electrical path to the electrical apparatus, and
• the battery control apparatus includes
• a total cell voltage calculating unit that calculates a sum of the voltages of the battery cells detected by the cell monitoring apparatus as a total cell voltage;
• a voltage acquiring unit that acquires a voltage of the resistor on the cell monitoring apparatus side;
• a consumed current calculating unit that calculates a consumed current that is consumed by the cell monitoring apparatus and the battery control apparatus based on a difference between the total cell voltage and the voltage acquired by the voltage acquiring unit;
• and
• a residual capacity calculating unit that calculates the residual capacity based on the charge-discharge current and the consumed current.