Patent ID: 8203311

Claim:
An apparatus for detecting a condition of a battery, the apparatus comprising: means for detecting discharging and charging current of the battery; means for detecting whether or not a negative acceleration of the charging current of the battery changes in sign from negative to zero during charging of the battery based on the charging current detected by the discharging and charging current detecting means; means for calculating an integrated charged capacity of the battery by integrating the charging current of the battery until the negative acceleration of the charging current changes in its sign from negative to zero during the charging of the battery; means for controlling output electric power of an alternator, which is electrically connected to charge the battery so as to keep the discharging current of the battery constant during discharging of the battery that occurs following the charging of the battery; and means for determining, when an integrated discharged capacity of the battery becomes equal to the integrated charged capacity, that charge polarization of the battery generated during the charging of the battery is cancelled.