The battery charging detects battery temperature and includes a temperature maintaining charging operation wherein average charging current is controlled to drive battery temperature to a holding temperature, and charging is performed while maintaining battery temperature at that holding temperature. In addition, a temperature increasing charging operation occurs prior to the temperature maintaining charging operation. The battery is charged with a current which raises battery temperature until the holding temperature is reached. When battery temperature rises to the holding temperature in the temperature increasing charging operation, charging can transition to the temperature maintaining charging operation.