In recent years, various techniques for automatically stopping a drive power source of a vehicle upon the fulfillment of a shutdown condition are proposed and introduced from the viewpoint of environmental protection.
For example, when an operation time period of a brake pedal by a driver reaches a predetermined time period during an idling of an internal combustion engine, which is a drive power source of the vehicle, the engine is forcibly stopped (JP 2000-274272A). Further, when at least one condition is met among the conditions that a vehicle speed is lower than a predetermined value, that a shift position is neutral or parking, and that a side brake is operated, the engine of the vehicle is forcibly stopped. However, even if the engine is forcibly stopped as above, power supply from a battery to various parts of the vehicle might be continued even after the stop of the engine. This also occurs in a case where the engine is stopped due to any trouble.
In a state where the engine is thus stopped, the battery is not charged by an alternator that is driven by the engine. Therefore, the power supply to the various parts of the vehicle from the battery continues for a long time, with the result that the battery is consumed unnecessarily. The engine may fail to be started again because of insufficient power supply from the battery.