Patent ID: 6762513
Filing Date: 2004-07-13
Classification: H02J,Y02T

Abstract:
Process for operating an electrical accessory device in a motor vehicle having a vehicle battery and an associated alternator, the electrical accessory device being interfaced to electronic controls, a means for detecting the voltage of the vehicle electrical system, a power supply control unit connected to the electrical accessory device and the vehicle battery, and an auxiliary energy storage device rechargeable by the alternator and connected to the power supply control unit, the process comprising the steps of:(a) separating the electrical accessory device from the vehicle battery by means of the power supply control unit, when detected battery voltage has fallen below a given first threshold value for a given first time interval; (b) connecting the electrical accessory device to the auxiliary power storage device by means of the power supply control unit, and after expiration of a second time interval, disconnecting the electrical accessory device from the auxiliary power storage device; and (c) reconnecting the electrical accessory device to the vehicle battery by means of the power supply control unit, and after expiration of a third time interval, disconnecting the electrical accessory device from the vehicle battery, wherein steps a) to c) are performed in succession except that, whenever the detected voltage of the vehicle electrical system has exceeded a given second threshold value which is greater than the first threshold value for a given fourth time interval at any time after performance of step (a), the step of reconnecting the electrical accessory device to the vehicle battery by means of the power supply control unit is performed.