Patent ID: 7667416

Claim:
An electrical power supply system for an electrically powered motor vehicle, said vehicle including an electric motor, a transmission device for transmitting energy between the drive wheels and the motor, and electrical accessories, in particular an air-conditioning device, said system comprising a first rechargeable battery serving to power the electric motor and a second rechargeable battery serving to power the electrical accessories of the vehicle, said system being characterized in that the first battery and the second battery are connected in parallel to said motor via a switch device, said switch device being arranged to conduct current for powering the motor from the first and second batteries as a function of a first energy threshold, said first energy threshold being a predetermined value for which the energy delivered by the first battery only is not sufficient for accelerating the vehicle, and said switch device conducting current from the second battery only to the motor as a function of a second energy threshold for the energy from the first battery, said second energy threshold lower than the first energy threshold.