Patent ID: 6919648

Claim:
A motor vehicle electric system comprising an internal combustion engine and, mechanically connected thereto, an integrated starter-generator that charges a double layer capacitor and a first battery to a first voltage via a bi-directional AC/DC converter in generator mode and is driven by the energy stored in the double layer capacitor or in the battery in motor mode, an intermediate circuit capacitor is arranged between the positive and negative direct voltage terminals of the bi-directional AC/DC converter, a first switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the plus pole of the battery, the minus pole of the AC/DC converter is grounded, and a second switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the positive terminal of the double layer capacitor, the negative terminal of said AC/DC converter is grounded.