12 V On-Board Electrical System, Basic Function - GF54.10-P-1014A

MODEL ALL (CAR) 

General 

The 12 V on-board electrical system includes all components for voltage generation, voltage regulation and energy storage. Via the 12 V on-board electrical system, loads e.g. the exterior lighting and the interior lighting are supplied with electrical energy. When the combustion engine is running, the alternator (except vehicles with starter alternator (vehicle versions with 48 V technology), hybrid vehicles) generates the electrical energy. The electrical energy is stored in the on-board electrical system battery.

Vehicles with 48 V technology 

For vehicles with 48 V technology, a starter alternator may be installed depending on the vehicle version involved. This generates the electrical energy for the 48 V on-board electrical system. Electrical energy can be exchanged between the 12 V on-board electrical system and the 48 V on-board electrical system via a DC/DC converter.

For vehicles without a starter-alternator, the electrical energy is drawn from the 12 V on-board electrical system.

Hybrid vehicles 

For hybrid vehicles, the electric machine generates the electrical energy for the high-voltage on-board electrical system. Electrical energy can be exchanged between the 12 V on-board electrical system and the high-voltage on-board electrical system via a DC/DC converter.

Schematic diagram of 12 V on-board electrical system