System battery and auxiliary battery

NOTE: If only the 12 V battery is disconnected, the vehicle is not de-energized due to the auxiliary battery. Both batteries must be disconnected so that the vehicle is completely de-energized.

F15, F16 example: Both batteries are installed in the luggage compartment together with the PCU control unit.

G11, G12 example: The auxiliary battery is installed at the front right of the engine compartment.

The vehicle electrical system battery is an AGM battery with 90 Ah. The auxiliary battery is a 50 Ah AGM battery.

The electrical connections are presented in the functional networking.

Fig 1: Overview Of System And Auxiliary Battery

Courtesy of BMW OF NORTH AMERICA, INC.

Example F15

Item	Explanation
1	Auxiliary battery
2	PCU control unit
3	System battery