Components of E38 Dual Battery System
- Starter Battery: Located in the right rear trunk wheel, the starter battery is connected to the starter motor and to the heating coils of the E-CATs (via the E-CAT module).
- Vehicle Circuit Battery: Located above the starter battery on a swing out mount, the vehicle circuit battery provides operating power for the balance of the vehicles electrical requirements and is directly connected to the vehicle generator.
- Battery Isolation Switch: Located on the swing out mount of the vehicle circuit battery the battery isolation switch opens and closes the circuit between both batteries based on monitored conditions.
NOTE:
The battery isolation switch is NOT used to boost a discharged starter battery with the voltage of the vehicle circuit battery to start the engine. The battery isolation switch can only withstand a maximum current flow of 60 amps.