See also:

Switching on/off manually
Press the button. On: the LED lights up. Off: the LED goes out. The PDC is shown on the Control Display. Switch on the backup camera via the iDrive. ...

Maintenance
The battery is maintenance-free, i.e., the electrolyte will last for the life of the battery. Your service center will be glad to advise you on questions regarding the battery. ...

Vehicle information
Owner's Manual Computer Vehicle ...