Power management

The power management a subsystem of the energy management. The power management is run from the engine control unit (DME or DDE: Digital Engine Electronics or Digital Diesel Electronics).

While driving, the power management regulates power consumption of the most important electrical consumers and the power output of the alternator, as well as the battery charge. The aim is to permit reliable starting of the combustion engine after a defined immobilization period from the viewpoint of the vehicle electrical system.

The result of the calculation may be a switch-off inhibitor or switch-on requester for the automatic engine start-stop.

Excessive power consumption must be avoided when the engine is off. This is why the power management either deactivates all major consumers of electrical power or reduces their consumption rates whenever Terminal 15 is ON but the engine is OFF. The displays remain active.

The following consumers of electrical power are affected, e.g.:

• Heated rear window
• Mirror heating
• Seat heating
• Blower.

Attention! 

Automatic start possible

If the state of charge of the battery drops below a specific value after an engine shutdown initiated by the automatic engine start-stop, the automatic engine start-stop starts the engine even if the driver has not taken explicit action.