On-Board Electrical System - Mercedes-Benz GLK-Class Service Manual

On-board electrical system

The ability of the vehicle to start is the top priority. The
aim of the on-board electrical system management is
therefore to ensure a positive battery charge balance.
The vehicle uses a number of different variables to
determine the current load state of the on-board elec-
trical system. This allows suitable measures to be
implemented quickly when required. Examples of
these include changes to charging voltage specifica-
tions, alternator rpm increases and reductions in the
power consumption of individual convenience
consumers.
To allow the vehicle to remain idle for long periods, the
load on the battery from the quiescent current must
be as low as possible. In addition to the optimization
of individual components, two other measures have
been introduced:
• Decentralized power management
• Quiescent (no-load) current switch
Introduction of the New GLK-Class (USA), Introduction into Service Manual for Model Series 204
Quiescent (no-load) current switch
In order to prevent undesirable control unit activities
when the vehicle is not in use, decentralized power
management is integrated into all control units as a
standardized software module. The quiescent current
switch is a bistable relay that is opened by the on-
board electrical system management when the vehicle
is idle and the run-on time has elapsed. All control
units that are not needed when the vehicle is idle are
still disconnected from the battery. This minimizes the
quiescent current demand.
Networking
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