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If a vehicle with a conventional electrical sys-
tem is left parked for a long time, the battery
will gradually lose its charge because certain
electrical devices, such as the electronic gear-
box lock continues to draw current even when
the ignition is off. In some cases there may not
be enough power available to start the engine.
Your vehicle is equipped with an intelligent
power management system to control the dis-
tribution of electrical energy. This significantly
improves reliability when starting the engine,
and also prolongs the useful life of the battery.
The main functions incorporated in the power
management system are battery diagnosis,
residual current management and a dynamic
power management system.
Battery diagnosis
The battery diagnosis function constantly reg-
isters the condition of the battery. Sensors de-
tect the battery voltage, battery current and
battery temperature. This enables the system
to calculate the current power level and charge
condition of the battery.
Residual current management
The residual current management reduces
power consumption while the vehicle is
parked. It controls the supply of power to the
various electrical devices while the ignition is
switched off. The system takes the battery di-
agnosis data into consideration.
Checking and refilling levels
Energy management
Depending on the power level of the battery,
switch off the individual electrical devices one
after the other to prevent the battery from los-
ing too much charge and to ensure that the
engine can be started reliably.
Dynamic power management
While the vehicle is moving, this function dis-
tributes the available power to the various
electrical devices and systems according to
their requirements. The power management
ensures that on-board systems do not con-
sume more electrical power than the alterna-
tor can supply, and thus maintains the maxi-
mum possible battery power level.
Note
● Neither is the power management system
able to overcome the given physical limits.
Please remember that the power and useful
life of the battery are limited.
● When there is a risk that the vehicle will not
start, the alternator power failure or low bat-
tery charge level warning lamp will be shown
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.
Flat battery
Starting ability has first priority. Short trips, city
traffic and low temperatures all place a heavy
load on the battery.
In these conditions a large amount of power
is consumed, but only a small amount is sup-
plied. The situation is also critical if electrical
devices are in use when the engine is not run-
ning. In this case power is consumed when
none is being generated.
In these situations you will be aware that the
power management system is intervening to
control the distribution of electrical power.
When the vehicle is parked for long periods
If you do not drive your vehicle for a period of
several days or weeks, the power management
will gradually shut off the electrical devices
one by one or reduce the amount of current
they are using. This limits the amount of power
consumed and helps to ensure reliable starting
even after a long period. Some convenience
functions, such as remote vehicle opening,
may not be available under certain circumstan-
ces. These functions will be restored when you
switch on the ignition and start the engine.
With the engine switched off
For example, if you listen to the sound system
with the engine switched off the battery will
run down.
If the energy consumption means there is a
risk that the engine will not start, a text will be
displayed in vehicles with a driver information
system.
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