Battery Run-Down Protection - Chevrolet Impala 2007 Impala Owner's Manual

The battery can be discharged at idle if the
electrical loads are very high. This is true for all
vehicles. This is because the generator (alternator)
may not be spinning fast enough at idle to
produce all the power that is needed for very high
electrical loads.
A high electrical load occurs when several of the
following loads are on: headlamps, high beams,
fog lamps, rear window defogger, climate
control fan at high speed, heated seats, engine
cooling fans, trailer loads, and loads plugged into
accessory power outlets.
EPM works to prevent excessive discharge of the
battery. It does this by balancing the generator's
output and the vehicle's electrical needs. It
can increase engine idle speed to generate more
power, whenever needed. It can temporarily
reduce the power demands of some accessories.
Normally, these actions occur in steps or levels,
without being noticeable. In rare cases at the
highest levels of corrective action, this action may
be noticeable to the driver. If so, a Driver
Information Center (DIC) message might be
displayed, such as Battery Saver Active or Service
Battery Charging System.
164
If this message is displayed, it is recommended
that the driver reduce the electrical loads as much
as possible. See DIC Warnings and Messages
on page 197.

Battery Run-Down Protection

This vehicle has a feature to help prevent the
battery from being drained, if the interior courtesy
lamps, reading/map lamps, visor vanity lamps
or trunk lamp are accidentally left on. If any
of these lamps are left on, they will automatically
turn off after 10 minutes, if the ignition is off.
The lamps will not come back on again until you
do the following:
•
Turn the ignition on, or
•
turn the exterior lamps control off, then
on again.
The headlamps will timeout after 10 minutes, if they
are manually turned on before the ignition is off.