GMC 2018 Acadia Denali Owner's Manual page 163

162 Lighting
Center (DIC), you may see the
voltage move up or down. This is
normal. If there is a problem, an
alert will be displayed.
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 of the
power needed for very high
electrical loads.
A high electrical load occurs when
several of the following are on, such
as: headlamps, high beams, 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 DIC battery voltage
and charging message displays. It is
recommended that the driver reduce
the electrical loads as much as
possible.
See Driver Information Center (DIC)
(Base and Midlevel) 0 137 or Driver
Information Center (DIC) (Uplevel)
0 140.
Battery Power Protection
The battery saver feature is
designed to protect the vehicle's
battery.
If some interior lamps are left on
and the ignition is turned off, the
battery rundown protection system
automatically turns the lamp off after
some time.
Exterior Lighting Battery
Saver
The exterior lamps turn off about
10 minutes after the ignition is
turned off, if the parking lamps or
headlamps have been manually left
on. This protects against draining
the battery. To restart the 10-minute
timer, turn the exterior lamp control
to the off position and then back to
the parking lamp or headlamp
position.
To keep the lamps on for more than
10 minutes, the ignition must be on
or in ACC/ACCESSORY.