Mercedes-Benz C-Class Operator's Manual page 296

Battery (vehicle)
294
ventilation while charging and jump-starting.
Do not lean over a battery.
G
WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do
not inhale any battery gases. Do not lean over
the battery. Keep children away from batter-
ies. Wash away battery acid immediately with
plenty of clean water and seek medical atten-
tion.
G
WARNING
A discharged battery can freeze at tempera-
tures below freezing point. When jump-start-
ing the vehicle or charging the battery, gases
can escape from the battery. There is a risk of
an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
! Only use battery chargers with a maxi-
mum charging voltage of 14.8 V.
All vehicles:
! Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment (
Open the hood.
X
Connect the battery charger to the positive
X
terminal and ground point in the same
order as when connecting the donor bat-
tery in the jump-starting procedure
( page 295).
Y
Never charge the battery if it is still installed in
the vehicle, unless you use a battery charger
which has been tested and approved by
Mercedes-Benz. A battery charger unit spe-
cially adapted for Mercedes-Benz vehicles
and tested and approved by Mercedes-Benz
is available as an accessory. It permits the
charging of the battery in its installed posi-
tion. Contact an authorized Mercedes-Benz
Center for further information and availabil-
page 295).
Y
ity. Read the battery charger's operating
instructions before charging the battery.
All vehicles except vehicles with a lith-
ium-ion battery: if the indicator/warning
lamps in the instrument cluster do not light up
at low temperatures, it is very likely that the
discharged battery has frozen. In this case
you may neither jump-start the vehicle nor
charge the battery. The service life of a
thawed-out battery may be shorter. The start-
ing characteristics can be impaired, particu-
larly at low temperatures. Have the thawed-
out battery checked at a qualified specialist
workshop.
Vehicles with a lithium-ion battery: at low
temperatures, do not charge a battery which
has been removed using a battery charger.
Allow the battery to warm up gently first, if
necessary. Otherwise, the service life can be
shortened and the starting characteristics
impaired, especially at low temperatures.
PLUG-IN HYBRID vehicles: if the battery
condition of charge is sufficient, the high-
voltage battery can also supply the 12 V bat-
tery with energy. This only happens if the con-
dition of charge of the 12 V battery requires
this, e.g. after using electrical consumers for
an extended period with the engine switched
off. As the on-board voltage is continuously
monitored this can also be performed when
the engine is switched off. The condition of
charge of the 12 V battery and the on-board
voltage are thereby kept stable for a longer
period.