Mercedes-Benz C-Class Convertible 2021 Operator's Manual page 345

* NOTE Damage to the battery from over‐
voltage
When charging using a battery charger with‐
out a maximum charging voltage, the battery
or the on-board electronics may be damaged.
Only use battery chargers with a maxi‐
#
mum charging voltage of 14.8 V.
All other vehicles
When charging the battery and during starting
assistance, always use the jump-start connec‐
tion point in the engine compartment.
* NOTE Damage to the battery from over‐
voltage
When charging using a battery charger with‐
out a maximum charging voltage, the battery
or the on-board electronics may be damaged.
Only use battery chargers with a maxi‐
#
mum charging voltage of 14.8 V.
& WARNING Risk of explosion from hydro‐
gen gas igniting
There is a danger of hydrogen gas igniting
when charging the battery if there is a short
circuit or sparks start to form.
Make sure that the positive terminal of
#
the connected battery does not come
into contact with vehicle parts.
Never place metal objects or tools on a
#
battery.
The described order of the battery
#
clamps must be observed when con‐
necting and disconnecting the battery.
When giving starting assistance, always
#
make sure that you only connect bat‐
tery terminals with identical polarity.
During starting assistance, you must
#
observe the described order for con‐
necting and disconnecting the jumper
cable.
Do not connect or disconnect the bat‐
#
tery clamps while the engine is running.
Breakdown assistance 343
& WARNING Risk of explosion during
charging process and starting assistance
During the charging process and starting
assistance, the battery may release an explo‐
sive gas mixture.
Avoid fire, open flames, creating sparks
#
and smoking.
Make sure there is sufficient ventila‐
#
tion.
Do not lean over a battery.
#
& WARNING Risk of explosion from a fro‐
zen battery
A discharged battery may freeze at tempera‐
tures slightly above or below freezing point.
During starting assistance or battery charg‐
ing, battery gas can be released.
Always allow a battery to thaw before
#
charging it or performing starting assis‐
tance.