WARNING■When you charge a battery, hydrogen is released, and a highly explosive
gas mixture is also produced. An explosion can be caused through sparkling
over during unclamping or loosening of the cable plug while the ignition is
on.■
Creating a bridge between the poles on the battery (e.g. with metal ob-
jects - cables) creates a short circuit - risk of damage to the battery, explo-
sion and burning of the battery, jets of acid spurting out.
■
Avoid creating sparks when working with cables and electrical devices.
Strong sparking represents a risk of injury.
■
Before carrying out any work on the electrical system, switch off the en-
gine, the ignition and all electrical consumers and disconnect the negative
terminal
.
■
“Quick-charging” the vehicle battery is dangerous and requires a special
charger and specialist knowledge.
■
We therefore recommend that vehicle batteries be “rapidly charged” by a
specialist garage.
CAUTION
On vehicles with the START/STOP system or additional heating (auxiliary heat-
ing), the pole terminal of the charger must not be connected directly to the
negative terminal of the vehicle battery, but only to the engine earth
» page 174 .
Replacing
Read and observe
and on page 157 first.
The new vehicle battery must have the same capacity, voltage, current and thesame size as the original battery. Suitable vehicle battery types can be pur-
chased from a specialist garage.
We recommend you have the battery replaced by a specialist garage.
Disconnecting or reconnecting
Read and observe
and on page 157 first.
Disconnecting
›
Switch off the ignition.
›
First, disconnect the negative terminal
first, then the positive
terminal
of the battery.
Connecting›First, connect the positive first, then the negative battery terminal.
After disconnecting and re-connecting the vehicle battery, the following func-
tions or devices are partially or completely inoperative.Function / deviceOperating measureElectric windows» page 59Time settings» page 31
CAUTION
■ Disconnect the vehicle battery only with the ignition turned off - there is a
risk of damaging the electrical system of the vehicle.■
Under no circumstances must the battery cables be connected incorrectly –
risk of a cable fire.
Note
■ After disconnecting and re-connecting the vehicle battery, we recommend
having the vehicle checked by a specialist to ensure that the full functionality
of all electrical systems is guaranteed.■
The data of the multi-function display will be reset.
Automatic load deactivation
Read and observe
and on page 157 first.
The vehicle voltage system automatically prevents the battery from discharg-ing when the battery is put under high levels of strain. This may be noticed
from the following.
▶ The idling speed is raised to allow the generator to deliver more electricity to
the electrical system.
▶ Where appropriate large convenience consumers, e.g. seat heaters, rear win-
dow heaters, have their power limited or shut off completely if necessary.
CAUTION
■ Despite such intervention by the vehicle electric system management, the
vehicle battery may be drained. For example, when the ignition is switched on
a long time with the engine turned off or the side or parking lights are turned
on during longer parking.■
Consumers which are supplied via a 12 V socket can cause the vehicle battery
to discharge when the ignition is switched off.
159Inspecting and replenishing
