Winter time
The vehicle battery only has a proportion of the starting power in lower tem-
peratures. A discharged vehicle battery may already freeze at temperatures
just below 0 °C .
We therefore recommend that you have the battery checked and, if necessary,
recharged by a specialist garage before the start of the winter.
Note
■ The battery acid level is also checked regularly by a specialist garage as part
of the inspection service.■
For technical reasons, on vehicles with the description “AGM”, the electrolyte
level cannot be checked.
Charging
Read and observe
and on page 190 first.
A properly charged vehicle battery is essential for reliably starting the engine.
›
Switch off the ignition and all of the electrical components.
›
Only when performing a “quick-charge”, disconnect both battery cables (first
“negative”, then “positive”).
›
Attach the terminal clamps of the charger to the battery terminals (red =
“positive”, black = “negative”).
›
Plug the mains cable of the charger into the power socket and switch on the
device.
›
After charging has been successful: Switch off the charger and remove the
mains cable from the power socket.
›
Only then disconnect the charger's terminal clamps.
›
Reconnect the cables to the battery (first “positive”, then “negative”).
It is not necessary to disconnect the cables of the battery if you recharge the
vehicle battery using low amperages (for example from a mini-charger). Refer
to the instructions of the charger manufacturer .
A charging current of 0.1 multiple of the total vehicle battery capacity (or low-
er) must be used until full charging is achieved.
It is necessary to disconnect both cables before charging the battery with high
amperages, known as “ rapid charging”.
The vent plugs of the vehicle battery should not be opened for charging.
WARNING“Quick-charging” the vehicle battery is dangerous and requires a special
charger and specialist knowledge.
CAUTION
On vehicles with the START/STOP system, 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 208, Jump-starting in vehicles with the
START-STOP system .
Note
We therefore recommend that vehicle batteries be rapid charged by a special-
ist garage.
Replace
Read and observe
and on page 190 first.
The new vehicle battery must have the same capacity, voltage, current and
size as the original battery. Suitable vehicle battery types can be purchased
from a specialist garage.
We recommend having the battery replaced by a specialist garage, where the
new vehicle battery will be installed properly and the original battery will be
disposed of in accordance with national regulations.
Disconnecting or reconnecting
Read and observe
and on page 190 first.
On disconnecting and reconnecting the vehicle battery the following functions
are initially deactivated or are no longer able to operate fault-free.
OperationOperating measureElectrical power window (operational faults)» page 62Panoramic sliding roof (operational faults)» page 214Enter the radio/navigation system code
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or » user manual of the naviga-
tion system 192General Maintenance
