Mercedes-Benz

Notes on starting assistance and charging the 12 V battery

When charging the battery and during starting assistance, always use the jump-start connection point in the engine compartment.

NOTE Damage to the battery from overvoltage

When charging using a battery charger without a restriction of the maximum charging voltage, the battery or the on-board electronics can be damaged.

Only use battery chargers with a maximum charging voltage of 14.8 V.

WARNING Risk of explosion due to hydrogen gas igniting

If, when charging a battery, there is a short circuit or sparks start to form, there is a danger of hydrogen gas igniting.

Take care that the positive clamp connected to a battery does not come into contact with vehicle parts.

Never place metal objects or tools on a battery.

When connecting and disconnecting the battery, always observe the sequence of battery clamps described.

Take care to only connect battery terminals of identical polarity when receiving starting assistance.

Observe the sequence described for connecting and disconnecting the jump leads when receiving starting assistance.

Do not connect or disconnect the battery terminals while the engine is running.

WARNING Risk of explosion due to explosive mixture of gases

An explosive mixture of gases can escape from the battery during charging and starting assistance.

Fire, naked flames, smoking and creating sparks must be avoided.

Make sure there is adequate ventilation.

Do not stand over the battery.

WARNING Risk of explosion from a frozen battery

A discharged battery may freeze at temperatures slightly above or below freezing point.

During starting assistance or battery charging, battery gas can be released.

Always allow a battery to thaw before charging it or performing starting assistance.

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 battery that has been thawed may be dramatically shortened. The starting characteristics may be impaired, especially at low temperatures.

It is recommended that you have a thawed battery checked at a qualified specialist workshop.

NOTEDamage caused by numerous or extended attempts to start the engine

Numerous or extended attempts to start the engine may damage the catalytic converter due to non-combusted fuel.

Avoid numerous and extended attempts to start the engine.

Observe the following points during starting assistance and when charging the battery:

Only use undamaged jump lead/charging cables with a sufficient cross-section and insulated terminal clamps.
Non-insulated parts of the terminal clamps must not come into contact with other metal parts while the jump lead/charging cable is connected to the battery/jump-start connection point.
The jump lead/charging cable must not come into contact with any parts which may move when the engine is running.
Always make sure that neither you nor the battery is electrostatically charged.
Keep away from fire and naked flames.
Do not lean over the battery.

Observe the additional following points when charging the battery:

Only use battery chargers tested and approved for Mercedes-Benz.
Read the battery charger's operating instructions before charging the battery.

Observe the additional following points during starting assistance:

For starting assistance, only use batteries with a nominal voltage of 12 V.
The vehicles must not touch.
Petrol engine: only accept starting assistance if the engine and exhaust system are cold.