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 from hydrogen 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 connecting and disconnecting the battery.

When giving starting assistance, always make sure that you only connect battery terminals with identical polarity.

During starting assistance, you must observe the described order for connecting and disconnecting the jump lead.

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

WARNING Risk of explosion during charging process and starting assistance

During the charging process and starting assistance, the battery may release an explosive gas mixture.

Avoid fire, naked flames, creating sparks and smoking.

Make sure there is sufficient ventilation.

Do not lean over a 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.