Mercedes-Benz

Starting assistance and charging the 12 V battery

Vehicles with a lithium-ion 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 maximum charging voltage, the battery or the on-board electronics may be damaged.

Only use battery chargers with a maximum charging voltage of 14.4 V.

All other vehicles

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

NOTEDamaging the battery through overvoltage

When using a battery charger without a maximum charging voltage, the battery or the vehicle electronics may be damaged.

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

WARNING Risk of explosion from hydrogen gas igniting

A battery generates hydrogen gas during the charging process. If there is a short circuit or sparks start to form, there is a danger of the hydrogen gas igniting.

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.

When connecting and disconnecting the battery, you must observe the described order for the battery clamps.

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 that there is sufficient ventilation during the charging process and during starting assistance.

Do not lean over a battery.

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.

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 may be released.

Always thaw a frozen battery out first before charging it or performing starting assistance.

NOTE Shortening the service life of the battery by charging the battery at low temperatures

Charging the battery at very low temperatures may shorten the service life of the battery and have a negative effect on starting.

Do not charge the battery at very low temperatures.

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

All vehicles

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 leads/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.
When charging: only use battery chargers tested and approved by Mercedes-Benz and read the battery charger's operating instructions before charging the battery.

Observe the additional following points during starting assistance:

Starting assistance may only be provided using 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.

Secure the vehicle by applying the electric parking brake.

Automatic transmission: Shift the transmission to position

Manual transmission: Shift into neutral.

Make sure that the ignition and all electrical consumers are switched off.

Open the engine bonnet.

Slide cover

of positive clamp

on the jump-starting connection point in the direction of the arrow.

Connect positive clamp

on your vehicle to positive pole of donor battery using the jump lead/charging cable. Always begin with positive clamp

on your own vehicle first.

During the starting assistance procedure:

start the engine of the donor vehicle and run at idle speed.

Connect the negative pole of the donor vehicle and earth point

of your own vehicle by using the jump lead/charging cable. Begin with the donor battery first.

During starting assistance:

start the engine of your own vehicle.

During the charging process:

start the charging process.

During starting assistance:

let the engines run for several minutes.

During starting assistance:

before disconnecting the jump lead, switch on an electrical consumer on your own vehicle, e.g. the rear window heater or lighting.

When the starting assistance/charging process is complete:

First, remove the jump lead/charging cable from earth point

and negative pole of the donor vehicle, then from positive clamp

and positive pole of the donor vehicle. Begin each time with the contacts on your own vehicle first.

After removing the jump lead/charging cable, close cover

of positive clamp

You can obtain further information on starting assistance at any qualified specialist workshop.