Mercedes-Benz

Starting assistance and charging the starter battery

Always use the jump-start connection in the engine compartment for starting assistance and when charging the battery.

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 warning/indicator lamps do not light up in the instrument display around or below freezing point, it is very likely that the discharged battery has frozen.

In this case, observe the following points:

do not give the vehicle starting assistance or charge the battery
the service life of a battery that has been thawed may be reduced drastically
the starting behaviour may deteriorate, particularly 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.

When jump-starting and charging the batteries, observe the following points:

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 leads/charging cables are connected to the battery/jump-start connection point
the jump leads/charging cables 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
always keep away from fire and naked flames
do not lean over a battery
when charging: only use a battery charger that has been tested and approved by Mercedes-Benz and read the operating instructions for your charger before charging the batteries

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 each other
vehicles with a petrol engine: only perform starting assistance when the engine and exhaust system are cold

Vehicles with a battery main switch:

check whether the battery main switch is inserted More

Secure the vehicle using the parking brake.

Vehicles with automatic transmission:

shift the transmission to position

Vehicles with manual transmission:

shift to neutral.

Switch off the ignition and all electrical consumers.

Open the bonnet More.

Example: jump-start connection

Right-hand drive vehicle: the jump-start connection may be on the opposite side.

Remove the cover from the positive terminal on the donor battery.

First, connect the positive terminal clamp of the jump leads/charging cables to the positive terminal of the other vehicle's battery.

With positive terminal clamp

of the jump lead/charging cable, slide the red protective cap on jump-starting connection

back with a clockwise turn.

Connect the other positive terminal clamp to the positive terminal of jump-start connection

During starting assistance:

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

First, connect the negative terminal clamp of the jump lead/charging cable to the negative pole of the donor battery.

Connect the other negative terminal clamp of the jump lead/charging cable to an earth point on your own vehicle (a bare metal part in the engine compartment).

During starting assistance:

start the engine on your own vehicle.

When charging:

start the charging process.

During starting assistance:

let the engine run for a few 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:

Remove the jump leads/charging cables in reverse order: first the negative clamp from the earth point in the engine compartment, then the negative clamp from the donor battery. Then the positive clamp from the positive terminal of jump-start connection

, then the positive clamp of the donor battery.

The red protective cap springs back to its initial position when positive terminal clamp is disconnected from jump-starting connection .

You can obtain further information at a qualified specialist workshop.