Starting the engine from the battery of another car

Safety instructions

If the wiring regulations are not adhered to exactly, there is a risk of burns due to electrolyte emissions from the battery. In addition, injury or injury may result from an exploding battery. In addition, the vehicle's electrical system may be damaged.

• Avoid contact of electrolyte with eyes, skin, fabrics and varnished surfaces. The electrolyte is corrosive. Wash off splashes of acid immediately with plenty of clean water. If necessary, call a doctor.
• Do not allow any sparks near the battery and do not bring open flames to it, as combustible gases can be released from the battery.
• Wear safety glasses.
• Take care that the auxiliary jump leads are not damaged by rotating parts such as the cooling fan.

The cross section of the starting wire for petrol engines with a displacement of up to approximately 2.5 liters must be at least 16 mm² (diameter approx. 5 mm). For diesel engines and gasoline engines with a displacement of more than approx. 2.5 liters, the wire cross section must be at least 25 mm². The working volumes are indicated for a car engine with a discharged battery. The cross section of the wire is indicated, as a rule, on its packaging.

Both batteries must be rated for 12V.

If equipped, open the battery cover.

A discharged battery can freeze even at -10°C. A frozen battery must be thawed before connecting the auxiliary jump lead.

A discharged battery must be properly connected to the vehicle's electrical system.

If possible, check the electrolyte level in the discharged battery, top up with distilled water if necessary, and close the filler caps.


Vehicles should be placed at a distance that excludes their contact with metal parts. Otherwise, current may flow even when the positive pole is connected.

Put both cars on the handbrake. Put the gear selector in the neutral position, in the presence of an automatic transmission, put the operating mode selector lever in position P.

Switch off all current consumers, including the car phone.

During the start-up process, the engine of the vehicle delivering current must be idling. This avoids possible damage to the generator due to voltage peaks during start-up.



Connect the start wires in the following sequence:

1. One end -1 - of the red wire is connected to the positive pole (+) discharged battery -A-.

2. Connect the other end -2- of the red wire to the positive pole (+) supplying battery -B-.

3. Connect one end -3- of the black wire to the negative pole (-) supplying battery current.

4. Connect the other end -4- of the black wire to the chassis -X- of the current-receiving vehicle.

Attention: Not to negative (-) terminal of a discharged battery.

A metal part firmly screwed to the engine is best suited for this. Under adverse circumstances, when a wire is connected to the negative pole of a discharged battery, it may explode due to sparks and the formation of explosive gas in it.

Attention: The terminals of the connected start wires must not come into contact with each other, likewise, the positive terminals must not come into contact with the body parts (bodies or frames) - risk of short circuit!.

The engine of the receiving vehicle (with dead battery) start and leave to idle. When starting, do not keep the starter running continuously for more than 10 seconds, because the terminals and wires heat up due to the high starting current. «Cooldown pause» there must be at least ½ minute between two successive start attempts.

After starting, do not disconnect the starter wires for about three more minutes.

To avoid voltage spikes when jumper wires are disconnected, turn on the heating fan and heated rear window glass in a vehicle with a dead battery. Do not turn on headlights. Incandescent lamps burn out when there is a power surge.

After starting, disconnect the start wires in the reverse order to the one that was available when they were connected: first, the end of the black wire -4- (-) at the car receiving the current, then at the car giving the current. Disconnect the red wire -2- first from the vehicle supplying current, and then from the vehicle receiving current.