The cross section of the auxiliary wire must be at least 16 mm for carburetor engines with a working volume of up to 2.5 liters2 (diameter 5 mm). For diesel engines and carbureted engines over 2.5 liters, the cross section must be at least 25 mm2. To a large extent, the choice of section also depends on the degree of charge of the battery. Auxiliary cable with insulated clamps and a cross section of 25 mm is recommended for purchase2, as it is also suitable for engines with a smaller displacement.
Caution: If the vehicle with the dead battery is equipped with ABS, disengage the anti-lock brake system, see 18.16.
- Both batteries must have a nominal voltage of 12 V.
- A discharged battery freezes already at -10°C. Before connecting the cable, be sure to thaw a frozen battery.
- A discharged battery must be normally connected to the on-board network.
- Check the electrolyte level in the discharged battery, top up with distilled water if necessary.
- If the battery banks have plugs, loosen or unscrew them and cover both batteries with rags.
- Place both cars so that there is no metal contact between them. Otherwise, the current will flow only after connecting the positive terminals.
- Apply the handbrake on both vehicles. Put the gearbox in neutral, set the automatic transmission to "R".
- Turn off all power consumers.
- Switch on the engine of the current-generating vehicle to idle.
- Connect the auxiliary cable in the following sequence:
1. Connect the red wire to the positive pole of the discharged battery -A-.
2. Connect the other end of the red wire to the positive pole of the current-carrying battery -B-.
3. Connect the black wire to the negative pole of the current-carrying battery.
4. Connect the other end of the black wire to a secure ground connection -X- of the vehicle to be started. This reduces voltage losses. The part that is well fixed on the engine block or the block itself is best suited for this. If you connect to the negative pole of a discharged battery, then under adverse circumstances, the battery may explode due to the formation of a spark or explosive gas evolution.
- Check again the installation of the pole clamps. Make sure that the auxiliary cable cannot be damaged by rotating parts such as the radiator fan impeller.
Attention: The terminals of the auxiliary cable must not be short-circuited when connecting the cable, in addition, the positive terminals must not have contact with ground (body or frame).
- Start the car engine with the dead battery and let it run. When starting, turn on the starter for no longer than 15 seconds, since the auxiliary cable and its clamps heat up from a large current? Therefore, take a break for cooling for at least ½ minute.
- The engine of a current-generating vehicle must always run at idle when starting. Thanks to this, its generator is protected from voltage surges during start-up. When reducing the speed, add gas to about 2000 rpm.
- Avoid approaching the battery with an open flame or a lit cigarette during starting as combustible gases may be emitted from the battery.
- Do not lean over the battery - risk of accident!
- After starting, disconnect the auxiliary cable in reverse order. Disconnect the black cable first on the current-receiving and then on the current-generating vehicle. Then disconnect the red cable, first on the current-producing, and then on the current-receiving car.
Attention: If the prescribed connection procedure is not followed, injury may result from the release of acid from the battery. In addition, there is a risk of battery explosion and the possibility of failure of the electrical devices of both vehicles.