Caution: If the wiring instructions are not followed exactly, there is a risk of burns from acid ejections from the battery. In addition, injury or injury due to battery explosion and damage to the vehicle's electrical system may result.
The cross section of the starting wire for petrol engines with a displacement of up to approximately 2.5 liters must be at least 18 mm2 (diameter approx. 5 mm). For diesel engines and petrol engines with a displacement of more than about 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 wire cross-section is usually indicated on the package of the auxiliary starting wire. When buying a new wire, it is recommended to purchase an auxiliary starter wire with insulated clamps and a section of 25 mm2, as it is also suitable for engines with smaller displacement.
Both batteries must be rated for 12V.
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.
Check the electrolyte level in the discharged battery, top up with distilled water if necessary.
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.
During the start-up process, the engine of the car delivering current must be idling. This avoids possible damage to the generator due to voltage peaks.
During start-up, do not bring an open flame or a lit cigarette close to the battery, as combustible gases are emitted from the battery.
Make sure that the auxiliary wires are not damaged by rotating parts, such as a fan.
Connect auxiliary start wires in the following sequence:
1. Connect the red wire to the positive connector (+) in the engine compartment of a vehicle with a dead battery. Remove the protective cap first. If the vehicle receiving the current is not a BMW 5 Series, connect the auxiliary cable to the positive battery post.
2. Connect the other end of the red wire to the positive connector (+) or, respectively, to the battery pole of the vehicle supplying current.
3. Connect the black wire to the earth connector on the casing of the shock absorber strut of the car that gives current. If the vehicle supplying current is not a BMW 5 Series, connect the black wire to the negative pole (-) battery.
4. Connect the other end of the black wire to the ground connector on the casing of the right shock absorber strut of the vehicle receiving the current. If the vehicle receiving the current is not a BMW 5 Series, connect the wire to a good ground. A metal part firmly screwed to the engine is best suited for this. Under adverse circumstances, when connecting a wire to the negative pole of a discharged battery, it could explode due to sparks and the formation of explosive gas in it.
Attention: The terminals of the connected auxiliary start wire must not come into contact with each other, likewise, the positive terminals must not come into contact with the body parts (bodies or frames).
Connection points for auxiliary wires in a car with a battery in the engine compartment:
1 - positive pole (+) current receiving battery -A-;
2 - positive pole (+) current-giving battery -B-;
3 - negative pole (-) current-giving battery -B-;
4 - the place of connection of the mass -X- of the vehicle receiving the current.
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, as the positive terminals and the wire heat up due to the high starting current. The pause between two successive start attempts must be at least ½ minute.
Do not lean over the battery - risk of burns from electrolyte acid!
Attention: For BMW vehicles, before disconnecting the auxiliary wires, switch on the initiation, heated rear window and the highest blower setting. This will avoid dangerous voltage peaks from the voltage regulator to the consumers.
After starting, disconnect the wires in reverse order: first disconnect the black wire (-) at the car receiving the current, and then at the car giving the current. Disconnect the red wire first from the car giving current, and then from the receiving car.