1. Make sure the other car's battery has a voltage of 12 V and approximately the same capacity (in ampere-hours), just like your battery.
2. Do not disconnect a discharged battery from the vehicle's electrical system!
3. To avoid short circuit, the bodies of both cars should not touch each other.
4. First, connect the positive (+) terminals of the batteries with an auxiliary cable. BMW 535i, 524td: connect the positive terminal of your battery, located in the engine compartment under the cap with the "+" sign, to the booster battery (the protective cap must be removed by pulling the tab - see the picture). Then connect one end of the auxiliary cable to the negative (-) terminal of the booster battery, and the other to the "ground" race on the body or engine of your car.
5. If the battery you are starting the car from is weak, you should first start and leave the engine of this car running. Once you have started the engine of your car, do not turn it off either. After starting the engine, turn on the lights, rear window heating and the heating system fan at maximum power before disconnecting the auxiliary cables. This is necessary to avoid a voltage surge in the vehicle's on-board network when disconnecting the cables. After this, disconnect the auxiliary cables in the reverse order to when connecting them, turn off the power consumers and leave the engine running to charge the battery.
Caution: Touching conductive elements of the ignition system while the engine is running is life-threatening!
To avoid injury or damage to both vehicles, please strictly follow the above sequence of actions.
BMW 520i, 525i
These vehicles use a digital electronic engine management system that uses data from the mass air flow sensor to start the engine. Do not use starting aerosols, as this will interfere with the sensor!
The original version is on the portal www.bmwman.ru