How to jump start a BMW safely: jump points and step by step

Knowing how to jump start a BMW safely is useful for every owner. A flat battery can happen after the car has stood for a while, after leaving lights on or simply because the battery is old.

On many BMWs, the battery is located in the boot, but the car has special jump points under the bonnet. Using them correctly protects the car's sensitive electronics. In this guide we explain where to find the jump points, how to connect the cables, how to start the car and what to do afterwards.

Before you start

Check that a flat battery is really the problem. Signs include no reaction when pressing the start button, a clicking noise, dim interior lights or warning messages about the battery.

You will need:

• Quality jump leads with thick cables and good clamps, or a portable battery booster.
• A donor car with a battery of the same voltage, usually 12 volts, if you use leads.
• The owner's manual of your car, which shows the exact jump points.

Never jump start a car if the battery is frozen, damaged or leaking.

Where the jump points are

Many BMWs have their battery in the boot, under the floor or behind a side panel, for better weight distribution. To make jump starting easier and safer, BMW provides jump points in the engine bay:

• A positive jump point, usually under a red plastic cover marked with a plus sign.
• A negative or earth point, often a marked bolt or nut on the body or engine bay structure.

On some models, the battery is under the bonnet, but the manual may still recommend using the marked jump points rather than connecting directly to the battery. Always follow your owner's manual.

How to jump start a BMW: step by step

1. Switch off both cars and all electrical consumers such as lights and climate control.
2. Open the positive jump point cover on your BMW.
3. Connect the red cable to the positive jump point of your BMW.
4. Connect the other end of the red cable to the positive terminal of the donor battery or its jump point.
5. Connect the black cable to the negative terminal or earth point of the donor car.
6. Connect the other end of the black cable to the earth point of your BMW, away from the battery.
7. Start the donor car and let it run for a few minutes.
8. Start your BMW.
9. Disconnect the cables in reverse order: black from your BMW, black from the donor, red from the donor, red from your BMW.

Make sure the clamps never touch each other or other metal parts while connected.

Using a portable battery booster

Portable battery boosters are popular because they do not need a second car. Connect the red clamp to the positive jump point and the black clamp to the earth point, switch on the booster and start the car. Follow the booster manufacturer's instructions carefully.

Keep the booster charged and store it in the car, especially if your BMW stands for long periods.

After the jump start

Once the engine is running:

• Let it run or drive for at least half an hour to recharge the battery. Short trips may not be enough.
• Expect warning messages, for example about the battery, the clock or driver assistance systems. Many disappear after a drive.
• Have the battery tested if it goes flat again. An old or damaged battery should be replaced.
• Charge the battery with a suitable charger if the car will stand again soon.

A battery that goes flat repeatedly can point to a drain. Our article on BMW battery drain explains how to find the cause. If the battery is replaced, it must be registered. Our article on BMW battery registration explains why.

Mistakes to avoid

• Connecting the cables in the wrong order or reversing polarity, which can damage electronics.
• Connecting the negative cable directly to the flat battery when the manual recommends an earth point.
• Using thin or cheap cables, which can overheat.
• Revving the donor car excessively.
• Trying many long start attempts in a row. Wait between attempts.
• Jump starting a damaged or frozen battery.

When in doubt, call roadside assistance.

Can a BMW jump start another car?

Many BMW owner's manuals allow the car to be used as a donor, using the jump points in the engine bay. Follow the instructions carefully, and switch off all electrical consumers in both cars.

Avoid using your BMW to start vehicles with very different electrical systems, such as large commercial vehicles.

Preventing flat batteries

• Drive regularly and include longer trips.
• Use a battery maintainer for long storage. Our guide on how to store your BMW for winter explains how.
• Check that lights and accessories are off when you leave the car.
• Replace an ageing battery before it fails.

A healthy battery is essential for a modern BMW, because many systems depend on stable voltage.

How to jump start a BMW at a glance

Item	Details
Battery location	Often in the boot on many models
Jump points	Positive and earth points in the engine bay
Connection order	Red to flat car, red to donor, black to donor, black to earth
Disconnect	In reverse order
After starting	Drive at least half an hour
Repeated flat battery	Test battery, check for drain
New battery	Must be registered

Frequently asked questions

Where are the jump points on a BMW?

Usually in the engine bay: a positive point under a red cover and a marked earth point. Check your owner's manual.

Can I jump start a BMW with the battery in the boot?

Yes. Use the jump points in the engine bay, which are connected to the battery.

How long should I drive after a jump start?

At least half an hour, or charge the battery with a suitable charger.

Can a jump start damage a BMW?

Incorrect connections or reversed polarity can damage electronics. Follow the correct order and use quality cables.

Sources

• BMW owner's manuals – jump starting
• BMW Group – battery and electrical system information