Don't run out of power and avoid battery failure

In 2024, the 12-volt battery was the main cause of breakdown for motorists in Luxembourg, with 8,123 cases recorded, an increase of 8 % on the previous year. This situation highlights the importance of taking care of your battery in order to avoid the inconvenience of a breakdown.

Why do batteries fail?

Batteries can lose up to 50 % of their charge in cold weather. Ageing is also a key factor, with an average life of 3 to 5 years. Both electric and internal combustion vehicles are affected by these failures, although the causes may differ slightly. It is important to note that 100 % electric cars also have a 12-volt battery, which can fail in the same way as combustion vehicles.

Tips to prevent battery failure

• Check your battery regularly: Have your battery checked every year, especially before winter. A charge test can prevent unexpected breakdowns.
• Avoid unnecessary accessories: Electronic accessories can drain the battery. Use them sparingly.
• Drive regularly: a car that remains stationary for long periods can see its battery discharge. Make regular journeys to maintain the charge.

What to do in the event of a breakdown

If your battery fails, contact a breakdown service such as the Automobile Club du Luxembourg (ACL) immediately. Road service staff are equipped with battery boosters and will succeed in restoring the vehicle's mobility in over 85 % of cases.

If you're able to do it safely, and if you have standard crocodile clips, you can try recharging the faulty battery yourself with the help of a second car.

Can a diesel car's 12V battery be repaired with a petrol car?

Yes, it is possible to repair a diesel car with a petrol car battery, but it depends on the power of the battery. Diesel car batteries are generally more powerful and require a higher capacity to start the engine. If the petrol car battery is powerful enough, it can help a diesel car. However, a small petrol battery will have difficulty starting a large diesel engine. It is therefore not advisable to do this if in doubt.

Can a 12V battery in a petrol car be repaired with a diesel car?

Troubleshooting a petrol car with a diesel car battery is generally easier and cheaper. Diesel batteries have a higher capacity and more power, which makes it possible to charge a petrol car battery efficiently. So, yes, it is possible and often recommended.

Can an electric car be used to repair the 12V battery in a combustion engine car?

We strongly advise against using an electric car's 12V battery to help a combustion engine car. The 12V batteries in electric cars are not designed to supply the power needed to start a combustion engine. The 12V battery in electric vehicles is mainly used to power starting systems and 12V accessories such as the radio, windscreen wipers, interior lighting and dashboard lights. Using an electric battery to start a combustion engine car can damage the electric car's 12V battery and its DC-DC converter. In theory, it may be possible to start an electric car with a thermal battery, but this depends on the model and specification of the vehicle. However, ACL advises against it.

Best practice for battery repairs

• Observe the correct polarity: connect the cables correctly to avoid damaging the electrical systems. The connection must be made with the engine off.
• Follow the steps for connecting and disconnecting : connect the cables in the correct order before starting the car with the battery in good condition. Then disconnect them safely after switching off the ignition with the car's battery in good condition. It is advisable to drive for a while with the car that has just been rescued.
• When in doubtAlways call in a professional.

The ACL Diagnostic Center offers a series of tests covering all your car's risk points, such as the battery, to provide a neutral and objective diagnosis of your vehicle's condition.