How Many Times Can you Use your Car Battery to Jump start another Car?

Do you often use your car battery to jump start other people’s cars?

If you do, then you might harbour this uncomfortable feeling that perhaps there is a number, a safe limit of times beyond which you should exceed or else the lifespan of the battery will be affected.

The number of times a car battery can be used to jumpstart another depends on several factors – the quality of the battery, its capacity (Ah), its ability to handle deep discharges and state of charge.

A fully charged good quality, large capacity battery can be used to jump start several times, unlike a smaller capacity, partially discharged or ageing battery.

The Danger of Using a Car battery to Jump start several Times

Can You Damage Your Battery by Jumpstarting another Car?

Yes, it is possible to damage your car’s battery, alternator and car computer when you use it to jump start another car if you:

  • accidentally reverse the jumper cable connections,
  • jumpstart a car with a faulty (battery (shorted cells), or
  • rev the car with the dead battery.

Related article: Why your car may not be able to start after jumping another car?

Jump starting another car using a car battery draws a significant amount of current from the battery.

If you use the car battery to jump start another car several consecutive times, you risk severely draining the battery and shortening the battery life.

An alternative is to use a jump start pack. Some can jump start a car between 20 – 40 times depending on their battery capacity.

They also usually have a battery charge status indicator that shows the inbuilt battery’s charge status.

Tips to Use Your Car Battery to Safely Jump start another Car

#1. Always consult the car owner’s handbook on how to safely jump start car.

Modern cars may have different battery positions or connections points and can be more susceptible to damage if not manufacturer’s instructions are not followed properly.

#2. Make sure the jumper cables are connected the right way (to the commended positive and negative battery terminals).

You can follow the connection and disconnection sequence for jumper cables to minimise the risk of damage to your car.

#3. Only use good quality jumper cables that can handle safely the starting current.

#4. Do not rev the car with the dead battery once it has started or the car that is being used to jumpstart.

This has been reported by several car owners as the likely reason why the alternator may be damaged. Instead, once the car with the dead battery has started, disconnect the jumper cables before you can rev the car.

#5. Do not jump start a car if the battery is showing visible signs of damage – possibly a crack, leak or likely to have an internal short.

If you do, you risk damaging the battery or alternator of the car being used to jump start.

Related article: Can you charge a car battery with jumper cables? (+ alternatives)

Final Words

The number of times you can use your car battery to jumpstart another car mainly depends on the battery capacity, state of charge, age and whether it can handle deep discharges.

In general, you want to avoid using the car battery to jump start another car multiple times consecutively as each attempt draws significant power from the battery which can shorten battery life.

Instead, consider buying a jumper starter pack. Depending on the jumper starter pack capacity, a fully charged unit can jumpstart a battery between 20-40 times depending on its capacity.

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