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Jumping a Car Battery Safely Every Time

Although roadside assistance is always available to help, jumping a car battery safely is a useful skill to know.

how to jump a car battery

A dead car battery means you’re going nowhere until you either replace it or get it jump started. Jumping a car battery doesn’t have to be a scary process. If you don’t know how, then you can call for roadside assistance, but you can also do it yourself. Here’s how to jump a car battery so you can be on your way as soon as possible.

Jumping a Car Battery: the steps

Safety first

Any time you work on your car, you need to be safe. Staying safe includes making sure that others are at a safe distance away and that you’re in a spot where it’s safe to get out of the car. You should pull out your owner’s manual, even if you already know how jumping a car battery works, to be sure you’re following the manufacturer’s recommendations. If you are in doubt about jumping your car, then call AAA Roadside Assistance for help with the process.


All you need are jumper cables. You should have these on-hand, tucked away for that inconvenient moment when your battery fails. They come in anywhere between 10 and 20 feet long with longer cables being easier to use. The extra length means less maneuvering to get the cables to reach from your car to the car providing the jump start.

There are also jump starters, which are essentially the cables with a built-in battery pack so you don’t need another car to help with the process. These are a bit bulkier and shouldn’t be stored in a hot car. Otherwise, a set of jumper cables in your trunk is all you need.


jumping a car battery


Positioning the vehicles

Ideally, you want both cars to face each other head on about 18 inches apart. Depending on where the breakdown happens, this might not be possible. Do your best to get as close to a head on as possible, but do not let the vehicles touch each other. (Some batteries are located under the back seat or in the trunk; consult the owner’s manual if you have trouble finding it.)

It’s important that there be at least 18 inches of space. Err on the side of caution rather than letting the vehicles touch. Be careful of car doors if the positioning isn’t ideal. You don’t want to open the door and have the two cars accidentally touch.

Once the cars are positioned, put both cars in park for an automatic transmission or neutral for a manual transmission. Set the parking brakes, turn off the ignitions, and remove the keys. Your cars are now ready.

jumping a car battery


Attaching the jumper cables

This is the part about jumping a car battery that makes people nervous, but there is no need to worry. Start by opening the hoods of both cars and finding the battery terminals. Usually, the terminals on the battery are red or black and you will see a + (red) and – (black) sign on the top. Make sure you can clearly see these signs because it’s essential if you’re going to jump the battery. If the terminals are dirty, use a rag or brush to knock off any dirt or debris until they’re clean.

Attach the red, positive cable clamp to the positive terminal of the dead battery. You want this connection to be secure so wiggle around the clamp to get a tight grip if it feels loose. Next attach the opposite end of the red, positive cable to the working vehicle’s positive battery terminal.

Stay over by the working car and attach the black, negative clamp to the working car’s negative battery terminal. Now, walk back over to the dead battery, but do not attach the negative clamp to the negative battery terminal. Instead, attach it to an unpainted metal part of the car like a bolt or the engine block. (Dead batteries can produce hydrogen gas – if there’s a spark you want it away from the battery.)

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Starting the car

Start the engine of the working car and let it run a minute or two before trying to start the dead car. If the car won’t turn over at first, wait a few more minutes and give it another try. Speeding up the idle for a minute or so can sometimes help.

If the car still doesn’t start, then you may need to call for roadside assistance. It could be a number of problems like battery corrosion, fuses or the starter. A professional can diagnose the problem and recommend a repair.

Disconnecting the jumper cables

There’s an order to disconnecting the cables, too. Remove the black, negative clamps and do not let them touch while the other cables are attached to the car. Next remove the red, positive clamps. Do not let the red and black cables touch. You can now close the hoods and stow your jumper cables. Once your car is running, take it to a local repair shop and to have the battery fully charged and tested.

It’s easy to learn how jumping a car battery works. With a set of jumper cables and the help of someone with a running car, you can do the job yourself in no time.

What was holding you back from learning how jumping a car battery works? Share your story in the comments below.

AAA Mobile Battery service makes buying a new battery easy. Our technicians will even test your current battery and charging system at your home or job. 


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