How To Jump a Car Battery (And When To Consider Roadside Assistance)

You can jump-start a dead car battery by using jumper cables to connect its terminals to the terminals of a functioning car battery or a standalone jump starter kit. However, if you don’t know how to jump a car battery, are alone or otherwise don’t have access to jumper cables or another vehicle with a working battery, you may be able to turn to your roadside assistance plan to request support.

Continue reading for more information about jump-starting a car, including how to use jumper cables safely and how to know when your battery needs to be replaced.

On This Page

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  What Should I Do if My Car Battery Is Dead?

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  What Do I Need To Jump a Car Battery?

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  How To Jump a Car Battery

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  Things To Consider When Jumping a Car Battery

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  What Should I Do if My Car Battery Dies After Jumping It?

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  Does Roadside Assistance Cover Car Batteries?

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  How To Get Roadside Assistance To Jump Your Car Battery

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  FAQs

What Should I Do if My Car Battery Is Dead?

If you believe your car battery is dead, check under the hood for corrosion or loose connections. When battery acid or similar substances build up and corrode your car battery, it can inhibit the connection between your battery’s terminals and the car’s electrical system — potentially preventing the vehicle from starting when the engine is cranked.^[1]

Once you’ve lifted the hood, use a wire brush and a specialized cleaning solution to scrub away any visible corrosion on the battery's surface. This should help improve your vehicle’s electrical connections. However, if the car still won’t start after you clean the battery, you will likely need to jump-start it to get it up and running again.^[1]

How Do I Know if My Car Battery Is Dead?

The following signs may indicate that your car battery is dead or severely damaged and needs to be replaced:^[2]

• The car doesn’t start when you turn the key in the ignition
• The interior lights, door chimes or central locking system stop working
• You can’t turn on the headlights or radio
• It is more difficult to start the car in the morning than later in the day because the battery drains too quickly overnight
• The battery case is swollen or cracked due to excessive heat, cold, overcharging or outgassing
• The battery terminals are visibly corroded

Keep in mind that car batteries typically last three to five years, so you may need to replace your battery multiple times during the lifespan of your vehicle.^[3]

What Do I Need To Jump a Car Battery?

To jump your dead battery, you will need a set of jumper cables — which you should keep in your car at all times — and access to a working car battery. Generally, this requires recruiting another person so you can connect your vehicle’s battery to theirs.

However, you may also use a portable jump starter (or jumper box) that contains its own battery. These devices typically cost around $100 to $300 and allow you to jump-start your car without someone else's assistance.^[4]

How To Jump a Car Battery

Read the following sections for a step-by-step breakdown of how to jump-start a car battery.^[5]

Find Someone With a Working Car Battery Willing To Help

Unless you have a portable jump starter kit, you’ll need help from someone else with a functioning car battery to jump-start your dead battery. Consider asking people nearby for help if you are in a parking lot or waving down passing drivers if you are stuck on the side of the highway. Alternatively, you could call a friend or family member in the area and ask them to come help.

Park the Second Vehicle Close to the Vehicle With the Dead Car Battery

Once you’ve found someone to help you, have them park their car close to yours — such that you can easily connect the vehicles’ respective batteries. This typically involves parking the cars side-by-side or with their front bumpers facing each other, though you may need to park them differently depending on where the battery is located in your car. Ensure both vehicles are turned off once they are positioned properly.

Identify and Locate the Car Battery Terminals

Open the hoods of both vehicles, or ensure you otherwise have access to both car batteries. Then, find the two batteries and pinpoint the terminal locations where you can attach jumper cables — consulting your owner’s manual for guidance if necessary. Each battery should have two terminals, one marked positive (+) and one marked negative (–), which may be covered by plastic shields that you’ll need to remove.

Connect the Jumper Cables

Connect the clamp on one end of the red jumper cable to the dead battery’s positive terminal, and then connect the other end of the red cable to the live battery’s positive terminal. Next, connect one end of the black jumper cable to the negative terminal on the good battery. Instead of connecting the final black cable clamp to the dead battery’s negative terminal, you will generally want to attach it to a bare metal bolt or bracket in the engine compartment.

Most vehicles have a grounding bolt specifically marked with a minus sign where you can attach the last jumper cable clamp.

Start the Car Engines

After connecting the jumper cables, start the car with the functioning battery. You may need to wait a few minutes before attempting to start the other vehicle to give its dead battery enough time to recharge. Fortunately, it is generally safe to jump-start a car in the rain, so you don’t need to worry about rushing through the process if your car happens to break down amid bad weather.

Disconnect the Jumper Cables

If your car starts running properly, you can carefully disconnect the jumper cables. To prevent electrical surges, disconnect the cables in the opposite order from how you connected them. For example, if your car needed the jump start, you must remove the black clamp from your car’s grounding bolt, the black clamp from the other car’s negative terminal, the red clamp from the other car’s positive terminal and the red clamp from your car’s positive terminal — in that order.

Keep the Car Running

Allow your car to keep running while you put away your jumper cables and close the hood. Then, drive for about 20 minutes or more to give the alternator time to send a charge to the battery. Once you are done driving, consider parking in an area with plenty of space in case your battery malfunctions again and you need to request another jump start.

Things To Consider When Jumping a Car Battery

While you won’t need help from someone else if you have a portable jump starter, the process of jumping your car should otherwise be similar, as your jump box’s battery should still have positive and negative terminals that connect to the red and black jumper cables, respectively.^[4] Regardless of how you jump your car, you must follow important safety precautions.

Connecting the jumper cables in the wrong order or letting the cable ends touch each other after connecting to the batteries may produce sparks that can damage your battery’s electronic components. Even worse, these sparks could cause hydrogen gas escaping from your car battery to explode, potentially resulting in serious bodily injury to yourself or anyone else standing nearby.^[6]

What Should I Do if My Car Battery Dies After Jumping It?

Your car battery may be failing if it stops working again shortly after you jump-start it, meaning you may need to replace it. It’s especially important to consider a replacement if your current battery is a few years old, as it may already be near the end of its lifespan. An employee at an auto parts store may be able to test your battery to determine whether it needs to be replaced.^[5]

Does Roadside Assistance Cover Car Batteries?

Roadside assistance providers can generally send someone to jump-start your car battery if you are left stranded on the side of the road after it dies. In some cases, you can contact a provider for assistance even if you don’t have an active roadside assistance membership or policy. However, if you request a battery replacement rather than a jump start, you may need to pay for the new battery out of pocket, depending on your roadside assistance provider.^[7]

When Should I Consider Roadside Assistance for a Dead Battery?

You should request a roadside assistance technician if it’s not feasible for you to jump your own battery. For example, you may need roadside support if you are alone, don’t have jumper cables or have stopped in a place where it might be dangerous to flag down another driver to ask for help. It may also be wise to contact an emergency roadside assistance service if you are not confident in your ability to safely connect jumper cables yourself.

How To Get Roadside Assistance To Jump Your Car Battery

You may be able to obtain roadside assistance coverage as a standalone subscription-based plan or as an add-on to your car insurance policy. To find the best rate for coverage, it’s helpful to compare quotes from about three to five different service providers. This can be a laborious task, though — especially if you individually reach out to each roadside assistance company.

Instead, consider comparison shopping online through SmartFinancial. After filling out a brief questionnaire, you can connect with agents on our platform who are prepared to help you compare car insurance policies that include roadside assistance. Get started on comparing free auto insurance quotes with no obligation today!