How To Jump-Start A Car

Car batteries can fail for many reasons. Whether you accidentally leave the lights on overnight or you have an older battery that needs replacing, there will likely come a time when you go to turn the key and your car doesn’t start. You know to grab the jumper cables, but now what?

This informational guide will answer all your questions about jumper cables, dead car batteries, and how to jump-start your car. Our team has put in the research to provide you with clear-cut and quality instructions so you can get back on the road and jump-start your car error-free.

Disclaimer: Working with car batteries poses risks such as electric shock and potential damage to vehicle systems if improperly handled. Please use caution while attempting any vehicle maintenance and always consult your car manufacturer’s manual.

Below we share step-by-step instructions to jump-start your dead car battery. 

Step 1: Park And Position The Booster Car

After grabbing a set of jumper cables, you need to park a second vehicle with a working battery beside the dead car, or facing bumper-to-bumper. The vehicles should be close enough for the jumper cables to reach both batteries, so be mindful of the distance if not using lengthy jumper cables.

The ignition needs to be off in both cars, and the car keys should be removed. You should turn off all lights and accessories, including your car’s air conditioning system and the radio. Activate the emergency parking brake in both vehicles as an extra precaution.

It’s important to note that in most gas-powered vehicles, you will find the battery under the hood. Depending on the car you are jumping and the vehicle you are using to jump the dead car, you should arrange the working vehicle accordingly to get both batteries as close to each other as possible.

Step 2: Find The Battery Terminals

After lifting the hood of both vehicles to access the car batteries, you need to locate and identify the battery terminals. There are two terminals in a car battery, one positive (+) and one negative (-) battery cable. Generally speaking, the positive terminal on your battery is associated with a red cap and the negative with black one, but you should check your owner’s manual if you are having trouble locating the terminals.

It is important to check that you can safely jump your car by making sure both batteries are in good condition. Terminals should have no corrosion. If you see a green- or white-colored substance on the posts, you should remove it with either a wire brush, aluminum foil, or iron wool. Corrosion can severely irritate your skin, so you should not directly touch the terminals.

Step 3: Attach Your Jumper Cables

Jumper cables have clamps on both ends to attach to the batteries. Red clamps attach to the positive battery terminals on each battery. Black clamps are for negative posts on the working battery, and the engine block of your dead car battery.

It’s especially important to note that all clamps are attached securely and correctly. Incorrect connection to either battery can result in damage to your car’s electrical system or alternator. There is also a risk of personal injury if the clamps are not securely attached, so make sure you have long enough cables. The metal clamps should also not touch each other while attached to the batteries.

Step-By-Step: Attaching Jumper Cables

• Step 1: Attach the red clamp to the positive terminal of the dead battery.
• Step 2: Attach the red clamp on the other end of the cable to the booster car’s positive terminal on the good battery.
• Step 3: Attach the black clamp to the negative terminal of the working car battery.
• Step 4: Attach the black clamp on the other end of the cable to a metal part of the dead battery car’s engine, like an unpainted bolt or bracket. Some automotive models have a grounding bolt or engine block for this purpose.

Step 4: Jump-Start Your Car

After checking that all cables are correctly and safely connected, start the engine of the booster car with the working battery. Then, start the car with the dead battery. 

If you don’t get the engine running on the first try, you may need to wait a few minutes to give the battery time to build charge. If needed, you can rev the engine of the booster car. This sends more energy to the working vehicle’s battery to get your jump-started car up and running.

Step 5: Remove Jumper Cables From Both Cars

Once the jump-started car is charged and running, you can disconnect the jumper cables in the reverse order they were initially attached to each battery. Keep metal clamps from touching each other when disconnecting the positive and negative cables from each battery.

Step-By-Step: Removing Jumper Cables

• Step 1: Disconnect the negative cable clamp from the jumped car.
• Step 2: Disconnect the negative clamp from the booster car battery.
• Step 3: Disconnect the positive cable clamp from the booster car.
• Step 4: Disconnect the positive clamp from the jumped car.

Step 6: Hit The Road

With both cars running smoothly, you can pack up your jumper cables and get behind the wheel. It’s recommended that you drive for about 30 minutes after jumping your vehicle to help the alternator charge your battery while it’s running. 

After driving, we suggest parking your car in a convenient spot in case it needs to be jumped again. If you have trouble starting your car again, you could need a new battery. If this happens, an auto parts store or your local dealership can run a diagnostic test and replace your battery if necessary. 

Jumper cables can help restart your dead car with the help of a working car battery. But with a jump starter, you don’t need another vehicle to get back on the road. A jump starter holds a charge on its own, so if you’ve charged the device up at home then you know you are covered if your battery gives out. Jump starters have a high power output and are compact, making it easy to keep them stored in your car in case of an emergency.

Our team of experts has tested more than 20 jump starters to find the best products available for drivers. Read our jump starter review if you’re looking for a quick way to get your battery up and running.

As mentioned, jump starters provide instant power to get your dead car battery up and running in only a few minutes. Car battery chargers are designed to restore a drained battery or maintain the power of an infrequently used battery.

Battery chargers provide a small amount of charge to your car battery to sustain the voltage and amperage of your battery. These chargers cannot be used to jump-start a car. Instead, they recharge a car battery and keep the battery working reliably and in top condition. Recharging your car battery can take anywhere between a few hours to a couple of days depending on the battery size and the amount of charge needed.

In summary, car battery chargers provide a small and consistent charge to a drained battery, while jump starters provide instant power to your dead car battery. We tested and reviewed many of the top car battery charger options on the market, in case you’d like to know more about specific models.

Jump-starting your car doesn’t have to be a hard task. When done correctly, you can be back on the road in only a few minutes. Our step-by-step guide gives insight and instructions on how to efficiently and safely jump-start your car in no time.

The most important consideration when jump-starting a dead car battery with jumper cables is to follow the steps in order. You should also keep the metal clamps on jumper cables from touching and look out for battery corrosion.

*Data accurate at time of publication.