How to Jump Start a Car Battery | Step-By-Step Guide

How to Jump Start a Car Battery

Most of us, if not all, know that heart-sinking moment when you get in your car and turn the key, only to hear a click-click-click and nothing else. Maybe you left a light on that drained your battery, maybe you’ve been ignoring a dashboard light indicating a problem, or maybe your battery just reached the end of its life. 

Regardless of the why, you need to know how to get your battery charged up enough to make it to an auto repair shop for testing/replacing. And unless you happen to have a giant portable battery handy to charge it up, you’ll need to jump start your car battery. 

To jump start a car battery, you need:

1. 1. Access to another car with a functioning battery (hopefully you have a neighbor that’s available or a friend that lives nearby).
   2. Jumper cables.
   3. This article to explain how to do it!

Here’s your step-by-step guide to jump start a car battery

1. Prepare the vehicles. Once you have access to a car with a ‘good’ battery, you need to park it close enough to your vehicle that the cables will reach. The most ideal way is to park the cars nose-to-nose. If that’s not an option, the cables should be able to reach if the cars are side by side. Once the cars are in position, make sure the engines are off and engage the parking brake. Then, open the hoods of both cars and locate each battery. If you struggle with this step, refer to your car’s manual. 

2. Identify the battery terminals. On the battery itself, you should see a “+” and a “-”, indicating a positive and a negative battery terminal. The positive terminal is usually covered by a red plastic cap, the black terminal is usually black and doesn’t have a cap.

Below is an image of a car battery and the terminals.

There might be some corrosion on the terminals, which will be white or green in color. If you see this, use a wire brush or aluminum foil to wipe it away (it will irritate your skin if you try to rub it off with bare hands, so don’t!). 

3. Connect the jumper cables to the correct battery terminals. Before connecting any of the cables, make sure none of the 4 clamps are touching each other. If you have someone helping you, have them hold one set, keeping them apart. If you don’t have help, lay one set on the ground away from each other.

Start on the car with the dead battery. Holding the cables apart, attach the red clamp to the positive terminal of the dead battery. Now, you’re going to want to set the black clamp down on a plastic part under the hood. Do not let the black clamp touch the red clamp or any metal.

Now, take the other red clamp (either laying on the ground or being held by someone else) and attach it to the positive terminal on the ‘good’ car’s battery, like you did with the other red clamp. Then, without letting the clamps touch, attach the black clamp to the negative terminal on the ‘good’ car’s battery.

Once both clamps are attached on the ‘good’ car, go back to the car with the dead battery. The red clamp that you did first should still be attached. Do not attach the black clamp to the negative terminal. Instead, find a piece of bare metal under the hood to connect it to, aka ‘grounding’ it. If you’re unsure where to attach this, a good option is always an unpainted bolt or bracket.

4. Start the car with the working battery. Let the car run for a few minutes to charge the dead battery.

5. Try to start the dead car. If the car isn’t starting, continue to let the battery charge from the working vehicle for a few more minutes and try again. The time it takes for the dead car to turn back on depends on just how depleted the battery was.

6. Disconnect the cables. Once the dead car is now able to turn back on, you’ll need to remove the cables. Do not turn off the car that was previously dead. You’ll want to disconnect the jumper cables in the reverse order of how you connected them.

a. Remove the black cable that you ‘grounded’ to the plain piece of metal on the previously dead car. 

b. Remove the black cable from the negative terminal of the working car’s battery.

c. Remove the red cable from the positive terminal of the working car’s battery. 

d. Lastly, remove the red cable from the positive terminal of the previously dead battery.

7. Let the battery charge. Now that you’ve gotten your car to turn on and disconnected the cables, leave your car running for at least 15-20 minutes to give the battery time to charge up. After you’ve let the battery charge, drive straight to a car repair shop to get the battery tested. If the culprit of the dead battery was a light left on, you might not need a new battery. However, if it’s been a few years, you probably need to get a new battery.

If you follow the above steps and your car still won’t turn on, this indicates an issue with the starter, ignition switch, or a fuse. If this is the case, you probably need to call a tow truck to get your vehicle properly diagnosed and repaired by a mechanic.

Jumping a car battery is a very valuable skill to know. You can’t always rely on cell service to call AAA or a friend, or even to look up how to jump start a car battery. By knowing the above steps, you should feel confident in your ability to revive a dead car battery in a pinch and get back on your way!