Notes

There are many possible reasons why your car isn't cranking. It could be the starter, or a dead alternator, or because a family of badgers took up residence in the engine. If your lights aren't dim, if your engine cranks quickly, or if you hear a loud screeching resembling that of extremely annoyed badgers, it probably isn't the battery. If, when you turn the ignition, you get nothing — or a really slow crank — the battery may well be the problem.

2. Have jumper cables.

Jumper cables in black and red are long.
Jumper cables are your friend. Always keep them in your car.
Always keep a pair of jumper cables in your car. Like, . Know where they are and what they look like. You'll notice that each side of the cables has one black clamp and one clamp of another color (usually red). This is not just to make them look cooler. We'll get to the reason in a second.

3. Get help from someone with a car with a working battery.

Two cars facing direct opposite with front engines open to change the battery.
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Once you have found a kind soul with a car that has a working battery and who is kind enough to help you out of this bind, make sure both cars are parked closely enough so that the jumper cables will reach. Unless you want to see sparks and possibly get a nasty shock (not nearly as fun as it may sound), make sure both cars are turned off. To avoid unnecessary drain on the batteries, turn off any battery-dependent components in cars, such as the air conditioner, the radio, and the lights.

4. Locate the battery in each car and find the positive and negative terminals.

An illustration depicts a working battery with a positive terminal on the left and a negative terminal on the right. Two electrode holders approach the positive and negative terminals.
Look for the "+" or "-" by each battery terminal.
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The hardest part of jump-starting a battery is remembering where to put the cables. The positive terminal is marked with a "+" sign (who would've guessed?). The negative terminal, by some strange coincidence, is marked with a minus, or "-," sign. In most cases, the positive terminal is red and the negative terminal is black. Similarly, the black clamps on your jumper cables are always negative and the red are always positive.

5. Connect the cables in the right order.

A guide step-by-step process for jumper cables placed on the batteries. Step 1. jumper cables connect with the plus sign on both dead and working batteries. Step 2. black jumper cables connect from the working battery minus button to the car.
Here's a handy guide to the four-step process for placing the jumper cables on the batteries.
As with many things in life, you want to place the clamps in the right order. Just as when you are giving feedback to your friend Marvin on his recent tuba recital, always start with the positive. Starting with the negative when jumping a battery — or when critiquing a four-hour tuba-only rendition of the soundtrack — might end up causing sparks to fly.

Connect a red (positive) clamp to the positive terminal of the dead battery. Then connect the other positive (red) cable to the positive terminal on the good battery. (Remember though: Both cars are turned off!)

A guide flow process diagram for jumper cables placed on the batteries.
Place the second black clamp on a grounded nut or bolt. Think of this "Goth" clamp as an outsider by choice — it doesn't want to hang out with the other clamps.
Click here for long description
Next, connect one of the negative (black) clamps to the working battery. Do attach the other black cable to the other negative terminal of the dead battery, or you may get a bit of a shock. Instead, connect the other black clamp to a clean, grounded metal surface, such as the bolt where the battery connects to the chassis. If you're not able to find this, look for another nut, bolt, or clean metal thing that is attached to the engine.

6. Ladies and gentlemen, start your engines!

First, start the car with the good battery. Wait a minute or two for the battery to warm up and then crank the car with the dead battery. If all goes well, the car will crank. If the car still won't crank, the battery may not be your problem. At this point, you may need to call a tow truck or a mechanic and come up with an elaborate lie to tell your parents.

If the car starts, gently give the engine a bit of gas. Don't rev the engine like you're about to start the Daytona 500, as this won't do any good . . . and it's annoying. Give it 30 to 60 seconds. Leave both cars running and then proceed with caution to remove the cables.

7. Remove the cables in the order.

In other words: take the black (-) clamp off the grounded bolt in the disabled car and then remove the other black (-) clamp from the car of the saintly person who volunteered to help you. Remove the red (+) clamp from the terminal of the good battery. Finally, remove the red (+) clamp from the dead battery — which, hopefully, is now working. As you remove the clamps, make sure that they don't touch.

With any luck, your car is now running. If so, be sure and keep the engine running for at least 20 minutes to give the battery plenty of time to recharge.

If your car didn't crank, you may have a permanently dead battery, need a new alternator, or should call the U.S. Fish and Wildlife Service to get those badgers out of your engine and back to a more badger-friendly environment.

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By following these easy steps, you should be able to expertly jump-start your car battery and get back home in time to avoid disaster. Enjoy your newfound knowledge!