Dead Battery? How to Jump-Start a Car Safely
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Quick answer: Connect red to the dead battery’s positive (+), red to the good battery’s +, black to the good battery’s negative (−), then the last black clamp to clean, unpainted metal on the dead car, away from the battery, never the dead battery’s − (AAA). Start the good car first, wait a few minutes, then try the dead one. Remove cables in reverse order (AAA).
⚠ Safety first:
- Check your owner’s manual first: every car is different. Some cars have specific jump-start points or warnings (AAA).
- Don’t jump a battery that is cracked, bulging, leaking or smells like rotten eggs. Replace it instead (AAA).
- Never jump or charge a frozen battery or one low on fluid: it may rupture or explode (AAA Batteries brochure).
- Both cars must use 12-volt batteries. Remove rings and watches. Wear safety glasses and gloves if you have them (AAA).
- Use cables with no frayed or exposed wire. Keep cables away from belts and fans (AAA).
Steps: easiest & free first
- Park close, but not touchingFREE
Both cars in park (or neutral) with the parking brake set, ignitions off, lights/radio/fan off (AAA; AAA Batteries brochure). - Look at the dead batteryFREE
Cracks, bulging, leaks or a rotten-egg smell = don’t jump; call for help (AAA). - Red to dead +, red to good +FREE
Connect firmly. Always positive to positive (AAA Club Alliance). - Black to good −, last black to bare metalFREE
The final clamp goes on a thick unpainted bolt or bracket on the dead car’s engine, as far from the battery as possible, to keep sparks away (AAA). - Start the good car, then the dead oneFREE
Let the working car run 3–5 minutes first. If the dead car cranks slowly, wait about 5 more minutes before another try (AAA). - Remove cables in reverse orderFREE
Last on, first off. Don’t let the clamps touch each other. - Keep it running and get the battery testedPRO
AAA Club Alliance suggests running it at least 30 minutes. If it won’t start after a third try, the battery likely needs replacing (AAA).
⚠ When to call a pro: a damaged, frozen or leaking battery; cables that are frayed; repeated clicking but no start; or a battery that keeps dying. Roadside services can test, jump or replace batteries. Renting a car or using a shared/borrowed car? Call the rental company or owner’s roadside number first. See roadside help & emergency kit.
💡 Prevent it: Keep a set of jumper cables in the car. NHTSA lists them in its recommended emergency kit (NHTSA).