It’ll happen eventually: your car (or someone else’s) will have a dead battery, and you’ll have to know how to jump-start a car safely. Luckily, it’s a simple process, but you’ll want to make sure you’re doing it right. Here’s how.
Before You (Jump) Start
Before you get started, make sure:
- Both vehicles are parked safely (it’s a good idea to use your emergency parking brake)
- Both vehicles are off
- Your set of jumper cables are in good condition
- Both batteries have the same voltage (typically 12V)
- You can identify both the positive and negative terminals on both vehicles
- All battery terminals are free from excessive corrosion
Make sure your vehicles are close enough so your cables will reach, but don’t let them touch—this may cause a short.
How to Connect Your Jumper Cables
Make sure you don’t let the red and black ends touch at any point during this process, and make sure they don’t touch your car. This may cause a dangerous spark.
Start with the Bad Battery & Red Cable
Connect the red jumper cable clamp to the positive (red) terminal on the bad battery.
Red Cable, Good Battery
Next, connect the red cable to the red positive terminal on the good battery.
Black Cable, Good Battery
Continue with the good battery by connecting the black cable clamp to the negative terminal.
Ground the Other Black (Negative) Cable
Finally, instead of connecting the black cable to the negative terminal of the bad battery, you need to ground it by attaching it to an unpainted metal surface. Look for any metal part that’s relatively close to the battery and secure the clamp.
Starting Your Car
Start the car with the good battery and let it charge the bad battery for about five minutes. Then, try to start the dead car. If it doesn’t start, turn the other car off, check the connection of the jumper cables and batteries and then try again, letting the bad battery charge longer. If it still won’t start, you may want to call a roadside assistance service to try using a battery pack to jump your car.
Once the car with the bad battery starts, make sure it doesn’t stall before disconnecting the jumper cables. Be sure to leave the car running for about 30 minutes after the jump to give the battery time to recharge!
Disconnect the Cables
Disconnect the cables in the opposite order:
- Disconnect the black clamp from the unpainted metal surface you used for grounding
- Disconnect the black clamp from the negative terminal of the good battery
- Disconnect the red clamp from the positive terminal of the good battery
- Disconnect the red clamp from the positive terminal of the bad battery