Question: My friend just called me saying his truck’s battery was dead and wanted to know if I could drive over and help jump-start it—the only thing is, I just have a regular car, and I don’t know if that’ll work. Can a car jump-start a truck?
Answer: Great question! A car should be able to jump-start a truck without issue if the jumper cables are connected properly.
How to jump-start a truck
To jump-start your friend’s truck, or any other car, follow these instructions:
- Position your car so the hood is facing the truck’s hood. Turn off your car.
- Connect one end of the positive jumper cable—this is typically colored red— to the positive terminal on the dead battery and the other end to the positive terminal on your car’s battery.
- Connect one end of the negative jumper cable—this is typically colored black— to the battery post on your car and the other end to some exposed metal under the truck’s hood, like an unpainted bolt. (Never connect to the dead battery’s negative terminal, as this could cause a fire.)
- Once the cables are connected, run your engine for a minute or two to charge up the dead battery.
- After a couple of minutes, the truck should be able to start without difficulty. If the truck starts, leave it running. Disconnect the clamps in reverse order, avoiding contact between clamps.
These steps should help you start engines with minor battery issues. However, if the truck has major battery problems, you might have to let your donor car run for up to 15 minutes before the truck will start. If that still doesn’t work, the truck may need a replacement battery or an electrical repair.
Can a car jump a semi-truck?
Your car is overwhelmingly likely to use a 12-volt system. If you are jump-starting a truck that also has a 12-volt system, then you are good.
However, some larger, commercial vehicles, such as semi-trucks, use a 24-volt system. You can’t jump start those with a 12-volt battery as it will cause problems for your car.
Even if the voltages are the same, trying to jump-start a large vehicle could be too much for a small car. Batteries have a rating called “cold cranking amps,” which shows how much current a battery can deliver in cold weather. The larger the vehicle, the more amps it needs to start. Small vehicles usually need 250-600 CCAs. A bus, truck or semi, could require around 1,000 CCAs.
Pulling too many amps from a smaller battery will cause a huge voltage drop, which can damage your battery. And if your jumper cables aren’t rated for that kind of amp draw, they might overheat, melt or smoke.
Xuyun Zeng is a content strategist with a wide-ranging content background including tech, journalism, cars and health care. After graduating with highest honors in journalism, Xuyun led a newspaper to win eight awards, helped start an award-winning film industry podcast and has written over a hundred articles about cars repair, state laws and insurance. Prior to joining Jerry, Xuyun worked as a freelance SEO consultant with a mission to create the best content that will help readers and grow organic traffic.
Alice Holbrook is an editor with more than a decade of experience covering personal finance, including car insurance. She\’s passionate about creating easy-to-understand content that demystifies intimidating topics for readers. Previously, she worked for NerdWallet, and her work has been featured by Newsweek, The Washington Post and the Associated Press, among others.
