When a battery loses its charge then the vehicle won’t start and it becomes necessary to use another vehicle for a jump start. Since jump starting a failed battery with a charged battery involves creating an electrical circuit, it is important follow the right steps to perform a jump a dead battery safely:
- Do your best to line up the vehicles so that the two batteries are close enough to connect jumper cables.
- Turn off the active vehicle
- Verify there is no odor (like sulfur) coming from either battery. If there is a sulfur odor do not attempt to jump start the vehicle. The battery could explode due to the gas that is released (hydrogen gas).
- The next steps involve connecting the cables. When connecting cables to the first vehicle, which is the dead vehicle, make sure the other ends of the cables are not touching each other.
- First connect the red cable to the positive (red) battery terminal on the dead battery or to the jump start locations specified in the owner’s manual.
- Connect the black cable to the negative terminal of the dead battery or to the jump start locations specified in the owner’s manual.
- Connect the positive (red) cable to the positive terminal of the working vehicle (or to the specified jump start location in the owner’s manual of the working vehicle).
- Connect the negative (black) cable to the negative terminal of the working vehicle (or to the specified jump start location in the owner’s manual of the working vehicle) or to anything metal. The metal must be bare or without any paint that would inhibit conduction of electricity. The engine block is sufficient. Yet, the negative terminal is often the most accessible.
- (More briefly the order is: dead red, dead black, live red, then live black. Red is always positive, black is always negative.)
- Start the working vehicle and allow it to run for approximately 5 minutes.
- Attempt to start the other vehicle. If the vehicle fails to start, there may be additional problems or the battery is no longer rechargeable.
- Take off the cables in reverse order (always remove negative first) and make sure the cables don’t touch each other as you’re removing them
- Removed the negative cable from the jumped vehicle
- Remove the positive cable from the jumped vehicle (make sure they don’t touch each other)
- Remove the negative cable from the previously working vehicle
- Remove the positive cable from the previously working vehicle.
That may seem like a lot of steps above to memorize, so here are some tricks to remember the process: first connect the Dead Red, Fred. This phrase will help you remember that when connecting the cables you’ll start with the positive cable on the dead battery. The order is dead red, dead black, live red, live black. Then it’s the reverse order to remove the cables after the dead battery is jumped: first remove the Jumped Black, Jack. Remove the jumped black, jumped red, then the previously live black, then the previously live red.
Never attempt to jump a dead battery in a diesel vehicle. Since a diesel engine battery requires much more power, attempting to jump start it could damage the running vehicle.
Typically you can attempt to jump a dead battery in a hybrid car, but if the high power battery is dead, the vehicle will not start. A hybrid can be used to jump start a regular gasoline vehicle.
How to Jump a Dead Battery is an original article from Crawford’s Auto Repair. Copyright © 2014, Jeff Crawford. Permission is granted to republish this article (text only) for personal or commercial use as long as the content, citation, and copyright notice all remain intact and unchanged. There must be an active “follow” link to CrawfordsAutoService.com. Any image seen with this article is the property of it’s respective author and requires it’s own permission.
How to Jump a Dead Battery is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.
