Jumping a Car Battery

If you are faced with a dead car battery, you might be able to jump start the car. This is usually the case if you accidentally left your lights or another accessory such as your car stereo on overnight. Jumping a car battery is not overly difficult, but it is not always possible or advisable.

Make sure you check your owner’s manual before attempting a jump start. Most vehicles can be jump started, but if your car is equipped with an electronic ignition system or other fragile electronic components, your owner’s manual may specifically warn you not to use jumper cables . If your manual advises against jump starting, you will have no choice but to buy a new car battery.

You also want to inspect the battery itself before attempting a jump start. If there are bulging areas or cracks in the case, you should replace the battery instead as the risk of an explosion is too great to try jump starting. If you have a battery with an “eye” or window and you see yellow, your battery will not accept a charge and needs to be replaced.

Safety First When Jumping a Car Battery

Car batteries are not like the AA batteries you put in your TV remote. Car batteries store electricity, are filled with sulfuric acid, and can explode. They require much more care when handling or working with them.

Metal jewelry like rings or bracelets can cause a short circuit or create a spark so remove all your jewelry before you go near the engine. If you have long hair, put it up. Do not wear loose clothing around an engine that is running.

Eye protection is extremely important when working with a car battery. Sunglasses or eyeglasses are not sufficient. A pair of safety goggles offering protection from the front and on the sides are a must. If the battery explodes, sulfuric acid will be released and fragments will be sent flying. You can be blinded or seriously injured without eye protection if the worst were to happen.

How to Jump Start a Car Battery

Jumping a Car Battery - How to Jump Start a Car Battery

Jump starting a car battery requires both a set of jumper cables and another vehicle. Driving around without a road emergency kit which includes a set of jumper cables is not a good idea. Especially if you live in a cold climate or drive an older car. If you don’t have jumper cables, it makes it a good bit more difficult to get help. You need another person willing to help you out who can also provide jumper cables.

Once you have a set of jumper cables and a healthy car to help you, position both vehicles so that the batteries are as close together as possible but make sure that the vehicles are not touching. Put both vehicles in Park or Neutral for manual transmissions and shut off both engines. Apply both parking brakes and pop both hoods open.

Now you’re ready to connect the jumper cables. Positive is red and negative is black. Attach one of the positive clips to the positive terminal on the car with the dead battery. The positive terminal is identified by a plus sign (+) or it may say POS on it. The positive terminal may also be clearly bigger than the negative terminal. Attach the other positive clip to the positive terminal of the good car’s battery.

Attach one of the black clips to the negative terminal of the good car. Attach the other black clip to an unpainted metal surface on the car with the dead battery away from the battery in order to ground it. Do not connect that last cable to the free battery terminal. Doing so could cause a spark, which could in turn cause your battery to explode.

Try starting the car with the dead battery. If it fails to start, start the good car and let the engine run for five minutes or so then try to start the car with the dead battery again. If it still will not start, you may be out of luck and in need of a tow truck, unfortunately.

If you are able to get the low battery car started, do not turn it off. You will want to drive around or leave the car running for at least twenty minutes to half an hour. Be aware that it can take significantly longer, like a few hours, to get the low battery back up to a full charge. This is especially the case during the winter when headlights, the heater, the defogger, and heated seats may be in use making it harder for the charging system to power everything and recharge the low battery at the same time. If you have a battery charger available, you can remove the battery from the vehicle and ensure that the battery gets fully charged.

Disconnecting the Jumper Cables

In an ideal world, you would be able to shut off both cars and remove the jumper cables. Because you are recharging a low battery that might not have enough power to start your car if you shut it off, that’s not very realistic. So be extra cautious when removing the jumper cables as you will be working around a running engine.

Carefully remove the jumper cables in the reverse order in which you put them on. Remove the negative (black) cable from the unpainted metal surface of the low battery car first. Then remove the black cable from the full battery car. Remove the red cable from the low battery’s positive terminal. Lastly, remove the red cable from the full battery.