A dead car battery can leave you stranded and be a real headache. But if you carry jumper cables or a battery jump box in your trunk and know how to use them properly, you can get back on the road in a few minutes.
We go more into detail below, but if you need a quick solution, here is how to jump-start a car. If you're using jumper cables, connect the red clamp to the positive (+) post on the dead battery. There's often a red plastic cover near it. Connect the red clamp on the other end of the cable to the positive post on the working battery. Next, connect the black clamp to the negative post (-) on the working battery. Finally, you'll want to attach the last black clamp to an unpainted metal surface under the hood of the car with the dead battery, then start up both cars with the donor car going first.
If you're using a jump-starter battery pack, make sure the cords are connected to the box, then connect the red clamp on the positive (+) post and the black clamp to the negative (-) post. Make sure the jumper box is turned on. Some will have a green confirmation light to indicate that the connection is good. Start the car and it should do the trick. If not, try again and if that fails, your battery is likely completely drained.
Once your engine is running — and if the battery is still good — the alternator will recharge the battery. If the car battery dies again or the jump start does nothing, we recommend either calling roadside assistance or taking it to an auto parts store to buy a replacement battery. Often, stores will install a car battery for free, but call ahead to make an appointment if possible.
Take precautions
Jump-starting a car is relatively easy, but you should do it with caution. Since the car battery is often located in the engine compartment, where flammable gases may be present, a spark could set off a fire. The goal is to hook up the weak battery to the live battery in the booster car without creating any sparks. Connecting the jumper cables in the right order will minimize the chance of sparking.
It's important to make sure the metal ends of the jumper cables do not touch each other or any metal surfaces on the car until they are connected to the correct battery terminals. This can be more difficult than it sounds. Most areas under the hood are metal. If two people are available to jump-start a car, one person can simply hold the ends of the jumper cables safely separated, while the other person moves between the cars and makes the proper connections. One person can safely jump-start a car, but it does require close attention. With this in mind, here is a step-by-step guide to jump-starting a car.