Inevitably, it will happen to you – and never at a convenient time. You need to go somewhere, you get in your car, hit the ignition, and nothing happens – not even a click. Sadly, you’re the victim of a dead battery. If you’re in luck, either you had the foresight to keep jumper cables in your trunk, or you’ll find someone who has a set. So now you can turn a potential headache into a minor annoyance. Jump start your car and be on your way. Just be sure to do it safely. Here’s how:
First, open your hood and check the condition of your battery. Look over the casing to make sure there are no cracks. Protecting your fingers from either grime or battery acid, use a piece of paper to lightly wriggle each battery post to make sure they have not broken loose. If one or both terminals is heavily corroded, use a cloth to wipe the corrosion away. [If you are at home, it would be a good idea to clean corrosion away. You can do this with a wire brush and a solution of baking soda and water. Pour the solution over the terminal and brush away the corrosion. Then use clean towels to wipe the top of the battery and the terminals dry. This will ensure a good connection when you jump start your car.]
Next, check your jumper cables. If there is any corrosion on the clamps, clean them in the same way as you did your terminals. Now, check the polarity of your cables. Most cables designate positive (+) with a red handle and negative (-) with a black handle. When you make your connections, you will want to be sure that these match up properly. Note: Some older cars – particularly British cars – are positive ground. So long as you keep the polarities correct, this does not matter.
Now it is time to make your connections. Position the boosting car close to the car with the dead battery. Do not let them touch. Turn off the ignition and all accessories for both cars. This is the step where you must take the most caution, because there is potential for sparks to ignite flammable gases. So you do not want any active electrical circuits. It is a good idea, if you have one, to lay a towel over your battery to “absorb” any gases the battery may emit. But make sure no loose ends come near any moving parts.
Next, set the parking brake in both cars and place both in either park (P) for an automatic transmission, or neutral (N) for a manual transmission. Now attach the jumper cables. Be careful to not let the ends of the jumper cables come into contact with one another while making your connections. At the very least, you will get a “shocking” surprise; at the worst, you could damage a battery. Follow this sequence:
1. Connect the positive cable clip (red) to the dead battery’s positive terminal.
2. Connect the other positive cable (red) to the boost car’s positive terminal.
3. Connect the negative cable clip (black) to the battery’s negative terminal.
4. Finally – and this is important – do not make your final connection on the negative terminal of the dead battery. Instead, attach this clip to a bare piece of metal – a bolt or a strut – of that car. This is your ground – or earth – connection.
Note: As referenced earlier, some cars are positive ground. In this case, connect negative to negative, attach one cable to the boosting car’s positive terminal, and then ground the other positive cable to bare metal on the receiving car.
Start the engine of the boost car and let it run for a couple of minutes to charge the dead battery. [Some car manufacturers advise you to not run the engine of the boosting car because, if a connection is broken, you could damage the electronics in one or both cars. Check your owner’s manual to see if they warn against this.] One way to see if the dead battery is charging is to turn on the dome light in the receiving car. If it lights, then the battery is getting sufficiently charged.
Try starting the car with the dead battery. If it does not start, rev the engine of the boost car, let it run for a minute or two, and try again. Once your engine starts, let it idle for a few minutes to charge the battery. Then disconnect the jumper cables in the reverse order to which you connected them. Again, be careful to not touch the ends of the jumper cables to anything while you do this.
That’s it! You’ve turned a major headache into a minor inconvenience. Now you can go on with your day.