Of course it’s going to happen in the pre-dawn darkness, on a winter’s day when you’re late for work: you grind the starter button, but all you get in return are a few faint clicks, or not even that. But never fear, with the aid of a neighbor’s – or your spouse’s – car and a set of jumper cables, you can jumpstart that dead battery and be on your way in minutes.
Even if you’ve never done it before, you can jumpstart a battery. Just be careful to remember that if either vehicle has an electronic ignition system or is an alternatively fueled vehicle, the use of jumper cables may damage it!
Your “helper” driver may carry jumper cables, but you really need to get your own and keep them in your car. Look for ones that are 4 to 6 gauge in size and at least 20 feet in length – the heavier cables and heavy-duty clamps will be more durable and provide a better connection, and because it’s not always possible to place vehicles right next to each other, having longer cables will ensure the batteries can reach each other.
When handling jumper cables, keep the red and black clamps from touching, and try to have one person at each end to make the connection so as to prevent the clamps from touching. If the clamps do touch when they are hot, you could cause a short and create some dangerous sparks in either vehicle or both.
First, make sure the running vehicle – the “helper” car – with a good battery is parked next to your dead vehicle. Open the hood of each car and find the battery location. Sometimes there’s a plastic hood covering the battery or the battery posts; you’ll need to remove it to access the posts
Now, determine which post is positive (+) and which is negative (-). The positive post may have a red cable attached, but it’s best to look for a plus or minus sign to determine its polarity.
Brush away any dirt or gunk from the posts so you can have as clean and solid a connection as possible.
First, connect one end of the red clamp to the positive post on the dead battery. Then connect the matching end of the red clamp to the positive post on the functioning battery.
Next, connect the black or negative clamp to the negative terminal on the good battery. Then – and not everyone understands the importance of this – instead of connecting the remaining negative clamp to the dead battery, find an unpainted engine bolt or piece of the vehicle’s frame and secure your clamp to that. This will ensure a safer jump situation.
Ladies and gentlemen, start your engines
Now, start the functioning vehicle first, then try to start the dead vehicle. If your vehicle fires up and your jump was successful, leave it running while you carefully disconnect the cables, making sure the clamps don’t touch. Keep your vehicle running until you’ve reached your destination, which will give it ample time to recharge so you aren’t stuck again with a drained battery.
If, however, the interior lights come on and you hear the engine turn over but it won’t start, then you may have another issue. Use a multimeter to test your battery voltage. It varies with vehicle types, but it should read slightly more than 12 volts when the vehicle is turned off. If your battery is in good shape, then it’s time to troubleshoot other issues.
And that’s a job for a mechanic. Might as well take the day off.