A dead car battery can be a nightmare if you are unprepared, but knowing how to properly use jumper cables can quickly get you back on the road. As car batteries get old, they lose power and a battery’s cold cranking amps, or CCA, may start to drop. A 635 CCA battery that has lost 25% of its power may not leave you stranded right away and therefore you may not know it’s going bad, however, one good cold snap in the weather and your car won’t start.
If you’ve planned ahead, you’ll have a set of jumper cables somewhere in your car. If you don’t, I suggest you get a pair before you need them. It will save you the hassle of having to approach eight different strangers before you find someone who does have cables. Having jumper cables of your own will most likely allow you to rope in the first person you see. Many people want to save the day, but few are actually prepared to do it.
Once you’ve recruited a motorist with a functioning car, have them park their car nose to nose with yours. If this is not feasible, have them pull along beside you as close as possible. The longer your jumper cables the easier this will be, so when purchasing yours go with a pair that’s 16 foot or longer. With hoods raised and the engine of the good car running, it is time to start connecting the cables.
Take a moment to look at the posts and make sure you understand which is positive (+) and which is negative (-). Now connect one red clamp of your jumper cables to the positive (+) post of the good battery. To be safe and make sure that you are not yet completing a full circuit, make sure that no clamps accidentally touch each other. Now connect the other red clamp to the positive (+) post on the dead battery. Then connect the black clamp to the negative (-) post of the dead battery. Last, connect the remaining black clamp to an unpainted metal surface or bolt of the engine of the car with the good battery rather than the negative (-) post of the good battery. This will serve as ground and complete the circuit, but will minimize the chance of an exploding battery. At this point you will probably hear a slight change in the sound of the running engine. This is fine.
Allow the good battery car to run for a few minutes while connected to the dead battery. After a couple of minutes, attempt to start the car with the dead battery. Once it starts, remove the jumper cables in the reverse order that you put them on, starting with the ground connection, the black clamp connected to the metal surface of the car with the good battery. Then the black jumper cable clamp on the negative (-) on the dead battery. Next the red positive (+) on the dead battery. And last, the red positive (+) on the good battery.
A smart thing to do before parting ways with your car battery hero is to test the dead battery and see if it can now start the car on its own. Let the car with the dead battery run for several minutes after taking off the jumper cables so that the alternator can charge it for a bit. Then, shut the car off and attempt to start it again. Once it starts, you should be set, but take the car to a local parts store as soon as possible for a battery testing. Most places will test it for free and let you know if it is time to replace the battery.