As anyone who ever had their car battery die on them when they least expected it could tell you, having a car battery charger can make all the difference. A car battery charger, sometimes referred to as a jump pack or a jump box, can be one of the most useful tools to keep in your vehicle. Having your car battery die at home is one thing, but if you're ever out somewhere else and walk out to a car that won't start, you'll wish that you would have gotten a car battery charger as soon as you were able to drive!
A car battery charger is a way to jump your car — we'll get into more detail on jumping later — without having to find jumper cables or finding another person who's willing to let you use their vehicle. It's a portable box that you can just keep in your trunk, and it has two cables, just like jumper cables, that attach to the posts on your battery to give it a boost.
Many car battery chargers also have a plethora of other excellent features other than just charging or jumping your battery. One of the best additional features of a high-quality jump box is a built-in air compressor and airline. This could prove invaluable if you were to ever walk out to your car and see a tire low on air. You can simply twist the airline onto the valve stem of your wheel and power it up. A second feature that many units will have is a bright LED light that you can turn on to help you see and help other drivers see you.
Now that you know what a car battery charger is, let’s take a more detailed look into how you use one. While some car battery chargers will be different from others, the general method of using one will be about the same.
Unfortunately, if you find yourself in a situation in which your car battery is dead, but you don’t have a battery charger, you’ll need to get your car jumped the old fashioned way. Jumping a car is so named because you’re jump-starting the vehicle by giving it a burst of power from another car’s battery. Luckily, jumping a car is much the same as starting your vehicle using a battery charger, so it’s easy to understand how to do both.
To just a car, you just need a set of jumper cables and another person's vehicle. Keep in mind that when you attach and eventually detach the clips if both the negative and positive is attached to the donor vehicle's battery, there will be current flowing through the cables, and you should be careful!
First, attach the red/positive clamp to the car’s positive post with the dead battery. Next, attach the other end of the red cable to the positive post on the donor car’s battery. With both the positive ends attached, the wires are not grounded, and there is no current flow through the cables. The next line to connect is the black end to the negative post of the donor vehicle. The battery is then grounded, and you should be careful with the other end of the black cable — don’t let it touch the positive end! You can then attach the last cable to an unpainted metal location on the car with the dead battery to complete the circuit. Once you do that, start the donor car and let it idle before you get in the car with the dead battery and start it up!