How Does an Auto Battery Charger Work?

Batteries: Electricity stored and restored

Automotive batteries are devices that convert stored chemical energy into electric voltage. A battery charger is a device that reverses the process in a way that ensures the long life of the battery and prevents dangers that come with charging too quickly.

Turning one kind of power into another

The electricity that comes out of your wall socket is entirely wrong for your car battery: its voltage is too high, it has too much amperage, and it is Alternating Current --- not the Direct Current the battery requires. That's what a charger does -- makes a safe supply of electricity to feed a hungry battery.

Rectifying the problem

The A.C. electricity from your outlet is run through two devices that convert it to the correct D.C. voltage. A transformer changes the voltage from 120 to 12, and a rectifier converts the electricity from A.C. to D.C. The amperage, the strength of the current, is set by other part of the charger.

Amped down

In all battery chargers, the strength, or amperage, of the 12-volt current to the battery is reduced so that the battery does not overheat, explode, or become damaged. The longer the battery takes to recharge, the better it is for the battery.

Types of Chargers

Battery chargers come in a variety of styles and prices. Some simply deliver a current, some use a timer to stop charging, and others use advanced electronics to detect when a battery is done charging.