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Is a Car Battery AC or DC?

A car battery warning light.

NAPA The Legend Professional BatteryHave you ever been stranded due to a dead car battery? If so, you certainly know that the battery plays a vital role in getting your vehicle up and running. Given the importance of this part, it can be useful to have a clear understanding of how a car battery works, and this may lead you to ask: “Is a car battery AC or DC?”

Car Battery Basics

Before we explore whether a car battery is AC or DC, it’s helpful to understand how this essential component works.

A car battery supports your vehicle in two ways:

  1. It provides the electrical energy your car needs to ignite its engine. To ignite, the engine needs help from the starter. Your car battery converts chemical energy into electrical energy, which gives the starter the voltage it needs to fire up the engine.
  2. It stabilizes the electrical energy needed to keep your car running. Your car relies on steady voltage to stay powered, and that voltage is provided by the car battery.

What’s the Difference Between AC and DC?

The terms AC and DC describe how current flows in a circuit. But what are these two types of power, and how do they differ?

AC Power

AC stands for alternating current, and AC power is defined as a charge that periodically changes direction. The flow of this type of power alternates between positive (upward) and negative (downward). The change in direction causes the energy to move in a wave-like motion.

This motion allows AC energy to travel farther than DC energy. For this reason, an AC current is typically used to deliver electricity from a power outlet, so the power that comes from the electrical outlets in your home or workplace is AC.

DC Power

DC stands for direct current. DC power uses an electrical current that moves in a straight line. Direct current can come from a wide range of sources, including batteries, solar cells, and fuel cells. A component called a rectifier can be used to convert AC power to DC power.

Compared to AC power, DC power delivers voltage in a more consistent way, which makes it the preferred means of power delivery for electronic devices. Many DC-powered devices get their voltage from batteries, while others use a built-in rectifier to convert power from AC to DC.

Is a Car Battery AC or DC?

So, is a car battery AC or DC? All batteries operate using direct current, and this principle applies to the lithium-ion batteries that power everything from your computer to your camera. It also applies to the battery that powers your car, which is most definitely DC.

Now that you know the difference between AC and DC and how it pertains to powering your vehicle, you can approach managing and maintaining your car, and specifically its battery, in a more confident and informed way.

Check out all the car battery products available on NAPA Online, or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on car batteries, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

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Warren Clarke View All

I'm a writer and editor who's a regular contributor with the New York Daily News and Carfax, and my content has appeared in over 20 publications. I've written content that covers industries such as automotive, medical, insurance, healthcare, real estate, plumbing, pest control, dental and hospitality.

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