Is A Car Battery AC Or DC?

Batteries are essential in our everyday life, from powering touch lights, remotes, and cars. They are ways of transferring power from one point to another. There are two types of batteries depending on voltage, AC (alternating current) and DC (Direct Current). As a car owner, you may be wondering what kind of battery does your car use and what is the difference between the two?

All batteries run on Direct current as there are no AC batteries.

To understand the car battery better, let’s examine what AC and DC mean and whatever benefits they may have.

Understanding the difference between AC and DC


As the names suggest, AC produces a current that is alternating in nature, which means it can cyclically change its direction. The current alternates between positive(upward) and negative (downward), which causes it to move in a wave-like motion. The alternating flow aid efficiency and allows it to travel faster than DC. It has made it ideal for delivering electricity to a power outlet. Most of the household electricity outlet runs on Alternating current.


Direct current is the current flowing only in one direction or a straight line. It means it has a constant voltage and polarity. Because the voltage is stable, it delivers power for many electronic devices such as laptops, television, and microwaves. It makes it easy for an electronic circuit like transistors to properly function as they will not be affected by other currents running through them. 

brand new car battery

Is a Car Battery AC or DC

The car battery runs on a direct current because the current flows in one direction, which is ideal for car mechanics. The DC electricity can be converted to chemical energy stored in the battery as batteries are chemical-based. The battery cannot store AC energy as the average voltage in a complete cycle will be equal to zero. It is, however, possible to convert AC power to DC power using rectifiers. It is seen in the case of a car system where the alternator charges the battery. The alternator produces AC passed through a rectifier and converted to DC before reaching the battery.

The upsides of using DC

There is some benefit that DC has over AC which makes it preferable for use in our electronics gadgets. Some of them are listed below:

  • DC Helps lessen carbon emissions and lessen the effect of environmental disasters
  • DC provides constant voltage and current
  • DC offers high efficiency at a lower cost
  • DC can transform chemical energy into mechanical energy.

Why the battery can’t store AC energy

AC is alternating current, flowing from positive to negative. Ir helps for better transmission of power. However, as the current switches, the positive phase charges the battery while the negative phase discharges it. It will be impossible for such a battery to hold a charge. 


Both AC and DC are useful based on the requirement of the appliances that will use them. However, it can be seen that all batteries run on direct current. Even though the alternator produces AC, it is converted by a rectifier to DC and stored in the battery. The use of DC is prompted by its ability to travel in a straight line and one direction. Car batteries use a chemical reaction to generate electricity and can not produce alternating current because it changes polarity. 

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