Can Car Batteries Recharge Itself? (Explained)

Cars have a lot of components to run themselves properly. Among all of the components it has, every car has a battery to power various car components properly. As a result, the charge level of a car battery may decrease over the course of time.

You may question whether a car battery recharges itself. Let us help you answer this question and provide you with some necessary information regarding this matter.

Can car batteries recharge itself?

Car batteries cannot recharge themselves. The battery in the car does not have any way or feature to recharge itself without the help of an external component in the car which is known as the alternator. The battery itself cannot recharge its cells because it was not designed to do that.

A car may have a battery inside the engine compartment. The main objective of this battery is to start the engine. The engine needs a jumping voltage to start itself. This voltage is provided by the battery inside a car’s engine.

Besides, starting the engine of a car, the battery of a car helps run other electrical components, power the headlights and other lights of the car while the engine is not running, run the media player in the car and many more.

Even after powering so many car components, it requires a small amount of electricity to run all of them. But the battery in a car cannot charge itself. It needs the help of the alternator to charge.

You may ask if a car battery can charge itself in a few popular scenarios of using the car. Let us discuss those common scenarios and understand if a car battery can charge itself or not and the reason behind it:

While driving:

A car battery cannot charge itself without the help of the alternator while driving. The cylinder’s motion helps the alternator create electricity and charge the car battery. 

After being drained:

After being drained, a car battery cannot recharge itself. A completely drained battery cannot recharge with the help of an alternator as the battery does not have any healthy cells to recharge.

Overnight:

A car battery cannot charge overnight by itself. A car battery does not have any feature to create electricity overnight. Moreover, the alternator cannot generate any electricity to recharge the car battery as the engine is turned off.

Can a flat/drained car battery recharge itself?

No, a flat/drained car battery cannot recharge itself. Any car battery cannot recharge itself as there is no component or feature in a car battery to help it create electricity by itself. Any car battery takes the help of an alternator to recharge.

But a flat/drained car battery cannot recharge itself. But there are ways to recharge a flat/drained car battery. You may jump start the car using any external power source and drive the car. 

This will help the flat/drained car battery to be recharged by the help of the alternator in the engine.

Another way to recharge a flat/drained car battery is to use a special kind of charger. It is known as a car battery charger. Using that charger, you can recharge your car battery. 

Both methods may require the help of an expert mechanic if you do not know the appropriate ways to perform them. You may have to consider calling in an expert for help.

When does a car battery charge itself? How long can a car battery recharge itself?

A car battery does not charge itself. A car battery does not come with any unique feature to produce electricity for itself. It uses the electricity stored in it and when the battery is empty, you will have to recharge it by yourself.

Although a car battery cannot recharge itself, it takes the help of another component called the alternator. This is available in the engine of the car and helps to recharge a car battery when you drive your car.

A car battery cannot recharge itself, but with the help of an alternator or car battery recharger, it may take around 10 – 24 hours to recharge fully. A car battery cannot recharge itself without the help of an alternator. 

If you need to just start your car, you may charge your car battery for 2 – 4 hours or even jump start your car.

Why do batteries come back to life if you let them rest?

You may find that your entirely drained/flat battery may come back to life after resting it for some time. It is common to see such a thing in car batteries and is known as the ‘self-recharging’ feature. 

Although this is not an appropriate way to recharge a car battery, it can be helpful to recharge your battery to some extent with the help of simple chemistry.

To understand how this happens, you will have to know how the battery works. For example, zinc/carbon batteries are common. While you use the battery, the battery will create a flow of electrons which will help you power the devices that are connected. 

Hydrogen gas builds up in the robs of the battery.

This hydrogen gas blocks the reaction of the battery, which makes it create electrons and makes it look like the car battery is flat. But while resting, the gas dissipates and the battery comes back to life as the blockage is gone.

The same thing occurs in car batteries which are lead batteries. The two poles get blocked by the product created while using the battery. When the battery is given a chance to rest, the products dissipate and blockage between the poles disappears. 

Therefore, the car battery comes back to life.

What’s required to recharge your car battery?

There are many ways to recharge your car battery. Based on the method that you will apply, the requirement of recharging your car battery will vary. Let us discuss some popular ways to recharge your car battery and requirements for those methods:

Use the car alternator:

The alternator of your car is the traditional way to recharge your car battery. This is the built-in recharge method in a car. To recharge your car battery using the alternator, you will have to drive your car for some distance. 

This will require you to consume fuel and time as well.

Connect to a car battery charger:

You may use a car battery charger to recharge your car battery. There are some specific car battery chargers available in the market which can provide the necessary amount of voltage required for your car battery to recharge itself. 

This will require you to get a hold of a car battery charger or visit the nearest car shop to get it recharged.

Use a doner battery:

Recharging your car battery using a doner battery is also a popular way to recharge your car battery. 

This will require a doner car battery from another car which has to be fully charged and has to provide the same voltage so that your car battery can charge swiftly and safely.

How does a car battery charge itself?

Car batteries cannot recharge themselves. The batteries do not come with any feature that can help them charge itself. 

Although some may say that a car battery has a ‘self-recharging’ feature, it is just a simple gas buildup between the battery nodes, which is actually not a feature.

But car batteries can recharge themselves with the help of an alternator. An alternator is a part of the engine that helps to recharge the car battery. You may ask how it recharges a car battery. Here are the steps that it follows to recharge a car battery:

Turn on your car:

To use the alternator to recharge the car battery, you will have to start your car first. If your battery is flat/dead, you may jumpstart your car by using a doner battery or a different car that has a good battery.

Drive your car at a constant speed:

After you start your car, you will have to drive your car at a constant speed. The constant speed will help the belt in the engine to move at a constant rate. 

This will help the alternator to get the necessary motion to work and the necessary mechanical power to operate.

The mechanical energy will convert to electrical energy:

As the belt moves, the alternator will convert the mechanical energy and convert it to electrical energy. The electrical energy that is created is small in amount. But enough for the car battery as a car consumes a tiny amount of electricity. 

The electrical energy that is produced will be stored in the car battery.

Final Thoughts 

A car battery cannot recharge itself. It does not have any feature to help it produce electricity to recharge itself. It takes the help of the alternator of a car to recharge itself. If the alternator is faulty, you will have to recharge your car battery from any external electrical source.