Does Idling A Car Charge the Battery? How It Works

Does idling a car charge the battery?” is a common question among car owners who are worried about the lifespan of their battery. A battery would function longer as long as it is fully charged and controls parts like ignition and other electronic functions.

Will Idling A Car Charge The Battery

There are different ways to charge your battery, but idling seems like the most convenient one for most drivers, leading to the question, does it work? Check out our complete guide to learn more about whether idling your car will charge the battery.

Will Idling Charge Your Car Battery?

Yes, idling will charge your car battery because the alternator is getting its power from the engine and using it to charge the battery. If you are using too many electronic systems like interior lights, headlights, and stereo while idling, it will reduce the charge.

As long as everything is in working order, the alternator will charge the battery whenever the engine is running, even if it is idling. But keep in mind that idling will not charge your car very quickly because the engine has no load on it.

Mechanic Charging The Battery

The rpms produced during engine idling are much lower compared to the rpms produced when you’re driving. The serpentine belt will be spinning slowly, and this will produce less electricity to charge the battery. Also, the alternator is not designed to charge car batteries but does so by default when you’re driving, so if you’re idling repeatedly, it can affect the alternator.

If you are idling to charge your battery, you should turn off as many electrical systems as possible, like AC, stereo, and all the lights. But some electronics will come up either way, and the onboard computers will function, taking some charge away from your battery.

How Does Idling Charge Your Car Battery?

Idling charges your car battery via the alternator, which functions whenever the engine is running. Whenever the engine is running, the alternator acts as a generator that produces electricity, which charges the battery and powers all the car’s electrical components.

The alternator is a belt-driven generator that runs whenever the engine has been started. The alternator charges the battery and reverses the chemical reactions when the car is off. It also provides power to all the electrical parts of your car. The charging process converts lead sulfate to lead and sulfuric acid, and this happens repeatedly.

So, even if you forget to turn off the lights, a battery charged repeatedly won’t die. But if the engine is running, but your car isn’t moving, that means that you’re idling. The alternator won’t get enough rpms to charge the battery and the electrical components at the same time.

The battery can get enough charge to stop it from dying when you idle your car, but if you leave your lights on all night, you might have a dead car battery once you come back in the morning. So, idling your car will only charge the battery if there is enough rpm to generate electricity. But if it doesn’t, you will be wasting your time.

How Long Should You Idle to Charge Your Car Battery?

You should idle for several hours to charge your battery. Since idling produces low rpms and there are other electronics in the car that take up the power from the alternator, it would take a much longer time to charge your battery.

Based on how long it takes to charge your battery when idling, it would be a better choice to drive your car or charge it in another way. It is not practical to car idle for several hours just to charge your battery, and it can eventually cause damage to your alternator and other parts.

It is sufficient to drive for about 30 minutes to charge your battery, as it would work faster rather than idling for several hours. The engine charges the alternator faster when moving too. Some people say that you should idle for about 20 minutes to charge your battery, but this is wrong and won’t be sufficient.

Is Idling a Good Way to Charge Your Battery?

No, idling is not a good way to charge your battery because it works slowly and takes a long time. Also, alternators are not designed to charge the car battery, so if you are idling for a long time, you can cause damage to the system.

Red And Blue Booster Cables For Charging The Battery

Cars are not meant to idle for a long time. When the car is idling, the engine won’t work at its optimum temperature. This means that the fuel won’t combust well, leaving a lot of exhaust particles and residue building up on the engine. Idling for too long constantly can reduce your engine performance.

Idling to charge your battery can also negatively affect the exhaust system. It would lead to increased emissions, and condensation would form in the exhaust system. The car won’t be able to get the water buildup out of the tailpipe without driving, as moving your car produces a high airflow. This causes the exhaust system to fail, which is why you should drive your car often.

When idling, you produce more exhaust from your car than if you’re driving, which pollutes the air. It is also bad for the environment if you keep on idling to charge the battery.

What Are Other Ways to Charge Your Battery?

Other ways to charge your battery include taking the car for a drive for about 15 minutes, using a battery charger, a solar charger, a trickle charger, or jumper cables. The cheapest way is to drive your car often, and the battery will always be charged.

Mechanic Using A Battery Charger For His Battery

Drive Your Car

Going for a drive is the fastest and most convenient way to charge your battery. When you push the accelerator and move the car, the alternator belt turns faster, leading to a higher AC current which leads to a more powerful charge.

Man Driving The Car in A Beautiful Day

The only downsides to driving your car to charge your battery are the fact that it takes up all your time and it also consumes a lot of fuel. If you use your car to commute regularly, you won’t have to worry about charging your battery.

Use a Battery Charger

A sure method is to use a car battery charger to charge your battery. Modern chargers won’t overheat, charge or damage the battery, as you can set them and forget about it. These chargers know how much charge to put in your battery. If you don’t drive often, you can purchase a charger.

If you’re going to use a charger, you should check the type of battery that you have. If you have a conventional battery, you can use a conventional charger. Then, find the lead terminals on top of the battery and clean them if they are corroded or dirty. Disconnect the battery and connect the charger.

You should check the user manual of the charger that you bought and follow the specific process to charge the battery. If not, it would be easy to cause damage or injure yourself.

Use a Trickle Charger

Another option is to use a trickle charger for your car. A trickle charger is a slow battery charging device, so you can connect it to the battery and leave it overnight. It is a good method if you haven’t been using your car for a long time and the battery is dying. You can charge your car and use it the next day.

Use A Solar Charger

If you don’t have access to an outlet to charge your car and you’re out for a long time, you should make use of a solar charger. The solar charger uses the energy from the sun to charge the battery, making it convenient.

Use Jumper Cables

If your battery is dead, the best thing to do is use jumper cables. Keep in mind that if you’re not good with jumper cables, you should avoid using them as they can be dangerous and damage your car. It can also cause injury.

Jumper Cables On Battery Heads to Charge it

You should connect the jumper cables and clamps tightly to your car and to the other car. Then, you can charge the dead battery and give your car a start. After using jumper cables, you should take your car for a ride so that the battery is fully charged.

How Can You Check if Your Car Battery is Charged?

You can check if your car battery is charged by using a multimeter. A fully charged battery should measure 12.6 volts or higher if it is not in use. But if you are driving, the car should measure between 13.7 volts and 14.7 volts.

A Yellow Multimeter Showing The Percentage of Battery

If the voltage of your battery is lower, the battery has to be charged. If you’re worried about the life of your battery, you can check it with a multimeter regularly. Also, if the battery voltage is reducing drastically, there might be a problem with your battery.

Frequently Asked Questions

How Long Will Your Car Battery Last Without Driving?

Your car battery will last as long as four weeks to two months without driving. Your battery dies if you leave your car without driving it for a long time. This is because your battery is in use whether you’re sitting behind the wheel or not.

What Can Shorten The Life of Your Battery?

Not driving your car regularly can shorten the life of your battery. The car’s battery can last for up to five years, but it depends on how often you drive. Other factors that shorten the lifespan of your battery are extreme temperatures and frequent short trips.

Will the Car Battery Charge Faster When Idling Than When Driving?

The car battery will not charge faster when idling than when driving. The battery will charge its best when the car is running, as the alternator produces more than enough power to charge it and power the electrical components of the car.

How Does Idling a Car Work to Charge the Battery?

Idling a car to charge the battery is a common method used by drivers. When the engine runs, the motorcycle alternator explained earlier comes into play. It converts mechanical energy from the rotating crankshaft into electrical energy, providing a steady flow of power to recharge the battery. However, prolonged idling can also have negative effects on the engine, fuel consumption, and overall efficiency.


Now that you know the answer to the question does idling a car charge the battery, you can ensure that your car battery is fully charged.

Here’s a summary of our article:

  • Idling a car will charge your battery, but it does so very slowly, and you need to turn off all electronics.
  • Idling charges your battery because when the engine is on, it powers the alternator, which in turn charges the battery.
  • You need to idle your car for several hours before it is charged, which is why it’s a better option to drive the car for about 15 minutes.
  • Idling your car for too long and too often might cause the engine and exhaust system to become faulty.
  • Other ways to charge your battery include driving your car often or for 15 minutes, using a charger, trickle charger, solar charger, or jumper cables.

You should drive your car regularly and maintain your battery so that it does not die. While idling will charge your battery, it will do more harm than good, and so you should consider driving instead.


5/5 - (18 votes)
Ran When Parked