Does A Car Battery Charge When Idling?

If you plan on charging your car battery, but you don’t want to drive, then you may be wondering whether the battery will charge when it’s idling. In this article, not only will you find out the answer to the question, but you’ll also learn much more! Such as how the battery gets charged, why idling may not be ideal, can the battery die while idling, and whether driving or idling is better!

So keep reading to find out everything you need to know!

Does A Car Battery Charge While Idling?

YES! If you leave your car idling, then the battery will be charging. However, the rate at which the car charges is going to be far slower than if you were driving your car because the RPM of idling compared to driving is a lot less.

Why You Should Avoid Idling Your Car To Charge It

You may think that you can just idle your car from now on to charge it up. But in fact, this probably isn’t the best idea, especially with newer cars. Here are a few reasons that you should avoid trying to charge your car through idling.

It May Still Not Produce Enough Power For Your Cars Needs

While this may not be a problem in older cars, newer cars tend to require more power as they have battery management systems in place that are designed to extend the battery’s life. However, this technology is a double-edged sword because it also makes it a lot more difficult for your car to charge at lower RPMs.

As well as this, if you’re using any of the electronics in your car, then this can also cause the car to use more power than it can produce, so you may just end up wasting your time.

The Engine Could Be Damaged

Another reason that you should avoid idling your car is that the engine could end up becoming damaged as well. Cars aren’t meant to sit idle for long periods of time, so the longer you leave them, the more carbon can build up under the hood. This can result in a lack of performance and overtime complete component failure.

Oil Will Be Used Up & Get Contaminated

One of the ways a car’s engine protects itself is by circulating oil around itself whilst running. If you’re keeping your engine idle, the oil will be used up even though the car isn’t going anywhere.

Condensation Buildup

When you drive, high airflow is created, which helps your car blow out any buildup of water that can occur in the tailpipe. However, when you’re just idling your car, the condensation will be able to buildup a lot more. Over time, this will cause the tailpipe to rust and eventually fail.

Wasting Gas

Of course, it goes without saying, if you’re just idling your car, then you’re going to be wasting gas. In fact, idling your car can use up to half a gallon of fuel per hour. So if you’re idling it for 20 minutes or more, a good amount of fuel is going to be used up.

It’s Bad For The Environment

And lastly, if you’re idling your car, it’s not great for the environment. Your car will be producing emissions for no reason, which contributes to air pollution, decreasing the air quality. In fact, sitting in one spot for an extended period of time whilst idling can have a direct impact on the air around you.

Male mechanic changing car battery

Can A Car Battery Die While Idling?

It’s more than possible for your car battery to die while you’re idling. If you have a lot of electronics running in the car, such as a heater, lights, and the radio, then the battery may end up getting drained faster than it can charge.

As well as this, if it’s cold outside, then the battery’s performance will already be affected, increasing the chance of this happening even further.

How Long Will A Battery Take To Charge While Idling?

If you still plan on idling your car to charge the battery, then you may be wondering how long it’s going to take. Of course, it all depends on the car, the level of charge currently in the battery, and any issues that your car may have. But if you do plan on idling your car to charge it a lot, it’s going to take hours.

As well as this, the battery may still not reach a full charge from idling alone. So it’s much better to take the car out for a drive or use a battery charger instead of trying to idle your car back to a full battery.

How Long Does It Take To Charge A Battery While Driving

When compared to charging a car while idling, driving provides so much more energy. In fact, it only takes around 30 minutes of driving to charge your battery up enough that you won’t need to worry about the battery dying completely.

Will Your Battery Charge In Neutral?

As long as your car is on, then the battery will slowly begin to be charged by the alternator. When you turn your car on, the alternator will turn on too. When this happens, the serpentine belt will begin turning, producing energy that your battery can store.

Will Revving The Engine Help The Battery Charge Faster?

If you rev the engine of your car, then the serpentine belt will move faster, producing more energy. So yes, revving the engine will increase the rate at which the battery is able to charge up. However, remember, even when this is the case, it’s still going to be nowhere near as fast as charging the battery through driving or with a battery charger.


As you can see, while it is possible for you to charge your car’s battery at idle, it’s definitely not the best solution. In some cases, the output of the battery will be higher than the rate at which it’s being charged, so the battery may still end up dying. And even if it doesn’t, leaving the engine running long enough to give the car any meaningful charge is still terrible for the battery!

So your best bet is still using a battery charger or driving the car!

If you liked this article, make sure you check out the rest of the website. Otherwise, have a great day!

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