Does Car Battery Recharge While Idling?

Cars have quite a self-sustainable electrical system integrated with their engine for battery power that takes the electricity from the car battery and even charges it back while the car is running. So does car battery recharge while idling?

Yes, your car battery automatically gets charged while your engine is running but the car isn’t even moving. This is because of that exact same self-sustainable charging system. In a deeper but simpler explanation, that is because of the alternator that provides power to your car battery while the car is idling. Please read further to know about it more in detail.

Does car battery recharge while idling?

Yes, a car battery keeps continuously charging while the car the idling. This happens when you turn on the engine of the car and let the alternator function properly. It is because battery charging from your car’s engine is the responsibility of the alternator in your engine.

It doesn’t require keeping the car to move as just keeping your engine turned on is enough for it. Now, this is not so important question as there’s more to it. So let’s dig deeper into the topic in the article ahead.

How is acar battery charged?

Knowing that your car battery charges while idling are equally important as you should know how it happens and how other electrically powered things run on a car. When a car starts, the ignition system of your car takes the first bit of a small spark from the battery to turn the engine on and start combusting.

After that, your car’s engine runs on its own combustion and uses gas as fuel. So it can only stop if your car runs out of fuel or there’s any other problem also you can stop it by turning it off with the keys. Other than that, the engine doesn’t stop nor does it take any more electrical energy from the car battery.

Here’s the thing car engines have a serpentine belt and when the engine runs, it runs that serpentine belt as well. Now, what does that serpentine belt do? That serpentine belt runs and powers up the entire electric portion of your car on its own without taking any help from the battery.

So your headlights, taillights, indicators, radio, and AC is getting power from that belt now. But another important thing that belt is responsible for is charging your battery and that happens with the help of an alternator. Hence, now your car’s serpentine belt is running every single electrical part of your car on its own and even charging the battery.

What is charging the battery in a car?

So the above explanation was about the entire electric system of any car. But if we talk about the battery specifically, then a major role in charging the battery is played by the alternator. This is because a serpentine belt will run as the engine runs and it will power the entire system.

But charging a battery requires an alternator to be there to make the electric power enough to store in the battery.

An alternator is basically an electromagnet that runs on the serpentine belt and eventually on the car engine. According to good performing records of the alternators, an alternator should be producing at least 14-15 volts of electricity.

And this can be in waves but on average the electric power should meet this requirement. Otherwise, even if the alternator is producing 13 volts of energy, it isn’t enough and you should think about changing it as soon as possible.

Now here comes the question of how much can an alternator cost and which alternator is best for your car. But let me tell you something it totally depends on your car’s manufacturer.

This is because the manufacturers decide to what extent should your car battery perform and what are the battery’s requirements for that. Meanwhile, once the engine is started, the car doesn’t need any more power from the battery and starts acting like a gas-powered generator.

So, does the alternator charge your battery while idling?

As we have already told you about it that when your car is idling and your alternator is running fine, your battery will be charging. It happens because of good physics concepts that when the engine is running the serpentine belt runs at the same time even without the car moving.

Simultaneously that serpentine belt runs the alternator that then generates electricity and provides to the car’s electrical components and the battery as well.

Now you may think that speeding up your car will make the engine run faster and eventually more electricity will be produced. This argument is quite logical to some extent but still, it needs to be clarified that this doesn’t affect electricity storage and usage.

This is because the electricity produced by speeding up your car is then regulated by the ECU of the car.

So no matter how you speed up the car only a fixed amount of energy is supplied to the engine and battery. Hence proved that even when the car is idling, the engine is still running and the alternator provides the same amount of electricity to the battery and other parts.

Conclusion

Does car battery recharge while idling? So it is clear that because of the simple yet complex physics, your car battery is always in charging mode when the car is idling. This is because of the alternator and the serpentine belt that runs the alternator.

And another important thing is that there is a misconception about high-speed driving that it recharges the battery faster. This is not true because the ECU regulates the power generated from the alternator and delivers only about 14-15 volts of electricity if the alternator is new or in good condition.

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FAQs – Does car battery recharge while idling?

Does running a car at an idle charge the battery?

Yes, when the car is idling the battery will still be recharging itself from the engine power generated by the alternator. But as common sense, these modern-day cars come with a lot of electrical components that use power to run.

Therefore, if the car is idling, it will not charge the battery at the same amount of power but very lower than that of while you are driving.

Can a car battery recharge by sitting?

Yes, a car battery can be recharged only by sitting if put on charge for like twenty-four hours. The process is slower and time taking but it doesn’t matter if you are just parking your car in the garage for a day or two.

It requires special kinds of chargers for that which you can buy from any local auto parts store. Also, these chargers are pretty affordable as well.

How long can a car idle before the battery dies?

A car can sit idle for like a month or two depending on your battery and its condition before the battery dies. This is mainly because of the fact that even if you are not driving your car or have not even turned on the AC or radio, still the battery is in use.

Hence, the battery dies eventually if you don’t drive the car or at least turn it on for two months at most because the battery is discharging continuously.

Does the revving engine in the parking charge a battery?

Well, this is a bit complex question because there are multiple opinions about that. Some say that when you rev the engine, your car’s engine crankshafts rotate a lot faster even when you’re parked.

So when they rotate so fast, it generates more electricity by converting more mechanical energy into electrical energy. But a few mechanics believe that this doesn’t affect electricity generation. Although we’ve talked with the engineers about it and they also believe that revving does generate more electricity in a car engine.

How long does a car battery take to recharge itself?

A regular battery of 4-8 amperes of requirements for electricity will take around 10-24 hours to fully recharge. But this time interval is for charging your battery to the fullest. On the other hand, if the battery is needed to start the engine at first, then the battery will still need to be charged for at least 2-4 hours.

This is just for the battery to be able to start the engine by turning the ignition on. Otherwise, charge the battery slowly so that the battery life and performance can be prolonged as much as possible.