Updated at: 07-08-2022 - By: Lucas

An alternator and a battery are among the most important parts of a car’s electrical system. When the engine is not running, it provides electricity to all of the car’s electrical systems. While the engine is running, it is critical to the alternator’s voltage regulator working properly.

Modern automotive electrical systems necessitate the use of a battery, whereas older systems relied on generators and could operate without a battery. In the case of a dead battery, your vehicle will not be able to start, and the alternator will be forced to work even harder, potentially destroying it.

Have you ever given any thought to the fact that a battery serves so many critical functions?

So, When Does A Car Battery Charge?

Does A Car Battery Charge While Driving

When the car is running, the battery receives a charge. The battery is constantly being recharged by the alternator’s steady supply of AC electricity. When the engine is operating, the alternator generates electricity. Every time your car’s engine runs, it recharges the battery.

This assumes, of course, that the battery is in good working order. It’s inevitable that the battery will run out of juice at some point. This means that when you turn on the ignition, your car’s battery charges.

Your next logical question might be whether or not a car battery recharges when it is idling. Yes! If the battery is in good condition and can hold a charge, the battery will also recharge while the car is in idle mode again. In other words, as long as the engine crankshaft continues to turn, the alternator will keep producing AC current and therefore charging the vehicle’s battery.

How Does Car Battery Charges

When the engine is operating, the alternator charges the battery; otherwise, an external charger is used. As long as the engine is running, the alternator will charge the battery. It’s because of this that when the engine is off, using most electrical gadgets like the dome lights or radio might drain the battery, but the battery is immediately recharged when the car is started up.

Car’s powerhouse is the alternator, connected to the crankshaft by a belt. The alternator’s rotor is turned by a rotor surrounded by magnets when the car’s engine is running. Electricity from the rotor’s rotation is converted to direct current (DC) and powers the vehicle’s electrical systems and components, including charging the battery.

RPMs improve the alternator’s ability to produce electricity, and any power that isn’t being consumed by accessories like headlights is used to charge the battery. When a car battery dies, the best way to recharge it is to use an external charger.

How Long Does It Take To Charge A Battery When The Car Is Idling?

This is a common concern, especially in light of the current corona pandemic, which has left many cars idling for an extended period of time. Allowing your car’s engine to idle while you replenish the battery is a smart move. While idling, though, how long does it take to fully recharge the battery.

One expert in electric engines says that to fully charge your battery, you should leave your car idling for at least an hour. The alternator must supply power to a slew of electrical components in a vehicle. This means that the battery can only be recharged with a tiny amount of energy.

There are many variables that can affect how long it takes for a battery to charge, including the number of electrical and computer systems in your car, the amount of power voltage provided by the alternator, and the state of the battery.

Allowing your engine to idle can help to recharge your car battery, but it is not the most efficient method of doing so. It’s preferable to take the car out for a spin rather than leave it idling. It’s advisable to use an external charger to keep your battery’s voltage low while it’s been parked for a long to avoid it getting flat or dead.

How Long Does It Take A Battery To Charge While Driving?

Does A Car Battery Charge While Driving-2

So, you’ve left your car in the parking lot for too long, and now the battery is dead. How long does it take for the battery to recharge while driving after it’s been jump-started? That’s a good question. Driving your automobile for at least 30 minutes is generally required to get a large charge out of it.

To be clear: just because you can drive for 30 minutes and get some juice back doesn’t imply you should do so. Some things to consider are how much the automobile battery was depleted, as well as the battery’s overall condition and age.

If your car’s engine hasn’t been operating for a long period of time, a 30-minute drive may not fully recharge the battery. The battery will still be charged, though, and this will keep it from going dead.

When the battery deteriorates over time, it loses its ability to charge. As a result, the battery’s life is shortened. You’ll lose all power in the automobile battery no matter how long you drive. If your battery looks like this, it’s time to get a new one.


Electrical systems in automobiles are a little more involved than they appear. We do hope, however, that you now know when and how a car battery charges. Because it is only one part of a much larger electrical circuit, if your automobile battery stops charging, you simply need to get a new one. The automotive alternator, on the other hand, is the actual source of the vehicle’s electrical power, making repairs to it more costly and time consuming.