How Long to Idle Car to Charge Battery

Last Updated on March 12, 2023 by Ryan

Idling a car to charge the battery is generally not recommended as it can be damaging to the engine. Generally, you should only idle your car for around 10 minutes at most before turning it off and restarting if necessary. It’s also important to make sure that the alternator is working properly; if it’s not, then idling will be ineffective in charging the battery.

If your alternator is functioning properly but you are still having difficulty starting your vehicle, try jumping it with another car or using a portable jump starter device instead of idling.

If your car battery is running low on power, you may be wondering how long to idle the car in order to charge it back up. The answer depends on a few factors, including the age of your battery and its current condition. Generally speaking, you can expect an idling engine to take around 30 minutes to bring a weak battery back up to full capacity.

However, if your car’s battery is nearing the end of its life span or has already failed completely, then charging it with an engine idle will not be effective. In this case you’ll need to replace the entire battery instead.

Will my car battery charge if I leave the engine running?

Will Idling Car 20 Minutes Charge Battery?

No, idling a car for 20 minutes will not charge the battery. The alternator in most cars is only capable of producing enough power to keep the battery at its current level, so if it’s already low, idling won’t do much to help. Additionally, many modern vehicles have systems in place that reduce engine output when the car is stationary and idle – this helps to save fuel but also reduces the amount of power being produced by the alternator.

In order to properly charge your car battery you need to be driving it at highway speeds or use an external charger/jumper cables.

How Long Does It Take to Charge a Car Battery at Idle?

It typically takes between 8-14 hours to charge a car battery at idle. Charging times can vary based on the type of charger and amount of power supplied, but it is important to note that charging a car battery at idle should not be done for extended periods of time as this could cause harm and damage to the battery. Additionally, if you are using an external charger, make sure it is designed specifically for automotive batteries in order to prevent overcharging or damaging your battery.

Does Revving in Idle Charge Battery?

No, revving your engine in idle does not charge the battery. Your car’s alternator is responsible for charging the battery while it’s running, and if you’re only idling then there won’t be enough power produced to charge it. In fact, by revving your engine without engaging the transmission can actually cause more wear-and-tear on components like spark plugs and belts as well as reduce fuel efficiency due to wasted energy.

If you need to boost a dead battery, contact roadside assistance or jump start it with another vehicle instead of trying to use your own car in idle mode.

Is It Better to Idle Or Drive to Charge Battery?

Idling your car to charge the battery is not a great idea, as it can put unnecessary strain on the engine and increase wear-and-tear over time. The best way to charge the battery is by driving your vehicle for at least 20 minutes, which allows enough time for alternator to generate sufficient energy to charge up the battery. Additionally, when you drive around while charging the battery, you are also able to test out other components in the car such as brakes and suspension.

This ensures that everything is working properly before taking longer trips or going on highways with higher speeds. Therefore, driving instead of idling is better for charging up your car’s battery.

How Long to Idle Car to Charge Battery


How Long to Leave a Car Running to Charge Battery Reddit

It is generally recommended to leave your car running for 10-15 minutes in order to charge a dead battery. This should be enough time for the alternator to bring the battery up to its full charge. However, if you have been driving and the battery is still not responding, you may need more time or even a jump start from someone else’s car.

Ultimately, it is important not to let your car run too long as this can put undue strain on other components of your vehicle.

How to Charge Car Battery While Parked

If your car battery is completely dead and you need to get it charged up, there are a couple of ways you can do this while the car is parked. One option is to use jumper cables connected from another vehicle’s running engine to the dead battery; however, if there isn’t another vehicle available, you can purchase a portable jump starter or charger that runs on electricity. This device needs to be plugged into an electrical outlet before it can be attached to your car’s battery terminals for charging.

How Long to Recharge Car Battery After Jump

If you’ve had to jump start your car, it’s important to know how long the battery needs to be recharged before driving again. Generally, after a successful jump start, you should drive for at least 15 minutes in order to recharge the battery. This will help ensure that your battery is fully charged and ready to go so that you don’t have any further issues with starting your engine.


In conclusion, it is important to understand the best way to charge a car battery and how long it should idle. For safety and efficiency, it is always recommended to use an external battery charger rather than idling the vehicle engine. If you must idle your car for charging purposes, be sure not to exceed 10 minutes total idle time as this can cause unnecessary stress on the engine and damage other components of the vehicle.

Finally, make sure that any necessary repairs or replacements are made in order to keep your car running smoothly and safely.


Leave a Comment