Can Car Battery Charge While Idling

The quick answer is “yes”, but there are a few things to consider before allowing your car to idle for an extended period of time in order to charge the battery. For starters, idling uses more fuel than turning the engine off and on, so it’s not the most efficient way to charge a battery. Additionally, if your alternator isn’t functioning properly, or if your battery is old and no longer holds a charge as well, then idling won’t help and could actually make the problem worse.

Is it better to charge your car battery while the engine is idling or turned off? There are pros and cons to both methods, so let’s take a look at each one. When you charge your battery while the engine is idling, the alternator is supplying power to both the battery and the electrical system.

This can put a strain on the alternator, causing it to overheat. Additionally, if there’s an issue with the charging system, it can cause problems with starting your car. However, charging your battery while the engine is off has its own drawbacks.

For one thing, you’ll be using up gasoline that could otherwise be saved. Additionally, if your battery dies while you’re driving, you won’t be able to use your car’s electrical systems (including lights and power steering) until the battery is charged again. So which method is best?

Ultimately, it depends on your situation. If you’re going to be driving for a long period of time and don’t want to risk having a dead battery, then it’s probably best to charge while idling. However, if you’re just making a short trip and want to save gas, then charging while the engine is off may be the way to go.

How Long Should I Idle My Car to Charge the Battery?

If your car has a manual transmission, it’s best to start the engine and let it idle for about 15 minutes before driving. This gives the battery time to charge up. If you have an automatic transmission, you can start the engine and let it idle for about 5 minutes before driving.

Can I Leave My Car Idle to Charge the Battery?

It is perfectly fine to leave your car idle with the engine running to charge the battery. In fact, it is often necessary to do this if your battery is low on power. However, you should only do this for a short period of time, as leaving your car idle for too long can cause problems.

Additionally, make sure that you are not idling in an enclosed space, as this can lead to dangerous levels of carbon monoxide buildup.

How Long to Charge Car Battery While Idling

Assuming you’re talking about a lead acid battery, there are different ways to charge them. The most common is called “flooded” where the electrolyte (the sulfuric acid and water mixture) covers the lead plates. These batteries can be damaged if overcharged so it’s important to know how long to charge car battery while idling.

The easiest way is to use a voltmeter or multimeter and check the voltage of the battery while it’s charging. You’ll want to stop charging once it reaches around 14.4-14.6 volts. If you don’t have a voltmeter, another method is to keep an eye on the amperage reading of your charger.

Once it drops below 2 amps, you can assume the battery is full and stop charging. Of course, these are just general guidelines and your mileage may vary depending on the type of charger and battery you’re using. It’s always best err on the side of caution to avoid damaging your battery.


Yes, your car battery can charge while idling. However, it will not charge as quickly as it would if you were driving. The reason for this is that the alternator charges the battery while the engine is running.

When you are idling, the engine is running but at a lower RPM than when you are driving. This means that the alternator has less power to charge the battery.

Leave a Comment