Keeping your battery charged will save you time and frustration when you need to start your car. Idling your vehicle can create a small electrical current to help charge your battery.
A car's alternator converts mechanical energy into electrical energy. When a car engine is running, mechanical power from the fan or serpentine belt turns the alternator, which creates electricity. This energy is used to power the electrical components of the car.
When a car idles, it runs at a lower RPM than when it drives. It generates enough power to run ancillaries such as the alternator; however at idling RPM, the alternator creates only a portion of its rated electrical power.
Does Idling Create Enough Current?
The greater the engine RPM, the more electrical current is created by the alternator. While idling your vehicle does create a small amount of current, the battery is charged faster and more fully when the vehicle is on the road at a higher RPM.