Can the Battery Be Charged While Idling in Place?
2 Answers
Yes, a car can charge its battery while idling in place. Idling refers to the engine running without any load, with the gear in neutral—a state often described as "working without output." Although the vehicle consumes fuel without moving or performing work, it can still charge the battery. However, idling consumes a significant amount of fuel and produces severe emissions pollution, so it is recommended to use a battery charger instead. Below are some precautions for charging the battery while idling: 1. Avoid using other power-consuming devices: If the car battery is low on charge and you turn on high-power devices like the air conditioner, high beams, or car audio system while idling, it may exceed the generator's maximum output, leading to permanent battery damage. 2. There's no need to rev the engine: Some suggest that revving the engine to increase RPM can speed up charging efficiency. In reality, as long as you avoid using high-power devices like the air conditioner while idling, revving the engine is completely unnecessary.
Speaking of the issue of idling to charge the battery, I think for the average driver, it can charge the battery, but the effect is quite slow. My experience tells me that during idling, the engine speed is very low, usually around 500-800 RPM, and the alternator's output power is minimal, barely able to replenish some battery charge. For example, if you idle for about ten minutes while waiting for a friend in a residential area, you might charge around 5%, but this is just a drop in the bucket. Worse, if the battery itself is aging or has a leakage issue, idling to charge won’t solve anything—instead, it wastes fuel and increases emissions, which is bad for the environment. I always advise people not to rely solely on this method. If the battery light comes on indicating a charging failure, it’s better to start the car and drive a short distance to increase the RPM or use a portable charger—that’s much more reliable. Remember, safety comes first. It’s okay for occasional emergencies, but long-term reliance on idling to charge will shorten the battery’s lifespan and increase the risk of failure.
