Can a Vehicle Charge When Idling with the Engine On?

[DelAlexander]

Yes, a vehicle can charge when idling with the engine on. The precautions for battery charging are: 1. A battery voltage below 10% of the rated voltage will lead to battery depletion; 2. Avoid water entering the battery during charging; 3. Connect the charger directly to the battery without removing it to prevent data loss. The steps for battery charging are: 1. Turn off the engine and remove the battery; 2. Open the vent caps on the battery; 3. Attach the red clamp of the dedicated charger to the positive terminal marked with a plus sign and the black clamp to the negative terminal marked with a minus sign; 4. Adjust to the second gear and select a 12V power source; 5. Plug in the charger, turn on the switch, and begin charging.

[Orlando]

I usually pay close attention to car maintenance. It's true that a vehicle can charge the battery when idling after ignition, because once the engine starts, it drives the alternator to generate current for battery charging - like a small self-sustaining system. However, charging efficiency is low at idle speed due to low RPM, resulting in slow charging. Prolonged idling also causes gasoline waste and increased carbon monoxide emissions. Doing this in garages or enclosed spaces may even pose poisoning risks. The battery's aging condition also affects charging effectiveness - unstable voltage leads to slower charging. I recommend the optimal method is driving the car around to achieve higher RPM for faster, more efficient charging that's also better for the vehicle. While idling can charge the battery, it's not ideal. Avoid prolonged idling to prevent engine damage and environmental pollution.

[Pam]

Once when my battery was almost dead, I kept the engine running in the parking lot for 20 minutes and found that the battery could charge a bit. When the car is idling without moving, it can charge the battery because the alternator supplies current to replenish energy. However, this process is much slower than driving—at idle, the engine speed is low, resulting in less power generation and poor charging efficiency, while also wasting fuel. If the battery is old, charging becomes even more difficult and may lead to mid-operation failures. I believe safety comes first; avoid doing this for extended periods, especially in enclosed spaces where carbon monoxide buildup poses risks. Simply put, it can charge but inefficiently. Driving for half an hour regularly is far better and more cost-effective than idling in place.

[LaHope]

The vehicle can indeed charge the battery when the engine is running without moving, as the engine's rotation drives the alternator to supply power to the battery. However, idling for charging is inefficient, consumes more fuel, and is not recommended for prolonged periods due to potential unsafe carbon monoxide emissions. A battery in good condition charges more smoothly.