Can idling the car charge the battery?
3 Answers
Idling the car can charge the battery. When the car is idling, the engine drives the alternator, which in turn charges the battery. However, charging the car battery by idling the engine is highly inefficient. If the battery is severely depleted, it is best to remove the battery and charge it using a charger. Here are some relevant details: 1. Before starting the car, the battery powers the vehicle's equipment. After starting the car and letting it idle, the alternator supplies the electricity, which is only sufficient for driving or idling. Due to the low engine speed, the alternator may generate just enough power for ignition, leaving no excess to charge the battery. Therefore, charging the battery by idling may take a very long time. 2. Prolonged idling is certainly harmful to the engine. Idling for half an hour could lead to significant carbon buildup. Avoid leaving the car unused for extended periods. If the car is not used for a long time, such as twenty days or a month, the battery cable should be disconnected, or the car should be started and driven for several dozen kilometers every two weeks to ensure the battery remains functional.
Idling the car can indeed charge the battery, as the running engine drives the alternator to generate electricity, thereby replenishing the battery's charge. However, this is not an efficient method—at idle, the alternator operates at low RPM, producing minimal charging current. If the battery is severely depleted, prolonged idling may be required to recover even a small amount of charge, making it far less efficient than driving to recharge. Based on my years of car ownership experience, idling also wastes fuel, increases the risk of engine carbon buildup, and generates more exhaust emissions, which is neither environmentally friendly nor economical. A better alternative is to drive a few hundred meters or minutes after starting the engine. Under increased engine load, the charging rate improves significantly while also preventing premature battery aging. Preventive maintenance, such as regularly checking the alternator's output voltage and battery fluid levels, is more reliable than relying on idling for charging.
You can charge it, but personally, I don't recommend doing so—it feels way too inefficient. The charging speed at idle is painfully slow, and fuel consumption increases, causing more pollution with higher exhaust emissions. As an ordinary driver, I've tried idling for half an hour just to barely revive a half-dead battery, which was far less effective than simply driving around for a short while. Most modern cars come with smart charging systems, and idling not only results in low efficiency but may also lead to engine carbon buildup. Simple advice: Don’t cut corners—start driving to charge the battery or use a professional charger for faster and safer results. This saves time and is eco-friendly, killing two birds with one stone.
