Can idling the engine charge the car battery?
2 Answers
Idling the engine can charge the car battery. Relevant explanations are as follows: 1. The battery can be charged as long as the vehicle is running: The generator will automatically charge the battery at idle speed. The charging power after successful startup can not only charge the battery but also continuously supply power to other electrical loads in the vehicle. During idling, the voltage output by the rectifier regulator is generally above 13 volts. 2. As long as the voltage output by the rectifier regulator is higher than the battery voltage: The battery will be in a charging state. The input voltage of the rectifier regulator is determined by the generator, and the generator will generate electricity as long as it rotates. Without considering the excitation control, the output voltage of the generator is directly proportional to its rotational speed. 3. The rotational speed of the generator: Depends on the engine speed. Although the speed is low during the startup phase and the generator's output voltage is relatively low, the generator will always have voltage output. As long as this voltage is above a certain value, it will continuously charge the battery.
Yes, idling your car can indeed charge the battery. My car is an older model, and I've tried this several times. For instance, when the battery is weak in winter, I simply start the engine and let it idle in the parking lot. After a while, the battery voltage meter shows the charge slowly increasing, indicating the alternator is working to recharge it. However, this method isn't very efficient, as the charging speed is relatively slow. At idle, the engine runs at just a few hundred RPM, so the alternator's output is limited compared to when driving at higher RPMs (over a thousand). Therefore, if the battery is truly low, I recommend idling for 5-10 minutes and then driving around for a bit—this will charge the battery more effectively and save fuel. Also, avoid prolonged idling, as it can lead to carbon buildup and waste fuel. For safety, only use this method briefly and preferably in a well-ventilated area, not in an enclosed garage. Overall, this is an emergency measure, not a long-term solution. Battery health relies on regular checks and driving.
