Can the battery be charged at idle speed?
2 Answers
Yes, the car battery can be charged while the engine is idling. The electricity generated by the alternator undergoes rectification and voltage stabilization, regardless of the car's operating state, ensuring a stable DC output voltage, which allows for normal battery charging. Additional Information: The car battery is an essential part of the vehicle and is divided into two types: traditional lead-acid batteries and maintenance-free batteries. Since the battery uses lead-calcium alloy for the grid frame, it produces less water decomposition during charging and has lower water evaporation. Additionally, the sealed structure of the casing minimizes the release of sulfuric acid gas. Compared to traditional batteries, maintenance-free batteries offer advantages such as no need to add any liquid, easy connection to terminals, and longer charge storage time.
The battery can indeed be charged at idle because the engine is running and the alternator is still generating electricity. However, the RPM is very low, typically around 800, resulting in low power generation and a slow charging speed. I remember last time my car battery was dead, idling for half an hour only charged it less than 20%, which was far from enough. If you drive normally on the highway and the RPM rises above 2,000, it can fill up a significant portion in just a few minutes. Moreover, prolonged idling is harmful to the engine—oil pressure may be insufficient, accelerating component wear, and it may even cause the car to burn more fuel, which isn’t cost-effective. So, it’s okay for emergencies, but it’s best to avoid relying on it regularly. Prioritize checking the alternator and battery health instead.
