How many kilometers does it generally take to fully charge a car battery?

[StGeorge]

Taking a 12V60Ah battery as an example, the charging method is as follows: Use constant voltage and current limiting for charging, with 14.8V constant voltage and 15A current limiting for 16 hours, followed by 3A constant current charging for 4 hours, totaling 20 hours. Below are the criteria for determining when the battery is fully charged: 1. Battery: A large number of bubbles are generated inside the battery, showing a "boiling" phenomenon. 2. Terminal voltage: The terminal voltage rises to the maximum value and does not increase further within two hours. 3. Electrolyte: The electrolyte rises to the highest level and does not increase further within two hours. 4. Precautions: If charging is needed, try to turn off electrical equipment as much as possible.

[Easton]

Actually, car battery charging mainly depends on engine running time rather than mileage. In my years of driving experience, I've found that driving at low speeds in the city for 20 minutes might only cover about 10 kilometers, yet the battery may not be fully charged at all. Maintaining around 80 km/h on the highway for half an hour to cover about 40 kilometers can generally achieve about 80% charge. This is because the alternator charges faster at higher engine speeds. If the battery is severely depleted, it might require over an hour of continuous driving, equivalent to 60 to 80 kilometers. The key is to avoid multiple short trips with frequent starts, as this keeps the battery undercharged and can shorten its lifespan. I recommend checking the battery status before long trips and using a charger for assistance if necessary.

[SanKhloe]

I used to wonder about this when I first started driving, but now I understand the principle: the battery charges based on engine rotation, and how many kilometers you need to drive depends on your speed. In city traffic with constant stops and starts, you might only cover a few kilometers in half an hour, resulting in slow charging; on the highway at 100 km/h, 20 minutes can charge most of the battery. In most cases, driving continuously for 20 to 30 minutes is enough to fully charge an empty battery. Kilometers? It depends on road conditions—like in traffic jams, driving for an hour might only cover a little over 10 kilometers, leading to low charging efficiency. I’ve also experienced a frozen and depleted battery in winter, requiring even longer driving time. To be safe, I warm up the car for a few minutes before long trips.

[DanielLynn]

Car battery charging depends on engine operating time, not just mileage. Simply put, charging is faster when the alternator runs at higher RPMs - highway driving saves more time than city driving. I know some technical details: 20 minutes of continuous driving can charge about 70-80%. Mileage varies greatly: 40km highway driving may fully charge it, while 20km city crawling might be needed. Older batteries or cold temperatures require longer charging. Maintaining RPM above 1500 is ideal. Avoid frequent short trips as they shorten battery lifespan.