How long do I need to drive after the car battery is dead to recharge it?
3 Answers
3-5 hours. Here are the relevant details: Engine charging: If you want to recharge a dead battery using the engine, take a 12V60Ah battery as an example. The charging method adopts constant voltage and limited current. Charge at 14.8V constant voltage and 15A limited current for 16 hours, then charge at 3A constant current for 4 hours, totaling 20 hours. The required charging time is relatively long. Charger charging: If the owner finds the battery dead, a more recommended method is to fully charge the battery using a charger. Generally, the battery capacity of a household car is around 60Ah, and the required charging current is one-tenth of the battery capacity, which is 6A. Charging at this current usually takes about 3-5 hours to fully charge.
Last time my car battery was drained, after starting it and driving to work for about 30 minutes, it was almost fully recharged. Actually, the charging time depends on the situation: if you're driving on the highway at higher speeds, the alternator runs faster, and it can charge up to about 70-80% in just over 20 minutes. But if you're stuck in city traffic or idling a lot, with the engine running at low RPM, charging is slower, and it might take over 40 minutes to fully charge. If the battery is new, it charges faster. If it's old or completely discharged, it might not hold a charge at all, and then you'd need to replace it. Usually, I recommend not just driving short distances, like a quick 5-minute trip to the supermarket, as this uses more power than it recharges, easily draining the battery. Doing this long-term shortens the battery's lifespan significantly. It's best to take a long drive at least once a week to keep it healthy.
I've also experienced a dead car battery while driving, which is quite annoying. After starting the car, it's best to drive for 20 to 30 minutes to ensure the battery recovers. For new cars, charging is faster—just about ten minutes will do. But for older cars or in stop-and-go city traffic, don't rush to turn off the engine; extending it to 40 minutes is safer. Safety-wise, don't assume everything's fine just because the car started. If you notice the dashboard lights dimming while driving, it might indicate insufficient charging, so pull over and check immediately. During regular maintenance, I always ask the mechanic to test the alternator and battery voltage to ensure they're within the working range. Also, I make sure to turn off lights and electronic devices when parking to prevent the battery from draining too quickly.
