How long does it take to fully charge the car battery when the engine is running?

[OEleanor]

It takes more than 30 minutes of engine running to fully charge the car battery. The battery is a type of storage cell that works by converting chemical energy into electrical energy. The functions of the battery are: 1. To supply power to the starting system, ignition system, electronic fuel injection system, and car's electrical appliances when starting the engine; 2. To power the car's electrical equipment when the engine is off or at low idle; 3. The battery acts as a voltage stabilizer for the vehicle's electrical system; 4. The battery stores excess electricity generated by the alternator. Methods for battery maintenance include: 1. Avoid parking the car in open parking lots for extended periods to prevent the battery from freezing and getting damaged; 2. Clean the battery terminals periodically and apply special grease to protect the circuitry; 3. Avoid using car electrical appliances after turning off the engine, as using the battery alone when the engine is not generating electricity can cause damage to it.

[LoganAnn]

I'm a novice driver who just bought a car not long ago, and I was also confused about this issue at first. The time it takes for a car to charge the battery after starting is actually quite complex, and I've learned this the hard way. For example, if the battery is severely depleted, it might take half an hour to an hour of driving to get it nearly full; if the battery is in good condition, a daily commute of 10-20 minutes can top it up a bit. But the key factor is driving style: low-speed city driving isn't very efficient for charging, you need to maintain speeds above 60 km/h on highways for faster charging. I used to frequently take short trips, which kept draining my battery, until I learned that I should take medium-length weekend drives lasting 40-50 minutes to keep it properly charged. Charging speed also depends on alternator output - older cars charge slower while newer models are faster. If your battery consistently won't hold a full charge, it's best to visit a repair shop to check for wiring issues or battery deterioration, to avoid embarrassing roadside breakdowns.

[SanPeyton]

As a fan who enjoys tinkering with automotive tech, I believe this question should be approached from the perspective of the car's charging system principles. When the car engine is running, it drives the alternator to rotate and charge the battery, but it's hard to give a unified charging time estimate. There are too many influencing factors: battery capacity, charging current, vehicle speed, engine RPM, etc. If you're stuck in city traffic crawling slowly, the alternator output may be insufficient, potentially taking one or two hours to fully charge. On the highway at higher RPMs, it might reach about 80% charge in just twenty minutes. Personally, I prefer using a car voltmeter to monitor battery voltage - normally reaching around 14.4 volts indicates full charge. Also, avoid idling to charge the battery; it wastes fuel, causes severe carbon buildup, and has pitiful efficiency. Driving is the most cost-effective method. I recommend taking trips of at least 30-40 minutes to balance the charge. Frequent short trips can lead to battery drain and shortened lifespan, while occasional highway runs make maintenance much easier - it saves battery replacement costs and maintains your vehicle better anyway.

[ClaireLynn]

I've spent over a decade in the workshop and seen countless battery charging issues. There's no fixed time for a car battery to fully recharge after starting - it all depends on your battery's condition. Generally, for new batteries or those in good shape, about 20 minutes of driving should suffice; but for older batteries or those with a history of discharge, it might take over an hour to fully charge. The key is not to be lazy by idling - charging is slower that way and it strains the alternator. Driving at higher speeds makes charging more efficient. I've even encountered owners complaining about incomplete charging, only to find out their battery was dead and needed replacement, or there was poor contact in the charging circuit. For daily maintenance, driving about half an hour helps keep the battery healthy and prevents unexpected breakdowns. Simply put, driving more is the golden rule.