How Long Should a Car Battery Be Charged?

[ThomasFitz]

Car batteries generally need to be charged for about 20 hours. Precautions for battery charging include: 1. Check whether the charger is dual-use for 12V and 24V. If there is only one battery, do not use a 24V charger; 2. For water-refillable batteries, open the caps during charging, while maintenance-free batteries can be charged directly. Methods for maintaining car batteries include: 1. Regularly clean the dust and oil stains on the battery terminals and apply special grease to protect the wiring harness; 2. Periodically inspect the battery accessories and connecting circuits; 3. Minimize the use of electrical devices in the car after turning off the engine; 4. Check the battery through the observation hole and replace it regularly; 5. If the vehicle is not used for a long time, start it periodically.

[Lacey]

I've been driving for over a decade and there's some nuance to battery charging. For regular passenger car batteries which are typically 45-60 ampere-hours, using a standard charger usually takes about 8 to 12 hours. I recommend using slow charging mode - though it takes longer, it's gentler on the battery plates. My routine is charging overnight until morning, but always monitor the battery temperature during charging and stop immediately if it feels too hot to touch. Older batteries require longer charging times, while new ones might finish 1-2 hours faster. Avoid using car electronics during charging as it will extend the charging duration. In winter, charging efficiency drops due to cold temperatures, so it's better to charge in a warmer garage. Charging time also depends on charger amperage - for instance, a 5-amp charger needs at least 10 hours to fully charge a 60Ah battery.

[Stanley]

As a helpful car owner who often assists neighbors with battery issues, I believe charging duration mainly depends on two factors: charger power and the remaining battery capacity. Typically, a standard charger with around 5 amps current takes about 10-15 hours to fully charge a 60Ah battery when completely drained. However, if the battery still has 30% charge left, the time can be halved. I recommend first using a multimeter to check the voltage—if it's below 12.4 volts, it's time to charge. During charging, monitor the charging indicator light; when it turns green, the battery is fully charged, usually within 6-12 hours. Remember, the charging environment temperature shouldn't be too low—around 15°C is optimal for charging efficiency. There's also a difference between lead-acid batteries and start-stop batteries, with the latter requiring slightly less charging time. Overcharging can cause the electrolyte to bubble, so avoid exceeding 24 hours.

[LeLeila]

Last time my car battery was dead and I called for roadside assistance. The technician said the charging time for a sedan depends on current compatibility. A 50Ah battery takes about 5 hours with a 10A charger, while a 60Ah one needs roughly 6 hours. But in reality, you should leave 10-20% extra capacity, so the actual charging time is 6-10 hours. It's best to use a charger with auto-stop function - stop when the green light comes on. Temperature rise on the battery surface during charging is normal; it's safe to continue below 50°C. If charging completes in less than 4 hours, the current might be too high and could damage the plates. I usually keep the hood open for ventilation during charging. If white smoke appears, cut power immediately. Before charging, check the electrolyte level and top up with distilled water if needed.