How long does it take to charge a 12V car battery?

[BriannaLee]

How long it takes to charge a 12V car battery depends on the charging current. The specific time is as follows: 1. Generally, the battery retains more than 20% of its charge, and the chemical conversion efficiency during charging is about 50%. To fully charge the battery, it requires an additional 150%*80% of the charge. 2. The optimal charging current for the battery is 10% of its capacity. However, the charging time required is 150%*80%/10%=12 hours, plus about 1 hour for the additional time needed for segmented charging. 3. To align with people's daily routines, a charging current of 13% of the battery's capacity is usually designed, resulting in a charging time of at least 150%*80%/13%=9.2 hours, plus about 1 hour for the additional time needed for segmented charging. 4. For fast charging, a current of 20% of the battery's capacity is typically used, with a charging time of 150%*80%/20%=6 hours. Using a higher current can shorten the charging time, but it may damage the battery, so it should be used with caution.