It can be used for 2 hours, and there are basically two forms of car charging. If the voltage is reduced directly, the 7AH battery is fully charged: 7*80%\/2=2.8 hours. However, the charging will not always use 2A current, and the current is constantly decreasing during the charging process, so the time can exceed 2.8 hours. In addition, if the battery is on the motorcycle, but also consider the next start of electricity, can not run out of electricity, at least 50% of the power to stay, then the time calculation can only be 7*50%\/2=1.75 hours.