Charging time more than 7 hours will have an impact on the device, as long as you are not a lot of times the impact is very small, it is recommended that you charge the device within 5-7 hours. In addition, 2-3 times a month for full cycle charging, that is, the power used within 10-20% of the charge, 6 hours usually can be charged between 20-28%, within 5-6 hours. Try not to use the device while charging, or remove the case and charge it in a cool place, out of direct sunlight