The current and voltage is unstable or the plug is not plugged in: this situation generally occurs when charging through the computer, because the computer's usb output is small, sometimes it will cause the phenomenon of unable to charge, change the socket to charge. 2. The charger and data cable connector are aging for a long time or the interface is dirty and can not be charged: you can change a charging head. Or take a fine piece of metallographic sandpaper to cut the appropriate size, fold it in half a few times, gently polish it at the data cable interface, and then plug it in and charge it.
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3, check whether the room temperature is too low or too high: Apple set the temperature for the battery is too low and too high protection, the temperature is too low and too high sometimes the phone will not be able to charge, to prevent deposition in the battery, resulting in internal short circuit of the battery.
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4, battery damage: If the above reasons are still unable to charge, suspect that the battery has been damaged, please go to after-sales testing and maintenance.