This is the lack of battery life caused by battery loss, so it can not be fully charged. The solution is as follows:
1 Check whether the original charger is used. If not, please replace the original charger and try again.
2 Replace another power socket.
3 If the battery can be removed, reinstall the battery or replace the original battery and charge it again.
4 Update the mobile system version: Settings - About the phone (about the device) - manual download update\/automatic download update (software update\/System update - update). Note: Back up the data on the device before the upgrade.