ASUS - ZenTalk

Averanhttps://zentalk.asus.com/en/discussion/comment/152508#Comment_1525081.Charge it to 100% once and overcharge it for 20-25 min or leave it plugged in with scheduled charging for the night See if that improves your sot 2. Else try following these ...

The phone was charged until 90% and used for less than 1 hour. After 4 hours the Android System drained a lot of the battery.

The same here. The phone was fine until last update .127. Now Android System is draining almost all battery in few hours.