Xiaomi: Control Whether Ultra Battery Saver Turns Off Automatically

Ultra battery saver on Xiaomi phones runs a separate automation from the standard battery saver mode. By default, the system assumes you only need the extreme restrictions while the battery is critically low, so it quietly deactivates the mode once charging brings the level back up to around 50 percent.

That auto-off can be useful if you just want a temporary emergency boost. It becomes a problem if you plan to keep the phone in minimal-function mode for longer, for example overnight or while traveling, and the mode disables itself before you are ready.

Where to change it

Go to Settings ➔ Battery & performance ➔ Settings ➔ Ultra battery saver. Inside this screen you find the Turn off automatically toggle. Switching it off keeps Ultra battery saver active regardless of charge level, until you disable the mode yourself. Switching it on restores the default behavior, where the phone exits the mode automatically once it is charged enough.

If your actual concern is that the regular battery saver mode also disables itself unexpectedly, check its separate settings entry instead, since the two features are configured independently.