In times when you don't need to use much of your phone, turn Extreme power saving mode on to extend battery life longer.
In this mode, standby time can last longer than usual, and you can only use the most basic functions such as phone calls, text messaging, and email.
With two fingers, swipe down from the status bar to open
Extreme power saving mode tile to turn the mode on.
Or to set when to automatically switch this mode on, tap below the tile. Select the check box, and then choose at which battery level the mode will turn on.