Battery saver mode changes certain settings to conserve battery power until you can recharge your phone. If you turn Battery saver mode On, it will automatically activate when the battery charge level drops to the level you set. If Battery saver mode is off, you’ll be prompted to turn on Battery saver mode when the battery reaches low levels.
From the Home screen, touch and hold the Recent Apps Key (in the Touch Keys bar) > Settings > Battery > Battery saver.
From the Battery saver screen, tap Turn Battery saver on (at the top of the screen) to set the phone to activate Battery saver mode immediately, when the charge drops to 10%, 20%, 30%, or 50%. If you turn off Battery saver mode, when the battery charge becomes low, a notification prompts you to turn it on.
From the Battery saver screen, checkmark the saving items you want, including Auto-sync, Wi-Fi, Bluetooth, Vibrate on tap, Brightness, Screen timeout, and Notification light.
After you modify the Battery saver settings to your preferences, tap the switch (at the upper-right corner of the screen) to toggle it On (blue) or Off (gray).