If the battery charge level drops to low levels, the phone automatically activates Power Saver mode to conserve battery power until you can recharge it. You can set the phone to activate Power Saver mode at 10%, 30%, 50%, 70%, or Never. Touch. The Power Saver mode icon is located in the Notifications panel. When the battery charge is low, a notification is displayed prompting you to turn on Power Saver.