Hold MENU, and select Power Manager.

Battery Saver

Allows you to customize system settings to extend battery life in watch mode (Customizing the Battery Saver Feature).

Power Modes

Allows you to customize system settings, activity settings, and GPS settings to extend battery life during an activity (Customizing Power Modes).

Battery Percentage

Displays remaining battery life as a percentage.

Battery Estimates

Displays remaining battery life as an estimated number of days or hours.