Check 3. Close unnecessary apps
You can reduce battery usage by turning off all unused apps. Close all unnecessary apps at once by following the steps below.
Step 1. From the watch screen, swipe up from the bottom of the screen to open the Apps screen.
Step 2. Tap Recent apps, to view recently opened apps.
Step 3. Drag a recent app window up or select the Close all icon that appears by sliding all the way to the left.