The quick answer: compare screen-off time with awake time and deep sleep over a recorded session. Battery Watch’s Screen & Sleep view helps you see the pattern. Usage Access adds historical screen information and per-app usage context.

Three different states, one battery

  • Screen on: you may be using the device, and the display is active.
  • Screen off but awake: the display is off, while the processor may still be handling background work.
  • Deep sleep: Battery Watch estimates time asleep from the difference between elapsed time and processor uptime. It is a timing-based estimate.

Doze is another part of Android’s power management. It limits certain background activity when the device is idle. It is related to idle behavior, but it is not a synonym for deep sleep.

Set up a useful observation

  1. Open Settings, then Power & access in Battery Watch.
  2. Enable persistent monitoring and allow notifications so the monitoring service can keep a foreground notification.
  3. Grant Usage Access if you want historical screen and per-app usage information.
  4. Leave the phone unplugged for a normal idle period. Review the resulting session and Screen & Sleep details afterward.
  5. Compare more than one session before changing settings. One short test may not represent your usual use.

Android and manufacturer background restrictions can interrupt tracking. A gap in a record is missing information, not evidence that the device spent the entire gap asleep.

What a wake lock tells you

A wake lock can keep the processor awake so an app can finish work. Music playback, navigation and synchronization may use one for a valid reason. With Shizuku or root, Battery Watch can inspect wake-lock information and expose supported per-app controls.

A per-app usage list or wake lock does not directly measure every app’s battery consumption. Use it as context alongside your device’s Android battery settings and repeated session observations.

Make one change at a time

If a pattern points to an app you do not need running in the background, review its own settings or its Android background-use settings first. Restricting or force-stopping an app may delay notifications or interrupt useful work.

For more control, Battery Watch offers automatic battery saver with Shizuku or root. Savings depend on the device, conditions and workload.

Further reading

Android explains the system behavior in Doze and App Standby and its wake-lock guidance.