Full Battery Alarm for OnePlus: Solutions
App Locking
To prevent the app from being killed in the background and the Battery Optimization setting from being reverted:
Start the app you want to protect.
Open Recent apps (swipe up and hold).
Long press on the app window and tap the Lock button at the upper right corner.
The locked app will display a closed padlock icon.
Note: This method is not 100% reliable. Periodically check system settings. Refer to the bug report filed with OnePlus for more details.
Battery Optimization
Go to System Settings > Apps > Gear Icon > Special Access > Battery Optimization.
Turn off battery optimization for the desired app.
Warning: OnePlus phones may randomly revert this setting. Locking the app in the Recent App list can help prevent this (refer to the App Locking solution above).
Navigate to System Settings > Battery > Battery Optimization.
Switch to 'All apps' in the top right menu.
Select Battery Charged Alarm > Don’t optimize.
Note: For OnePlus 3 and earlier, you may need to disable Doze mode in Developer options.
App Auto-Launch
If your OnePlus phone includes an App Auto-Launch feature that restricts background apps, disable it for Battery Charged Alarm.
Enhanced/Advanced Optimization
For OnePlus 6 and later models:
Go to System Settings > Battery > Battery Optimization > (three dots) > Advanced Optimization.
Disable both Deep Optimization (Adaptive Battery) and Sleep Standby Optimization.
For OnePlus models below 6:
Go to System Settings > Battery > Battery Optimization > (three dots) > Enhanced Optimization.
Note: Disabling these settings may help with issues such as losing Bluetooth connection to smartwatches or fitness trackers.
Recent Apps Clearing Behavior
Swiping an app away may close it on OnePlus devices, unlike other Android phones. Adjust your recent app clear behavior settings to prevent apps from being killed when swiped away.