The app will not work on some devices due to restrictions, such as smartphones with Chinese firmware that stops all background work, or shells with strong restrictions.
To use the app, give it permission to send notifications, which you can disable if you don't need them, but it will let you know that the app is working (disable by unchecking the service in the settings, not by disabling the permission itself). The most important thing is to give the app permission to disable optimization.

The app notifies you:
— When the charger is connected
— When the charger is disconnected
— When the battery level reaches a certain level

Alert settings:
Say by voice — the built-in speech synthesis will be used. If this feature doesn't work, try writing the text in English, as the speech synthesis may not support Russian
Select audio — choose any audio, such as an audio meme, a loud siren, or whatever your imagination allows
Default — the audio I selected is used
Repeat — the number of times the alert is repeated
Pause — the pause between repetitions in seconds
When charging — an important parameter that changes the purpose of the alert. If it is enabled, the alert will only be triggered when the device is connected to a charging source. If it is disabled, the alert will only be triggered when the device is not connected to a charging source.