By default, notifications are disabled, but you can easily enable them from the settings and choose the type of icons to display, this will activate permanent monitoring of the battery even after reboot.
You can download custom packs here.
Note that because not all users use the notification, the best visuals are provided as external package, only basic notification icons are provided in standard.
External packages can be downloaded and activated from the settings.
Read the section on how to save CPU time if you only want the notification icons!
How it works
The notifications are permanent and will not be cleared unless you disable them in the settings.
Clicking a notification opens the main screen allowing you to check state, graphics and history depending on your personal setup.
Notifications are started at boot time, even if no widget is active, it will automatically start the history logging, so make sure to disable this service if not needed in the save CPU time help page.