This script notifies when battery is above 80% while charging and when battery is below 40% while running on battery (you can customize the charge percentage in script).
[*] Install git (if already installed, ignore)
sudo apt install git
[1] Install battery information viewer
sudo apt install acpi sox libsox-fmt-all libnotify-bin
[2] Clone this project in your home folder
git clone https://github.com/s01k/battery-notify-linux
[*] Test the audio and notification by
notify-send -u critical "Please unplug your AC adapter" "Battery level can charge above 80%" -i battery-full-charged && play ~/battery-notify-linux/loud_alarm.mp3
[*] To add custom music, copy any music file in "battery-full-notify-linux" folder, and change the music file name in
play ~/battery-notify-linux/your file name.mp3
[3] Make the "batteryfull.sh" file (inside battery-notify-linux folder) executable and execute it by double click (or) in terminal.
[*] Add the script in your startup (different DEs have different method, please check online for "add script/application in startup for linux mint") for automatically starting the script whenever your OS starts.
battery-full-notification-KDE5 by jruedaq