The battery level of my Bluetooth headphones was not displayed by default. To correct this, a simple change is all that is needed:

Adjust configuration file

In the file /etc/bluetooth/main.conf, an

Experimental=true

must be inserted in the section “[General]“. You can then restart either the entire computer or only the Bluetooth service with

sudo systemctl restart bluetooth

and the battery status is displayed in the settings under “Energy”, for example:

Ubuntu zeigt in den Einstellungen Akkustand an

Show battery status in the top bar

So that I don’t have to take the diversions via the settings, I display the battery status of the headphones directly in the top bar next to the time. I use the following Gnome extension for this:

https://extensions.gnome.org/extension/5615/battery-indicator-upower/

Akkustand von Bluetooth Kopfhörer in Ubuntu