I never noticed, but Ubuntu isnt showing the battery level of connected Bluetooth devices. One needs to enable experimental features in bluetoothd first!
sed -i -r 's/ExecStart=.+/& -E/' /etc/systemd/system/bluetooth.service
systemctl daemon-reload
systemctl restart bluetoothRunning upower -d will show the information:
Device: /org/freedesktop/UPower/devices/headset_dev_AA_AA_AA_BB_BB_BB
native-path: /org/bluez/hci0/dev_AA_AA_AA_BB_BB_BB
model: Bluetooth Speaker
serial: AA:CC:DD:DD:EE:AA
power supply: no
updated: So 12 Jun 2022 09:06:20 CEST (49 seconds ago)
has history: yes
has statistics: no
headset
warning-level: none
percentage: 100%
icon-name: 'battery-missing-symbolic'