At first, you need to enumerate the Power devices in your system (like the Main battery, Wireless Mouse battery, …) with the following command:
upower --enumerate
This will output something like:
/org/freedesktop/UPower/devices/keyboard_hidpp_battery_4
/org/freedesktop/UPower/devices/mouse_hidpp_battery_5
/org/freedesktop/UPower/devices/DisplayDevice
(mine isn’t a Notebook, so it has no Main battery). Take the Path which corresponds to the device you want to get information about (e.g. copy it to the Clipboard), and then run:
upower -i /org/freedesktop/UPower/devices/keyboard_hidpp_battery_4
Now, you get information about the battery stats for this device:
native-path: hidpp_battery_4
model: Wireless Keyboard
serial: 4023-00-00-00-00
power supply: no
updated: Thu 21 Jan 2021 06:34:15 AM CET (98 seconds ago)
has history: yes
has statistics: yes
keyboard
present: yes
rechargeable: yes
state: discharging
warning-level: none
battery-level: normal
percentage: 55% (should be ignored)
icon-name: 'battery-low-symbolic'
Alternatively, if you just want a one-liner for displaying all devices and their stat:
upower --enumerate | xargs -n1 upower -i