Message to support

I am having problems with my laptop's battery.
I use Linux (Pop!_OS 21.10, a variant of Ubuntu).

I tried to run the Lenovo live USB Linux diagnostics tool to see if it might have a battery diagnostics tool, but was unable to boot it, hitting this problem: https://forums.lenovo.com/topic/view/27/5101058

Sometimes the battery discharges with a nice, reasonable linear discharge curve:

2022-02-20 13:47

Sometimes when I disconnect the battery from the charger, it will not even show anything.

Right now that's after a wake-up from being in the charger.

$ cat /sys/class/power_supply/BAT0/present
1
$ cat /sys/class/power_supply/BAT0/power_now
cat: /sys/class/power_supply/BAT0/power_now: No such device
$ cat /sys/class/power_supply/BAT0/voltage_now
cat: /sys/class/power_supply/BAT0/voltage_now: No such device
$ cat /sys/class/power_supply/BAT0/energy_full
66390000
$ cat /sys/class/power_supply/BAT0/energy_now
cat: /sys/class/power_supply/BAT0/energy_now: No such device

2022-02-20 13:59

And now it seems to be here:

$ cat /sys/class/power_supply/BAT0/capacity
86
$ cat /sys/class/power_supply/BAT0/power_now
21977000
$ cat /sys/class/power_supply/BAT0/voltage_now
15598000
$ cat /sys/class/power_supply/BAT0/energy_now
56910000

2022-02-20 15:24

And now it's here again:

$ cat /sys/class/power_supply/BAT0/capacity
34

2022-02-24 16:19

Support case submitted: https://pcsupport.lenovo.com/ch/en/products/laptops-and-netbooks/thinkpad-x-series-laptops/thinkpad-x1-extreme-3rd-gen-type-20tk-20tl/20tk/20tkcto1ww/r90zjsj9/repair?problemId=E0376KLCQF