Hello! My girlfriend's HP laptop running kubuntu 24.04 has this problem: when it's turned off (either from the GUI or poweroff) it discharges overnight, from 100% to 0% in a few days.
I searched the web to look for fixes:
wake on lan is disabled in the BIOS
USB ports have no settings in the bios, but there's nothing connected to them anyway
the system is actually powered off, not sleeping (at least if poweroff actually works)
everything, firmware included, is up to date
She doesn't remember having this problem from the beginning, but cannot tell when this started occurring
Did any of you ever encounter this problem? I don't know what else to do, and it's quite annoying.
I would check the journalctl logs to ensure it is fully turning off. If here is still battery drain and you are sure the laptop is off, then its a hardware issue rather than software.
But basically you shut the computer off, then on then do
journalctl -S -3m
Will show the last 3 mins of logs which you can go through and try to read the logs up until the moment it actually turns off to see what is happening.