I have a lowend netbook with debian-type linux only (no dualboot). Power management should be via XFCE4's xfce4-power-manager-settings.

I'm having weird behavior with suspend and trying to identify/troubleshoot it. It seems to be usually draining power and never charging when the lid is closed for many hours.

I tried explicitly entering power off, hibernate and suspend followed by unplugging then leaving it a few hours but couldn't replicate. It seems to be doing something on its own after being unplugged a long time.

What logs can I look at to see when my device changes its power modes, what were the triggers, what settings are governing it etc?

I can't tell if it's a software issue or there is some sort of power saving thing going on in the hardware or what.

Just hoping for some investigation tips here, I know its not enough info to solve.

Edit to clarify no dual boot.