[geek1011]

What does the output of "grep -Er . /sys/class/power_supply/*/uevent" look like after unplugging at 100%, 10 min into reading a book, and while idle at 50%?

Note that you'll want to run this while WiFi is off. This can be done by piping it into a file and/or syslog from a NickelMenu cmd_spawn/cmd_output. Something like "menu_item:main:Save power stats:cmd_output:grep -Er . /sys/class/power_supply/*/uevent | logger -st power 2>&1 | tee /mnt/onboard/power_`date +%s`.log" (and the same for menu_item:reader) would work.

It would probably also be a good idea to record the CPU usage too.