the halt command is like a handbrake for the kernel, so it basically shuts everything down hard and stops, but it does not power off the system without you telling it to, so that is why your LEDs stayed on after you used the other parameter.
you could just try to downgrade/ upgrade the kernel, do s shutdown for a few hours during daytime when the computer is not beeing used, then turn it back on and check the percentage.
you will see the drain if it’s not a full night, but it might not be so drastic.
if it’s completely shut down there should be no loss in percentage, even for a short period of time as there probably is now…
I’ll try to think up another solution, but a bit busy today as I mentioned on the last post
probably related to this kernel bug though:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2059738
downgrading the kernel should fix it as a workaround it would seem.