This won't directly help you, but with Linux I learned that the laptop not olny knows the battery charge level, but whether the ac adapter is powered up and plugged in. Now on my laptop, which died on me, there was a big amp drain that caused the battery to run low even with the adapter plugged in. That meant the draw was too much for the adapter and it could not maintain the -19.5 vdc level it was rated at. It finally fried that adapter and the upgraded adapter I got for it. The repair shop could not find the problem, so I am out for the repairs and the price of a suitable repllacement. Be glad you don;t have those problems.
I can suggest trying a different LiveCD and install, even to a USB drive. That way you can eliminate the possibility of a software glitch in the Linux build or layered software, Go with an older LiveCD in case it is in the kernel upgrade. This is called easter-egging, and what it really is is making change to elimate possibilites untul you nail down the cause, Then if ir is software related, post it to answer your own question, and maybe open a bug report on what you learned from your efforts.