I bought this laptop brand new in February this year, and only in the last week or so has it started showing this brokenness. The degradation was somewhat gradual, since I was able to run the laptop only on battery power, and it would shut down at some point, even though battery indicator was far from empty. But now it's not even turning on at all on battery power, and it shuts down immediately when I remove mains.
acpi, I sometimes get:
Battery 0: Charging, 99%, charging at zero rate - will never fully charge.
Battery 0: Charging, 99%, 00:19:41 until charged
Could this output be wrong, claiming 99% when the battery is nowhere near that?