The computer was bought new, from Los Alamos Linux in 2016. It has two batteries
- BAT 0 is working great -- vendor=SMP, model:=00HW023, serial=1035, energy-full-design=23.5, energy-full=21.4, capacity=90%, technology=lithium-polymer
- BAT1 is the problem -- vendor=SANYO, model=01av405, serial=2477, energy-full-design=26.33, energy-full=22.07, capacity=83%, technology=lithium-ion
The issue isn't short battery life (although it is short) - it's that one minute it says 50% remaining, the next it says 4% remaining.