I recently bought a used Thinkpad T480. It has two batteries. New version of this laptop are supposed to have an 17-hour battery life. I don't expect Linux to necessarily match that, but even still I'm having odd behavior.
My Linux system (Ubuntu 22.04.1, running Kubuntu with 5.15.0-58-generic).
1st, when I unplug from power, it takes about 2 or 4 minutes for the system to even recognize it is unplugged and switch. This isn't just a KDE problem, since upower on the console has the same issue. Any thoughts on why this is so?
2nd, is battery performance themselves. I know these batteries are used, but their performance is WAAAY worse than I expect. I use the watch + upower command to check details:
upower -i /org/freedesktop/UPower/devices/battery_BAT0
native-path: BAT0
vendor: SMP
model: 01AV421
serial: 1660
power supply: yes
updated: Tue 17 Jan 2023 04:08:18 PM PST (88 seconds ago)
has history: yes
has statistics: yes
battery
present: yes
rechargeable: yes
state: discharging
warning-level: none
energy: 20.99 Wh
energy-empty: 0 Wh
energy-full: 22.39 Wh
energy-full-design: 24 Wh
energy-rate: 6.33 W
voltage: 12.197 V
charge-cycles: 91
time to empty: 3.3 hours
percentage: 93%
capacity: 93.2917%
technology: lithium-polymer
icon-name: 'battery-full-symbolic'
upower -i /org/freedesktop/UPower/devices/battery_BAT1
native-path: BAT1
vendor: Celxpert
model: 01AV424
serial: 516
power supply: yes
updated: Tue 17 Jan 2023 04:10:18 PM PST (90 seconds ago)
has history: yes
has statistics: yes
battery
present: yes
rechargeable: yes
state: fully-charged
warning-level: none
energy: 19.27 Wh
energy-empty: 0 Wh
energy-full: 19.27 Wh
energy-full-design: 24.05 Wh
energy-rate: 0 W
voltage: 12.675 V
charge-cycles: 213
percentage: 100%
capacity: 80.1247%
technology: lithium-polymer
icon-name: 'battery-full-charged-symbolic'
When it is plugged it, upower initially estimates 10.0 hours of battery performance. When I unplug it, then the estimate drops to 5.0 hours, then a few minutes later, it drops to 3.0 hours, then it jumps back up to 4.0 hours. Finally it settles around the 3.3-hour mark. Meanwhile the KDE power icon estimates 7.5 hours.
A causal usage test confirms I get only about 3.3-hours of battery before the whole system loses power. (Also KDE does NOT warn me about power getting low, but that maybe another story.). I don't see any evidence that it even draws power from the second-battery (BAT1).
Is there anything I can do software-wise to improve this? This battery life is atrocious.
