battery level percentage different with and without power connected to laptop

[Heather Ellsworth]

Hardware: Lenovo T590
OS: 19.10

I have the battery percentage displayed next to the battery icon in the top bar (Tweaks -> Top Bar -> Battery Percentage). When the power cord is connected, it says 100%. However, if I unplug the power cord, the percentage drops down to 94% immediately. Plug in the power cord again, and it's back to 100%.

If I let the battery discharge a bit so the unplugged state shows 91%, then plug in the power cable, it says 100% briefly before updating to be 91%. Let it charge for a few minutes so with the power connected it says 92%, then unplug the power and it says 93%.

The percentage displayed when the power is connected vs when the power is not connected is not consistent with each other like it should be.

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: gnome-shell 3.34.0-1ubuntu1
ProcVersionSignature: Ubuntu 5.3.0-13.14-generic 5.3.0
Uname: Linux 5.3.0-13-generic x86_64
ApportVersion: 2.20.11-0ubuntu7
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Sep 30 11:22:42 2019
DisplayManager: gdm3
InstallationDate: Installed on 2019-09-13 (16 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
RelatedPackageVersions: mutter-common 3.34.0-3ubuntu1
SourcePackage: gnome-shell
UpgradeStatus: Upgraded to eoan on 2019-09-19 (11 days ago)

[Heather Ellsworth (hellsworth)]

The output of `upower -d` with the power cable plugged in.

[Heather Ellsworth (hellsworth)]

The output of `upower -d` with the power cable unplugged.

[Heather Ellsworth (hellsworth)]

Brief video displaying the behavior. You can see when the power is connected or not because the lightning bolt shows up when the power is connected.

[Daniel van Vugt (vanvugt)]

I remember seeing this in Paris on my laptop. So confirmed.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Heather Ellsworth (hellsworth)]

After testing this a bit more, I noticed that when plugging in the power the battery percentage says 100% for *some period of time* before changing to match the percentage that upower has. The time it takes for the percentage to go from 100%->true% varies anywhere from a second to minutes but it does eventually seem to settle back on the upower reported percentage.

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 19.10 (eoan) reached end-of-life on July 17, 2020.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in.