With the release of KDE 4.11 I saw this nice picture showing that the battery applet supports Logitech hardware (at least mouse) battery status.
http://www.kde.org/announcements/4.11/s ... applet.jpg

In my case it does not work and upower does not see it either.

Code: Select all

$ upower -e
/org/freedesktop/UPower/devices/line_power_ADP0
/org/freedesktop/UPower/devices/battery_BAT0

I looked around and I found a utility called Solaar which recognizes my Unifying receiver with a M310 mouse and a K520 keyboard connected on it. It even shows their battery status.

Can anyone help to troubleshoot this? I would like to have everything integrated in the battery applet.

My system specs:
Dell XPS 13 Developer Edition with Kubuntu 13.04 installed from scratch and updated to KDE 4.11 using kubuntu backports repository.
Solaar was also installed from a repository.

I can confirm your experience, my Logitech keyboard battery shows in Solaar but not in the battery plasmoid

I wonder if this is a upower issue as it does not show when running upower -e

Logitech awareness is recent to upower, supposedly added in 0.9.19, maybe a newer version is required

KDE is only able to show the information made available to it by UPower - so you probably do need to upgrade to a more recent version of UPower to get this functionality.