I'm using LXPanel 0.9.3 and I'm noticing that the lxpanel process is periodically writing into ~/.cache/lxsession/LXDE/run.log the line " (lxpanel:1065): WARNING : Battery 0 not found" even if the system is on idle. This happens on a desktop PC without a battery where the battery applet is activated but configured to hide if no battery could be found. I would not expect with this setup to get this warning. Even if the battery applet would be configured to not hide if no battery could be found I would not expect to see this warning getting spammed (I'm not sure if this setup should throw a warning at all).
I'm agree, this looks as a bug, in such setup it should do test silently.