Comment 13 for bug 357412

Unfortunately, the code in aircraft-manager-util (the script that does the real work) looks a bit like magic to me. It uses a raw interface to the hardware ports and figuring out whether or not it does the right thing requires a lower level understanding of what the hardware is doing than I have.

The best that I can suggest is to toggle the AC status. The following commands will do it:

    sudo aircraft-manager-util AC_CHARGING off
    sudo aircraft-manager-util AC_CHARGING on

If that and the suggestions in the two threads that you referenced don't solve the problem, then my best guess would be that it's a problem with the battery. Folks on the 'Ubuntu on the Dell Mini' google group might have additional suggestions.