I understood pretty well what you said. That is why I was so flabbergasted. You are now partially contradicting yourself. Your first post was "Battery is not important" and now "Use it efficiently" (why if it's not important?) and "Battery is not important" at the same time.
Now on topic: from what I've seen so far googling this seems to be a bug. Multiple distributions (Arch, RH etc.) have patched this upstream. Not sure if fix is available for Ubuntu (which Ubuntu are we talking about here?)