Battery intermittently "disappears"
I've got two Activo AV-1000 netbooks. First one had its HD go bust and since I didn't have Win7 installation discs at hand when I got it replaced, I threw Fedora 17 on it. However, it suffered from major battery-related issue that I'll try to describe... firstly, the battery intermittently "disappeared" - the battery icon in the system tray kept flashing (disappeared and then reappeared after a fraction of a second and then disappeared again after ~1second again). At first I though this was a Gnome3 issue, but this happened on KDE as well. Secondly, the system kept getting progressively slower and slower, and I found this was due to upowerd eating out the CPU (eventually, the system would become unusable). Anyway, simply taking out the battery fixed it, and I later ended up replacing F17 with Win7. That laptop had previously had some problems, so I figured it's just a dud and didn't look into that issue any further.
Now, though, the second one, that's my main netbook, exact same model... had Debian stable on it (have also previously had Slackware, which worked just fine), but got a bit tired of having somewhat outdated software, decided to install F17, and 10 minutes afterwards I thoroughly regretted it... the exact same problem as described reappeared: the icon intermittently alternates between adaptor online, full battery and adaptor offline, no battery detected (using xfce); upowerd CPU usage has steadily gotten higher and is currently fluctuating between 20% and 35% (the system has been running for roughly an hour).
Any ideas what could possibly be wrong?