I uninstalled flipclock this afternoon, and I've had a couple of reboots on power since then. I guess it's looking like i should go ahead and order a battery.
Edit: Anyone have a suggestion on where to order them?
I received the new battery yesterday, and my n810 has been on the charger for ~12 hours without a reboot. That's about 12 times as long as normal, so I am hopeful that this fixed things. Thanks for your help.
I've had my tablet reboot at least 3 times (that I witnessed) in the last 2 hours, while not hooked up to a charger. The tablet was in idle. It did it at least once yesterday, since then I uninstalled anything I had installed recently. I have flipclock (like mentioned previously in this thread) but I've had that installed for a long time and never had any problems with it.
<edit> I have a N810, Diablo (current version, 43-7)
At least in my case, it is not Flipclock's fault. It is the battery. But all my reboots are while charging, with different chargers (some seem to provoke reboots more often than others, though).