Yesterday, my battery lasted around 14 hours with moderate use and wireless + bluetooth on.

Last night as a test, with a full battery, I clicked power + Turn off. I then turned it back on, made sure it was in "offline" mode and locked the screen. This would ensure that nothing I had started running would interfere.

It was stone cold dead when I woke up 8 hours later.

What the heck?

I haven't used the RSS reader, so it has nothing to update on mine.

I have noticed sometimes I'll have it sitting on my desk and suddenly the screen comes on for no reason. Typically I've had the wireless active when that happens, so I attributed it to that.