[Nate the great]

I started an empirical battery test at 7pm on Sunday. One condition I set was to keep the radio off as much as possible and essentially recreate the way I used my PRS500. I also have had it in sleep mode the entire time. I never turned it off.

53 hours into the test, I noticed that the battery is down one bar (75%).

So I guess I am looking at weekly charges. Not as good as the Sony, but acceptable.