I received a new Kindle on Thursday. Charged it and purposely left the units EVDO on over the last several days. This morning (Sunday) I woke up to read my morning paper and the unit was dead. I thought when I went to bed last night the battery meter showed 3/4 charged. So I did go from Thursday afternoon until Sunday without a charge. I'm not sure if that is good or bad. With my old Kindle (I had it replaced for the new one) I could go up to 7 plus days without a charge as long as I manged the wireless and only turned it on when needed and didn't use it much.
My 2 cents,