My Voyage never lasted weeks, nor did my Oasis1. I got like 3-4 days out of both of those. I get about 2-3 days out of the O2. It depends on how much you read, not how many weeks. I can say, I have never ever gotten weeks out of any kindles I owned.
So yeah, a bit less than my Voyage and O1, but its still fine for what it is. I like to read a book a day. There is no device in existence I would get weeks out. Until they make a kindle with built in solar, I keep charging them as needed.
No kindle charges as fast as the O2 so that helps a lot.
My phone lasts longer than my kindles. My new phone that is. It goes on average 4 days.
But then I don't read on my phone.