I just started getting this same problem but I'm using Sanyo Eneloops. It's consuming batteries when it is off. I recently put in a freshly charged pair of Eneloops (that work well in other devices like games, cameras, etc.) and in 36 hours of being off they were dead. It was never powered on. It's worked well for most of the month that I've had it until the last week or so. It's always had a 4GB card in it. Have you had any luck with solving this? I'm going to check the altimeter recording settings tonight to see if this is a problem.--E.
