Some people in this thread seem to have made the perilous mistake of taking the battery status symbol seriously. When the battery status says "almost full", it means "this battery is going down soon, baby!"

I have made the mistake of looking at the battery status bar and concluding I had plenty of juice and WAY LESS THAN FIVE MIN|UTES LATER I had to stop a Skype call because I was getting the low battery warning. Fortunately, I always have a full battery waiting in the wings.

(By the way, the "low battery" signal is also very unreliable. I was once jogging and about to take the branch of the run that makes it a seven mile loop. Then I got the "low battery" signal so I swerved off to finish a shorter run--I didn't want to jog without my sounds! To my surprise, the mp3s I was listening to were still going strong by the time I finished.)

The moral: just because you think you've got lots of juice left in your battery doesn't make it so. And many of these problems are caused by a low battery -- and I wonder if sometimes the quality of the electrical connection where you plug in to recharge also plays a role.