I have a 1st generation iPod touch (3.1.3 OS) and it keeps randomly shutting off if I don't have it plugged in. It doesn't matter what I'm doing. It was fully charged and I was listening to music and it died in 5 minutes. Sometimes it doesn't even last that long. When I plugged it back in it said the battery was around 90%. I had the wifi shut off so I know that's not the problem. I've tried shutting it down many times and that doesn't help.