Originally Posted by Satan1974

When you unlock the car, all of the "background" electronics wake up. When you lock the car, they switch off after about ten-fifteen minutes. I would say - put the iPod somewhere you can see it, but still connected (if possible, I don't know how long the lead is). Lock your car, then half an hour later, look through the window but don't unlock it. I expect you'll see that it's switched off.