Yesterday I finished a ride and stopped/saved the activity. The Edge 530 went back to the "main" screen. I did not explicitly turn the device off. When I attempted to use the device this morning I discovered that the battery was dead. I seem to remember the Edge 520 having an "auto power-off" feature, whereby after a certain period of inactivity the device would power down. Am I remembering this correctly? Does the 530 have this?