Congrats on your slow draining battery. I have also noted that the Edge 500 battery will continue operating for quite a while when the battery needs charging. While riding with cadence, heartrate, and speed sensors, plus course navigation, my older Edge 500 unit operated for about 45 minutes with the "battery low" annunciation on. The screen then blanked. However, all data was saved and I successfully downloaded some fast times to Garmin Connect.