Garmin Edge 480 |best| Link

During our stress test (100km ride, 6 hours, navigation active, Bluetooth connected to phone), the battery dropped from 100% to 72%. This suggests Garmin is being conservative with the 24-hour rating. With "Battery Saver Mode" (which polls GPS less frequently), you could easily stretch this to a 30-hour ultra-endurance event or a week of commuting without charging.