Garmin Edge 820 Battery Test Update

In this recent post, https://the5krunner.com/2016/08/05/navigation-fest-edge-820-and-others-do-9-hours-of-trail-navigation/, I managed to get about 8 hours of battery using turn-by-turn (TBT) navigation – GPS+GLONASS, HRV/per-second recording, HRM and a PM. It lasted between 7.5 or 8.5 hours. I tried a VERY similar route again today (near identical). This time I managed only 6 hours of battery. The only material…