So along with my ongoing woes with the battery I did a battery test overnight and before going to sleep I set off a run activity and placed the watch on my bedside table. 6 hours later I woke up and glanced at the watch. I had done ~800 steps and travelled 13km! Eh? The watch has been stationary and not even on my wrist. How on earth can I have done a 13km run while I am asleep and watch not even being worn?
If the watch is indoors it has limited GPS signal but is trying to determine your position. GPS has an accuracy tolerance even with a good lock. If you look at the map from the activity you won't have a spot but a squiggle. Every point recorded is subject to this tolerance and at either end of the tolerance, there is a distance. Say one spot is accurate to 5 meters, you could jump 5 meters with each reading. Moving a few feet ever second for 6 hours adds up.
I am going to have to do the test again as I was wondering about the 13km I completely forgot to check the battery level until much later in the day!! DOH :)
I don't have its % on the watch face just a battery icon (I use the standard Garmin digital face).