I have a GPS Rangeman, GPR-B1000. Like the watch a lot. I noticed some behavior lately that seems odd to me. My watch is currently showing 3 bars of charge and spends time off my wrist near a south facing window with a fair amount of sunlight. I normally use a watch face that shows the sunrise and sunset times for my location.
I recently put the watch outside on a sunny day to charge. It was also a warm day, with temperatures in the mid-80s Fahrenheit (but well below the top end of the range of 41 to 95 F mentioned in the manual). After some time (probably a couple of hours) the watch, on its own, shifted back to the default face which does not show sunrise and sunset times. The second thing it did was show only one bar of charge and warn me to charge it. This seemed odd, as the watch had shown 3 bars of charge before I put it in the sun to charge and I would have thought the charge level would only increase.
The manual notes (page 5) that you should not charge the watch in direct sunlight for long periods. It also notes that you should not use the charger in temperatures above 95 F. So what happened was probably a result of having the watch in direct sunlight for too long on a hot day.
When I bought the watch back in the house (temperature around 72 F) and looked at it an hour or so later, it was back to showing 3 bars of charge. It was still on the default watch face.
I have more recently seen this behavior in less extreme conditions. I had the watch in a south window on a sunny day in the house, with a temperature around 72 F. The watch switched on its own from the display screen with sunrise and sunset times to the default screen. It did, however, continue to show 3 bars of charge.
Last weekend, I was out for a bike ride on a warm (temperature around 80 Fahrenheit) and sunny day. The watch was on my wrist, in and out of shade. The watch again shifted from the sunrise/sunset time face to the default display. And at the end of the 1 1/2 hour ride, it showed no bars or charge and warned me to charge it.
I am planning on taking the watch on several trips where I will be outside in warm and sunny conditions. I am wondering whether I will have problems with the watch.
I don't particularly mind it shifting to the default face -- I can shift it back. But I worry when it suggests it has no charge.