I was recently reading the Forerunner 920XT review. The 920XT apparently does not allow you to charge the watch while in activity. I’m wondering who approved that? Even the old and cheaper series 410 allowed to do that as I wrote. I know the watch is aimed at triathletes and the battery life is enough for even an Ironman triathlon if you’re a bit trained, but there are longer races. Races I like participating in - ultra running (or ultra marathons if you wish).
Unless you decrease the “sampling” interval significantly any watch will hit the limit. Consider some 24 hours, 30 hours times. Anyway happy I replaced my 410 by fēnix 2 some time ago. It’s a great watch, though slightly bigger. But more importantly allows you to charge and keep moving. That’s all I need, basically. Show me time, distance and charge. If you can show time while charging (fēnix 2 does) even better.
So here you are. If you’re searching interwebs for the information whether fēnix 2 charges in activity - yes it does (and you can fully operate the watch). Hope the 920XT behavior is a glitch not a trend.