I have the Fenix 5s and the battery does not last an entire Ironman without charging it during the race, even after shutting off most features. I have a small wrist and the size of the watch is perfect. I am due for a new one and looking at the Fenix 6s or Fenix Pro (next size up). Does anyone have experience with the 6s lasting a 12-13 hour Ironman/Ultrarun?

Thanks!