850 Battery is Perfect
I was initially worried about the battery life from initial reviews but decided to pull the trigger for the better screen.
Yesterday I just completed my first century. 100miles in 6h30m with 4 stops. I run my 850 pretty much stock out of the box with connected heart and power sensors with screen brightness at auto. At the end of the ride I was left with 48% battery life.
I genuinely cannot think of a scenario where I would need more battery life than this. And if I ever needed to run an 10h ride or something obscene, I would just carry a light weight battery pack.
For 99% of use cases the 850 battery is perfect. Don’t bother with the negative reviews, the screen resolution is worth it!
Edit: adjusted for elapsed time instead of moving time