I'm asking this question here because the FR935 has been around longer than the 945.
I have a FR945 (no warranty) that has not seen much use until I started using it 24/7 recently. It may have been lying around with no charge for some time. That's never good for a battery.
The battery lasts 2 days and it charges too fast (20 minutes to 100%), suggesting part of the battery isn't functioning.
Youtube has some videos on battery replacement for the Forerunner 235 and 735xt. But when I look at replacement parts, it seems that the entire screen+bezel should be taken off instead of only the screen (as you'd do for a smartphone screen repair).
Normally I'd buy a broken similar watch for parts off Ebay to practice on first, but there are none at this time.
So, anyone opened theirs up? How? Did you manage to get it closed and waterproof? I'd appreciate hearing from you!