mines the same, full charge and only collects about 9 miles of data before battery goes to about 20% and saves the workout and then lasts about 30 minutes and dies

can you change the batteries in them?

Thanks for your reply! I think I will just return this watch and get an Apple Watch instead. Im not sure how Garmin can justify charging $300+ for a watch that doesn't update in a reasonable time frame. 

I have noticed something similar, in the opposite end of the scale. When I charge the watch to 100 percent, it will still be at 100 percent well after one night of sleep. The scale is not linear. 

Well I just disabled mine so will see . Given that it is mid day I won't really know for sure until the morning after tomorrow since I do a full charge at about the same time every morning.

Note that battery life is not linear. I charged mine to 100% yesterday and I'm now at 99% after ~23 hours of usage. By tomorrow it should drop as usual (~10% a day unless I'm doing an activity).

I've re-charged my VS4 for a test, and same as you, BB of 100 at the end of the day. So definitely wrong. In my experience VS5 is close to my Fenix 8 estimates on stress levels and BB.

Ah interesting! It’s such a shame because I love Garmin but am now not really reviewing the data because of this. Also now a continual issue with the charging cables is making me think of a change. I’d prefer not though.