What's your typical battery life?

Same here. Out of my disappointments with the 645, battery life is not one of them. I charge every few days during a shower or overnight and run about 12-15 miles per week, and I don't know that I've even gotten under 35% yet. At least for the average runner, the battery IMO is great.

Update re battery life (FR645 non music) now I’ve stopping “playing” with the settings
I’m quite impressed.
Basically good for 6 days use with average of 1hr GPS activity tracking per day
Or 12h gps tracking
Or 11d smartwatching

Stats:
6 days, 4 hours Total usage (to 1% battery)
5:55 hours of running/cycling GPS activity tracking

Settings:
Wireless & BT on.
Notifications/backlight on at default settings (8s)
HR monitoring on 24/7 (except one period of 7 hours)
Watch face : NoFrills (includes live step-count, Heart-rate, and Seconds: all things to avoid if maximising battery life!)

I did no activity tracking for first 48h & saw 9% battery drop/day, equivalent to about 11 days possible.
The 5:55 hrs GPS activity tracking saw a combined drop of 46% (i checked battery level at start and end of each activity)
So that’s 7.71 minutes per % battery drop, which would make almost 13 hours continuous tracking.

Other Notes:
Notifications Minimum 25/day so at least 20m combined backlight time, probably more.
You get at least an extra 0.5% on zero and it fails gracefully. I just lost the last 50 m of walking before battery died
Recharge is really quick. Not much more than an hour.

For me it's roughly 9 hours for GPS+ Glonass+ HR. I've had 2 FR645s and the both were basically the same in terms of the battery life.

I am using about 5% an hour with everything turned off. I have to charge it daily and I am not using any features. This has so far been a very expensive clock

Garmin 645 no M

7-9 days only smartwatch usage

2 months of use I check the battery with an app (Battery Analyzer). (10-12% at day)

I use only the smartwatch functionalities, notifications (lots!), steps counts , calories, weather of watch faces, NO Gps ativity (only for weather or calibrations sometimes).

Backlight auto, Wifi On (sync with my network), BT On (sync with my smartphone), at night I dont get the watch on my skin, but I never turn it off.

My NuviCam factory battery lasted 3 years 6 months. When it finally refused to hold a charge, the symptoms were as follows:

• The UI faded to barely readable. Regardless of charge indication, the unit display will fade and be barely readable.
  
• The car charger, when plugged in, dims the display.
  
• The unit responds as expected, if plugged in and the software is updated.
  

Here is what not-to-do when you see these symptoms:

• Don't try to crack the unit to see if you can replace the battery. It's glued in and you will wreck the unit if you force it.
  
• Don't unplug all the ribbon connections that are required to unplug to change the battery. The battery is designed to force you to send the unit in, to replace.
  
• Don't pay the $160 plus tax to replace it, because the refurbished one you get back, isn't why they set it up this way. The travel data is what you are sending them.
  

Does anyone have any information that might contradict this battery life data? Would love to hear from you.

This is the thread about the Forerunner 645(M)...
?

Two questions...

With the 645, has anyone tried tracking an activity with GPS on from 100% battery life until it died? Curious as to how long exactly that would last. I do adventure races which are typically 12 or 24 hours, so just curious.

Second, I doubt it, but will the watch still track an activity while it is charging?