I am surprised to learn that Apple Watch Ultra has a larger battery than Garmin Fenix 6X that I use today:
Now lets hope the "battery optimization" to be released later this year will do magic with those precious 542mA...
The biggest problem I have in comparing any of these units is that their top line battery numbers are useless.
Take the Enduro 2 as an example:
Garmin’s site says:
34 days
110 hours of GPS
78 All Satellite Systems
68 All Satellite Systems and Multi-band
20 All Satellite Systems with Music.
(It does not seem to list an All Satellite Systems, Multi-band and music.)
For the Forerunner 945 LTE the numbers are:
14 days
GPS Mode with Music up to 12 hours
GPS Mode with LTE Live Track up to 10 hours
GPS Mode with Music and LTE Live Track up to 7 hours.
While that top line number of 14 days is cool, what I want to understand is if I actually use the GPS every day, what it really does to battery life.
My regular activities are: two hours of GPS walking/jogging every day (at a minimum – each dog gets a minimum of two miles, plus some about of time running with other dogs in the field while I pace around

), usually with my phone, one hour of indoor workouts every day (yoga and HIIT) one to two hours of jogging (on the track), usually without my phone and listening to music several times a week.
With my Apple Watch, I know I have to charge it every day, (usually I put it on the charger when I shower after the two dog walks), and again before I go to bed. Both times are about 15 – 20 minutes (it takes 45 min from 0-80% with fast charging and I am rarely under 15%).
What I would like to understand is how often I would have to charge either of these Garmin watches with a similar activity pattern.
I would also like to know how long does it takes to charge either of these watches from about 10%