The OS probably does eat up battery life. I suppose given the Apple watch is more a Swiss army knife that’s meant to do everything, not just fitness.
I don’t know what processor is used on Garmin watches but doubt it requires or has the processing power of an Apple Watch. I‘m not sure with respect to smart watch capabilities as I’ve been mostly looking at their Forerunner models which focus on fitness.
For instance they just release a few new models including this 965
which has an incredible 23 days of smartwatch use. This is how they arrive at their estimated battery life:
|Notifications per Day||50|
|Number of Interactions per Day||160|
|Device-Generated Alerts per Day (Move or Goal Alerts)||2|
|Hours per Day Outside of Bluetooth Range of Phone||1|
|Display Brightness and Timeout||Default Settings|
|Average Number of Hours per Day Spent Outside1||5|
|Number of Gestures per Day||750|
|Pulse Ox Mode||Disabled by Default|
|Number of Minutes of Streaming Music||0|
|Number of Timed Activities||0|
Up to 23 Days
I admit it’s not entirely easy to compare Apples to Garmins. But damn, I‘d love to see Apple’s mainstream models get at least closer to a week between charges.