Memory out of range

I was kinda wondering what your app actually does with all that data. 

Yes your app can store its own fields in FIT files, but:

- activity data (i.e. data recorded continuously during the activity, at a max rate of once per second) has to be numerical (integer or float), not strings

- there’s a limit to how many fields you can store in a FIT file (the limit is a bit less than what you store in that example object ). last time I checked, the limit was 16 fields

- the worst part is the limit applies to the entire activity, not just your app. meaning that even if your CIQ data field app by itself doesn’t exceed the limit, if another CIQ data field app which writes FIT data is installed alongside yours, they might combine to break the limit.

However if you are writing a device app and not a data field, you might be able to squeeze most of your data in. You might have to drop some of it, like the timestamps. (There’s no point in writing timestamps unless you need millisecond-level precision)

See: https://forums.garmin.com/developer/connect-iq/f/discussion/234758/what-is-the-limiting-number-of-developer-fields-that-can-be-added-under-session?pifragment-1298=1

https://developer.garmin.com/connect-iq/core-topics/activity-recording/

https://developer.garmin.com/connect-iq/api-docs/Toybox/ActivityRecording/Session.html#createField-instance_function

https://developer.garmin.com/connect-iq/api-docs/Toybox/WatchUi/DataField.html#createField-instance_function