Practical limits to activity time/duration/length

From the document How Do I Manually Upload an Activity I Recorded to Garmin Connect? 

Garmin Connect supports .fit, .gpx, and .tcx files. These files cannot exceed size limit of 25 megabytes (MB) per file. There is also a limit of 99,999 total points per file. 

And although it refers to the manually imported files, I suspect that the same limits apply for the standard file transfer too. 99.999 points with the Every Second Recording equals to slightly less than 28 hours. The size of the file strongly depends on the number of sensors, and additional IQ data fields you use, but at a few sample activities I checked, it was around 60 bytes per second (with every second recording). With the 25MB limit, it would be sufficient for over 100 hours, if I calculate right. Check the size per second on some of you older activities.

It means you are more limited by the max number of points, than by the file size (assuming your watch has sufficient free storage space). In other words, you better change to the "smart recording" and make some tests, to see how many points per hour you get, in average. You can then calculate whether it will be within the limit or not.

Another problem though, is the battery. You will need to recharge regularly during those 10 days.

... BTW, I would recommend splitting the race into multiple activities anyway, regardless the limits. It is much safer, and certainly better losing just a small part, than losing everything, in case something goes wrong. You can always merge the individual files into a single activity, for example with the File Combiner at https://www.fitfiletools.com/ 

Thank you! That is super useful. I'll test further but it sounds like it should be done as a few separate activities to be safe... 

The watch will definitely have to be recharged a few times. Although, with the correct battery setting selected it should last ~100 hours in GPS only mode (no multiband, HR, BT, music, pulse ox. etc.) Couple that with solar and being outdoors for 20 hours/day, it should last quite some time. There is a LOT of sun above the 60th parallel this time of year 

toadzurg said:

t should last ~100 hours in GPS only mode

Yes, theoretically yes, but I would definitely not rely on it  It may be also a pity not having the HR.

Good luck with the race! And please let us know how it finished, and whether the recording completed successfully.

Definitely will! It would be cool to have all the data, but wrist based HR without a strap is not super accurate. I think its common for all upper body sports.

Also if you have an activity on pause your watch will not record stress or sleep data, if you care about those. 

toadzurg said:

wrist based HR without a strap is not super accurate. I think its common for all upper body sports.

I do not own the F7, so cannot judge. I have Instinct 2, which is very light, and it records the HR almost as reliably as my HRM-Pro. With the heavy watches like the F7 or MK2, it is certainly much more challenging, because due to the increased inertia, they tend to move more on the wrist.

Are you doing the Yukon 1K? That's epic! Would love to hear about your experience after you finish the race as well.

Yep! I'll post an update after :) 

toadzurg said:

but wrist based HR without a strap is not super accurate

I’ve been finding the OHR on the F7 almost as good as the strap for most activities.  IMHO there’s been massive progress since OHR made its debut to the extent I no longer feel I have to wear a strap. Even had some good sprints recorded the other day with the OHR. Apparently you won’t actually save much battery not having the strap. I have seen somewhere where it’s more battery economical to have the strap than not. 
Good luck with the event. Would be really good to see the joined activity posted when you finish.