FIT file too big (40Mb) for my activity : How can I add it in my Garmin Connect ?

Do you understand my activity !

It's a very long activity: 143 hours.

The size of the file is of course larger.

I get it, I know how demanding can be an ultra trail (btw, congrats about the Tor). 

My question is about this function that can be found in settings:

Data Recording

Sets how the watch records activity data. The Smart recording option (default) allows for longer activity recordings. The Every Second recording option provides more detailed activity recordings, but may not record entire activities that last for longer periods of time.

If you change this to 1 second (as dc rainmaker suggests) you will end up  with bigger FIT files. In your case you should have sei it as "smart recording".

Your activity is very much an edge case.  By all means suggest Garmin increase the limit. However, that most certainly will not happen any time soon. In the mean time, why not save the activity as suggested while recharging? Stitchthe smaller files together afterwards. 

Dr Phil said:

Stictch the smaller files together afterwards.

And then what? You still end up with a file which is too large for garmin connect.

3322154 said:

I already tried to reduce my file with other app ( with FitFileTools)

While that site is helpful in many cases, such as fixing corrupt files, not so great at file size reduction.

3322154 said:

The file size is 40Mb : It's a very small file

Based on typical computer file size, it does seem very small, but I've seen several cases where files greater than 25 MB won't be accepted by Garmin Connect. Nothing else wrong with the file. Not corrupt in any way, just too big. I agree that Garmin should increase this limitation.

3322154 said:

(I can send you my file / I will upload to a sharedrive)

tmk2 said:

You still end up with a file which is too large for garmin connect.

But not for other sites.

While it would be good to see Garmin make changes to the file size, that is unlikely to happen anytime soon. In the meantime we have to work within the parameters of what we have whether we like it or not. 
Most of the runners at ultras I’ve been involved in have supporters, and I would have thought that would be the case for the OP here. Even if not, watches have to be recharged at some point for an activity of this size. It’s no difficulty to stop the activity, save the activity, recharge the watch, and start again. As I’ve said, I’d much rather have a number of smaller files anyway rather than risk losing the whole event. 

Dr Phil said:

You still end up with a file which is too large for garmin connect.

But not for other sites.

For other sites the original large file can be used. There's no point in splitting it into smaller parts and then stitching it back together.

Dr Phil said:

It’s no difficulty to stop the activity, save the activity, recharge the watch, and start again.

I don't want to tell anybody how to run their ultra races, but this way you lose large (and quite important) parts of general situation awareness. After the first split you don't even know the cumulative distance and time, you don't know your averages, you don't know the ETA. Even course navigation can become tricky in some circumstances. If you don't have this kind of information during the race, then there's little point in using the watch at all (again, my personal experience and opinion).

3322154

How did you prevent the activity from being saved while you were charging the watch? I've tried this and each time the activity has been saved and had to be restarted. My process was as follows: 

1. Start an activity
2. Either, Stop the activity and select Resume Later OR just plug the watch into a charger without stopping the activity.
3. Charge the watch
4. Press start to resume only to find the activity has been saved and a new one has to be started.

On this basis I can't see how it is possible to create a single file on the watch that spans 143 hours. What did you do? The process you took to achieve the single file spanning 143 hours might be of use to others.

3322154

Bumping this to get a reply from the OP to my post seeking more information about how he recorded 143 hours of continuous activity.