Instinct 2 Solar Navigation

It can't, unfortunately, or at least not reliably.

There's a weird bug going on in Garmin watches for a long time now, even devices with a lot of memory fail to load gpx turn by turn instructions after like 100, but not consistently, just sometimes.

For me, there are times when I can load really long trails with many junctions without problems (not like 100 mile though, the longest was 50km), but sometimes it loads only like 50...

You can do 2 things:

-buy a watch with maps, it can automatically generate turn instructions using it's built in map, indefinitely

-use an app on instinct like locus, it sends navigation instructions from phone to the connect iq app, works like a charm for me

(You can also use the phone's GPS but record to the watch using this app, this way can walk for days with a power bank in the backpack, the watch lasts ages without GPS)

So if i buy a Fenix 7SS, i will have no crashes?

Fenix 7S is a better option - I2 navigation is limited to 50 waypoints and often crashes (memory issues, unlike it's predecessor which was super solid). You could bypass this by splitting the route into several smaller ones, but F7 has plenty of more nice navigation features not ported to Instinct (it can tell you information about upcoming trail junction, has nice screen showing distance to upcoming points - we're eagerly waiting for this to be ported to Instinct ;) ).

How many waypoints for F7? Enough for 100 miles?

I don't think F7 has any limit in waypoints - you have to ask on related subforum :) the 50 waypoint limit is artificial - Fenix1/2 had laughable amount of memory in comparision to modern Instinct and could handle more. We just have to wait till Garmin hopefully reworks the navigation, however I'm pessimistic here - they never did so in Instinct 1 :( 

Ultrawalker said:

How many waypoints for F7? Enough for 100 miles?

From the article User Data File Limitations of the fenix 7 Series | Garmin Customer Support : 

Keep the following limitations in mind when sending or creating files for your watch:

• 1,000 waypoints (saved locations)
• 100 courses
• 200 points per course
• Activities: limited only by storage space available on the watch, oldest activities will automatically be deleted when additional storage space is needed for new activities
• 25 workouts
• Unlimited points per activity (limited only by storage space available on the watch)

What happens after the 50 points limit? Will the breadcrumb route go on but without turn by turn navigation? If i see the line to follow, that's enough for me. Or will it crash and you have zero guidance?

The point number in route will be reduced. This means some of the points mid-route might be missing (can't say for sure, but tendency is to remove the points in later part of the route). It will seem complete, but occasionally will lead through a building or a turn will be super wide. Navigation is still functional, just not that precise. Not a great problem on a road bike ride, but in the mountains where trails tend to wind around can be problematic