@Tarrintaal
Yes, on many ultras ranging from about 4.5hrs/50km to 100hrs/450km. I normally have the watch permanently on the navigation screen and as far as I can tell it makes no real difference to how long the battery lasts.
You will definitely be ok for 30hrs unless you have the backlight on. If closer to 40hrs, you might need to be careful about some settings (though, if you’re out for that long, you’ll almost certainly have at least 10-15mins in an aid station at some point, where you could easily add about 25% points to the battery with a power bank).
Specific things to consider:
Backlight - turn it off completely, including raise to wake. If it’s too dim to see the watch without it, you will/should have your headtorch on anyway.
Autolaps - vibration & backlight when they trigger can add to battery drain, turn off or set infrequently (e.g. every 10km rather than every km).
Wrist HR - can you use an external sensor or just not bother with HR at all? When using an external sensor I get battery drain consistent with a 50-55hr run time (performance mode, autolaps every km, always on the map screen, climb alerts on). The wrist HR isn’t accurate for me so I’ve never used it on an ultra - therefore not sure if 40hrs+ is reliably achievable with it on. Hopefully others on the forum will have some experience to share - but if using the wrist sensor and likely to be out for nearly 40hrs, I’d make sure you are able to charge the watch briefly (10-15mins as above) if needed.
SuuntoPlus apps - I don’t know but some might increase battery drain, so don’t use any unless you really need them. Because I’m on the map screen all the time I don’t use any. I’d guess that those processing data that otherwise wouldn’t be (e.g. ZoneSense) could use more extra power than those just repackaging core data (i.e. time, speed and distance based stuff) but I don’t know.
In two of my recent ultras, using the configuration described - performance mode; backlight off; always on the map screen; 1km autolaps; climb alerts on; screen always on (no timeout); no SuuntoPlus; connected to either a Polar Verity Sense or Suunto HR belt - battery drain has been:
25hr48min, 170km - 47% battery used
9hrs6min, 85km - 17% battery used
For a 51hr/300km race last year, set as above except no HR sensor (wrist or external), it lasted the race with I think about 10% battery left.
Hope this helps. I’ve found the watch great for ultras - I think I’ve used it for 9 so far, covering about 1900km - so let me know if any other questions about how I’ve used it.
What race are you doing?