Fenix 5 shows/calculates completely wrong total ascent

Made a test-ride (mountainbike) withe Fenix 5 and Edge 500:

Fenix 5: Ascent 722 hm (this time I tried automatic calibration on ...with "off" I got already wrong results).
Edge 500: 792 hm (Edge was always good in this point)
Calculated manually from the altimeter-profil (recorded by Fenix): 776 hm

This means: Fenix records the altimeter pretty correctly, but it calculates the acent horrible wrong. This is too much difference. What the heck is Garmin doing??

Any ideas??

Edit: Basecamp shows 798 hm (with the gpx-file recorded by the Fenix 5). Unbelievable ....does the Fenix 5 "smooth" the profile and calculate wrong ascent???

0 tosonny over 8 years ago

Hi have found a hint in a forum concerning ascent. Garmin maybe (don´t know if thats true) calculates the ascent with the recorded track-points. I had the setup "intelligent" on my Fenix. On the Edge 500 "every second". I will try if "every second" brings a difference.

Folks, how are your experiences and settings?

(Unfortunalety Garmin-support ignores my questions so far.)

0 tosonny over 8 years ago

Today another test ride with Fenix 5 vs. Edge 500. Both the same setting (recording data every second):

Edge 500: trackpoints 10 489. Ascent 890 hm, descent 879 hm

Fenix 5: trackpoints 9 600 (started a bit later and ended a bit earlier, but no influence on ascent ...all flat). Ascent 783 hm, descent 815 hm

Fenix 5-track in basecamp: Ascent 869 hm, descent 891 hm

Either my Fenix 5 is grap or the firmware. Is there really no Fenix 5-User that do some mountainbiking and can tell about his experiences??? I cannot imagine that there is no one that can help.

0 eiwill over 8 years ago

I have used an Edge 800 together with the Fenix 5X during my recent MTB rides and I have found the numbers to be pretty much the same on the two units.

I haven't studied the details behind the numbers to the same extent as you have, nor have I used BaseCamp.

My morning ride today (data recording 1 sec on both units):
Distance:
Edge 800: 37,33 km
Fenix 5X: 37,31 km

Ascent:
Edge 800: 764 m
Fenix 5X: 760 m

Descent:
Edge 800: 753 m
Fenix 5X: 760 m (again)

0 tosonny over 8 years ago

Seems that bei Fenix 5 is not working properly.

0 Former Member over 8 years ago

The Fenix 5 being wrist mounted means it is more susceptible to temperature changes due to body heat transferring too it; and the temperature changes of the unit it's self can affect the altitude measurements since they can mess with the pressure readings.

As a test; perhaps try mounting the watch to the handle bars for a ride and see how it compares to the edge?

0 tosonny over 8 years ago

fiera Mariono

1) It is always on the handlebar.
2) Altitude is absolutely perfect.
3) Recorded ascent/descent/altitude-profile is perfect.
4) Shown/calculated ascent/descent is crap.

0 tosonny over 8 years ago

From Garmin-support:

As a rule, weekly revisions of the device firmware are still taking place. We would ask you to install it at the time of publication.

At the same time, we pass on the well-known deviations (also the mentioned link) to the software developers for the verification that this can be adapted with one of the upcoming updates.

A reset to factory settings or re-uploading of the firmware does not help here.

0 NoTex over 8 years ago

Generally I have good results with my 5x. The deviations are within +/-3%. Best accuracy is with an outside temperature of about 15°C. If it's becoming warmer the trend goes to underestimating total ascent, if it's becoming colder the trend goes to overestimating. I think this is due to a non-linear temperature dependence of the correlation between air pressure and altitude change. I noticed the same with my Fenix 3.

0 tosonny over 8 years ago

The Fenix 5x has - due to its maps function - not the same firmware. That´s what Garmin-support says ....because I asked and wondered about the fact, that the 5x shows ascent/descent correctly. It seems to be a bug in the firmware for the 5/5s.

0 Former Member over 8 years ago

Yesterday i went for a hiking.
It was a continuous ascent from 1315 mt to 2057 mt = 742 altitude gain.
My Fenix5 reported 2013 at the summit (-44 mt) and 597 mt total ascent (-145 mt).
Yes, I know that precision is influenced by temperature, that a wrist-worn unit has higher variation, that changes in atmospheric pressure .... bla ... bla...
But my friend's SUUNTO SPARTAN ULTRA was perfect: only 4 mt difference in total ascent!