Altimeter Fenix 5

That’s why I have turned to the Suunto and altimeter/barometer is spot on even in frequently weather changing environment. I had big issues with Garmin in low altitudes it is going very often to negative values, I don’t live under the ground...

But what we see in the graphs is that the altitude changes are not always correlating with the Barometer changes.

As far as I can see, they correlate perfectly, and your watch behaves exactly as it should in Auto mode.

The more your watch overestimates the Barometric pressure (which is measured ambient pressure corrected to equivalent sea level ambient pressure) compared to your nearby weather station, the more it also overestimates your altitude. This is exactly what your diagram shows: The closer the blue and the orange barometric pressure lines are to each other, the closer the grey altitude line is to you original altimeter calibration.

Th is how the relation between altitude, ambient pressure and equivalent sea level pressure is supposed to work: If the the watch thinks that it is at a higher altitude than it really is, it will also calculate a too high Barometric Pressure. And vice versa, if it thinks that the Barometric Pressure is higher than it really is, it will calculate a too high altitude.

You have the choice between three modes:

• Barometer mode:
  The watch will think that any ambient pressure comes from a change in equivalent air pressure at sea level.
  This will work as long as you stay at the same altitude and have calibrated the watch to that altitude. Your watch will show correct Ambient Pressure, Barometric Pressure and Elevation.
  But if you go to the mountains near München and the ambient pressure drops because of the altitude is increasing, the watch will think that the equivalent pressure at sea level has dropped, and that you are still at München altitude. So the watch will show a too low Elevation and a too low Barometric Pressure. But it will still show the correct Ambient Pressure.
  
• Altimeter mode:
  The watch will think that any ambient pressure comes from a change in your altitude.
  This will work as long as the equivalent pressure at sea level remains constant, and you have calibrated your watch to this pressure (or altitude). Your watch will show correct Ambient Pressure, Barometric Pressure and Elevation.
  But if the equivalent pressure at sea level is decreased, the watch will think that you have moved to a higher altitude, and it will update the Elevation while keeping the Barometric Pressure constant. So the watch will show a too low Elevation and a too low Barometric Pressure. But it will still show the correct Ambient Pressure.
  
• Auto mode:
  The watch continuously tries to guess whether ambient pressure variations were caused by you moving to another altitude or by variations in the equivalent pressure at sea level. And it will switch between Barometer mode and Altimeter mode accordingly. Every time the watch makes a wrong guess - which it will, since it can only be a guess - your altimeter and your barometer will drift a little.
  

In short: A barometric altimeter (or a barometer you want to be able to use at changing altitudes and still show the correct equivalent pressure at sea level) needs constant recalibration. You can't just set it once and forget about it.

Allan that doesn't explain why altimeter move from - 10 000m to +20 000m...

Allan that doesn't explain why altimeter move from - 10 000m to +20 000m...

If you look back on previous posts on this thread you will see that the wild fluctuations in altitude are likely caused by faulty ambient pressure readings, which is a raw measurement that the watch makes.

The prevailing thought is that it has to do with bad pressure sensors. Others have brought up the issues with watch faces and possibly mobile android causing some sort of glitch. Looking at the fenix 3HR thread where others had similar issues, it leads me to believe that garmin must just either use cheap pressure sensors, have poor quality control, or both.

I'm on my second watch with the same issue, wondering if I should return it again or switch to a different brand that is more reliable. I would really love this watch if it actually did what it was supposed to.

I agree that Garmin failed to fix altimeter/barometer issue on all their devices for years I’ve had f3hr/f5 and both had same glitches, so poor design, sw,fw,hw or all combinations of them. I am quite often going for hiking or mounteneering so altimeter readings for me are quite important, now I am using Suunto Spartan Sport Baro and altimeter never failed even in frequently weather changing environment, so seems Suunto opened holy grail of altimeter reading :)

Goog morning, see here
https://forums.garmin.com/forum/on-t...x-3-hr/144392-

This is Fenix 3 HR 1000+ posts thread. It seems that this issue is nothing new to Garmin :(


I've got mine Fenix 5 Sapphire just after Christmas and I'm not sure if it had erratic altimeter from the very beginning. I started to dig into the problem when watch hasn't counted any floors after 11 floors climb.

Tried numerous configurations, read the forum and decided to remove all custom watch faces and widgets two days ago, In the meantime watch got upgrade to 7.60.
Last two days was in automatic mode with steady altitude, but I stayed home whole two days.
Two days the moment I got out of home this happened:


When I put watch in Barometer mode altitude stays steady, but immediately when I put it to Altimeter or Auto my altitude goes nuts.

Is there anything I should try before returning this watch and requesting new one? :(

Allan that doesn't explain why altimeter move from - 10 000m to +20 000m...

Why did you expect that my post should explain that?

The person I was replying to does not have the problem you mention. His problem is entirely different.

Why did you expect that my post should explain that?

The person I was replying to does not have the problem you mention. His problem is entirely different.

@ SebLeclercq and AllanOlesen67 - You're both right :-)

The explanation and my graphs gives and understanding that ambient pressure, barometric sealevel pressure and altitude are corelating and changing due different weather conditions. Furthermore - if the watch is in Auto modus – the recalibration feature try’s to assume if ambient pressure changes are a result of weather changes or geographical moves from the user. In many post her I have missing this basic understanding.
The graph and the explanation also demonstrates that my watch is working well.

It does not explain why my watch showed unrealistic altitude datas and Sea-level Pressure (as you SebLeclercq and many other user are reporting here) some weeks ago and what made the change to get correct result as I'm facing in the moment.

What I have changed so far?

• Update to 7.1
  
• Removal of all external watch faces
  
• keeping the gear away from water (no shower, no washing)
  

I started my measurement and got the explained correct results. One time with Auto Mode (and you see some aberrations which Allan explained), one time on Barometric mode (I add the graph here in this post). The Barometric pressure to ambient pressure has a average deviation of 0,2 hPa or 0,02% to the scaled weather station of the university next door to me.

I’m curious now how it works with

• the new 7.6 Software
  
• external watch faces
  
• soap baths etc.
  

I know there was a strange behaviour also on my watch and I’m still searching how I can reproduce this.
Major thing is that we always have to check the ambient pressure (see post of AllanOlesen67 on 12-12-2017) to see if the sensor or the software is producing strange results.
ciq.forums.garmin.com/.../1299687.png

K.Schuetz After 7.6 didn't had any problem. As I said before, the problem stopped after deleted all watches faces (since then, added big numbers watch face without any problem), no soap baths either. Did several runs in cold weather with synthetic clothes and I have been using wool jackets.

Usually I rinse the watch in cold water and soap after each exercise and let it dry.

K.Schuetz I'm a bit afraid to jinx it, but after 7.6 and removing all watch faces my watch has been operating without any problems. I also rinse the watch in running water and dry it off after workouts. Low temperature and synthetic clothing has not been a problem either. As I suspect my phone to mess it up, I now do any changes I want on it directly through the buttons or via usb-cable from a computer. I still have it connected to the phone by Bluetooth for notifications and workout data transfer.