Altimeter drift while on stable elevation

forums.garmin.com/.../altitude-changes-over-night-while-sleeping

Thank you. It is not good for you to have the same problem, but I am kind of relieved that I am not the only one. I compared with older Fenixes and the Fenix '1' behaves the same as the 7.  But with Fenix 1 and 2, I knew they had to be calibrated every hour or or so, as every ABC watch and Suunto Ambit at that time. Since Fenix 3, I haven't had to do that - until now. I think it is a software problem.

Maybe it helps to cover the sensor opening with waterproof tape before swimming?

That is not necessary. I swim several times a week and have no similar problems.

If you have altimeter/barometer problems that cannot be resolved contact Garmin Support. It is quite possible there is a hardware problem.

Thanks for reacting, but now I'm really worried my device is defective.. it still also has recurring USB connection issues, but not all the ime. I was putting off contacting Garmin Support, guess I'll better do that now.

Dr Phil said:

If you have altimeter/barometer problems that cannot be resolved contact Garmin Support. It is quite possible there is a hardware problem.

I contacted Support in my area. They had never heard of this problem, but did make a case for it. I'll update here when I hear back, they said it could take a while. In the mean time I keep the watch as dry as possible because that is the best 'fix' for now.

Hi. 
Issue you described I already reported as a bug some time ago. 
I started to observe it with Q3 software update and have same symptoms. Over the night calibration altitude dropped down 30 to 40 meters. 

Please vote my bug report. 

regards

Adam

Adam-1972 said:

Please vote my bug report. 

@Adam: can you post the link? I think I already upvoted it but I can't find it anymore. And there may be others who have the same problem and want to upvote it too.

As to the case via Garmin Support; I received a questionnaire to rate my experience with Garmin Support, and I am not sure if that means the case has been closed, or not.

Any developments on your part? Any difference with beta 15.68? 

Just a theory, starting with the the Fenix 5 Plus they disabled the baro/temp sensor in the pool swim activity because having the sensor powered on while exposed to chlorine could damage it. As there is no temperature recording during pool swims on later devices, I guess that this is also true for Fenix 7.

I did not have the pool swim activity running all the time I was at the pool. As a cool down, I like to leisurely swim in the recreational pool with the watch in everyday watch mode. Maybe that damaged the sensor a little. 

Or is it software? Big changes in weather, temperature and humidity levels throw it off for a few to 24 hours, almost as if there is some adjustment going on that does not when it should, resulting in erroneous drift. Otherwise it is OK. I wish I had more ways to test. Or the source code.

i have the same problem with my epix gen 2 software 17.23

contact Garmin Support

I wrote 8 months ago that I would post an update if I heard from them. They said it could take a while. But after 8 months, I don't expect an answer.

How big your problem is?
Could you show some pictures?
Altitude drift is always possible because watch uses air pressure to calculate it and when it changes during day also altitude will change.
Then slow altitude drift is nothing impossible, problem described here at the beginning was issue with auto calibration over night and as fas as I know this issue was solved.
At least I don't see it on my watch for some time.