Altimeter Fenix 5

My Altimeter has been all over the place from 5k feet to -1k feet. I reset it and it moves again. We are very cold here (-15 mornings and +20 during the day) so that might have something to do with it.

Ok, I thought that had the problem fixed but it isn't. We have a Polar wind with low temperatures of 1ºC (don't laugh) and got several spikes in altitude.
What solved the problem was:
Put some water in the hole and don't calibrate the altimeter. The altitude will start to decrease.

Personally it's not a big problem because I can live with 2 weeks/year with this problem.

Mine was fine all day until after my cycle this evening. Quick rinse with water and 10 mins later, the altitude had climbed from the usual 30ft to 6000ft. No body wash involved this time, so it looks like water caused the F5's sensor to go crazy.. being a tri watch this is not great!

Update: pouring water in the hole... it went from -50 to -1300 at the moment and rising (well, decreasing). lol.

jose.cboliveira Count yourself lucky! I'm into my second month and 3rd watch with these issues.

I've stayed in auto watchmode for the last week or so with the new (3rd) watch and have had altitude spikes up to 65000 ft almost every day. I'm switching to altimeter mode today and will see how it goes.

btw, Has anyone brought this up with the beta team? I'm wondering if they are in the loop since customer service doesn't seem to be too concerned.

I've got you all beat. This is a picture of my brand new three day old piece of crap Fenix 5. This is my third brand new Fenix 5 since launch. The LCD on the first two failed but this one is the first one to have a failed altimeter, barometer, and temperature.

I've performed at least 5 GPS calibrations on the altimeter today.

I really like this watch a lot and held off on the Fenix 3 for years waiting for this one, so I will take it back to REI and get FOURTH NEW ONE. ciq.forums.garmin.com/.../1306252.jpg

I've stayed in auto watchmode for the last week or so with the new (3rd) watch and have had altitude spikes up to 65000 ft almost every day. I'm switching to altimeter mode today and will see how it goes.

Changing modes will do absolutely nothing in your case. If you see 65000 ft spikes, you have a faulty reading from the pressure sensor. Changing to altimeter mode will not fix that.

Changing modes will do absolutely nothing in your case. If you see 65000 ft spikes, you have a faulty reading from the pressure sensor. Changing to altimeter mode will not fix that.

I'm not sure I totally agree. I do agree that high altitude is based on low pressure reading. The question is why is the ambient pressure reading all over the place.

I'm fairly convinced this is a software issue (or hardware design/software ineraction) rather than hardware quality given that many of us have the same problems on device after device. In auto watchmode, there is definitely an issue. I'm playing with Altimeter watchmode this week to see if the problem is the same. I suspect it will be. Next week I'll use Barometer watchmode. Past experience tells me that the watch will be more stable in barometer mode, but I never performed any real controlled study. I suspect that there are issues with the conversion of ambient pressure to altitude algorithm along with the feedback loop for calibrating the ambient pressure sensor. Just a hypothesis at this point though.

I'm fairly convinced this is a software issue (or hardware design/software ineraction) rather than hardware quality given that many of us have the same problems on device after device.

Some of these users have avoided the problem by avoiding static electricity from their clothing. This very much points to a hardware issue. It also points to the watch being sensitive to certain usage patterns which could explain why the same users are experiencing the problem on one watch after another.

Also, it seems far fetched that software should cause the reading from the pressure sensor to be wrong. The software path from sensor readout to storing of the value is probably quite short and uncomplicated, with not much chance of a bug. (There have been some reports of a custom watch face perhaps triggering the problem, but nobody has reported the steps necessary to replicate this.)

I think there is more to this issue than we (or Garmin) knows. And I did acknowledge in my last post that this could be a hardware/software interaction.

Further, I don't fully understand how static electricity would cause the ambient pressure reading to slowly drop from ~790 mbar (Local altitude is ~2100m) to ~100 mbar over the course of several hours and then return to a "normal" value over the next several hours. Can you help explain that? My smartphone pressure sensor doesn't do that in the same environment. It seems that the software is doing something in this case even if it is compensating for bad hardware design. If that is true, perhaps some software changes could address the issue.

Lastly, when I put the watch into barometer mode last month, I saw far fewer pressure drops (altitude spikes). That also supports my theory that software may be involved. But like I said, I want to confirm this next week.

That all said, I will experiment with the water/soap soak and or some kind of anti-static tape.

Cheers all. Hopefully, they get a fix soon and we can all get new watches.

UPDATE: I'm sold on the static electricity theory. I was able to easily make the ambient pressure drop by rubbing the watch in my hair. I live in a very dry climate, so even easier. By washing in soapy water as others have mentioned, the pressure starts rising again. Rub the hair, dropping, etc.

So my questions are: Why is the reaction so slow? (software?) and what can be done until Garmin fixes that is more permanent than daily washing? I'll be trying the anti-static tape, but I'd be interested to see if anyone else comes up with something. Maybe rubbing lotion into the holes?

Further, I don't fully understand how static electricity would cause the ambient pressure reading to slowly drop from ~790 mbar (Local altitude is ~2100m) to ~100 mbar over the course of several hours and then return to a "normal" value over the next several hours. Can you help explain that?

No. I have absolutely no idea how the static electricity affects the measurement. All I am saying is that pure software errors can't be affected by anything physically influencing the watch. There has to be something hardware related for that to happen.

Similar problem... I recently bought a new Fenix 5 sapphire. I went for a short run with constant elevation at around ~10m. After finishing, when I looked at the data it indicated an elevation gain of >700m. The temperature was all wrong, at -30C!!! Then, I monitored the watch and the temperature fluctuated between -40C and -25C. The altitude skyrocketed to 20,000m. I tried synchronizing the watch, resetting, etc, and nothing. Later on, the temperature, pressure and altitude all went to "--" (no data shown). Recently, the watch has started to show temperature/pressure/altitude data again. The temperature started at around 0C and escalated to 20C (correct temperature) in a period of several hours. The altitude went from 15000m to -100m, and then started increasing again. Right now, altitude is at 4300m. The correct one should be 10m... Then, it has decreased to 1400m.

The watch was bought less than two weeks ago. It has suffered no damage. I called Garmin USA but they won't replace because the watch was bought in EU, and now it is to me to deal with EU although I am not based there...

What do you advice? I have had several Suunto devices with barometric sensor and never faced this issue!