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Edge 840: rain or sweat and elevation/grade inaccuracy

As observed with other previous Edge series (a.o. mine 830), the units are quite sensitive to liquid, be it sweat or rain, with spectacular erroneous altitude, grade and elevation gain readings as a result. Only after thorough and time consuming drying of the unit this stops.

This as a result of a hardware design failure, where water can enter the tiny port to the pressure sensor, hidden behind the USB 'protection' cover, which basically seals the electric USB port but, of course, not the pressure sensor port. No firmware update can resolve that.

Looking at pictures of the 840, I observe a similar design and execution of the cover lid (USB-C or micro USB does not make the difference here) and I really wonder if the described issue has been solved here (could be a motivation for me to buy the 840 sooner).

Is there anybody in the 840 owners group that have experiences with altitude readings in rainy or sweaty conditions?

An answer from Garmin where they confirm that this hardware bug has been mitigated is appreciated as well of course!

0 aweatherall over 1 year ago

The barometric sensor port is in a different location on the 840 than on the 830.

On the 830 it was behind the USB cover on the 840 it is on the side if the quarter turn mount.

0 daniel.belliniducati.com over 1 year ago

Hello my 840 Solar has the same issue. In case of rain elevation and grade basically are not measured. This issue is very consistent (sigh) and has been happening will all firmwares. Yesterday it measured 768 meters of ascent vs 2500 real

0 Martin Borsje over 1 year ago in reply to daniel.belliniducati.com

Very sad to hear, but thanks for noticing it here. I guess that Garmin relocated the sensor port location because of the "water issues" with some previous models, as the 830.

Some questions to me:

Did Garmin hardware development execute a root cause analysis on the water sensitivity of the barometric sensor and how to definitively mitigate that in future models?

Did Garmin test is with the pre-manufacturing batches of a.o. the 840, successfully? To me this would be a no brainer.

To enhance statistics, feedback from more 840 and alike owners is most valuable!

0 fabernova over 1 year ago in reply to daniel.belliniducati.com

Unfortunately I have to confirm the very same issues...3h under the rain today, and no reliable grade info (grade was always around+-1%, no matter I was climbing or descending) and total elevation recorded 220m when the actual is 1450m. Quite annoying, also learning this problem was already present in previous units.

0 6865192 over 1 year ago

I’ve had wildly inaccurate measuring of elevation while mountain biking in dry conditions with my 840. I’m not sure what’s up.

0 lapinou 11 months ago

Seems to be quite inaccurate indeed when it's raining, but more in the range of 10-15% lower compared to the same ride in the dry or Strava's data.

Doesn't seem consistent though: when I'm checking the "live" elevation during the ride on my 840, there will be times where elevation is rightly registered and sometimes not.