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Inaccurate altimeter on new Instinct Solar

3472614
over 3 years ago

I have been reading numerous posts about altimeter issues and had hoped I might be immune - nope! One primary reason why I dropped $400.00 for this watch was for hiking and trekking; the altimeter is important to me, especially when backpacking and trekking.

I calibrated the altimeter to my known elevation outside my front door and did three short test hikes over the course of a week. Along the exact same route, the Instinct recorded the peak elevation as 545ft, 209ft, and finally 422ft. 

How can I rely on the device to provide accurate data when required for acclimatization purposes at high altitude if it can't even handle a short 500 foot hill at home?

  • 0 over 3 years ago in reply to R L

    No, I just looked online at the Instinct Solar manual and you can calibrate your altimeter and barometer independently.  Here's a clip from the manual.

    "You can manually calibrate the barometer if you know the correct elevation or the correct sea level pressure."

    That being the case, I never contradicted myself and calibrating both is possible.  I don't know where the misunderstanding is, so I'll try to explain in an example.  I just got home and I can see both my elevation and pressure readings are incorrect.  This can happen for several different reason, but those aren't important for this discussion.  I just looked on my phone and I know the current pressure as I have a weather station less than a 1/2 mile from my house.  If I go and calibrate just my altimeter to the correct known elevation, my barometer will also adjust, but in my case it's still off by .03 inHg's from the correct pressure.  If I were to start an activity without going in a setting the correct pressure, one of three things will happen. 1.  If in barometer mode my altitude won't change.  2. If in altimeter mode, as soon as my barometer changes on it's own to the correct pressure, the watch sees this as elevation change even if I'm on a flat surface.  3.  If in auto mode, the watch will try and figure out why the pressure changed and it will switch to either altimeter or barometer mode.  Sometimes it guesses right, other times it does.  So, as I've said from the start.  For the most accurate readings you need to calibrate both prior to your activity and then set the watch in the mode that best fits your environment.  Your recommended solution just prevents the altitude from auto calibrating which will do you no good if the barometer isn't correct from the start because as it starts correcting itself to the correct pressure, it will affect your elevation depending on what watch mode you're in. 

  • 0 over 3 years ago

    Which firmware version are you using? My values were previously off by +-50m max. With the new version 11.76 I woke up 250 meter lower than I went to bed. And I had just calibrated the altimeter the same evening.

    Not quite sure what the calibration does, if the value only lasts a couple of hours before drifting wildly.