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Garmin 945 Altimeter issue
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A few days ago all my runs and bike activities on my Garmin Forerunner 945 started to record a really high elevation gain. I live in Florida and my daily run is normally only around 10 feet. Today it had 334! The same for my bike rides as well.

I tried to recalibrate the Altimeter following the instructions using GPS and DEM but neither worked.

Has anyone experienced similar issues and if so were you able to fix them?
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Re: Garmin 945 Altimeter issue [Tweeks07] [ In reply to ]
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Typically, when a Garmin altimeter dies, the errors are in the tens of thousands of feet, not hundreds.

Mine died in Florida after a swim in the Gulf. My next run after the swim had 16K feet of elevation.
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Re: Garmin 945 Altimeter issue [Tweeks07] [ In reply to ]
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Tweeks07 wrote:
A few days ago all my runs and bike activities on my Garmin Forerunner 945 started to record a really high elevation gain. I live in Florida and my daily run is normally only around 10 feet. Today it had 334! The same for my bike rides as well.

I tried to recalibrate the Altimeter following the instructions using GPS and DEM but neither worked.

Has anyone experienced similar issues and if so were you able to fix them?

This sounds high but not out of the question for a workout during changing weather. The altimeter uses barometric pressure, so if the pressure is changing in a stationary spot, the watch will read that as elevation change. FWIW, I've had some wacky gain/loss on treadmill workouts.

Was it relatively constant throughout the workout? That would indicate drifting barometric pressure. Or you could look at the recorded pressure in the area during your workouts on some weather sites.
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Re: Garmin 945 Altimeter issue [exxxviii] [ In reply to ]
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Mine died on the 935 a long time ago and usually a 10k run with maybe 100 ft elevation change records 1000+ ft
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Re: Garmin 945 Altimeter issue [Tweeks07] [ In reply to ]
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As others have mentioned, when the altimeter dies, elevation is usually in the 1000s of feet. A few hundred may be as simple as starting an activity before a full satellite lock or changing weather conditions.
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Re: Garmin 945 Altimeter issue [Tweeks07] [ In reply to ]
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this has happened to me a couple of times.

If you call Garmin support they will walk you through the diagnosis and if it's failed they will usually give you credit towards a new watch even if out of warranty.

Good luck,
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Re: Garmin 945 Altimeter issue [Tweeks07] [ In reply to ]
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It's a common issue with the sensor. Happened to me on a 920XT (once) and 935 (twice), every time I got a new/refurbished watch under warranty.

Apart from re-setting, which you already have done, they recommended me to soak the watch for half an hour in handwarm soapy water. The reason being is that the faults my be caused by crystals on the sensor, build up over time with swimming in swimming pools (their words), or possibly salty sweat. You could try that, but I would also contact Garmin.
It's one of the reasons why I've been considering buying a 735XT next, instead of a 945. The 735 doesn't have a barometric sensor, it calculates elevation by GPS (which is inaccurate, but won't break).
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Re: Garmin 945 Altimeter issue [Tweeks07] [ In reply to ]
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I'm another guy who's had a couple of barometric sensors fail on Garmins (even after the warm soapy water Nd using a fine soft 'teepee tooth gap brush to clean out the sensor hole- which did solve the problem once).
It typically would read 65k feet and then drop slowly... then back to 65k... drop slowly etc etc.

Like one of the other guys here I eventually sacked it off when the Garmin watch failed (again) for another reason, and went and got a non-baro watch (I got a Polar instead of Garmin - seems Garmin customer service in the US is good..but in the UK where I am it's been wank most of the time I've had to use it... which has been too often).
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Re: Garmin 945 Altimeter issue [Tweeks07] [ In reply to ]
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My post is a little off OP's topic, sorry, but didn't feel like this deserved its own thread:

I've noticed when uploading workouts from my Apple Watch (Series 5) that Strava always greatly increases the elevation gain on rides, but not on runs. On runs the elevation gain on Strava is often a little higher than what the Apple Watch reports but is usually pretty close and on average is about the same, average difference of +3.5 feet/mile on my last ten runs that averaged 48 feet/mile, and the gain is not always higher on Strava, sometimes it's a little lower.

On rides though there is a lot of disagreement between Strava and Apple Watch: for my last ten rides the average difference is +12.1 feet/mile and the elevation gain is always higher on Strava vs. Watch, average +25% and range +19-43% on my last ten rides. This is the case on basically every ride I do, not just these last ten.

Any guesses on what's going on here? Is Strava known to give generous estimates of elevation gain, or relatedly is the Apple Watch altimeter of questionable accuracy on bike rides for some reason (but not on runs)? From what I can determine, Apple Watch is using an altimeter to get elevation while Strava is checking some geospatial database. I don't think it's because there's more climbing on my rides vs. my runs: there's more total climbing of course because I typically ride a lot further than I run, but the average feet/mile in the workouts above are essentially the same, 48 for runs and 49 for rides. On my longest runs this year (four runs each of ~20 miles) the stats are ~the same as above: Strava and the watch only differ on average by ~1 ft/mi and Strava elevation gain is only about 4% greater. Relatedly, I also don't think it's necessarily a sensor issue (in that case the % disagreement on runs should be larger).
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