Edge 520 Plus total elevation gain inaccurate?

Got a brand new 520 Edge Plus and seeing exactly this. Group of 6 riders, 5 of us have different Garmins. After 65km of MTB riding, an Edge 705 showed 576m gained, an Edge 1030 showed 583m gained, an Edge 530 showed 590m gained - all very consistent. And then my Edge 520 Plus showed a measly 488m gained. I previously owned an Edge 705 and before that an Edge 305 and I know the total "normal" gains for various MTB routes I do, and the new Edge 520 Plus is always 20-25% lower, and not matching any other Garmin, or a map-based calculation of elevation gain either. I consider the barometric unit defective on my new Edge and pushing for a repair / return. If there's any other way to correct or possibly calibrate the device through e.g. a firmware menu, I would love to know.

Allan

Seeing same behavior discussed in Edge 530 forum, and I gave some input based on some extensive testing I've done with my Edge 520 Plus. Would encourage Daniel to try out the same approach if possible and report back what step triggers the behavior of total ascent getting wrong: https://forums.garmin.com/sports-fitness/cycling/f/edge-530/228979/total-ascent-under-calculated-during-all-rides-noticed-elevation-field-decreasing-during-recent-6-minute-300-ft-climb

Mine tends to be accurate on clear, warm days and inaccurate on wet, muggy ones. As a workaround I would suggest using Strava's 'correct elevation' tool, which can be applied by navigating to the ride's page of strava and clicking the link 'Elevation (?)' under the current elevation figure.

As I returned my Edge 520 Plus for exactly the issue with ascent tracking, I can't test any more and have gone back to my trusty old Edge 705 that functions perfectly - but battery life is starting to be an issue, so still have to make a move to a new cycling computer in the future.

However I do have a strong suspicion on what is causing the issue, which can easily be tested: Based on experience also from a co-riders Edge 820, I suspect it's the Bluetooth connection to the phone and the Garmin Connect or Garmin Connect IQ apps that are keeping the Edge 520 Plus overloaded, so it misses recording many of the altitude changes from the barometer.

This should be very easy to test: Find a short hilly route to drive, preferably with many smaller ups/downs - it probably only need to be around 5km / 100hm. Do one run with Edge connected to phone and on phone have BOTH Garmin Connect and Garmin Connect IQ paired and connected to Edge 520 Plus. Then disable Bluetooth on the phone so no connection can be made and do the same route one more time. Then compare total ascent across the two runs - is the latter e.g. 20% more ascent than the former?

If anyone is able to do such a test, please report back. Getting to a scenario where we know how to avoid the issue may even make me come back and repurchase the Edge 520 Plus :-) Though I would hate to miss out on the LiveTrack and crash notification features, which are big for me coming for a decade old Edge 705.