Outdoor Recreation Archive

fēnix 5 Plus Series Fenix 5s Plus Altitude / Elevation problems - any solutions?

Fenix 5s Plus Altitude / Elevation problems - any solutions?

Former Member over 6 years ago

Hi, I’ve returned 3 Fenix 5s watches due to faulty altimeters. I then got a Forerunner 735 which worked perfectly but didn’t like the look of for daily wear. I got the Fenix 5s plus about a month ago and the elevation is all over the place. I run the same routes all the time and generally do laps and the elevation data is completely different every time - seems to differ on every lap, never mind every run. I run with a friend who wears a FR 235 and her elevation graph is perfect whereas mine makes no sense. I start at 60 feet and will always end up at least 30 feet lower when I return to my start point. Last week I ran a completely flat 5k but the elevation graph looks like I spent the whole 5km running downhill - which wouldn’t make any sense at all considering it was an out and back route.

I have been reading the forums and changed settings of Watch Mode to Altimeter only tonight and while sitting on the sofa I have apparently descended from 360 feet to 339 feet.

Any idea what are the best settings to prevent this? I don’t understand how 4 Fenix 5s watches later I’m still having trouble. The trouble with this one is starting way earlier and I didn’t have the altitude drift issues with the other watches.

My main priority is to get the elevation working for my runs. Tomorrow I have a hill repeat session and I don’t trust the watch to work at all!

Thanks in advance for any help.

0 Former Member over 6 years ago

Is auto-calibration turned on?

I had a similar issue, in which altitude was not consistent and I turned auto-calibration off. I enter manually the starting altitude at the beginning of the activity.

0 Former Member over 6 years ago

Thanks for the reply. I changed it to auto calibration at start and also the watch mode to altimeter and this morning was an improvement though I still needed to enable elevation correction in Connect after to get it more correct. It then means what shows up in Strava is incorrect if transfers directly. I’ll leave that setting for my next few runs and see what happens.

0 Former Member over 6 years ago

I’ve just spoken to Garmin on the phone and they have emailed me the latest beta software to see if that works. I don’t see altitude or elevation mentioned as something they have changed in the various updates though ????. Has this worked for anybody?

0 Former Member over 6 years ago

As far as I know, most watches don't have a "True" altimeter but rather calculate the altitude based on barometric pressure. As this changes all the time, there will always be a deviation in the altitude. See Garmin's explanation in the support page: https://support.garmin.com/en-GB/?faq=QPc5x3ZFUv1QyoxITW2vZ6&searchType=noProduct

0 Former Member over 6 years ago

To update, I changed some settings so auto calibrate is at the start of a run only and I turned off auto calibration while I’m not doing an activity. There is a slight improvement in that the altitude drift is not as huge while I’m not doing an activity. It still tends to decrease steadily (albeit) slower throughout the day though. During an activity the elevation graph is still not true as such. Today I was doing speed work doing laps of a pitch and it looked like I was going uphill throughout the run. Elevation correction afterwards fixed it and I have to do it after every run. Therefore Garmin Connect then looks correct but Strava looks incorrect as it takes the data from GC before I get to enable corrections.

I wish It worked the same way as my forerunner 735 in terms of elevation. Otherwise I love the watch.

0 Former Member over 6 years ago

The first pic here is the elevation graph from my watch after running loops round football pitches the other day. The second one is after I enabled corrections in Garmin Connect. Considering I was running loops the second one is obviously correct for the route I was running. Can anybody explain how I get the watch to give me the correct graph after a run? I calibrate etc obviously. ciq.forums.garmin.com/.../1468654.jpg

0 crutlefish over 6 years ago

Did the weather change at all whilst you were running those loops? A small shift if barometric pressure could potential confuse especially given the very small actual variance in altitude.

My guess is that the weather got slightly better halfway through the run, as you can see that the watch is still tracking you going up and down an elevation.

(For what it is worth, I really dislike that the graphs are based on the lowest value, not zero. So it looks like you've run up and down, when it all actuality, you've covered very little elevation in that run)

0 Former Member over 6 years ago

KarenMcHu Your friend's 235 and your 745 didn't have a barometer. Elevation from those devices use geographical surveys just like enabling elevation corrects on Connect. The reason you're seeing elevation changes is because the barometer in your watch is detecting changes in pressure. You have 3 modes you can use. "Auto" tries to interpret if the pressure change was due to actual elevation change or weather. Sometimes this works well, other times it "guesses" wrong. "Altimeter" mode sees all pressure changes as a change in elevation. "Barometer" mode locks the altimeter and sees all pressure changes due to weather. Depending on the terrain and weather you are training in you can select which will work best for you. The key is too manually calibrate the altimeter and barometer prior to your activity and re-calibrate often to known values.

0 Former Member over 6 years ago

Thanks for the replies. The weather is very settled this week so there may have been a slight increase in temperature by a degree or two but otherwise clear skies, light breeze and no change.

I get that it guesses wrong sometimes but this is literally all the time which I never had before on my other Fenix 5s’s. The issue with them was the altimeter just completely going altogether after a few months. I have done a full reset on it today as advised by Garmin and hopefully tomorrow’s run will be an improvement. I had it set to Altimeter mode which did give a very slight improvement. It seems to be better not having the continuos calibration on too.

crutlefish - I agree, the graph looks like I was covering steep terrain before you examine the numbers whereas I was running around flat football pitches ????

0 ekutter-dnu over 6 years ago

You're also talking about very small elevation variations here. The barometric pressure is going to be more accurate at detecting elevation changes than the GPS, but it still has its limits. The drift could easily be from weather or from just the temperature difference as your watch acclimates to the outside temperature or is impacted by your body heat.

Corrected elevation is just throwing away the elevation recorded by your watch and using the 2D GPS coordinates to look up elevation on a map. In very flat settings, this may be more accurate. But with any real hills and mountains, it would likely be much worse.