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"ETA to Dest" wildly inaccurate in V9.75

Jeff
6 months ago

My Edge 830 is running version 9.75. Many years/iterations ago (Edge 800?) I found the "ETA at Dest" field - time for completing a route - to be quite accurate after a few hours. This is no longer the case. I took some photos of my gps from a recent ride and the table below contains the results. For some reason the Edge is using a wildly incorrect expected speed.  On the left is the raw data from the photos. The middle is the calculated predicted speed that the ETA represents given the remaining distance. The table on the right is what the ETA would be if it was calculated from the average speed up to that point. 

Can this be fixed so it is useful again? Is there some logic behind the current behavior?

Data from Edge 830: calculated from remaining dist/avg speed/current time
current time dist to dest avg speed garmin eta calculated predicted speed hours to dest eta
07:00:00 AM 124 n/a n/a n/a n/a
09:20:00 AM 94.08 13.4 08:27:00 PM 8.46 7.02 04:21:15 PM
01:58:00 PM 43.85 12.6 06:58:00 PM 8.77 3.48 05:26:48 PM
03:47:00 PM 25.27 12.5 06:17:00 PM 10.11 2.02 05:48:17 PM
04:00:00 PM 14.25 12.7 06:00:00 PM 7.13 1.12 05:07:19 PM
04:55:00 PM 9.93 12.7 06:00:00 PM 9.17 0.78 05:41:54 PM
actual finish time: 05:40:37 PM
  • 0 6 months ago

    I mentioned this on the "540" forum a good while back and got no answers. To put it bluntly, " Time to Destination" is very inaccurate and unusable. Garmin seems to have some stupid algorithm to calculate it and it is not based on average speed or even current speed. The only time it seems to be right is when you are almost at your destination.

    It is also not just V9.75, it has been like it many versions back.

    But, if you use a 3rd party datafield, based on current speed or average speed, it will be spot on.

    I also use Virtual Partner a lot too on my old "800" but using my "530" it is unusable as it is also way out with timings but never got a reply when I mentioned that also.

    So basically, Garmin has a timing issue with its 530's and 830's in its firmware.

  • 0 6 months ago in reply to leginswal

    I called today and spoke with someone who said they'd file an engineering report. I'm not hopeful but maybe. He said "If this was a problem with the current devices, they'd be getting lots more calls about it." Maybe everyone who has this problem should call?  (https://support.garmin.com/en-US/?productID=621232&tab=topics and click 'call' on the bottom of the page to request a callback).

  • 0 6 months ago in reply to Jeff

    They have probably not had many calls about it because most people have not noticed the error and just accepted the "Time" given in the date field as being correct and not done the "Sums" in their head to see the inaccuracy.

    I never got any comebacks from Garmin about it which over the years I have accepted as normal for them. For a leading exponent of navigation devices, when it comes to training devices, they are useless. The aviation and maritime industry would not put up with using flawed devices full of bugs.

  • 0 6 months ago in reply to leginswal

    Many are probably like me, they just don't bother giving up valuable time in their life to complain.  When I saw that the ETA was always wrong I just replaced that field with "distance remaining" and do the math in my head as I ride.