low Fric unable to update profile

[RoadWarrior]

Hello all,

I did a training ride today, short bursts, and once finished PP gave me for the first 2 go's a far to high power value,
over 1300 Watts.
now i checked using 'Analyze - Check calibration' and it showed me that a correction would change the values significantly:
Original values:


Accepting calibration changes:


We can also see that the calibration changes are marked as very significant:


When I choose to send the profile to iBike, I receive the following error:


where is this discrepancy coming from?
I did a calibration ride, as lined out in the instructions: ride until power climbed to 50w, after ride the same way back.
I used it only on 1 bike so far.
everything else seems to be measured normal, but I can't upload the calibration changes since I checked the PP inside isaac after the initial calibration ride.

the original and corrected files are attached.

Please advise

[Velocomp]

The problem is the first 90 seconds of your ride. PP was in a very different rotational position compared to its original cal ride. You can see this from the very high slope at the beginning of the ride.

Screen Shot 2020-08-17 at 1.22.26 PM.png (147.11 KiB) Viewed 4810 times

I edited out the first 90 seconds of the ride, then applied the Check calibration feature for the remainder. This worked. Your PP was pretty close to being correctly calibrated, so the correction doesn't make much of a difference.

[RoadWarrior]

thank you, but where does he take these wrong rotation positions from?

[Velocomp]

If you remove PP from the mount between rides, or you bump it during or between rides, or you walk with the bike with PP on, any of these things can cause the tilt calibration to change. During the first 90 seconds of each ride, if there is an issue PP will automatically correct itself.

[RoadWarrior]

Understood. this means in order to have 'clean' data in Garmin f.e. the ride should not be started in Garmin until 2min into movement then.

[Velocomp]

That would work...

[RoadWarrior]

Thank you,

today I found another strange thing.

I did a lunch ride, approx 21k in nasty weather (rain and wind the blew in the middle section from front left)

did half the loop yesterday and used more power based on pp than today with nastier weather and over a longer time in these conditions.
(I can understand that bursting 11k gives more than 21k, but the speed against the wind was nearly same)

I had a look at the ride file afterwards and found the following:

Start and end of ride show an increased amount of power. End of ride shows 4000km/h


Now from before discussion I understand the starting, and could imagine the end (I hang my bike upright on the wall, but stopped the activity on garmin before)
looking at the calibration check we can see that it says 'Noticeable Change' with Power changing from 195 to 201W.


Accepting the changes also shows a change of the wind in the middle section where I had nasty wind from left front.


If I try to send the new calibration to the device I get the known error, based on the values at the beginning and end:



I did cut off the start and end of the file and also defined that it is not a out and in ride, since I passed my starting spot in 700m distance when I reached half of the loop. (Even it is an in and out ride, but the ride is in the middle there where Isaac expects the end, see the annotations in the above screenshots), I also changed the elevation of the start and endpoint manually from 170m to 5m above sealevel:


we can see the values that all change and make the whole ride more accurate.
But we can also see, that the PP misunderstands/misinterprets the IN/OUT ride, since he takes my starting point to the first turning point as OUT-ride and then the distance to the 2nd turning point he defines as 'IN end at halfway to 2nd turn' when passing starting point in a distance of 700m to the east.

After this has been done, the wind in the middle segment changed again and the used power also changed:


As we can see in the Calibration check, the change is moderate:


but then if I try to send this calibration to the device, with start and end cut off, I get this error:


what am I missing?

please find the original file and the changed attached.

[Velocomp]

The root cause of this problem is that your device is in a different position from where it was when you calibrated.

You should mount your device in its position, make sure it can't rotate, then do a new cal ride.

Once you do this you should be OK.

[RoadWarrior]

Thank you, but what do you mean by 'in a different position from where it was calibrated'?

It hangs under my Garmin like it did when it was calibrated.

Or do you want to line out that the little play of the device inside the GoPro mount has this impact?

[Velocomp]

PowerPod can measure angle differences as small as 0.05%--that is a ½ foot elevation change for 1000 feet traveled down the road.

The instructions say that:

1) The device should be attached and rotated such that the device tabs butt-up against the mount

2) When in the correct position, the device should be tightened down so that it cannot rotate at all

3) If the device is rotated/bumped, it will take 90 seconds to recalibrate

Your PowerPod is not in the same angle as it was when calibrated. Though PP firmware will automatically figure out the change, if you're trying to use Isaac features then you should do a new calibration.

[lorduintah]

The best scenario is to leave the PP mounted on the bike and never move it or take it off.

If you cannot do that - never move the mounting bracket on the bike and just take the PP off - but when you put it back on it needs to be tilted as far as possible (not moving the mounting bracket) so that it rotates to the stop forward or backward whichever end of the rotation you started with for the calibration. This does not take a lot of force, just rotate it until you cannot anymore - force this and the bracket on the PP may break,

If necessary buy a longer USB cable - extension - so that you can leave the PP alone on the mount on the bike - even when charging it.

I do not unmount or fiddle with the position of my PP and I can go back to the same place I originally calibrated - ride over that same trail and go back - check my calibration and there is virtually no alteration to any of the values suggested. Wind, tilt, friction, nada.

[RoadWarrior]

The best scenario is to leave the PP mounted on the bike and never move it or take it off.

If you cannot do that - never move the mounting bracket on the bike and just take the PP off - but when you put it back on it needs to be tilted as far as possible (not moving the mounting bracket) so that it rotates to the stop forward or backward whichever end of the rotation you started with for the calibration. This does not take a lot of force, just rotate it until you cannot anymore - force this and the bracket on the PP may break,

If necessary buy a longer USB cable - extension - so that you can leave the PP alone on the mount on the bike - even when charging it.

I do not unmount or fiddle with the position of my PP and I can go back to the same place I originally calibrated - ride over that same trail and go back - check my calibration and there is virtually no alteration to any of the values suggested. Wind, tilt, friction, nada.

I only took the PP off, never the mount.
I will check with your advice and see how it goes. Thank you