P1 pedals failing calibration to AP

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Patspeedy
Posts: 15
Joined: Sat Jun 29, 2019 5:19 pm

P1 pedals failing calibration to AP

Post by Patspeedy »

Has any one been able to calibrate they P1 pedals when using AP as power source on Garmin 512 , the pedals calibrate if paired to Garmin normally and also calibrate no problem with Wahoo element but when trying to calibrate them when using AP they just sit trying to calibrate but can’t so no offset is stored in AP ,, and I would take it that for a accurate calibration ride they have to be calibrated in AP as it would not know the-pedal power offset and all readings would be inaccurate ???
Velocomp
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Re: P1 pedals failing calibration to AP

Post by Velocomp »

P1 calibration is something that you do with your Garmin. Here is what the P1 instructions say:

"Each PowerTap P1 pedal is dynamically calibrated from the factory to the highest standard. Calibration values cannot be changed by the user. However, it is important to periodically zero the offset manually. Before performing a manual zero unclip from the pedals and make sure there is nothing contacting either pedal. Navigate to the sensor screen on the Joule GPS+ or other head unit and select Calibration. Initially, numbers will display related to the previous zeroing of the calibration offset. With Manual Zero selected Press the ENTER button to zero the offset."

The calibration coefficient is stored in your P1s, so AeroPod will read the calibrated value of P1 power.

Please post a .ibr ride file from AP with your P1s paired to AP. We will take a look!
John Hamann
Patspeedy
Posts: 15
Joined: Sat Jun 29, 2019 5:19 pm

Re: P1 pedals failing calibration to AP

Post by Patspeedy »

John ,here is a file but not a great one as,, i was getting live cda data after a out ad back but i think the calibration was not correct but it gave me the answer i was looking for from just after 20min till around 24 , what i did notice was that while i had AP power on Garmin cda screen and my wahoo element was connected to P1 as well to give me speed and power , even though the wahoo was reasonably stable in power the power on garmin from AP was fluctuating widly almost half of what wahoo was reading at Times hence i was asking about the P1 offset cal , the P1 offset was set by garmin when P1 was connected to garmin as power source and AP not connected and both the wahoo and garmin was reading same offset of P1,, when riding looking at both the power on wahoo and garmin it almost looked that AP was only reading one leg

i am using wahoo cadence and speed sensors , speed sensor on front wheel for a good reading , would it be better to leave wahoo cadence sensor off crank arm and just let P1 give cadence if AP picks it up ?

iBike_08_04_2019_1105_16_km_HiDef.ibr

Thanks
Pat
Patspeedy
Posts: 15
Joined: Sat Jun 29, 2019 5:19 pm

Re: P1 pedals failing calibration to AP

Post by Patspeedy »

here is the .LBR FILE
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iBike_08_04_2019_1105_16_km_HiDef.ibr
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Velocomp
Velocomp CEO
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Re: P1 pedals failing calibration to AP

Post by Velocomp »

The good news is that the P1 is paired to your AeroPod and that its readings look normal.

That's the end of the good news... :-(

1) Your Wahoo speed sensor is very noisy. Look at the graph: from minute 5 to 8 speed is quiet (no speed spikes) but after that...lots of speed spikes. We've seen this behavior before in Wahoo sensors; it is one reason we greatly prefer Garmin sensors. Garmin does not have this problem.

2) You'll also see that, wherever the speed signal becomes noisy, the slope and power signals are correspondingly noisy. This is the likely cause of your AP watts variation

3) The cadence signal is very noisy too.

I would replace the Wahoo speed sensor with a Garmin sensor, and I would remove the Wahoo cadence sensor from your bike. AP will use cadence data from the P1s.
Attachments
Screen Shot 2019-08-05 at 3.13.57 PM.png
Screen Shot 2019-08-05 at 3.13.57 PM.png (124.24 KiB) Viewed 4645 times
John Hamann
Patspeedy
Posts: 15
Joined: Sat Jun 29, 2019 5:19 pm

Re: P1 pedals failing calibration to AP

Post by Patspeedy »

John , many thanks for your excellent help , I just have a new Garmin speed2 sensor that I will install and hopefully that will cure the problem when the weather is correct again to be able to have another go as getting the correct weather conditions in Ireland can be very difficult , again your help much appreciated , Pat
Patspeedy
Posts: 15
Joined: Sat Jun 29, 2019 5:19 pm

Re: P1 pedals failing calibration to AP

Post by Patspeedy »

John i am attaching a file with the new Garmin speed2 instead of the Wahoo and cadence from the P1,can i have your opinion please , Today was a good morning weather and wind wise for Ireland to get a test done as i have lost a lot of time because of bad sensors so would you mind if i can ask you a few questions to see if i can fast forward my understanding of the results of the AP ???? Thanks Pat
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iBike_08_08_2019_1124_9_km.ibr
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Velocomp
Velocomp CEO
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Re: P1 pedals failing calibration to AP

Post by Velocomp »

This looks infinitely better!!

Your Crr is too high (unless you're riding a fat bike) so I adjusted it for a road bike.

Load the attached profile and you are on your way!
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Patspeedy.ibp
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John Hamann
Patspeedy
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Joined: Sat Jun 29, 2019 5:19 pm

Re: P1 pedals failing calibration to AP

Post by Patspeedy »

Thank you ,, I have 2 questions about being able to test on undulating road and winds are always about 10kph at best where i live [sorry if these have been answered before was searching but could not find answers]

1; when doing calibration run is it speed or power avg that matters most ??

2; when testing trying to hold a even speed with a even power is impossible with wind and slight up and down gradient so which is the most important to give accurate field display results steady speed or steady power as impossible on course profile that i use to do both. or use just one stretch of road of the course which would be about 2.5km in length with slight incline for testing then able to hold power and speed at reasonable avgerage state

Thank You
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: P1 pedals failing calibration to AP

Post by Velocomp »

Patspeedy wrote: Fri Aug 09, 2019 10:04 am Thank you ,, I have 2 questions about being able to test on undulating road and winds are always about 10kph at best where i live [sorry if these have been answered before was searching but could not find answers]

1; when doing calibration run is it speed or power avg that matters most ??

2; when testing trying to hold a even speed with a even power is impossible with wind and slight up and down gradient so which is the most important to give accurate field display results steady speed or steady power as impossible on course profile that i use to do both. or use just one stretch of road of the course which would be about 2.5km in length with slight incline for testing then able to hold power and speed at reasonable avgerage state

Thank You
1. Constant power is best

2. If your course is uneven then a good workaround is to do test laps; that is, an out-and-back ride. Laps will average-out the effects of the undulations.
John Hamann
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