PowerPod V3 0W while going downhill and windspeed odd readings

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diemol55
Posts: 4
Joined: Wed Jan 06, 2021 2:24 am

PowerPod V3 0W while going downhill and windspeed odd readings

Post by diemol55 »

Hi team,

I've got the PowerPod V3 a couple of weeks ago I have to say, this technology is great the way physics are correlated with the variables recorded by the sensors is just great I love these kinds of tech. I'm using a wahoo kickr core head unit, magnetless wahoo rpm, and speed sensors, and the PowerPod is mounted on the stem totally cleared. However, I've got the feeling that there is something not calibrated "I guess" properly because there are moments in where the power readings are just not consistent, I live in Melbourne and winds are a serious thing here I've been riding through really hard headwinds and feeling the effort on my legs but the head unit just doesn't go up and on the other hand, when cruising with less headwind I feel a more accurate reading however when the wind turns strong again even on the same surface and gradient the power reading goes down and believe me I can feel the effort, easily I'd be pushing at least 10% more power I have attached a riding file for the situation described above named as Flatt_Ride I can notice that there's a lot of tailwind readings and, to be honest, it didn't feel like I was experiencing tailwinds that day however I could be wrong.

On the other hand, there's this other case very lumpy route with lots of ups and downs and having weird readings again, uphill the sensor works great in my experience the reading for climbing are super consistent but when it turns into a downhill the story is totally different power readings go to zero even when pedaling and sometimes pedaling strong to keep the pace again lots of tailwinds recorded. I have attached this ride as Kew Boulevard.

Just for the record, I have done successfully the cal ride following the instructions step by step I felt like the cal ride went well.

I've seen in other posts that you guys do a comprehensive analysis of the ride files I'm really interested in getting an assessment of the files I have attached if possible, I truly love the product, and other than these specific situations I feel that the device and technology is super reliable I'll say that this technology is even better than the conventional crank-based ones, there are lots of more parameters taking into account here that really make the difference.

I hope you can look into my files and I look forward to hearing from you guys.

You're doing a great job, thanks in advance for the support

Best regards

Diego
Attachments
Kew_Boulevard_2.ibr
(245.12 KiB) Downloaded 107 times
Flat_Ride.ibr
(366.55 KiB) Downloaded 110 times
Kew Boulevard.ibr
(245.12 KiB) Downloaded 116 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: PowerPod V3 0W while going downhill and windspeed odd readings

Post by Velocomp »

Are you riding a TT bike? Your CdA is quite low for a person of your weight.
John Hamann
diemol55
Posts: 4
Joined: Wed Jan 06, 2021 2:24 am

Re: PowerPod V3 0W while going downhill and windspeed odd readings

Post by diemol55 »

Hi John,

Thanks for the quick response, no I'm not riding a TT bike I'm on a Look 675 light road bike. I have to mention that I might have changed the Cda with the calibration analysis for the Kew Boulevard ride I've read on other posts that this is not recommended, do o have to calibrate again and on the other hand I'm waiting for a pitot tube will this one improve the device's performance?
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: PowerPod V3 0W while going downhill and windspeed odd readings

Post by Velocomp »

I corrected both ride files with a higher CdA, estimated to be 0.396 based on your weight.

Your "flat ride" had PP bumped out of position near the end of the ride. I used the "Analyze Route" function to fix this.

Your calibration looks good, except for the too-low CdA.

Load the corrected profile into your PP.

When you get your pitot tube you'll need to do a new cal ride.
Attachments
Flat_Ride_corr.ibr
(472.9 KiB) Downloaded 113 times
Kew_Boulevard_2_corr.ibr
(302.08 KiB) Downloaded 112 times
Kew.ibp
(525 Bytes) Downloaded 102 times
John Hamann
diemol55
Posts: 4
Joined: Wed Jan 06, 2021 2:24 am

Re: PowerPod V3 0W while going downhill and windspeed odd readings

Post by diemol55 »

Great, thanks John I will try the new setup and let you know
diemol55
Posts: 4
Joined: Wed Jan 06, 2021 2:24 am

Re: PowerPod V3 0W while going downhill and windspeed odd readings

Post by diemol55 »

Hi John,

Alright, I've just done a decent ride 30k, and here is the file the new parameters made the readings better the PP was perceiving the wind changes better however there are two observations I would like to mention. First one, on the 16 to 18km section I was experiencing a really hard headwind and my HR went up to around 155bpm normally at this range I will be pushing around 180 to 200W on my indoor trainer, according to Isaac I was doing 155W obviously I'm just assuming this comparison makes sense if not please just disregard it. The second situation I had was on 22.9Km the power went off to 418W at 25Km/h and super light effort it was like this for a couple hundred of meters and then it just went back to normal.

Thanks guys for your great support.

Find the file attached named New_Flat.

Cheers

Diego
Attachments
New_Flat.ibr
(374.58 KiB) Downloaded 104 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: PowerPod V3 0W while going downhill and windspeed odd readings

Post by Velocomp »

I don't see any obvious problem with wind speed. It's difficult to judge wind speed while riding a bike, and the segment between km 16 and 18 shows only a slight net headwind.

In general, riding on an indoor trainer produces higher watts/HR numbers than outdoors, because the outdoor riding generally allows for coasting.

At km 22.9 you were climbing a hill, resulting in the high watts.
John Hamann
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