AeroPod, PowerPod and Newton

I've recently bought a Powerpod v2 and completed the O&B calibration. After using it 4-5 times across two bikes I'm finding the power readings are far lower than I'd expect for the effort expended. The O&B calibration has been completed on both bikes after it was installed.

Over the last 18 months I've used a Powerpod V1, P2M crank based meter, Tacx Neo as a trainer and a set of Garmin Vector 3 pedals, all of which gave consistent measurements so I feel I know what to expect, but I'm currently seeing average watts up to 50w lower than I'd expect. Today I've also recorded the same ride with the P2M meter and the Powerpod and after using the Power Meter comparison tool I can see:

1) Powerpod starting elevation is below sea level. This is across multiple rides but changing it to reflect the correct starting elevation doesn't change anything
2) Rider + Bike weight may fluctuate slightly (+/- 1kg) but this doesn't appear to update the average to a great extent
2) The watts are lower across the ride. For one ride they started in tandem, but within a mile the Powerpod had drifted down. On the other they are off from the start, with the Powerpod consistently lower.

I've attached two rides here where I *think* I've included the details from both power meters. Have I calibrated incorrectly or is there a setting that needs to be tweaked? I know how consistent the Powerpod can be from my experience with v1 (which was generally in line with the readings for the P2M meter after the initial calibration) so I'd appreciate if someone could help me solve what I may be doing wrong when setting this v2 up.

This morning I again recalibrated with a fresh profile (and confirmed weights) & full O&B ride and yet both rides are again very low in wattage, with PP giving around 120w average compared to nearly 190w for my P2M crank based meter. When comparing the rides the only points they come close to each other is when I'm putting in the effort up a hill or pushing off from a stop, which is when the powerpod rises to meet the reading of the P2M before dropping back down again.

I've attached the calibration ride from this morning along with one of the rides from both the device & the other power meter. Can anyone help me understand what I am looking at? Have I been overestimating my FTP based on P2M / Neo / Garmin so far or have I messed up the calibration in some way (for the 3rd time)?

I realise it's less than a day since my initial post but I've seen / heard nothing either from here or technicalsupport@velocomp.com where I also sent the same issue. Even an acknowledgement that 'we're checking this for you' would be great to know as I'm running out of time to return what I feel may be a faulty product and I'd rather search for an alternative than have a Powerpod that gives such wildly different results to all my previous experiences (which also includes another Powerpod).

Thanks

Your ride file shows a temperature of 31 Fahrenheit. Is this approximately correct?

It should be 3-4 degrees celsius - 37-39 degrees fahrenheit

OK, temperature is close enough...you ride in cold weather!

There are 2 things going on:

1) Your calibration is a bit off. I used the "Check Calibration" feature to correct the wind

2) ASSUMING your DFPM is correct, the merged ride file shows that your CdA should be around 0.50. This could be OK if you're wearing winter clothing, to keep from freezing!

Corrected ride file is attached.

Many thanks John,

I really appreciate the response. Yes, definitely winter clothing at the moment. Although it's getting to Spring now so it's nice that the weather is creeping past sub zero degrees C in the mornings. Means fewer layers as well!

Power looks close enough for me in the tweaked file. Glad to see it is a setting rather than a fault (with the assumption the DFPM is correct as you state!). Is there a reason the CdA would be captured in the calibration as relatively low for my conditions? I've checked and it is consistent across the 3 calibration rides I've completed in the last week with minor differences, assumed due to the weight of the bikes (one heavier than the other).

The plan is for the Powerpod to be used on a bike as the only power meter and as we move into summer the overall weight will change as further layers are dropped. However I won't have the luxury of a 2nd reading to validate power readings and I was planning on updating the profile weight details every so often to keep honest.