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Power estimate Connect IQ field

mtsarpilot
over 4 years ago

Anyone know of a Connect IQ field that does a power estimate calculation?  I'm not looking to spend huge dollars on power pedals or other power sensing device, but I'm curious general power output.  It seems most of the necessary information to do a rough calculation is available in the Edge device including: speed, altitude, grade, possibly factor in heart rate. Other data can be configured through GCM including: weight, surface type (road, trail), tire type (smooth, knobby), etc. and a rough calculation could be made of power output.  Yes, it would not factor in wind which is a notable gap, but hey, can only get so much for free.  

There are websites that demonstrate a calculation formula is known, such as https://www.omnicalculator.com/sports/cycling-wattage 

And to a weak extend, a static wind value is known if you enable Weather on the device as now we have at least one wind figure (not great but better than nothing) and we have a heading in the Edge so can even do a partial if not at least poor job of factoring in wind.

Has anyone developed such a Connect IQ field that you've seen that I am missing?

Thanks

  • 0 over 4 years ago

    Hi,

    I have tried a number of connect-IQ data fields and ePower seems to do the best job for me, I have tried three or four others and I even wrote a formula in AppBuilder to calculate power using the rate of change of the calorie count (plus a couple of fudge factors). I judge accuracy by comparing power values for specific uphill segments (averaged by eye from graphs created by ePower and viewable in the connect app) to the Strava estimates for those segments. The power values are a bit noisy (with some large fluctuations), but less so than other Connect-IQ power data fields. I think the noise is due to inaccuracies in the elevation data provided by the Garmin (altimeter? gps?). 

    I would be very interested in other people's experience with the various power estimates. It seems to me that the Garmin is collecting enough information to provide decent estimates of power.

    Thanks.

  • 0 over 4 years ago in reply to 3949666

    Great reference.  I just did a test run with ePower.  It is an impressive data field.  I need to do some tweaking with the parameters to get to the most accurate estimates, but it does a pretty good job.  It also records power and grade into the .fit file which is fantastic.  

    There are a couple changes I have suggested to the developer.  The biggest one is the power estimate is on a 10 second moving average.  In hilly/mountain country this is way too long.  The lag is huge and you never get to a stable power level as it is constantly playing catch-up as the terrain grade varies constantly.  Would be best to give the user a configuration of 3 or 10 second power average.

    Thanks for the reference to ePower

  • 0 over 4 years ago in reply to mtsarpilot

    I suspect shortening the averaging time will make the power readings even more noisy.

    BTW, did you hear from the developer?

  • 0 over 4 years ago in reply to 3949666

    Yes, I have been communicating with the developer.  Exploring ideas.

  • 0 over 3 years ago

    apps.garmin.com/.../apps

    Check my apps they have estimated power based on an algorithm