Not zero, but ridiculously low power readings

[gbussey]

Aloha, first time poster. In general, enjoying my PP v3 but on occasion get some weird readings, leading to a couple of questions:
1. When I start up at the beginning of a ride, sometimes I get the question "calibrate?" - this last ride I said yes, to which I got the response "unclip and hit calibrate button." So I unclipped and hit the button. But no instructions on what to do next. Sit? Reclip and start pedaling? I sat for a bit, but when nothing seemed to be happening, I went and started a smooth, relatively non-stop ride. Still never got a signal that calibration was done, so eventually went back to my regular screens on my Garmin, and all seemed OK for the next 2 hours and 50 minutes or so. So what was I supposed to do?
2. After the first almost three hours, I took a break - maybe ten minutes or so? When I started riding again - into a very strong headwind - at first my power readings were reasonable, but then shot up to over 700 (I wish) and then dropped to zero to single and very low double digits, and continued seemingly random ups and downs for about 40 minutes. Eventually I'd get extended periods of decent readings but would still get periods of garbage readings. Ride factors - started on some rough road, but since I was doing an out and back - no rougher than what I'd ridden out on. #2 - Also had some rain coming down a big climb, but again, at first the readings after that were OK, and even after everything dried out, still got bizarre numbers. #3 - nothing was blocking the wind port. #4 - the wind was strong (riding in Hawaiian trade winds on a pretty breezy day) and variable, and the worst was riding directly into a headwind - but the ride data shows almost no wind? (think that is how to interpret.)

Raw July 27 2019 ride data.ibr

(994.56 KiB) Downloaded 134 times

[Velocomp]

1) "Calibrate" is a bike computer function that has meaning for conventional power meters, but has no meaning for PP; PP does not require recalibration. You can hit the button if you wish but it won't affect PP calibration in any way whatsoever.

2) In your ride file I can see where your wind sensor becomes obstructed on the ride down, no doubt due to rain. When the wind port is obstructed due to rain you can get wacky readings. Around mile 60 the port fully cleared itself, wind readings returned to normal, and all was well.

If you do a fair amount of riding in the rain you might want to get a pitot tube, which will lessen the problem

https://velocomp-llc.myshopify.com/coll ... pitot-tube

[gbussey]

Thanks. I was wondering about the rain issue, and at first when it happened again later down the road, I wrote that off as a cause, but then realized that 1) there was another brief rain shower and 2) when drafting behind my riding partner, I was getting road water and dirt splashed into my clothes and glasses, so maybe into the wind port as well.

So - re the pitot tube - I ride in lots of blustery, often direction changing winds (one of the side-effects of living on an island with a combo of trade winds AND mountains that deflect and disrupt wind patterns). Will the pitot tube be able to handle that kind of changing wind environment?

[Velocomp]

Yes