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PowerTap P1 Not Communicating with 520

My P1 pedals and 520 were working seamlessly a few months ago.

Work got crazy, and I had to shelf the bike for about 6 weeks. When I got back on, the pedals and headset were obviously having trouble talking to each other. This went in three stages:

First, the data was all over the place. The power and cadence numbers would bounce from what looked to be about right, then drop to zero, then go somewhere in the middle, seemingly every second.

Second, the data was reduced to just output from the right pedal. It was accurate, but 50% of my actual cadence & power. This is weird too, because the right pedal is slave to the left.

Third, the data reverted back to stage one for a bit, and then dropped off altogether. Now, no matter how many times I recalibrate, re-pair, change batteries, etc., I don't get data reading on the 520.

To the extent it matters, I currently have the cleats with the float - but will be switching to the zero float (as soon as I get around to putting them on my shoes). But I get no data at all right now, even riding around the block in socks in the middle of the night while trying to figure it out.

Any ideas?

Thanks much!
-N

0 ncazier over 9 years ago

One more thing. I suspect that this is a problem on the PowerTap side of things, as both my 520 and 500 won't pick up the P1 pedals - but both computers pick up my old SL+ powermeter.

0 Former Member over 9 years ago

Have your tried new batteries? Ah yes you have. Note to self - read the whole message before replying

0 aweatherall over 9 years ago

Do the pedals talk with the PowerTap iPhone app?

0 ncazier over 9 years ago

They do talk to the App. Lately, I've been in "stage one" of my trouble more than anything.

Attached are two files. One of today's ride where the data would show a high power number (about accurate to my perceived effort), then a low reading (like 57 watts...was a number that showed up a lot), then zero. Those three numbers would repeat in a fairly regular, fairly quick sequence. I thought that I might be getting over-sensitive readings, so I changed the 520 to only show 3s, and then 10s averages - but it did the same thing.

This is a new development. Attached are two files, one showing today's ride - and one from this summer along (mostly) the same route where the P1s and 520 were getting along.

I've been in contact with both companies' product support reps, but no answer yet.

0 ncazier over 9 years ago

Unfortunately, both sides of this issue (Garmin and PowerTap) have started pointing the finger of blame at the other. It's hard to know what's wrong though - so it looks like the pedals are going to be shipped back to Saris for testing - which means a few weeks without power. (I survived for years without it, I suppose I can go a few weeks now.)

At this point, my question is if there is anything that might have happened to my 520 (either of my own doing or via an update) that is causing such inaccurate data? Is there a preferred setting on the 520 to properly read the P1s? There's obviously data coming out of the things, but it's all messed up. If it's a simple fix like changing a setting on the 520, that would obviously be preferable to shipping the pedals back-and-forth.

-N

0 aweatherall over 9 years ago

The only setting on the 520 would be to make sure that the crank length value is correctly set. The crank length acts as a scalar so the only impact it would have on the power data is to inflate or deflate the value if it were incorrectly set.

0 j_wardy over 9 years ago

when i changed the batteries in my vectors, i got pretty much the same issue. erradic power numbers and cadence also when I tried to set the install angles. tried trouble shooting on the 520, but the problem went away once I pulled the batteries out and reinstalled.

0 ncazier over 9 years ago

I'll try to re-set after changing the batteries again. Crank length is correct on all devices.

Apparently, the newest PowerTap firmware was also supposed to be installed one pedal at a time.

I'll try that tonight and see if it fixes anything.

Thanks for the input everybody. It's been helpful.
-N

0 aweatherall over 9 years ago

Good point. Check that the software version is the same on both pedals. There were a few that did leave the factory with different versions on each side.

0 ncazier over 9 years ago

Got both pedals updated finally - still bad data. It looks like the left pedal isn't recording data, and it takes like 30 minutes for it to start sending the right pedal's information to the head unit. Pedals are back in Saris' hands now - hopefully we get this worked out, I was really excited for these.

-N