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Strange power dropouts... but other data looks fine
Posted: Tue Sep 02, 2008 10:42 pm
by rruff
I've never seen this before, and it seems very odd. I'm climbing ~3% grade at ~18mph with a slight headwind... and for 44 sec the power reading is zero. I noticed this at the time also... the readout was zero. How could the iBike be computing zero power when it gets all the other variables correct? I could understand why it would be off if one of the sensors was having trouble... but apparently from the data they were all fine. This wasn't the only time that power went to zero on this ride, but it was the longest one.
Re: Strange power dropouts... but other data looks fine
Posted: Tue Sep 02, 2008 11:39 pm
by coachboyd
I don't see any cadence info. Am I correct in assuming you only have a wired speed mount?
Re: Strange power dropouts... but other data looks fine
Posted: Wed Sep 03, 2008 12:37 pm
by rruff
Yes, that is true.
BTW... the voltage is 2.82... is this high enough?
Re: Strange power dropouts... but other data looks fine
Posted: Wed Sep 03, 2008 12:54 pm
by iodaniell
rruff wrote:Yes, that is true.
BTW... the voltage is 2.82... is this high enough?
2.82 vdc should be fine.
I think coachboyd is on the right track--something is causing the iBike to see zero cadence.
Re: Strange power dropouts... but other data looks fine
Posted: Wed Sep 03, 2008 2:55 pm
by coachboyd
rruff wrote:Yes, that is true.
BTW... the voltage is 2.82... is this high enough?
Can you post the file on here? If you don't have a cadence sensor on the bike, then it shouldn't be going to zero watts when you are going uphill. The thing I am worried about is the big difference between your aero and cda numbers. That gives you a wind scaling around 1.5 (1.488 when I played around. I am thinking it could be something with that).
Were you using the brake mount that you built on your TT bike (I see TT profile selected). Let me take a look at this file and see if I can find something that jumps out at me, but so far it's the high wind scaling number that does.
Re: Strange power dropouts... but other data looks fine
Posted: Wed Sep 03, 2008 6:14 pm
by rruff
Just had a look at the file myself. Even though I have no cadence, the iBike somehow began registering a cadence... then it would stop (ie register zero cadence)... and when this happened it would register zero power. I used it in the rain on Sunday... don't know if this might have messed something up.
The wind scaling is what it needs to be to make the wind come out right... seems to work pretty well.
It isn't causing this problem, but the brake bolt mount seems to be vibration-effected. Road vibration seems to consistently make the tilt read lower than it should by 0-.4%. It gets fixed pretty well in the software after the fact, but it is very unreliable on fast bumpy sections.
Re: Strange power dropouts... but other data looks fine
Posted: Thu Sep 04, 2008 11:41 am
by rruff
Just noticed that my iBike was showing "Cad" instead of "Cal" on the main screen. When I deleted all the files it went back to "Cal" so I guess the cadence is turned off now.
Is there some way I can "fix" this ride file? I set all the cadence values to .001, but unfortunately iBike2 still preserved the dropouts in "analyze tilt and power".
Re: Strange power dropouts... but other data looks fine
Posted: Fri Sep 05, 2008 12:58 am
by rruff
Had no problems today... data looks fine.
Re: Strange power dropouts... but other data looks fine
Posted: Fri Sep 05, 2008 7:48 pm
by coachboyd
rruff wrote:, but unfortunately iBike2 still preserved the dropouts in "analyze tilt and power".
I noticed that too, and no matter how I played with your profile I couldn't get it to go away. I put 90 rpm for your entire ride, I even switched the profile after the ride to a road bike position, I could not get watts to show up right there. I haven't seen anything like this before.