Help Power meter owners.... Help!

theBlob

Bokeh master
Sep 28, 2011
2,863
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...
#1
Very disapointed today.

Sending my Quarq Elsa back for servicing/ repair whatever. From the beginning it has chewed through batteries, to the tune of every 2-3 weeks. way under their 400hr advertised expectancy. And recently it has started to spike all over the place. Sometimes it will be fine other days I will have 30-40 spikes to edit out of my outputted ride files. Seriously rediculous. I had arranged to send it back last week but it suddenly started being good again until 2 days ago then it was back to its tricks. So in the box it goes...

Check this segment out on todays recovery ride.... (click on performance/power) It was a recovery ride so every one of those spikes is an error.


How am I going to go riding without power numbers? I might have to quit ha ha ha! Anyone got a power tap i can rent borrow? Seriously! I have seem some offered in the past haven't I??

If anyone has one I can use for a few weeks I would be very grateful!
 

Franz

Banned Biker
Jun 5, 2013
31
6
18
43
Tokyo
#2
I have a large supply of power meters at my disposal, which you are welcome to borrow.

I am on a lifetime contract with every power meter company out there - they use my stats to determine how many zeros to use on their displays.
 
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FarEast

Maximum Pace
May 25, 2009
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#3
oh Fran now we know you are full of it as otherwise my Power meter would only show a constant big zero!

Now if it was wired up to your mouth there would be a display big enough.
 
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GSAstuto

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Oct 11, 2009
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#5
Most SRM devices are troubled by various issues. Mainly driven by OCD riders who are weight weenies and couldn't tolerate an extra 5gr worth of battery or associated electronics. The old(er) Powertaps were /are really rock solid and seem to go a very long time on the battery pack. The newer ones are finally getting up to a 500hr or so per CR2032 - mainly due to the updated 'sleep' programming. I'd say 400hrs from any ANT+ device with a single CR2032 is a good run for its money! If you purchased your unit in Japan, then the local dealer /distributor should be able to assist with any warranty or update issues. Another reason I love Powertap - the service from the distributor is awesome! I'm riding a G3C and it's basically mano-e-mano with any production hub (SRM or not). Though, now I have SRAM RED cranks - looking at the Quarq option, too. My contingency is simple - Saris Powercal. While it's not direct strain-gauge data, it does correspond close enough to my <real> power readings to be useful. Now that I have the codes to calibrate it internally - it's very very close to my actual SRM device. Again, a great alternative (and fall back) for your existing power data device.
 
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theBlob

Bokeh master
Sep 28, 2011
2,863
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129
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#6
I think I'll look into it, thanks Tim.

Can't hurt to have a back up as I am primarily using the meter to control my stress balance, having nothing for a few weeks is not going to kill me but it is going to mess up my long term graphs.
 
May 22, 2007
3,572
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halffastcycling.com
#8
The old(er) Powertaps were /are really rock solid and seem to go a very long time on the battery pack. The newer ones are finally getting up to a 500hr or so per CR2032 - mainly due to the updated 'sleep' programming. I'd say 400hrs from any ANT+ device with a single CR2032 is a good run for its money!
へ〜。My PT hub seems to take 2 x LR44. Actually what was in it was 2 x EPX76, but the Interweb assured me that xx44 is equivalent. Do the new ones take 2032 now? Is that a good reason to upgrade?
 

GSAstuto

Maximum Pace
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#9
Actually the older version with the 2xEPX76 (better battery) has longer life. Torque tube is identical. Weight was reduced quite a bit in the G3 (Generation 3) series by redesign the hub shell and generally making all the electronic bits lighter. Unless you feel the 80gr or so difference is a Podium maker (or killer) then there's no real reason to upgrade or change. And if your unit is operating fine - another reason not to change it!
 
May 22, 2007
3,572
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Kawasaki
halffastcycling.com
#10
Actually the older version with the 2xEPX76 (better battery) has longer life...
Thanks. I wasn't planning to change anyway, but that's good to know.

So a question for Tim and/or Joe - given that the OEM battery Energizer EPX76 is not widely available here, which of the many alternatives (CX44, SR44, LR44 etc. etc.) would be the best to use in my PT hub?
 

GSAstuto

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Oct 11, 2009
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#11
EXP76 you can generally get at the BIC Camera or Yodobashi Camera - it's more of a 'pro' battery. The others are fine - but if you can get the SR44 its better - and about the same as the EXP (silver oxide)
 

Gunjira

Maximum Pace
Oct 2, 2009
1,002
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#12
Most SRM devices are troubled by various issues. Mainly driven by OCD riders who are weight weenies and couldn't tolerate an extra 5gr worth of battery or associated electronics. The old(er) Powertaps were /are really rock solid and seem to go a very long time on the battery pack. The newer ones are finally getting up to a 500hr or so per CR2032 - mainly due to the updated 'sleep' programming. I'd say 400hrs from any ANT+ device with a single CR2032 is a good run for its money! If you purchased your unit in Japan, then the local dealer /distributor should be able to assist with any warranty or update issues. Another reason I love Powertap - the service from the distributor is awesome! I'm riding a G3C and it's basically mano-e-mano with any production hub (SRM or not). Though, now I have SRAM RED cranks - looking at the Quarq option, too. My contingency is simple - Saris Powercal. While it's not direct strain-gauge data, it does correspond close enough to my <real> power readings to be useful. Now that I have the codes to calibrate it internally - it's very very close to my actual SRM device. Again, a great alternative (and fall back) for your existing power data device.
You have got to help me with calibrating my powercal. I really like the strap, the hrm function and comparing stress scores, but my power readings are way off. KOMs on 30min climbs with 150W off.
 

GSAstuto

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#13
You can calibrate them with PowerAgent. PC Only! Use a ANT+ stick in the PC to communicate to the strap.

Ex. 1) If PowerCal readings 50w higher than PowerTap
A: 2.55
B: -190 -140
C: 150

Ex. 2) If PowerCal readings 30w lower than PowerTap
A: 2.55
B: -190 -220
C: 150

Do a powertest (like 30min or longer is best) with a pre-calibrated device (PowerTap or Trainer). Then match it with the PowerCal. I do this incrementally - mine is getting closer - but still low compared to my PT hub readings.
 

joewein

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Oct 25, 2011
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#14
EXP76 you can generally get at the BIC Camera or Yodobashi Camera - it's more of a 'pro' battery. The others are fine - but if you can get the SR44 its better - and about the same as the EXP (silver oxide)
EPX76 and SR44 I think are two different names for the same thing - a silver oxide battery in the same form factor and similar voltage as the alkaline LR44. They're typically 150-200% the capacity of the cheaper alkaline (which uses the same chemistry as household AA's and AAA's) but also cost a bit more. You mostly save the hassle of changing batteries more often, or being without a usable device at an inopportune time.

With other button cells (CR2032) I tend to buy a pack of 10 on Amazon, which costs about as much as buying two in a supermarket or convenience store. Batteries tend to have a high markup in retail.
 

GSAstuto

Maximum Pace
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#16
Nice ! The Powertap also lets you manually calibrate it - at least through the Joule unit. I use this more often to make sure that it is properly 'zeroed' . If the torque tube readout is within the factory designated range - then the output will be considered 'accurate'.

James - since you have a Powertap, you might consider getting a Joule unit as well. It has a few more functions in terms of console and also you can instantly review ride data from past rides - and if you've done the PowerAgent download/upload you get a very deep analysis of power on the console (nice if you are doing intervals or repeats on the same road section) - so like for me - a certain part of the road always gives me some trouble, I can focus on optimizing my form on it - then check quickly. Like am I in-saddle, out-saddle, position, rocking, tilting, ankling or fatigue levels.

Have any of you actually done a calibration with a weighted load?

Good pages and info on calibration:

http://www.cyclingpowerlab.com/PowerMeterCalibration.aspx
 

FarEast

Maximum Pace
May 25, 2009
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#17
Did a side by side comparison when looking for new head units to replace the Garmin 500 and the 510 is perfect for what I am doing and all the Joule unit would be for is to just do a manual calibration not really worth it.