Power2Max Power Meter Issues

harringtonp

Hi,

Own a P2M since Oct 2013 and use it a lot (on 4th or 5th battery). Normally when I calibrate it (you don't have to, Garmin 500 asks if you want to) I might see a reading like -963 when its a cold day or something like -939 in warm weather.

Recently on a few occasions I have seen cailbration readings in the -800's returned and it show power readings way below what it should be showing. It usually corrects itself but it could be 20 minutes into the spin before this happens.

I know there are quite a few on here with P2Ms, has anybody else seen this issue ?

Will just add for those who don't own a PM and are thinking of purchasing one that apart from these recent blips it has been an incredibly reliable PM.

Statler

Have one on a road bike and one on a TT bike, never had an issue like that, any time I calibrate them the readings are consistent. Worth dropping their support an email, I found them great to deal with when I had a few queries re cranks/ bottom bracket compatibility when I was buying.

Smalltom

Mine reads 830 territory each time IIRC. Have it 4 years now n it's on the winter bike and faultless. I always leave out the bike in the weather while I get my gear on and then turn on the Garmin. Habit I guess but temp etc in garage is always different than outside.

harringtonp

Smalltom wrote: »

Mine reads 830 territory each time IIRC. Have it 4 years now n it's on the winter bike and faultless. I always leave out the bike in the weather while I get my gear on and then turn on the Garmin. Habit I guess but temp etc in garage is always different than outside.

Yes I gather calibration is temperature related and nothing else. Before last spin bike was in van and then against it while I was getting changed and van was quite warm. I did stop after a few minutes on the road to try and force a calibration but it didn't take. It did however recalibrate itself some time after that but at that point 2 of my 5 3 minutes intervals were without good power readings.

harringtonp

Emailed support, scratching my head a bit, thought the problem explanation was reasonably clear. Okay there is a language barrier. Got

"thanks for your message.

The zero point/zero value is very individual and from you p2m different to other (also SRM). These values can´t be compared with other values. This value says nothing about the accuracy of your power2max.

Please note:
The zero point is continuously variable and is adjusted by the automatic. Maybe you have adjusted the zero only accidentally. Jst watch once if this still happens a second time.

Please let us know if this is helpful. If not, please come back to us. "

in response to


"The power meter purchased below in October 2013 has recently been slow to calibrate on some cycles. Normally when I calibrate it after being asked by a Garmin Edge 500 I might see a reading like -963 when its a cold day or something like -939 in warm weather.

Recently on a few occasions I have seen calibration readings in the -800's returned and it show power readings way below what it should be showing. It usually corrects itself but it could be 20 minutes into the spin before this happens.

Any ideas what may be happening ? "

Quigs Snr

I don't generally calibrate mine with the garmin... it takes too long usually... It is supposed to self calibrate if you just freewheel for a few seconds. Mine seems to anyway.. readings are very consistent.

As an FYI, as far as I can tell I was maybe the first (at least first reported on the internet) issue with an original P2M classic.. sent it back, got a type S and an apology, so for me their service was pretty great.

harringtonp

Quigs Snr wrote: »

I don't generally calibrate mine with the garmin... it takes too long usually... It is supposed to self calibrate if you just freewheel for a few seconds. Mine seems to anyway.. readings are very consistent.

As an FYI, as far as I can tell I was maybe the first (at least first reported on the internet) issue with an original P2M classic.. sent it back, got a type S and an apology, so for me their service was pretty great.

I was using an edge 705 and it never asked me to calibrate. The 500 always does once it detects the pm so I often choose yes. Think I will go no in future and make sure I have enough free wheeling time early in session for automatic calibration.

Quigs Snr

harringtonp wrote: »

I was using an edge 705 and it never asked me to calibrate. The 500 always does once it detects the pm so I often choose yes. Think I will go no in future and make sure I have enough free wheeling time early in session for automatic calibration.

My Edge 500 prompts me also.. I just click no. Usually I put the bike outside the door.. head in sort myself out and then its picked up the satellites and gotten used to the temperature by the time I get on it. I live at the top of a hill so I am freewheeling early on... as I said I get very consistent readings.

But if you are not... send it back before the warranty is gone. The email communications may lose something in translation, but the service itself has been good so far for me. (I have had 3 now. The one that broke, its replacement and another one I got in a smaller BCD)

harringtonp

Quigs Snr wrote: »

My Edge 500 prompts me also.. I just click no. Usually I put the bike outside the door.. head in sort myself out and then its picked up the satellites and gotten used to the temperature by the time I get on it. I live at the top of a hill so I am freewheeling early on... as I said I get very consistent readings.

But if you are not... send it back before the warranty is gone. The email communications may lose something in translation, but the service itself has been good so far for me. (I have had 3 now. The one that broke, its replacement and another one I got in a smaller BCD)

Thanks, without checking would think warranty is well past, almost 3 years. But actually I
don't consider it a problem as yet as I only see it slow to calibrate sporadically and this may be partially due to me switching from the 705 to 500 and using it differently on startup. Will see how I get on with it in the next couple of months. If the problem persists I'll get back on to their support.

Bambaata

Another vote of confidence in their support if you do need to go that route. I water damaged my classic and they gave me the newer version at less than half price

clog

I've two power2max meters, never had a problem with them. Never really bothered to calibrate them unless I've swapped cranks over or changed battery/head unit.
Prompted by this thread I calibrated both on a Garmin 1000.

First one was on a Sram crank returned:-776

Second one on Rotor crank returned: -1455

Was a bit worried by the difference and ended up taking both bikes out one after the other on a hill near the house. Tried to keep both efforts similar and ended up with nearly the same times. The power figures differed by 3 watts 202v199. I re checked the calibration figures after the rides and they were very similar to the original ones.
I examined these figures against my Strava data for the hill (approx 400 ascents) and they fit well against similar time/power efforts.
Whatever the difference in the numbers between the two meters they seem to both be working fine and giving very similar watt outputs.

Smalltom

Im reluctantly here eating my 'reliability' words. Jumped on the bike a week ago and garmin wouldnt find the p2m. I assumed dead battery and thought i missed the prompt normally received. I headed off on the good bike. When i returned i changed the battery and the 'battery low' prompt appeared and the red light stayed on instead of the green. I calibrated it anf hot the number 4. Got onto p2m and the unit is gone to Germany. Anyone experience this? I havent done anything to the bike etc differently than normal. They told me that getting this calibration number is 'not good'. Thanks.

harringtonp

Smalltom wrote: »

Im reluctantly here eating my 'reliability' words. Jumped on the bike a week ago and garmin wouldnt find the p2m. I assumed dead battery and thought i missed the prompt normally received. I headed off on the good bike. When i returned i changed the battery and the 'battery low' prompt appeared and the red light stayed on instead of the green. I calibrated it anf hot the number 4. Got onto p2m and the unit is gone to Germany. Anyone experience this? I havent done anything to the bike etc differently than normal. They told me that getting this calibration number is 'not good'. Thanks.

Have to say mine has been good since 2013 and used a lot. Are they charging you for the work ? Let us know how you get on.

Smalltom

harringtonp wrote: »

Have to say mine has been good since 2013 and used a lot. Are they charging you for the work ? Let us know how you get on.

I have mine since 2013 too and this is the first issue. They never mentioned charging me. Just said they would be back to me within 12 days of receiving it so its wait and see. My bloody rotor 3D chainset is useless now though!!! Once I hear back ill post here.

Smalltom

So the latest as of last Friday is that the battery housing cracked causing water ingress and frying the computer. They sent me pics of the issue and said it was from over tightening the three screws. I cant argue with them tbh. The did say however that a number of hairline cracks were also present from causes unknown (my words, not theirs). I spoke with a buddy of mine and he suggested that this could be from the plastic decentragating. However the warranty is 2 years out so i am on a sticky wicket. P2M offered me a replacement type s for €349 with a 2 year warranty which im happy about truth be told, so i.ordered it this afternoon. All in all, not a bad outcome. If they told me to feck off, i broke it, i couldnt argue. Ah well-bike stuff coming in the post is always good lol.

Quigs Snr

buddy of mine had the same issue with water causing power numbers to drop out on a type s. Turned out he had way over tightened the battery door, pulling one of the corner free internally and also cracking the retaining plastic ring behind the crank.

He was luckily. . his dried out and kept working whilet they send him free parts to repair despite being out of warranty.

Quigs Snr

buddy of mine had the same issue with water causing power numbers to drop out on a type s. Turned out he had way over tightened the battery door, pulling one of the corner free internally and also cracking the retaining plastic ring behind the crank.

He was lucky. . his dried out and kept working whilet they send him free parts to repair despite being out of warranty.

mossym

i alwys thought that cover was prone to overtightening. i;ve never had an issue withmine, but i did a lot of scuba diving for years and know what overtightenign an oring can do so i've been ultra careful with mine. i can see how easily it would happen though.

anything with an oring to sel will leak if you overtighten.

harringtonp

Smalltom wrote: »

So the latest as of last Friday is that the battery housing cracked causing water ingress and frying the computer. They sent me pics of the issue and said it was from over tightening the three screws. I cant argue with them tbh. The did say however that a number of hairline cracks were also present from causes unknown (my words, not theirs). I spoke with a buddy of mine and he suggested that this could be from the plastic decentragating. However the warranty is 2 years out so i am on a sticky wicket. P2M offered me a replacement type s for €349 with a 2 year warranty which im happy about truth be told, so i.ordered it this afternoon. All in all, not a bad outcome. If they told me to feck off, i broke it, i couldnt argue. Ah well-bike stuff coming in the post is always good lol.

Yes if your situation is anything like mine it would have seen a lot use. Over tightening screws is something one needs to be so careful about, I destroyed a stem in this way. Try and use a torque meter when dealing with anything carbon and with other things like the P2M screws I'm always telling myself to use less force than naturally inclined to.

A replacement for 349 doesn't sound too bad, is it a case of them keeping the old crankset and sending out a new type s one (presume you didn't send away the chainrings) ? And how does the type s compare weight wise with the original purchase ?

Smalltom

harringtonp wrote: »

Yes if your situation is anything like mine it would have seen a lot use. Over tightening screws is something one needs to be so careful about, I destroyed a stem in this way. Try and use a torque meter when dealing with anything carbon and with other things like the P2M screws I'm always telling myself to use less force than naturally inclined to.

A replacement for 349 doesn't sound too bad, is it a case of them keeping the old crankset and sending out a new type s one (presume you didn't send away the chainrings) ? And how does the type s compare weight wise with the original purchase ?

I have the crank and chainrings which are perfect and didnt have to post them over. Its a bit lighter afaik, maybe a mouthful of water in weight. The Germans are sound I'm glad to say lol. In fairness my.powertap pedals stopped working after 5 rides and they sent on a brand new set, no questions.