Is this power meter faulty?

[ianct]

Bought a new Ultegra 4iiii power meter and took a first ride today. Paired fine with a Garmin 530 and did the calibration (and again mid-ride because I thought something was wrong). On a gentle hill, seated in a Zone 2-3 heart rate effort, keeping the pedalling as smooth as I can, the power is fluctuating wildly over about 5sec from around 270W-160W - jumping up and down 20-30W at a time. I'm keeping the pedalling pretty consistent and the bike is smooth and stable and going at the same speed - there is no way the power is fluctuating anything like that much.

Checked in with 4iiii and they sent me a link to a tech document saying the unit supplies raw power data and I must implement 3, 5 or 10 sec smoothing at the head unit. Does this sound right? Anyone have experience with this? I'm new to the power meter game so trying to work out if I have a faulty unit or this is normal?

[Bike Dewing]

7 minutes ago, ianct said:

Bought a new Ultegra 4iiii power meter and took a first ride today. Paired fine with a Garmin 530 and did the calibration (and again mid-ride because I thought something was wrong). On a gentle hill, seated in a Zone 2-3 heart rate effort, keeping the pedalling as smooth as I can, the power is fluctuating wildly over about 5sec from around 270W-160W - jumping up and down 20-30W at a time. I'm keeping the pedalling pretty consistent and the bike is smooth and stable and going at the same speed - there is no way the power is fluctuating anything like that much.

Checked in with 4iiii and they sent me a link to a tech document saying the unit supplies raw power data and I must implement 3, 5 or 10 sec smoothing at the head unit. Does this sound right? Anyone have experience with this? I'm new to the power meter game so trying to work out if I have a faulty unit or this is normal?

I mean I have no experience with power meters but this doesn’t sound right.. for training plans and specific workouts it will tell you to hold a specific amount of watts for various periods of time, and they range in accuracy up to like 4% I think I’ve seen.. 

I would say it’s malfunctioning 

[Titleist]

Try another battery and look at 3 second power. If it keeps doing the same then it’s faulty.

Edited January 24 by Titleist

[Jbr]

use 3 secs power, and see how that looks. I never use anything less that 3s power

[Rudi Pollard]

The standard immediate power reading fluctuates a lot. As mentioned rather use the 3s ave reading. That should sort you out.

Lots of technical details which  explains it but because it's a left side only meter the immediate  power reading will fluctuate a lot through your pedal stroke depending if you're pushing down, pulling up, or in the dead zone... 3s average normalises that effect for you.

[cadenceblur]

OP, as correctly suggested use the 3 or 5 second power. 
You mentioned that you’re new to PM’s - that is how  they read, the strain guages will tell you exactly what wattage you are producing, 

The smoothing is required otherwise you will be all over the place with your effort as you are at present. 

Jump to the bit about averaging 

https://www.cyclistshub.com/how-do-cycling-power-meters-work/

Edited January 24 by cadenceblur

[Frosty]

1 hour ago, ianct said:

Bought a new Ultegra 4iiii power meter and took a first ride today. Paired fine with a Garmin 530 and did the calibration (and again mid-ride because I thought something was wrong). On a gentle hill, seated in a Zone 2-3 heart rate effort, keeping the pedalling as smooth as I can, the power is fluctuating wildly over about 5sec from around 270W-160W - jumping up and down 20-30W at a time.

Have you got a .fit file to share?
Are you using Intervals.icu or even the Strava analysis that can show your workout summary?

I have two 4iiii PMs and they are fine.

Here is a relatively steady 7-minutes (Intervals on top and Strava below).
The bottom chart (first image) has raw power and a 3s average on one plot (it'sdifficult to see unless you zoom in, and also move the cursor along the timeline). But you can see the point in time has 143 (raw) and 155 (3s) the power, with a lot of change in the raw power for a relatively steady eddie pace).

 

[lechatnoir]

If you have the option to get your bike on a smart trainer in ERG mode and can check the power output at various levels from the 2 units it'll tell you the answer. 

But, if it seems odd, it's best to get it checked out, even if for your own peace of mind.

Please let us know what you find and if there's a resolution

[ianct]

Thanks everyone - will test the smoothing and report back here asap.

[Donovan Le Cok]

I use a 4iiii on one of my bikes and I don't need to do any 3-second averaging, the data is really good. What value did you get when you calibrate?

Have you done a firmware update?

[Mongoose!]

15 hours ago, Bichael Dewing said:

I mean I have no experience with power meters but.

here is my advice... 🙃

[Bike Dewing]

3 minutes ago, Mongoose! said:

here is my advice... 🙃

Wasn’t advice.. was an observation based on common sense from what I’ve been told and have read about power meters.. I have no practical experience with them though..🤷🏼‍♂️

[Bike Dewing]

20 minutes ago, Mongoose! said:

here is my advice... 🙃

Also, are you a journalist by any chance.? 😳🤣

you’ve done a fantastic job of cutting up a quote so it’s out of context making the quoted sound like a ******* idiot..🤦‍♂️🤣🤣

maybe I am an idiot..? Now I’m questioning myself.!! 😰 gees again, well done.!! Maybe this is how Britney feels🖕🏻.. 

[Mongoose!]

4 minutes ago, Bichael Dewing said:

Also, are you a journalist by any chance.? 😳🤣

you’ve done a fantastic job of cutting up a quote so it’s out of context making the quoted sound like a ******* idiot..🤦‍♂️🤣🤣

maybe I am an idiot..? Now I’m questioning myself.!! 😰 gees again, well done.!! Maybe this is how Britney feels🖕🏻.. 

Haha. Sorry but I couldn't resist 

[Bike Dewing]

1 minute ago, Mongoose! said:

Haha. Sorry but I couldn't resist 

Understandable.. my marriage would be a lot more stable if I resisted saying certain things out loud.. I don’t, so it isn’t .!🤷🏼‍♂️🤷🏼‍♂️🤣🤣

[Andreas_187]

16 hours ago, ianct said:

Bought a new Ultegra 4iiii power meter and took a first ride today. Paired fine with a Garmin 530 and did the calibration (and again mid-ride because I thought something was wrong). On a gentle hill, seated in a Zone 2-3 heart rate effort, keeping the pedalling as smooth as I can, the power is fluctuating wildly over about 5sec from around 270W-160W - jumping up and down 20-30W at a time. I'm keeping the pedalling pretty consistent and the bike is smooth and stable and going at the same speed - there is no way the power is fluctuating anything like that much.

Checked in with 4iiii and they sent me a link to a tech document saying the unit supplies raw power data and I must implement 3, 5 or 10 sec smoothing at the head unit. Does this sound right? Anyone have experience with this? I'm new to the power meter game so trying to work out if I have a faulty unit or this is normal?

I have the latest 4iiii single sided power meter and my experience the same as yours. Going up a steady climb smooths out the power somewhat but, for example, I would not be able to go and ride a climb at somewhere between 195w and 205w. I could maybe get it in the range on 185w to 215w