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Thursday, September 26, 2019

Review: Velocomp Powerpod V3

I'd resisted getting a power meter for years. To begin with, they're expensive, usually exceeding $600 when all is said and done. Secondly, most of them require you to either replace your wheel, cranks, or pedals. The pedal ones are particularly bad, since none of the power meters that are pedal based have walkable cleats!

When the Velocomp Powerpod v3 had a flash sale for $200, I decided it was worth a try. It was relatively light, was reasonably priced, and most of all, had technology that appealed to the software engineer in me. The approach Velocomp takes with power meters is to have a device with an integrated wind sensor, barometer, and several accelerometers that would also pair with your wheel sensor and cadence sensor.

The wind sensor would be used to calculate the opposing force via wind resistance. The barometer would be used to calculate opposing force from climbing (along with distance measurements from the wheel sensor). You would calculate rolling resistance from the deceleration when coasting (you would know when the cycling was coasting via the cadence sensor). You could even take into account a gravel road or bumps via an internal accelerometer that has a model for gravel. Tie everything together and you'd have a power meter that didn't need strain gauges. You could also tie everything together by automatically recalibrating at the start of every ride just in case the cyclist changed wheels, tire pressure, or even hand positions.

Of course, that meant that you couldn't have anything in front of the Powerpod that blocked the wind. Since I ride with a handlebar bag, the typical handlebar setup wouldn't work, but I'd already solved that problem for my light, so now I solved it by getting another Origin8 stub and a shim. The result was a pod that hung on the fork above the hub, in pretty much an ideal position.

The device has the mark of a home-made job. For instance, there's just one LED and one button. You pair your sensors by holding down that one button to turn it on. The LED is supposed to tell yellow so you can pair it with the wheel sensor (the cadence sensor is optional, but as indicated above, is also used to provide more data for calibration). But mine never turned yellow, no matter what. You can also pair a HRM sensor to it so that you can graph the HR data alongside the power. Then you're going to pair your head unit and go out for a calibration ride which is about 10 minutes long. You ride out and watch your power meter go from 0-50W, then turn around and ride back. When you get back to your start it'll read 100W and then start reporting real power. That's it! I recently tried calibrating it without following the out and back instructions, and to my surprise it calibrated fine as well. I guess it just needs a lot more data as the calibration required more time.

There are additional inputs you can provide for more accuracy, including your body weight and the weight of your bike. However, you don't have to stress very much about being absolutely accurate. This is where I wished the device would just sync with my Garmin connect account to extract body weight, for instance.

The device is extremely dependent on software, so software bugs would cause the power meter to lock up. At first I thought I had a defective unit or had broken it, but customer support told me to just hold down the power button for 15s to reset it. The reset didn't cause it to lose its calibration, but it did reset the internal clock so I had to tell it what the time was the next time I connected it to a PC (fortunately, the PC would also let me correct the date/times in the ride fall as well). In theory, the unit could be removed from the bike and then replaced, but every time you did that it'd have to recalibrate to its new position, so I simply solved that issue by bringing the laptop over and connecting it to download data. I suspect that the "bike-to-bike" move feature isn't going to be used very often, but so far recalibration hasn't been a major hassle.

Customer support answered relatively quickly, even on a Saturday or Sunday. So whatever else I can say, the company seemed to be very responsive. I thought at first that meant it was a one-man shop, but a visit to LinkedIn revealed that the company had about 15 employees or so, and had been around for quite a while. On reflection, the product itself contributes to the feeling that Velocomp is a one man shop. For instance, there's only a single LED, and it's blink states are used to indicate whether it's on, acquiring a pairing with a sensor, is low on power, or is charging. That's way too overloaded, and as a result I ran out of power once without realizing it, and I could never figure out when the device has been charged. I just end up plugging it in and leaving it plugged in overnight.

The device comes with software mysteriously called "Issac" after "Issac Newton", back when the product was called the Newton. The software graphs your power alongside your cadence, and can even merge your GPS files so you can visualize your power graph on Google Earth.

The big question people have is accuracy. I'm not about to buy a $600 power meter so I can verify the accuracy of the unit, but as far as I can tell, it's self-consistent. Obviously if you make a mistake by entering too high a body weight you'll get high readings for power, and of course, if you do an entire ride standing up but you calibrated the unit by being in the drops you might get power readings too low. But all in all, the unit has been very responsive and pretty good about adjusting for wheel swaps, etc.

Another issue with a device like this: what do you do with all this data? The big one as far as I can tell, is to integrate power into your training with a website such as Xert. These units will tell you (after you sync the data with Garmin Connect or Strava) what your fitness status is, how much power you have available, and even more intriguingly, how tired you are. You can then use that data to decide how hard to train and how much to rest. I was very surprised to see that even though I've always considered myself too lazy to seriously train, that I had a high enough volume of riding and physical activity that Xert and other that I was tired and should consider backing off or riding at lower intensity.

Immediately after acquiring the unit, I made my fastest time ever up a benchmark hill. I had the Garmin set to display power information, but went too hard at first and had to slow down. The power meter showed me sustaining a 200+W power output but as I got tired my power curve would drop. So if you're trying to pace yourself you'd figure out your long term sustainable power and try to stick to that instead of having power drop off, but it did show me how someone like a triathlete would use this data in a race. I'm likely to just ignore it and have fun.

The big limitation of a unit like this (as opposed to the pedal based or crank based system) is that it's only going to measure overall power use. So if you were on a triplet with your two kids, it could only measure the overall power produced by all of you, whereas the crank based unit would tell you how hard you were working. On the other hand, the wheel-based power meters also have the same issue, and you don't see anyone dismissing the legitimacy of those devices as power meters. You just have to be aware of the limitations of the unit before you buy.

All in all, the device punches well above its price class. I think if you want a power meter, it's well worth considering a powerpod over the more expensive alternatives. Certainly for training and racing purposes, most of the time you're not after absolute power, but relative power to see whether you're improving or need to back off. In which case, I see no reason to spend the extra money for a "real" power meter --- if you're serious about getting faster (I'm not), spend the difference on a coach or training service that will use the additional data to help you get stronger faster!


Unknown said...

Hello. Do you mantain the considerations about the Velocomp PowerPod? I mean, it is worth buying? Regards

Piaw Na said...

I think so. It's been very reliable for the last year, and the Velocomp guys respond very promptly to questions and requests for support. I like that it auto-calibrates when you switch tires, etc.

AA said...

I got one about a month ago, 10+ rides and 5 calibrations later, decided to send it back today. The power meter keeps falling to zero reading every 20 minutes or so. Also I am very skeptical about its accuracy, especially while riding against the wind. I have no idea how anyone has managed to successfully use it. So many positive reviews including DCR, maybe I just got a dud unit.

AA said...

I got one about a month ago, 10+ rides and 5 calibrations later, decided that it is not worth it, and I am sending it back today. The power meter keeps falling to zero reading every 20 minutes or so and remains like that for 10-15 minutes. Also I am very skeptical about its accuracy, especially while riding against the wind or climbing up or riding down. I have no idea how anyone has managed to successfully use it. It is reasonable on a flat track with no wind. So many positive reviews on this unit including DCR, maybe I just got a dud unit.