TQ motor

[WillShootPhotos]

Curious as to TQ HPR50 Practical Peak Power

While I understand the concept of peak power, it's practical utility still eludes me.

My understanding is that the HPR50 can produce a peak output of 300W, but sustain only 250W on a continuous basis. The output is programmed to be automatically curtailed at some point to protect the motor from overheating and damage. My interest is in learning, from anyone who has experienced it firsthand, what combination of conditions led to the curtailment: duration(minutes? seconds??), speed, grade steepness, or … that would provide some insight as to what the peak 50W actually delivers.

Thanks in advance, Rob.

Rob,

Back when I first got my Domane+ SLR, I was curious to see how quickly I could ride a known test piece of sorts locally in Las Vegas. It is just under 3 miles, avg 4% (which is deceptive as it keeps ramping up as you get further up the climb, maxing at 8 or 9 percent) Here is the segment on Strava:

Villa Ridge | Strava Ride Segment in Las Vegas, NV

www.strava.com

My motor was set to double input wattage to a max of 300W. It was mid July of 2023,late AM, and it was prob 100 degrees ambient while doing the climb. I'd been out on the bike for a few hours by the time I got to this climb.

The top orange line is the TQ output - it is pegged at 300W for the first 6 minutes or so, then it appears (I'm guessing, as I don't recall seeing any overheat messages) that it had been in "sustain" mode at 300 too long, so you can see it drop to 275W, then 250, back up to 275, and for the last 3 minutes, it is around 250W as a max.

The upper green line is the wattage the TQ motor reported I was putting in - the blue line is the power from my Garmin pedals. The TQ was over measuring consistently. I've a few theories as to why - but they are prob moot now that TQ has updated the systems to report more accurate human input power. So I'll skip blathering on about that.

From here I was pretty cooked and was glad I still had some charge left to get the rest of the way home.

Hope this helps.

- Will

 

[rdv]

Will,
great information. Better than I was hoping for. My primary takeaway is that 300W can be counted on for a handful of minutes provided the rider can produce 150W for that period. That is evident from the motor out and Garmin power input graphs.
Another way to look at it is that it should be possible to take on a 1 mile long climb at 10 mph (and corresponding grade) for 6 minutes.
Two other parameters that could influence peak performance are system weight and speed. Might you recall those?

Pushing my luck, but any thoughts of repeating the experiment?

Some related firmware thoughts:
My rider wattage as reported by TQ jumps around so much as to make little useful sense. I would prefer that it be reported as a more stable average over 5 or 10 seconds.
Unfortunately as I discuss in post#110, I have difficulty producing more than 100W on a sustained basis and would welcome a firmware boost in assist to 300% (no motor change).

In the meantime (ever?) I can push myself a bit more confidently thanks to your input.
Rob

 

[WillShootPhotos]

Will,
great information. Better than I was hoping for. My primary takeaway is that 300W can be counted on for a handful of minutes provided the rider can produce 150W for that period. That is evident from the motor out and Garmin power input graphs.
Another way to look at it is that it should be possible to take on a 1 mile long climb at 10 mph (and corresponding grade) for 6 minutes.
Two other parameters that could influence peak performance are system weight and speed. Might you recall those?

Pushing my luck, but any thoughts of repeating the experiment?

Some related firmware thoughts:
My rider wattage as reported by TQ jumps around so much as to make little useful sense. I would prefer that it be reported as a more stable average over 5 or 10 seconds.
Unfortunately as I discuss in post#110, I have difficulty producing more than 100W on a sustained basis and would welcome a firmware boost in assist to 300% (no motor change).

In the meantime (ever?) I can push myself a bit more confidently thanks to your input.
Rob

Rob,

Glad to help - I'm not against repeating that ride, I did it just the other day - but not sure I'll go that hard on a day that hot again...

System weight would be my 185 (I've been steady +/- 1 or 2 el bees for the past few years), plus the size L Domane+ SLR that I'll put at 29 lbs (mine is one size larger than TREK's product page size of 56) and I was down to about half a bottle of water, but I'll still go 2 lbs to cover cages, etc. I guess if you're really splitting hairs, you'd have to add my kit, shoes, helmet, phone, etc... another 5 seem fair? so 221 (if my maths are correct) ish... I don't know if the data exactly matches the segment, but I think it is close as makes no difference, but the segment stats that day were:

Here is that eBike segment:

Villa Ridge - EBike (matches normal segment S/F) | Strava E-Bike Segment in Las Vegas, Nevada

www.strava.com

Tis freshly minted, so I'm sure it'll take a bit of time to update KOM, etc... pretty sure it isn't me...

Since the data in my spreadsheet that I used to make the chart iis timed and it shows right at 10 min, this segment is missing some of the (most likely) base of the climb... which would have the overall data speed/average/etc be just a touch higher (as it was flattest there in the whole segment).

Additional numbers from the strava route:
Max Speed: 25.2
Cadence was avg 97 max of 113 (yeah, I'm a spinner, used to ride on the velodrome too)
Max power was 295 W, avg 156 W (which was my target, to see if I could get 300 out of the motor for as long as possible, tho with slowing for a stop sign and oscillating up and down through the segment overall - I'm glad the avg from me was pretty close to my target)

As to the wattage coming from the TQ system - are you looking at the TQ display? Or are you using a cycling computer? I have (at times) not been using the power pedals when they're on a different bike, and I've paired my Garmin to the TQ and I'm pretty sure you can choose (from the Garmin display choices) to show instant, 3 sec avg, or - if you want em both on the same display - both! YMMV on Wahoo, or other, but I'd guess they can display 3 sec avg too... I've never looked for a longer average, I used to be coached and they really hammered home a consistent output (to smooth the pedal stroke, and to be more efficient and not spike too high, *cough* like I did on this climb *cough cough* LMAO)

I'd think that unless TQ gets enough requests to bump max assist over 200%, I'm not sure they'd do it... also, there may be some engineering reasons why, that it may over torque the motor to try to 3x a 100W input to hit 300 W out... but that's above my pay grade...

Keep those questions a comin'!

- Will

 

[mschwett]

Rob,

Glad to help - I'm not against repeating that ride, I did it just the other day - but not sure I'll go that hard on a day that hot again...

System weight would be my 185 (I've been steady +/- 1 or 2 el bees for the past few years), plus the size L Domane+ SLR that I'll put at 29 lbs (mine is one size larger than TREK's product page size of 56) and I was down to about half a bottle of water, but I'll still go 2 lbs to cover cages, etc. I guess if you're really splitting hairs, you'd have to add my kit, shoes, helmet, phone, etc... another 5 seem fair? so 221 (if my maths are correct) ish... I don't know if the data exactly matches the segment, but I think it is close as makes no difference, but the segment stats that day were:
View attachment 182684

Here is that eBike segment:

Villa Ridge - EBike (matches normal segment S/F) | Strava E-Bike Segment in Las Vegas, Nevada

www.strava.com

Tis freshly minted, so I'm sure it'll take a bit of time to update KOM, etc... pretty sure it isn't me...

Since the data in my spreadsheet that I used to make the chart iis timed and it shows right at 10 min, this segment is missing some of the (most likely) base of the climb... which would have the overall data speed/average/etc be just a touch higher (as it was flattest there in the whole segment).

Additional numbers from the strava route:
Max Speed: 25.2
Cadence was avg 97 max of 113 (yeah, I'm a spinner, used to ride on the velodrome too)
Max power was 295 W, avg 156 W (which was my target, to see if I could get 300 out of the motor for as long as possible, tho with slowing for a stop sign and oscillating up and down through the segment overall - I'm glad the avg from me was pretty close to my target)

As to the wattage coming from the TQ system - are you looking at the TQ display? Or are you using a cycling computer? I have (at times) not been using the power pedals when they're on a different bike, and I've paired my Garmin to the TQ and I'm pretty sure you can choose (from the Garmin display choices) to show instant, 3 sec avg, or - if you want em both on the same display - both! YMMV on Wahoo, or other, but I'd guess they can display 3 sec avg too... I've never looked for a longer average, I used to be coached and they really hammered home a consistent output (to smooth the pedal stroke, and to be more efficient and not spike too high, *cough* like I did on this climb *cough cough* LMAO)

I'd think that unless TQ gets enough requests to bump max assist over 200%, I'm not sure they'd do it... also, there may be some engineering reasons why, that it may over torque the motor to try to 3x a 100W input to hit 300 W out... but that's above my pay grade...

Keep those questions a comin'!

- Will

This is great data! It’s very interesting to see how completely inaccurate the motor‘s estimate of rider power is. Very few people have power meters on their e-bikes. My specialized turbo creo was closer than what you’re showing here, but also over-reported when the motor was in use, while my scott with a mahle x20 actually under-reports by around 15%. I have a 4iiii power meter on the cranks on that bike, but i haven’t been able to get the rider power data out of the mahle system in a format that makes it easy to compare with the 4iiii data. Maybe worth another try!

Do you happen to know what type of sensor they actually use in the mid-drivers for rider power? It’s obviously not as sophisticated (or expensive!) as typical crank based power meters. The mahle part is in the bottom bracket, not the cranks, only costs $200 or so, but is obviously different than what a mid-drive would require.

 

[WillShootPhotos]

This is great data! It’s very interesting to see how completely inaccurate the motor‘s estimate of rider power is. Very few people have power meters on their e-bikes. My specialized turbo creo was closer than what you’re showing here, but also over-reported when the motor was in use, while my scott with a mahle x20 actually under-reports by around 15%. I have a 4iiii power meter on the cranks on that bike, but i haven’t been able to get the rider power data out of the mahle system in a format that makes it easy to compare with the 4iiii data. Maybe worth another try!

Do you happen to know what type of sensor they actually use in the mid-drivers for rider power? It’s obviously not as sophisticated (or expensive!) as typical crank based power meters. The mahle part is in the bottom bracket, not the cranks, only costs $200 or so, but is obviously different than what a mid-drive would require.

I have no idea the tech inside the motor; but I know they say they've improved the power reading since I did that ride. I did read an interview with one of the TQ engineers who said (about their MTB program) that their tech is so sophisticated that within a few pedal strokes they know the rider's weight, and if they're on flat pedals or clipped in... I'll try to remember to run another comparison soon.

 

[rdv]

At first thought Will's speed, in km/h, was mistakenly reported as mph. Yikes, uphill at 19.1 mph, good thing he's on a class 3 bike or he'd outpace the assist (needed?).

It will be interesting to see what the 'improved' TQ power readings reveal when Will gives it a try.
Curiously, his July 2023 chart suggests that the motor doesn't believe its own measurement of human input either. There are 3 dips in motor wattage in the the first 6 minutes that drop to ~250W, responding to a drop in ~actual rider input (blue) to ~100W, whereas the reported rider input (green) does not fall below 200W, which should have called for 300W from the motor.

Good point about the added demand on torque. Might indeed rule out assist levels greater than 200%. Though I liked the idea of light assist and regular road bike feel, foregoing 50~100W of assistance out of 250~300W when needed the most is a bit of a bummer, but with a little extra care and a little less speed, I'll manage for a good while yet.

 

[WillShootPhotos]

At first thought Will's speed, in km/h, was mistakenly reported as mph. Yikes, uphill at 19.1 mph, good thing he's on a class 3 bike or he'd outpace the assist (needed?).

It will be interesting to see what the 'improved' TQ power readings reveal when Will gives it a try.
Curiously, his July 2023 chart suggests that the motor doesn't believe its own measurement of human input either. There are 3 dips in motor wattage in the the first 6 minutes that drop to ~250W, responding to a drop in ~actual rider input (blue) to ~100W, whereas the reported rider input (green) does not fall below 200W, which should have called for 300W from the motor.

Good point about the added demand on torque. Might indeed rule out assist levels greater than 200%. Though I liked the idea of light assist and regular road bike feel, foregoing 50~100W of assistance out of 250~300W when needed the most is a bit of a bummer, but with a little extra care and a little less speed, I'll manage for a good while yet.

I also noticed the dips in power that don't directly correspond to dips in TQ provided power; but, bear with me, I think that this a) is by design, and 2) makes sense...

I think it's is part of how TQ smooths out the support power... so the motor support isn't surging and waning with every change in human power input. On the ride, it wasn't noticeable... other than in a positive way. That I didn't have to "over push" to get the support power back (which was nice!). I think if they "accurately" matched input power, the ride experience would really be herkey jerky... I'm a fan of how they have it now.

- Will

 

[rdv]

A stroll through the weeds.

Indeed, the smoothing applied by TQ to achieve a “natural” feel is evidenced by those 3 dips in the first 6 minutes of your ride plots. While the credible human input (blue) briefly dropped to ~100W, the motor (orange) still contributed ~250W, whereas strict 200%adherence would have lowered the assistance to ~200W.

At the same time, the plot that TQ is reporting as human input (green) is not at all credible. Since it doesn't drop below 200W over the same 6minutes, it would have been expected to generate the capped 300W of motor support throughout, not drop to 250W for a measly 25% boost. It will be interesting to see to what extent this metric has been improved.

I noticed early on that the smoothing could be adjusted with the app's pedal response and settled on using rapid in Eco and slow in Medium and High. The quick jump in Eco (up to 100W boost) helps in engaging the pedals and getting going from a stop, while the more gradual transition (from/to~200W boost) at pauses in rider input makes for a more balanced ride.

 

[Calcoaster]

Rob,

Back when I first got my Domane+ SLR, I was curious to see how quickly I could ride a known test piece of sorts locally in Las Vegas. It is just under 3 miles, avg 4% (which is deceptive as it keeps ramping up as you get further up the climb, maxing at 8 or 9 percent) Here is the segment on Strava:

Villa Ridge | Strava Ride Segment in Las Vegas, NV

www.strava.com

My motor was set to double input wattage to a max of 300W. It was mid July of 2023,late AM, and it was prob 100 degrees ambient while doing the climb. I'd been out on the bike for a few hours by the time I got to this climb.
View attachment 182645
The top orange line is the TQ output - it is pegged at 300W for the first 6 minutes or so, then it appears (I'm guessing, as I don't recall seeing any overheat messages) that it had been in "sustain" mode at 300 too long, so you can see it drop to 275W, then 250, back up to 275, and for the last 3 minutes, it is around 250W as a max.

The upper green line is the wattage the TQ motor reported I was putting in - the blue line is the power from my Garmin pedals. The TQ was over measuring consistently. I've a few theories as to why - but they are prob moot now that TQ has updated the systems to report more accurate human input power. So I'll skip blathering on about that.

From here I was pretty cooked and was glad I still had some charge left to get the rest of the way home.

Hope this helps.

- Will

Interesting that your Trek rider power reporting is consistently higher than your power pedals. Most others report the opposite. And what is the lower green line?
Did you get the latest update, and if so any improvement in rider power accuracy?

 

[WillShootPhotos]

Interesting that your Trek rider power reporting is consistently higher than your power pedals. Most others report the opposite. And what is the lower green line?
Did you get the latest update, and if so any improvement in rider power accuracy?

The lowest green line is cadence (there is a key at the bottom of the chart, but it is TINY...)

I will do another comparison of power pedals output vs TQ, but the TREK app seems to no longer stay active after I start my ride. I'm guessing some "stay active in the background" permission for reset on an app or security update. Phones are so focused on saving battery these days.

More as I know it.

- Will

 

[Calcoaster]

The lowest green line is cadence (there is a key at the bottom of the chart, but it is TINY...)

I will do another comparison of power pedals output vs TQ, but the TREK app seems to no longer stay active after I start my ride. I'm guessing some "stay active in the background" permission for reset on an app or security update. Phones are so focused on saving battery these days.

More as I know it.

- Will

Thanks!