Need ebikes.ca modeling "custom motor" specs for Q128c
- Thread starter pullin-gs
- Start date
If you mean you need the numbers ebikes.ca used for modelling within the simulator, then AFAIK they'd have to provide that to you; I don't know of a way to get any of the actual model info from it, only results using the model info built into it at their end on their server(s).
I wish they listed all this modelling info on the simulator page or at least linked from it, but I've never found anything like that.
I wish they listed all this modelling info on the simulator page or at least linked from it, but I've never found anything like that.
Simulator does not have this motor as an option.....thus the need to create "custom" motor.
How to get:
Measure KV at rated voltage, stator resistance of phase windings, number of poles, gear ratio, no load current.
I did this for another motor and would just assume avoid the trouble again if someone has already done the leg work.
How to get:
Measure KV at rated voltage, stator resistance of phase windings, number of poles, gear ratio, no load current.
I did this for another motor and would just assume avoid the trouble again if someone has already done the leg work.
Chalo
100 TW
I gotta say, that's not a motor for folks with a prurient interest in performance. It's just a motor, adequate for hauling around a medium-sized person at 20 mph or so in ordinary street conditions. If you're inclined to maximize it for whatever reason, you'll probably break it.
From my personal experience of that motor, I can say that 201 RPM is nominal speed at some arbitrary load, and not the free RPM at its rated voltage.
What are you trying to determine?
From my personal experience of that motor, I can say that 201 RPM is nominal speed at some arbitrary load, and not the free RPM at its rated voltage.
What are you trying to determine?
Chalo said:
You are so wrong on all fronts about this inexpensive motor.
From my personal experience (I own 2 builds using this motor)......
Here is the build thread:https://endless-sphere.com/forums/viewtopic.php?f=3&t=98760&p=1460895&hilit=terratrike#p1460895
Over four thousand miles and going strong. Cruises 25 MPH....maximum 28MPH (30 with backwind).
I have the 36V 328RPM (shortly after build thread, I overvolted it to 44V using 12S1P 8AH pouch pack).
Note: Maximum current limited by controller to 25 amps....peak power-band flatlines at about 1000 watts maximum.
This is what Schwalbe Marathon tires look like after 4,000 miles:
I've seen dyno graphs for the Q128C before and can say with confidence that there are much better motors on the market with better efficiency and power to weight.
If you think the Q128C is the bee's knees, then try the Shengyi SX2 and you'll probably be blown away.
The kind of bike you ride gives you a significant edge in aerodynamics so sustaining 28mph on a small geared motor is not a shocker, i think Chalo was referring to the more common use case of an upright bike.
Your 20 inch wheels also give you an amazing torque advantage. Any motor has more push. Although with geared motors, gear friction losses are a larger percentage of your efficiency loss when you're running well beyond the RPM they were designed for. That's the downside.
If you think the Q128C is the bee's knees, then try the Shengyi SX2 and you'll probably be blown away.
The kind of bike you ride gives you a significant edge in aerodynamics so sustaining 28mph on a small geared motor is not a shocker, i think Chalo was referring to the more common use case of an upright bike.
Your 20 inch wheels also give you an amazing torque advantage. Any motor has more push. Although with geared motors, gear friction losses are a larger percentage of your efficiency loss when you're running well beyond the RPM they were designed for. That's the downside.
It might be off a bit. My rear tire wears even faster though? I'm on my 4th rear tire (the first three were the cheap tires the trike shipped with....fourth is a wider Marathon and is holding up well).Comrade said:pullin-gs said:
Are you sure your alignment is good? I have only 1,000 miles on my Terratrike but I can still see the factory ridge in the center of the tire from the rubber mold.
That said, I do drive it fast in the curvy paths and golfcart trails around here. The right tire wears faster than the left also, which ties into lateral force wear is uneven in that I favor faster left hand turns more than right.
Please share a dyno graph for another 5lb (or less) 1000W motor.neptronix said:
That said, this trike is purpose build for stealth, light weight, and maneuverable speed.
If I were looking for a more powerful motor for an upright build, I provision appropriately.
This is my last build....a 2KW max dirt-Ebike. Pushes through loose sand and deep ruts/climbs the likes that most weekend jeep drivers cant navigate out in forests and jeep trails in my area.
https://endless-sphere.com/forums/viewtopic.php?f=6&t=111042&p=1627643&hilit=G062#p1627643
https://www.youtube.com/watch?v=v9e7vcZStVw
pullin-gs said:
No such motor exists, unless you want to get into mid drives.
The Q128C is a 6.6lb 500W rated motor. Like i said, you're getting more wattage out of it because of your small wheel and aerodynamic advantage. That says more about your vehicle than the motor.
The wayback machine cannot pull up the rescinded dyno graph for this motor. But i remember the peak efficiency was in the low 80's. That's why i never considered it, and also deleted the spec sheet i had downloaded like ~5 years ago.
The Shengyi is ~0.3lb heavier and has the best peak efficiency i've seen in any geared motor. That means you can beat it harder and for longer. I couldn't get a dyno sheet for it, but we do have the simulator and we know the simulator has a very strong relation to reality.
Also, you say 1000 watts, when that's your peak rating, not your continuous load. Motors are rated based on continuous load, not peak. Your continuous load as you describe it is within the 500w rating on flat ground.
Q128C comes in 800W variant. https://bmsbattery.com/motor/1130-18552-q128c-135mm-36v800w-cst-rear-driving-ebike-hub-motor.html#/213-rpm-201neptronix said:
And as far as "you're getting more wattage out of it because of your small wheel "....
Watts are watts. Wheel size, ride platform have nothing to do with getting more watts or not out of a motor.
Maybe you meant to say "speed at given wattage is better relative to other rides because of the aero performance of your trike"?
pullin-gs said:
That's another one i saw a disappointing dyno sheet for, where the motor really couldn't handle the 800w. The results on the Q128H were even worse. BMS battery really tends to overstate things and also has progressively been removing dyno sheets because they contradict the company's ratings..
I remember that the dyno graph looked like they're using 0.5mm laminations still and using a 26 inch wheel, at the 800w power mark, efficiency was in the upper 70's and this indicates to me that eddy current losses are dominating, and also, this would be probably the worst motor to put in a 20 inch wheel because that eddy current loss problem would get exacerbated by the higher RPM.
pullin-gs said:
It has a very sizeable difference. A MXUS '3kw' hub is a legit 3kw motor in a 16 inch motorcycle wheel. In a 26 inch bicycle wheel, it's a 2.25kw motor. Sometimes the opposite happens - a geared motor can have an actually lower rated watts in a 20" wheel, depending on the pole count, gear design, etc. of course - you always end up with a torque advantage no matter what.
A full recumbent bike versus a fully upright bike makes a gigantic difference, you're looking at a ~33% reduction in real life wattage per mph between the two.
These are massive confounding variables, and is the reason why we should consider recumbent bikes and upright bikes to be completely different critters when designing powertrains for them.
neptronix said:pullin-gs said:
That's another one i saw a disappointing dyno sheet for, where the motor really couldn't handle the 800w. The results on the Q128H were even worse. BMS battery really tends to overstate things and also has progressively been removing dyno sheets because they contradict the company's ratings..
I'd love to see these dyno sheets? Please do share!
When it comes right down to it, you can talk-the-talk (quote other peoples dyno sheets and rumored results) or walk-the-walk and purpose build and engineer based on requirements and stated vendor performance and first-person OBSERVED performance from other builders.
In regards to the disappointing dyno sheets, I must question their accuracy in that my motor simulation for the Q128C Trike build is SPOT-ON to the actual observed performance capability using industry standard efficiencies based on MOSFET commutation and one-stage of helical spur gearing.
My requirement: 20MPH on flat, but very light (mid-drive and direct drive out of question). For me, that translates to 350watts minimum just to push through the air on flat. Add into that 6 percent hills (I have a many of those in my area....but only one that is steeper) and I need 800W AT THE WHEEL to sustain 20 MPH. The trike does this all day. Hills are only 1/4 mile max, so peak heat is a non-issue.
Now on the other hand, If I need lots more power and low end torque for a beefier ride, take a look at my 2KW gear-drive fat build to see how I figured things out for it.
https://endless-sphere.com/forums/viewtopic.php?f=6&t=111042&p=1627643&hilit=G062#p1627643
https://www.youtube.com/watch?v=v9e7vcZStVw
pullin-gs said:I'd love to see these dyno sheets? Please do share!
When it comes right down to it, you can talk-the-talk (quote other peoples dyno sheets and results) or purpose build and engineer based on requirements and stated vendor performance and first-person OBSERVED performance from other builders.
I know, i prefer to do both.
pullin-gs said:
Ah yeah, a lot of little geared hubs would do that job. My application is a lot more extreme. That's why i'm picky as hell.
pullin-gs said:
Those wide bafangs are pretty magical.
pullin-gs said:
That's one of the reasons i generally avoid bafang products.. that and the lack of published performance specifications.
Vetting a new motor from them is about on par with the alibaba no-name vendor mystery motor buying experience.. except that the company has a name.
I took a big gamble going with a new model Bafang gear motor. I jumped because of other people observing that Bafang 750W rated gear motors are actually rated under what motor can safely handle.neptronix said:
In the end I had to mess around with cell-count and controller in order to get power and wheel RPM (speed) that I needed.
Initially I expected (guessed more like it) that I would need to go with a 52V pack of some sort.
In the end I built a 44V 30AH pack.
Motor is rated for 1000W. I push a bit over 1500W sustained and motor barely gets warm. Fingers crossed that it holds up....1100 hard off-road miles so far.
When I ride the forest roads and jeep trails I keep the controller amps pegged at 35A for about 1/3 of my riding pushing through loose sand and washed out rutted roads.
I am thinking about building a fat 24x4 wheel (right now I run 26x4 fat build) and maybe upping max amps of controller to 40A?
