Motor/controller suggestions for Yamaha XT225 conversion

JRP3

1 kW
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Jan 14, 2008
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Central NY State
I'd like good low end torque, ideally a 60mph top speed but I could live with 50mph. I have two 44V nominal 47ah Samsung packs I plan to run in series for 100V max. The bike in ICE form is 240lbs. I've been looking at some of the QS motors as they seem popular, specifically the 3000 Watt with gear reduction and the 4000 Watt without reduction:
https://www.qsmotor.com/product/3kw-mid-drive-motor/
https://www.qsmotor.com/product/4000w-mid-drive-motor/
Are there other better options, and what controllers would be appropriate?
 

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Regarding controller, if you can get one, an ASI BAC2000 would be sized just right for you based upon the battery specs provided, if you use a 3PH PMDC motor. An ASI BAC4000 would give you more accelertion, and would be justifiable if you have a big enough motor fot it.

If you want torque, a hub motor is an easier/more reliable means to get it than a mid-drive configuration. If you go the mid-drive route, there are much better options than those from QS with regard to peak/continuous power vs weight, but you will have to make sure the gearing is right for your application given that your bike is much heavier than a typical ebike. The Astroflight motors have some insane power density. Twin Astroflight 3220s could hve you approaching 20 horsepower peak, reliably, with the combined weight of two motors being only 8 lbs.

As far as hubmotors go, many of the QS variants are sized right, albeit for the peak/continuous power they can provide they are rather heavy. A Leafbike 2,000W might work as well and you'll gain some efficiency and have significantly less unsprung weight vs the offerings from QS, but do your research to make sure a Leafbike would be enough. Your vehicle's total laden weight will determine whether any of the Leafbike variants can work. While 44V with a 3T wind Leafike in your expected wheelsize would top out at roughly 60 mph, the sturdiest Leafbike motor available will be bordering on the edge of viable in the best case scenario, while a QS would have more than enough copper mass. If the Leafbike ends up inadequate, you will likely damage or destroy it. You're looking at about 35A phase current continuous from the Leafbike, even though with a hubsink and Ferrofluid it can handle 250A peak for 10+ seconds at a time(The BAC2000 I recommended is limited to 200A, but if you decide to use a BAC4000, a Leafike will be too small). At 44V, expect to get about 2 kW continuous from a Leafbike after hubsink and ferrofluid are installed, even though 10 kW peak can be had with enough battery and controller to run it. If you try a Leafbike, make sure you specify the 3T wind as it will provide the rpm/V you need to come close to your top speed goal for the specified voltage. Deciding to install a faring could make a big difference regarding which motors are viable for your application.

If you can get one, a CroMotor would also work better than a QS for your application and make more than enough power/torque. Much more robust than the Leafbike, while its efficiency and peak/continuous power vs weight is somewhere between the Leafbike and the QS. It may in fact make more peak/continuous power than any QS motor of similar weight and it's VERY torquey. So torque that even though you're converting a motorcycle, you'll likely need further modification to avoid destroying things. Pay attention to winding specs and kV value, as 44V may not be enough to reach your speed goals with this, but torque will very much be in abundance.

Too bad Humonsters are no longer available. That torquey 6-phase design will require 2 controllers, BUT its efficiency is significantly better than anything you can buy today, as well as its potential peak power per unit of weight.
 
I'm not sure you've got facts behind some of that. Sometimes i wonder if the oldtimers that used to post here sometimes were e-grinning too much - it was a time of enthusiasm, an 80100 was powerful and a 12070 was a colossus. Special firmwares were needed to run it! A cromotor was a unicorn. Astros ruled. Then most of it disappeared..

Speed up to today: The astros were dynoed to be a not so fantastic motor here a while ago. Cromotors were hyped but were they ever dynoed to be special?
Leaf motor on a moto? I'd guess the peak torque of that motor is more suited on a bike.

If you can back up your post with facts then i'd be happy to see them, cause i didn't see any way back then. Did you own and ride an astro, all qs mid drives, a cromotor and a leaf 3t and a hubmonster? How were they in comparison?
 
Don't know about "special", but a CroMotor can make about 10 hp peak with relative ease at a similar pack voltage to what OP is planning to run, getting about 75% efficiency while doing so:

https://endless-sphere.com/forums/viewtopic.php?f=30&t=43102&start=25#p998698

One thing I didn't consider(I was drunk when I typed that post) was that the CroMotor was made to fit into bicycle dropouts, so probably WOULDN'T be a good choice for this motorcycle. But it definitely has the power/torque needed to accelerate quickly and for the desired performance parameters, and is light at only 11 kg.

The same can be said for the Leafbike 1500W and below, it was made to fit into bicycle dropouts, but Leafbike does make a 2,000W version for scooters and motorcycles. In the massive thread on the Leafbike motor, there is hidden inside some dyno data, and the general consensus is that the 1500W version of the motor when run at 72V and modified with ferrofluid and hubsink is really a 3 kW continuous motor that can handle 10 kW peak electrically. The 2,000W Leafbike motor has significantly more copper mass and a wider stator width than the 1500W, and while I'd need to do some more research to confirm, it MIGHT fit into this motorcycle. Peak efficiency is about 91%. The Leafbike thread is below:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=66489

As for the Astros, I was going by a combination of manufacturer's specs and what I've read on this forum. I haven't seen hard dyno data for them. There's been a number of impressive builds with these motors, the one that stood out to me most being recumpence's Astroflight powered KMX Typhoon that does 0-50 mph in about 4 seconds. All up that bike was what, 120 lbs?

https://www.youtube.com/watch?v=WKAMus3oSdw

These Astroflights aren't cheap though.

If budget is an overriding consideration, the OP really can't go wrong with an appropriately-selected QS motor either. It WILL do the job, but the motorcycle will end up a little bit heavier and perhaps a little bit less efficient. Small price to pay for ironclad reliability. A QS hubmotor for a scooter or a motorcycle application might be an easier install than the QS middrive and provide more low-end torque. The middrive will eliminate the unsprung weight and excess mass of the hub motor, at the sacrifice of the low-end torque but also probably not destroy things either. Finding a place to mount a QS mid drive with the battery taking up all of the space will be a challenge. But this is far from OP's first EV conversion, so he could probably handle the installation of a mid drive.

If the OP wants to cruise at a 60 mph top speed, he will definitely need a motor that won't overheat from the continuous power requirement this will impose, which on a motorcycle of this type, will be around 7-10 kW. But if he wants to cruise at 40 mph with brief bursts to 60 mph, many ebike motors will in theory work quite well, but again, they have to actually fit.

Another possibility is to put a hub motor in each wheel to prevent overheating.

My personal experience is only with the conversions I've built, which include a series-DC powered car, and use of a Leafbike 4T and Leafbike 3T in my custom e-trike/velomobile build.

larsb said:
I'm not sure you've got facts behind some of that. Sometimes i wonder if the oldtimers that used to post here sometimes were e-grinning too much - it was a time of enthusiasm, an 80100 was powerful and a 12070 was a colossus. Special firmwares were needed to run it! A cromotor was a unicorn. Astros ruled. Then most of it disappeared..

Speed up to today: The astros were dynoed to be a not so fantastic motor here a while ago. Cromotors were hyped but were they ever dynoed to be special?
Leaf motor on a moto? I'd guess the peak torque of that motor is more suited on a bike.

If you can back up your post with facts then i'd be happy to see them, cause i didn't see any way back then. Did you own and ride an astro, all qs mid drives, a cromotor and a leaf 3t and a hubmonster? How were they in comparison?
 
I have used the QS 3000W mid drive motor at 300A DC with 72V nominal battery so about 20kW of power in, don't have numbers for the efficiency though but the phase resistance is about 5mohm so not a lot of copper losses, it's got segmented magnets too so specs are good.. That's OK for a 10.5 kg motor
 
larsb said:
I have used the QS 3000W mid drive motor at 300A DC with 72V nominal battery so about 20kW of power in, don't have numbers for the efficiency though but the phase resistance is about 5mohm so not a lot of copper losses, it's got segmented magnets too so specs are good.. That's OK for a 10.5 kg motor

What controller did you pair it with and how heavy is your bike?
 
The Toecutter said:
The middrive will eliminate the unsprung weight and excess mass of the hub motor, at the sacrifice of the low-end torque but also probably not destroy things either.
I figured the gearing would give enough low end torque as well as a way to adjust it if needed with different sprockets.

Finding a place to mount a QS mid drive with the battery taking up all of the space will be a challenge. But this is far from OP's first EV conversion, so he could probably handle the installation of a mid drive.
There is enough room above where the motor would go once I remove the fairings and tank that I don't think it will be an issue.
If the OP wants to cruise at a 60 mph top speed, he will definitely need a motor that won't overheat from the continuous power requirement this will impose, which on a motorcycle of this type, will be around 7-10 kW. But if he wants to cruise at 40 mph with brief bursts to 60 mph, many ebike motors will in theory work quite well, but again, they have to actually fit.
I'd like to be able to cruise at 55 mph with the ability to hit 60 mph burst if needed. Most road travel will be around 45 mph.
 
I’ve used Votol em-150 and APT96600 with this motor, both work well. I’d get something else today, especially the Votols seem to have a lot of problems and the APT controller program has been problematic for all users i’ve seen. I’d get a fardriver today, it looks like a good controller with good program. Check dougf and j bjork threads, a lot of good data there.
 
JRP3 said:
I'd like to be able to cruise at 55 mph with the ability to hit 60 mph burst if needed. Most road travel will be around 45 mph.

Better safe than sorry. Without knowing your motorcycle's drag coefficient, if you must be able to cruise 55 mph, better err on the side of too much motor rather than too little.

https://www.qsmotor.com/product/8000w-mid-drive-motor/

I could easily see 55 mph requiring 6 kW or more to maintain.

How's the Fiero holding up?
 
JRP3 said:
Took it off the road last year, bought a Model 3 to replace it.

How many miles did it get out of the LiFePO4 batteries? What was their status when you took the car off the road?

Any future plans for the Fiero?
 
The Toecutter said:
JRP3 said:
Took it off the road last year, bought a Model 3 to replace it.

How many miles did it get out of the LiFePO4 batteries? What was their status when you took the car off the road?

Any future plans for the Fiero?

One cell that was wonky from the beginning failed, I figured it would when I installed it but wanted to see what would happen. I never ran a BMS and drove the car till it stopped moving at least 4 times, so around 2V per cell, lower under load. I replaced the bad cell and the pack would get me about 30 miles vs the original 40+. I'm pulling out all the batteries and electronics, might use the pack as home backup, keeping the motor/controller for some other future project, hope to sell the Fiero as is for someone else to use as a project vehicle. Put about 26K miles on it as an EV.
 
The Toecutter said:
JRP3 said:
I'd like to be able to cruise at 55 mph with the ability to hit 60 mph burst if needed. Most road travel will be around 45 mph.

Better safe than sorry. Without knowing your motorcycle's drag coefficient, if you must be able to cruise 55 mph, better err on the side of too much motor rather than too little.

https://www.qsmotor.com/product/8000w-mid-drive-motor/

I could easily see 55 mph requiring 6 kW or more to maintain.
6 kW seems a bit high but I don't really know.

Interesting the QS 3KW geared motor is 120 nm torque with the gearing vs 80 nm for the 4KW and 112 nm for the 8KW.
 
They're probably rated at different phase current values and/or have different winding turn counts.

Check the EV Album. 100 Wh/mile is common for motorcycles travelling around 50-60 mph. That works out to 5-6 kW. Some are better, some are worse, and I've seen and read of motorcycles that needed 10 kW to hold 60 mph. Ideally, you'll have a motor with a continuous rating that offers a slight increase over that 5-6 kW to accommodate accelerations and going up hills.

As light as motorcycles are, their Cd*A value tends to be similar to that of a typical compact car. Similar can be said for an unfaired ebike. The power requirements will scale accordingly. At low speeds where air drag isn't as much of an issue, a motorcycle's and ebike's relatively low weight allow for some astounding efficiency. At 30 mph, you might only need 1,200-1,500W to cruise, or 40-50 Wh/mile. Even then, most of the consumption will still be aerodynamic drag! Double that speed, and the power needed to overcome air drag has been multiplied by a factor of 8 versus what it was at 30 mph, whereas rolling resistance will have only doubled.

If they could fit, many ebike motors in the 1500W-3kW continuous range would probably be suitable if you only needed to cruise 40 mph. But since you want 55 mph, that completely changes everything, given how drag force increases exponentially with speed. You do not want your cruising speed's power requirements to exceed the continuous power capability of the motor, or you risk damaging it. That said, the size of the battery pack will limit the potential for this to happen, and you might only need to consider a 1-hour rating instead of continuous rating, given the short range(relative to an OEM EV car) your pack will provide.

I have no experience with the QS motors. It is possible that like the Leafbike, the manufacturer is being overly conservative in their rating and that it may be the case that it can actually handle more continuous power than they claim. But I wouldn't count on that. Those with experience using the QS line of motors would have some valuable input to add, and someone here may even have some dyno info to share.
 
sure. The QS 3000W mid motors can be driven way over 3kW. I tried to get my controller to overheat when the Votols started to get popular and people had issues with cutouts on them, i have a 10% 1km long hill here which i rode up and down until i got tired of it, some runs uphill even with brakes applied and DC set at 200A . I managed to get the controller hot but not overheated and motor was not overly hot to the touch. Top speed was 110kph with the gearing i had then, i emptied half my battery (20s30Ah) at top speed without overheating it. If your goal is road driving at 50-60mph then it'll be a more than capable match.
 
larsb said:
sure. The QS 3000W mid motors can be driven way over 3kW. I tried to get my controller to overheat when the Votols started to get popular and people had issues with cutouts on them, i have a 10% 1km long hill here which i rode up and down until i got tired of it, some runs uphill even with brakes applied and DC set at 200A . I managed to get the controller hot but not overheated and motor was not overly hot to the touch. Top speed was 110kph with the gearing i had then, i emptied half my battery (20s30Ah) at top speed without overheating it. If your goal is road driving at 50-60mph then it'll be a more than capable match.

That's helpful. How heavy is your bike?
 
I did a quick mock up with tape and an inner tube, tube is a bit over 9 inches for reference, tape is battery dimensions. The QS 8KW is 8 inch diameter so I could fit that if I go that big.
 

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Reading another thread this is something to consider with the larger 8KW motor:

The big diameter of the motor would mean the shaft will be too high and far from the swing arm pivot point.
The length of the motor would also mean it will stick out a lot to the right side when it has to be in line with the chain.
You wont be able to keep the brake pedal, and it might even be in the way of the foot.
https://endless-sphere.com/forums/viewtopic.php?f=12&t=109878&start=50#p1619683

He had to use a jackshaft setup which I'd like to avoid.

FPHoGS2.jpg
 
JRP3 said:
That's helpful. How heavy is your bike?
I don't know the weight of my bike, never weighed it. i'd guess between 100-120kg with everything on it. Battery is too small to go fast for a long time so i guess your ride has to be somewhat heavier?
 
Reading various threads it seems people are struggling to get the Fardriver dialed in properly, some are having problems with basic setup, and documentation is poor. My project is on hold until either I see more people able to setup the Fardriver the way they want or a better controller option appears.
https://endless-sphere.com/forums/viewtopic.php?f=12&t=109878&p=1723852&hilit=fardriver#p1723852
https://endless-sphere.com/forums/viewtopic.php?f=30&t=112177&hilit=fardriver#p1676369
 
You could do a Nucular 12FET(if you can get one), any of the medium to large ASI BAC models, VESC, or even go old school with a Lyon or Lewbowski trapezoidal controller, which won't impose a significant efficiency penalty vs the former options because you've decided on a mid drive. You might even be able to get a Flipsky to work for your project(an overpowered but very compact electric skateboard controller). There are lots of options that can be made to work for your project, some more reliably than others.

My only experience so far regarding BLDC motor controllers is using a Phaserunner, but that's WAY undersized for your project regarding continuous kW capability.

JRP3 said:
Reading various threads it seems people are struggling to get the Fardriver dialed in properly, some are having problems with basic setup, and documentation is poor. My project is on hold until either I see more people able to setup the Fardriver the way they want or a better controller option appears.
https://endless-sphere.com/forums/viewtopic.php?f=12&t=109878&p=1723852&hilit=fardriver#p1723852
https://endless-sphere.com/forums/viewtopic.php?f=30&t=112177&hilit=fardriver#p1676369
 
JRP3 said:
I need over 100V capacity for the fully charged pack.

Why so? Couldn't you run the 44V packs in parallel and use a different ratio for the mid drive?

Sabvoton does make 96V controllers as well, among others. There are options out there. I'm still in the process of researching them for my build, since I intend to eventually reach triple digit speeds.
 
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