Is a 50KW Out Runner motor any good for a retro street motorcycle?

[E-GSX]

Here's a link to it:

50KW 154120154Brushless out runner Motor 35-80kv large air craft [50KW 154120154] - $1,024.00 : RC, hobby shop specalizing in Motors, Drones, UAS, robots, motion controll, BGC, FPV, brushlessgimbal.ca

RC, hobby shop specalizing in Motors, Drones, UAS, robots, motion controll, BGC, FPV 50KW 154120154Brushless out runner Motor 35-80kv large air craft [50KW 154120154] - 15412015470(Sensorless, sesnored ) Any kv not higher than 80KV (35, 55, 80) Large scale 40kw Brushless out runner motor for...

brushlessgimbal.ca

I'm looking to retrofit a 90's model Suzuki 1100cc shaft drive. I have asked the vendor for more data as I don't see any torque values. I plan on coupling the motor to the shaft via a u-joint. The rear diff is a 2.66:1 ratio, and it has a 17" rear wheel.

 

[gromike]

Most likely a bad choice for a motorcycle. It looks to be aircooled by the air pushed through it. How would you get clean air through it to cool the motor?

 

[scianiac]

We have seen these motors used for light motorcycles and while it certainly is possible there are some issues. The power ratings of brushless motors are pretty much totally made up. While that motors is sold as 50KW and somehow a larger motor from QS is sold as a fraction of that power, they are both correct but that's because it depends on so many variables. I bet that motor will easily put out 50KW peak while pumping something like 1+ of those KW into just dumping air through itself just to keep the heating down to a level so it won't instantly overheat.

I think high power outrunners have their place in light EVs but that's when you just want absolute maximum peak power to weight ratio for short periods of time and you're willing to use interesting cooling methods. But if you want a solid, reliable, motor with good continuous power and a wide operating RPM range you want a nice big (comparably) IPM motor.

 

[mxlemming]

This is actually quite a big motor at 6" diameter and 4"high. Many people have created motorbikes with similar. 50kW is probably a pipe dream though, as scianiac points out. I have the 120mm diameter version on my bike and it's no use above about 6 or 7kW, due to the inductance you just can't push more power in. Listed as a 12kW motor.

 

[E-GSX]

We have seen these motors used for light motorcycles and while it certainly is possible there are some issues. The power ratings of brushless motors are pretty much totally made up. While that motors is sold as 50KW and somehow a larger motor from QS is sold as a fraction of that power, they are both correct but that's because it depends on so many variables. I bet that motor will easily put out 50KW peak while pumping something like 1+ of those KW into just dumping air through itself just to keep the heating down to a level so it won't instantly overheat.

I think high power outrunners have their place in light EVs but that's when you just want absolute maximum peak power to weight ratio for short periods of time and you're willing to use interesting cooling methods. But if you want a solid, reliable, motor with good continuous power and a wide operating RPM range you want a nice big (comparably) IPM motor.

Thanks for the advice. What do you think of this one?

Motenergy ME1616 Brushless 20 kW - 55 kW Liquid-Cooled IPM Motor 48-120V - - Brushless IPM Motors - MOTORS - EV PARTS

<p>The ME1616 is a Radial Air Gap, Permanent Magnet Synchronous Motor (PMSM) with an Internal Permanent Magnet Rotor (IPM). This motor is designed to work with sinusoidal (sine wave) controllers such as the Sevcon Gen4.<br /><br /><strong>Features</strong

www.electricmotorsport.com

My bike has a large front mount oil cooler I could use to cool the motor and controller if needed. I see that site sells a pump kit for $270 that has most of what I'd need.

 

[dominik h]

...... I have the 120mm diameter version on my bike and it's no use above about 6 or 7kW, due to the inductance you just can't push more power in. Listed as a 12kW motor.

To push more power you need higher voltage then you actually use.

 

[dominik h]

Thanks for the advice. What do you think of this one?

Motenergy ME1616 Brushless 20 kW - 55 kW Liquid-Cooled IPM Motor 48-120V - - Brushless IPM Motors - MOTORS - EV PARTS

<p>The ME1616 is a Radial Air Gap, Permanent Magnet Synchronous Motor (PMSM) with an Internal Permanent Magnet Rotor (IPM). This motor is designed to work with sinusoidal (sine wave) controllers such as the Sevcon Gen4.<br /><br /><strong>Features</strong

www.electricmotorsport.com

This motor will be good, but you need an extra reduction gearobx , or you have to use a very big gear on the rear wheel.

 

[E-GSX]

This motor will be good, but you need an extra reduction gearobx , or you have to use a very big gear on the rear wheel.

My bike is shaft drive and I'd like to keep that. It has a 2.66:1 final drive so that is all the reduction I'd have. I undertook this after watching this YT Video where a guy took a shaft drive Honda and used a NetGain HyPer9 motor and 36x120AH batteries (36S1P, 115V, 120AH, 13.8KW) to operate it. He claims a top speed of 145 MPH, 0-60 in 3.5 seconds, and a range of 155-170 miles. As near as I can tell, that bike used a 3.18:1 final drive ratio and taller 26.2" (130/90-17) rear tire vs my 25.8" 160/70-17.

I've researched the 21700 3.6V 5.0AH cells for a battery pack and measured the frame. I think I can get sufficient power using 5x 33S10P packs (for 119V 250 AH 29KW) where the ICE and trans used to be, so it's a matter of finding the best motor for my purpose. The NetGain HyPer9 he used (88KW/173 ft-lbs torque) with controller is now $5,400, so I want to see if there is a less-costly alternative since I don't need that kind of power. I'm looking to commute 80-100 miles/day at up to 75 MPH, most cruising will be around 65 MPH.

 

[eee291]

If you don't wanna mess with an additional gearbox, you will need a motor that has an insane torque rating like 200-300 ft lb.

 

[E-GSX]

Something is not adding up. The YT video of a similar operational bike used what he considered to be an overpowered motor that maxxed out at 173 ft-lbs (235 NM), and connected via direct drive gave real world performance far in excess of what I need. To get a motor with 200 ft-lbs would be a NM value of around 300. None of the ones I've looked at go that high. I did find an Emrax 228 that's rated at 230 NM peak TQ, but from what I can tell, the cost is higher than the NetGain motor. It's also about 9" in diameter, but about 10" shorter than the NetGain.

 

[dominik h]

In the video there is a huge motor with 120pounds weight. Probably that motor has enough tourque to get away without another reduction, and with the fact that it is heavy you can shurely overpower him in low rpm without getting to hot.
A gearing for 145mph is too high for, when you only need 70-80mph.

The smaller ME motor you have mentioned weights only 50pounds and probably a third to half the tourque of the bigger motor and probably needs higher rpm to produce the power you want.

You have to find a power / tourque graph for your desired motor and do the maths and then decide if it is good for you.

 

[eee291]

I admit the 300 ft lb figure I gave is a bit high. 200 is more realistic for your bike.

Take a look at this for comparison.

Zero SR Gear ratios and Torque

Zero SR Gear ratios and Torque

www.electricmotorcycleforum.com

The Zero SR gets 630nm to the rear wheel. Depending on the weight of your bike, you might want to aim for 700nm.
700/2.66=263nm or 193 ft lb. Finding a motor with that much torque is going to get expensive.

Looking at the motor you posted before, if I'm reading the chart right, then efficiency will be terrible with a 2.66:1 ratio.

So either you accept the slow acceleration and bad efficiency, 372nm to the rear wheel with just 60% efficiency at 130kph or about 20% efficiency at 50kmh.
(Note, this is my estimate since I don't know the outside diameter of the tire.)
Or, you forget about the Cardan shaft and go with a chain or belt drive.

TL;DR, You pretty much need to double the gear ratio to make this thing accelerate well.

 

[Mihai_F]

The motor in the first link, they say 50kw, i would like to see how many seconds that motor lasts at 50Kw, i mean i have a monster motor at 216mm diameter, 8kg, big beefy coils, and at 18kw in 2 minutes hits 80degC at 25degC ambient. So what the heck? 50Kw at 154mm and barely 6kg, is max instant pawer for 1 second or what, that is just advertising in order to "wow" folks, my opinion. maybe cooling it with liquid nitrogen...

 

[mxlemming]

To push more power you need higher voltage then you actually use.

Sure, with enough voltage you can get as much power as you want. I have the 65kV version, on 20s. It free spins at about 1000eHz, 4300rpm. At that speed, it gets very hot even just free spinning. I take your point that with 30s, I could spin it 1000eHz and would be able to hold much higher phase current, but if I let it free spin it would roast itself...

 

[E-GSX]

I admit the 300 ft lb figure I gave is a bit high. 200 is more realistic for your bike.

Take a look at this for comparison.

Zero SR Gear ratios and Torque

Zero SR Gear ratios and Torque

www.electricmotorcycleforum.com

The Zero SR gets 630nm to the rear wheel. Depending on the weight of your bike, you might want to aim for 700nm.
700/2.66=263nm or 193 ft lb. Finding a motor with that much torque is going to get expensive.

Looking at the motor you posted before, if I'm reading the chart right, then efficiency will be terrible with a 2.66:1 ratio.
View attachment 346844
So either you accept the slow acceleration and bad efficiency, 372nm to the rear wheel with just 60% efficiency at 130kph or about 20% efficiency at 50kmh.
(Note, this is my estimate since I don't know the outside diameter of the tire.)
Or, you forget about the Cardan shaft and go with a chain or belt drive.

TL;DR, You pretty much need to double the gear ratio to make this thing accelerate well.

I wish Suzuki final drive ratios were as easy to find/change as Chevys/Fords. I see the Zeros use over a 4:1 ratio. I may look at some other shaft drive bikes and see what types of ratios were used. Thanks again for the info.

Edit- A brief search across several brands with shaft drive showed the highest numerical ratio was 3.5:1 for the Suzuki C50, which is still in production. No free lunch, as it uses a 15" rear wheel, but at least it's 4" wide. I'll keep looking up data.

 

[E-GSX]

As an update, I found the Yamaha FJR1300 and some others use a 3.67:1 final drive. It also uses a 17" cast rear wheel slightly wider than mine. In the process of doing that, I found some "high torque" sprockets and have looked into them as well. As an example, a 20mm (sprockets are also available in 30 and 50mm width) wide 22 tooth front sprocket mated to a 90 tooth rear one gives me 4.09:1. I looked at how my shaft drive mounts. First I drew up a 1-piece 90T sprocket that would have a pocket for the rear wheel outer bearing. It was overly complex for my e-machine shop software. I then simplified it to a splined hub with a smooth extension the sprocket could attach to, so the sprocket would bolt on in place of the final drive. I am attaching a concept picture.

For belt tension, it looks like I could use the left side muffler hanger frame extension to mount a spring-loaded tensioner. So far, the belt drive appears to be the most viable route.

 

[E-GSX]

I also have been reading about the QS138 H90 V3, which has a built-in 2.35:1 reduction. That gives it more TQ than the larger QS180. I entered data into a spreadsheet and since my combined primary/secondary drive ratio is like 1.77:1, this is better than what I have and the 2980 shaft RPM limit of the motor would still power the bike to a decent top speed, while the upper power band of the motor (4K motor, 1702 shaft) would allow an acceptable highway cruise speed. If I go the belt drive route, I can tailor this further.

 

[eee291]

You sure the QS138 has enough power for your bike?
For my Derbi Senda acceleration i very good but I've never run it for long at top speed.

 

[E-GSX]

You sure the QS138 has enough power for your bike?
For my Derbi Senda acceleration i very good but I've never run it for long at top speed.

I have learned there are at least 4 versions of that motor. The QS138 70H V1 is rated at 3KW, with 55nm max torque. The info says it is for up to a 12" rear wheel.

There's another one called 70H V2, which is also rated at 3KW and 55nm of max torque. It has a spline drive.

Then there is the 90H (not V3), max torque is 72nm, rated at 4KW. The information says it is for up to a 17" rear wheel (which is my size).
QS138 90H 72V IPM PMSM Mid Drive Motor

This motor is perfect for medium to large size electric motorcycles. With its extra long body compared to the 70h model you will be able to achieve a higher torque and power. This motor is capable of over 35kW Bursts!

The one I'm looking at is the 90H V3.
This Motor is the Most compact and powerful motor on the market that includes a built in gear reduction. This will allow for direct drive applications on larger wheel powersport vehicles with out the need for an oversized rear sprocket.

Since it has a built-in 2.35:1 reduction (which is better than my bike's 1.77:1 primary & secondary), there is motor torque and shaft torque. The max motor torque at 72v is 72 (see 90H above), which means at 2.35:1 it is 169nm at the output shaft. This site says (as have others I've read) that this motor is way under rated and can operate reliably @ 20KW with as stated above short bursts to 35.

At this point, that's the direction I'm going to go. I'll mock up a mount & adapter to connect it to my shaft drive to see if it can move the bike and how well. If that's unsatisfactory, I can always go the belt drive route. $700 is a lot more affordable than the $3K for the HyPer9, which makes 235nm. One other thing I noticed today when looking at the bike was the swingarm is in fact double sided. The left side contains a tube for the driveshaft. I don't think my idea of a wider Yamaha wheel would work there.

On my spreadsheet, my OEM IC engine at around 1500 RPM (launch) in first gear makes around 320 RW torque. The V3 if I don't run a higher voltage is 169 * 2.67 final drive or 451 RW torque. With 72nm, this is only 192nm. At 70 MPH in 5th gear, about 4K RPM (peak torque is at 4,750), the RW torque is 408. My spreadsheet shows I should be OK for cruising around this speed.

I also read about a possible liquid cooled version of the 90H. If that comes out by the time I'm ready to buy (which will be at least 6 months from now), I can make use of it since my bike has a good sized front mount oil cooler.

 

[eee291]

I don't know if the geared version can handle 30kw+ I'd be worried about short gear life...
I've got the normal 90H with a 14T 428 sprocket, and I know it can handle whatever I throw at it, I'm just not so sure with the geared version.

 

[Chalo]

I had a GSX1100G that was my main transportation for many years. The shaft drive was its chief mechanical virtue. If I wanted to do a highway capable e-conversion, I would start with something lighter and more aerodynamically efficient. There's a lot of unhelpful pork in that big ole bike, when your fuel weighs so much.

 

[E-GSX]

My bike has the factory fairing that will help. Since it's free and I like it, I plan to stick with this project. Not much of a market for them, especially with leaking carbs. I think it's worth more in parts.

 

[Chalo]

My bike has the factory fairing that will help. Since it's free and I like it, I plan to stick with this project. Not much of a market for them, especially with leaking carbs. I think it's worth more in parts.

Note that touring fairings usually increase drag vs no fairing, because they're for sheltering the rider rather than reducing Cd. So keeping the fairing should be seen as a comfort and convenience feature rather than as a performance benefit. I used a National Cycle Plexifairing on my GSX1100G, and either with it without it I could have gotten much better fuel economy from a contemporary hatchback car.

"Bullet" fairings do help reduce overall drag (depending on rider position), as do most sportbike full fairings with lowers.

 

[E-GSX]

Yes definitely a comfort issue. If I want really good gas mileage I'll just ride my BMW RT, 46 vs 31 when the GSX was in daily use. This is really a learn as I go project. If it works out I may branch out to converting an older car of mine.

 

[SlowCo]

I have learned there are at least 4 versions of that motor. The QS138 70H V1 is rated at 3KW, with 55nm max torque. The info says it is for up to a 12" rear wheel.

There's another one called 70H V2, which is also rated at 3KW and 55nm of max torque. It has a spline drive.

Then there is the 90H (not V3), max torque is 72nm, rated at 4KW. The information says it is for up to a 17" rear wheel (which is my size).
QS138 90H 72V IPM PMSM Mid Drive Motor

This motor is perfect for medium to large size electric motorcycles. With its extra long body compared to the 70h model you will be able to achieve a higher torque and power. This motor is capable of over 35kW Bursts!

The one I'm looking at is the 90H V3.

I also read about a possible liquid cooled version of the 90H. If that comes out by the time I'm ready to buy (which will be at least 6 months from now), I can make use of it since my bike has a good sized front mount oil cooler.

Sounds like a great project!

QS motors (SiAECOSYS) are here on this forum for direct support: QS Motor thread on E-S
Their direct AliExpress store has the QS138 90H V3 with gear reduction in a kit with controller and accessories: QS138 90H V3 geared kit
And they are working on a new hairpin motor with gear reduction (still a pre production CNC and not yet a cast production version): SiA 200-50 CNC gear reduction
That might be the best solution I think especially as soon as the hopefully cheaper cast gearbox version is released.
(please let me know if the links work as I had to adjust them)

Good luck and enjoy building!