# Motor recommendation for motorcycle conversion



## dougingraham (Jul 26, 2011)

Not sure how much power it takes to go 130 mph on a motorcycle. If you can do it with 73 HP you might be able to use an HPEVS AC-20 motor. Here is a link to the 144 V dyno graphs. With a 24" diameter tire you would need a 4.394 reduction ratio so that 8000 RPM equates to 130 mph. You would see ~215 lb-ft at the face of the tire at 130 mph. It would be 255 lb-ft at zero rpm. Depending on what the motorcycle weighs would depend on this is quick or not. If the bike with rider weighs 500 lbs then you would be seeing an average of around 1/2 G of acceleration from 0 to 130 mph with reduction as speed increases due to air drag.

You would need a 144 volt nominal battery that can do 500 amps for the 2-3 minutes you need. AC-20 weighs ~60 lbs. The limiting factor with the HPEVS is the Curtis controller. The larger and heavier motors are still limited by the output of the controller.


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## bigmotherwhale (Apr 15, 2011)

remy hvh250


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## paravion (Feb 19, 2016)

dougingraham said:


> Not sure how much power it takes to go 130 mph on a motorcycle. If you can do it with 73 HP you might be able to use an HPEVS AC-20 motor. Here is a link to the 144 V dyno graphs. With a 24" diameter tire you would need a 4.394 reduction ratio so that 8000 RPM equates to 130 mph. You would see ~215 lb-ft at the face of the tire at 130 mph. It would be 255 lb-ft at zero rpm. Depending on what the motorcycle weighs would depend on this is quick or not. If the bike with rider weighs 500 lbs then you would be seeing an average of around 1/2 G of acceleration from 0 to 130 mph with reduction as speed increases due to air drag.
> 
> You would need a 144 volt nominal battery that can do 500 amps for the 2-3 minutes you need. AC-20 weighs ~60 lbs. The limiting factor with the HPEVS is the Curtis controller. The larger and heavier motors are still limited by the output of the controller.


Hi Doug,

This is an extremely helpful and generous reply, thank you. Would it be too much to ask for you to break down the math you used to make these calculations? It would be great if I were able to do these calcs on my own - teach a man to fish, etc... 

If the HPEVS is limited by the controller, are there any other affordable controller options? 



> remy hvh250


I have also come across this motor while researching Lightning motorcycles, however from the outset, while I cannot find any current indicative pricing, they seem to be worth north of $10k - but as I said I haven't actually made contact to find out what they cost today. Also, from my understanding they would require liquid cooling, which may be over engineering for this particular project.


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## electron bom (Dec 4, 2014)

I'd go with a Servcon Gen 4
DLC-28 PMAC motor
6500rpm
38kw peak
75ftlbs tq
35lbs weight

If you ran a 3.0:1 gear: top speed of 161mph with a 25" tire and depending on drivetrain loss, somewhere in the neighborhood of 200wtq. 
The motor is liquid cooled, but the rpms and braking regen might be worth it. If you don't want to deal with liquid cooling, then you can go with a PM DC motor which will be cheaper, but you'll forfeit rpms and braking regen. 

Electric motorsport sells a kit:
http://www.electricmotorsport.com/ev-parts/motor-drive-kits/pmac-15kw-cont-38kw-pk-liquid-cooled-motor-drive-system-72-84v-550a.html


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## frodus (Apr 12, 2008)

electron bom said:


> I'd go with a Servcon Gen 4
> DLC-28 PMAC motor
> 6500rpm
> 38kw peak
> ...


You'll never hit 160mph with that motor. The power required for a bike to reach 160mph is much higher than what that motor could put out. RPM calcs are only part of it. You need a certain amount of HP to get to that speed and maintain it. It "might" get to 100mph.


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## Hollie Maea (Dec 9, 2009)

Depends a lot on the motorcycle. We recently did an electric Harley streetglide. Using a 100kW motor (Remy HVH250) we were just barely able to hit 120mph. Granted, the Harley is a big heavy brick wall, and pretty much any other motorcycle would do better. But you're going to need a very slippery bike to hit 130 even with the AC-20. And certainly you won't do it with anything running off a Sevcon Gen 4.


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## electron bom (Dec 4, 2014)

Point well taken, it's more appropriate to say gear limited to 161mph.
Of course it might not even hit 100 mph if he is driving into a headwind, with a side car, holding a fat person, but we don't know what kind of drag or weight were dealing with so conjecture abounds.


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