Need advice QS 3000 hub motor build

Jonspeed

1 mW
Joined
Aug 16, 2021
Messages
12
Hello
I am converting a 2004 yamaha wr450f to electric and would like to know (real world) how would a qs 3000w hub motor (not v3) perform on this bike. I would like to know what speed I can reach using 72v battery (A123 cells 16p config) 300a bms, savoton 100a controller. The bikes weight is about 150kg with 80kg rider. I really just need a ball park figure to see if it would be worth it or if i should go for the qs v3 5000 (which i know is much better but seems to much for my project). The speed limit here is 80kph the average traffic flow is 60kph not much highway driving at all, so i really don't need it to be a speed demon just reliable with decent acceleration.
 
I personally would tell you to do the biggest/most powerful motor for heat absorption. I’d use this if I was going to do your bike with a hub…… https://www.qsmotor.com/product/17-inch-12kw-hub-motor/

Tom
 
Thank you for the advice, that one looks perfect for my second build (cbr 900rr) much heavier than the dirt bike but that will be a few months away (just started the battery). I would like something with spokes because i like the dirt bike look and would like to use my current rim and tyre, the 273 seems way to big and looks to be very heavy but i am new to this so i really dont know.
 
j bjork said:
I wouldent consider any hub motor for a dirt bike, possibly for use as a middrive.

Hi do you have any particular reason why you would not use a hub motor, i considered a mid drive but unless i use a belt drive they are way to noisy.
 
I would use a bigger controller.

I have a 5kw hub motor in my scooter and a sabvoton SVMC72150. It is pulling up to 14kw but acceleration is not realy good. 12-13 seconds to 80kph.
Scooter wheigts with 250kg with driver.

Controller should have 500-600phase amps for better acceleration.
 
When you mentioned “ speed limit here is 80kph the average traffic flow is 60kph not much highway driving at all” I thought you were using it for the street. Since I have one (high powered hub bike) I can tell you that hubs excell on smoother surfaces. They can be hard to set up when the wheel/tire leaves the ground & when using a lot of travel as in off road situations. Not saying it won’t work just not ideal. I only jump mine on rare occasions and I do find the bike very unbalanced……mine only weighs in around 125-135 lbs. getting into a “whoops” section will literally beat me to death! What mine is though is completely silent! Other than the sound of the tires on the pavement you can not hear anything which is just wonderful.

While definitely not a motorcycle like you are building but same/similar design with 7+ front travel and 10+ inches rear travel I would consider my bike a really good smooth flowing trail/street machine and not a motocross type bike. As long as the tire is touching the ground the bike is amazing so in my case the rear motor weight is not of huge concern. I find the larger mass good for heat absorption which equals longer run times. Also, you need way more power. I’m running 17KW and could run up to 20KW. 17 is lots of fun and not pushing my “3KW” motor hard enough to kill it. For the size bike you want to build I’d say 20KW would be the lowest you would want to go for a “fun” bike. Id run that 12KW motor linked above in the 30 to 40 KW range and think it would be very “fun” on smooth trails and the street!

Tom
 

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If you want to ride hard in rocky terrain it dosent only beat the rider to death :lol:

FdMdOs4.jpg


tbpVK2r.jpg


This is with a chinesium rim, a quality rim takes a lot more beating.
But I think you get the point.
 
Hello there. I have a 12" 3000w v4 hub motor from qs and I can likely help with a few figures.

I run mine in a refitted emmo proton (grom size street bike) and I have a 72v 35ah battery. Bike and rider total around 400 pounds when added together. I've got mine on a fairly conservative tune as I drive mine on the roads and only need to keep up with 60kph traffic which it does rather easily.

The motor is restricted to 40A (almost exactly 3000w) normally and reaches a top speed of around 60-65kph depending on the wind/slope.
In sport mode I draw 70A and on a nice windy back road I was able to reach 77kph.

The torque however is not great at these settings which I really don't mind as its my first bike and I'm just city commuting, but in my opinion it would not be great for any kind of hard trail riding. Especially if you have a larger back wheel than a my tiny 120/70/12
 
j bjork said:
If you want to ride hard in rocky terrain it dosent only beat the rider to death :lol:

Wow…..you beat that one to death!!! You have definitely ridden yours harder than I have ridden mine.

Tom
 
j bjork said:
On a dirtbike you want good suspension, not 15kg extra unsprung mass.
I dont think the noise is a problem on a dirtbike, a street bike would be a different thing.

That is a good point.
 
dominik h said:
I would use a bigger controller.

I have a 5kw hub motor in my scooter and a sabvoton SVMC72150. It is pulling up to 14kw but acceleration is not realy good. 12-13 seconds to 80kph.
Scooter wheigts with 250kg with driver.

Controller should have 500-600phase amps for better acceleration.

Ok I looked into that controller a bit, I will get that one instead.
 
litespeed said:
When you mentioned “ speed limit here is 80kph the average traffic flow is 60kph not much highway driving at all” I thought you were using it for the street. Since I have one (high powered hub bike) I can tell you that hubs excell on smoother surfaces. They can be hard to set up when the wheel/tire leaves the ground & when using a lot of travel as in off road situations. Not saying it won’t work just not ideal. I only jump mine on rare occasions and I do find the bike very unbalanced……mine only weighs in around 125-135 lbs. getting into a “whoops” section will literally beat me to death! What mine is though is completely silent! Other than the sound of the tires on the pavement you can not hear anything which is just wonderful.

While definitely not a motorcycle like you are building but same/similar design with 7+ front travel and 10+ inches rear travel I would consider my bike a really good smooth flowing trail/street machine and not a motocross type bike. As long as the tire is touching the ground the bike is amazing so in my case the rear motor weight is not of huge concern. I find the larger mass good for heat absorption which equals longer run times. Also, you need way more power. I’m running 17KW and could run up to 20KW. 17 is lots of fun and not pushing my “3KW” motor hard enough to kill it. For the size bike you want to build I’d say 20KW would be the lowest you would want to go for a “fun” bike. Id run that 12KW motor linked above in the 30 to 40 KW range and think it would be very “fun” on smooth trails and the street!

Tom
The bike is a commuter but i was hoping to do a little weekend trail riding, but its not a necessity. wow that is a lot of power from that motor now i really want to get it.
 
j bjork said:
If you want to ride hard in rocky terrain it dosent only beat the rider to death :lol:

FdMdOs4.jpg


tbpVK2r.jpg


This is with a chinesium rim, a quality rim takes a lot more beating.
But I think you get the point.

Great info, no off roading, and no cheap rims lol. thank you
 
Millhouse_5 said:
Hello there. I have a 12" 3000w v4 hub motor from qs and I can likely help with a few figures.

I run mine in a refitted emmo proton (grom size street bike) and I have a 72v 35ah battery. Bike and rider total around 400 pounds when added together. I've got mine on a fairly conservative tune as I drive mine on the roads and only need to keep up with 60kph traffic which it does rather easily.

The motor is restricted to 40A (almost exactly 3000w) normally and reaches a top speed of around 60-65kph depending on the wind/slope.
In sport mode I draw 70A and on a nice windy back road I was able to reach 77kph.

The torque however is not great at these settings which I really don't mind as its my first bike and I'm just city commuting, but in my opinion it would not be great for any kind of hard trail riding. Especially if you have a larger back wheel than a my tiny 120/70/12

Perfect this is just what i was looking for. Your specs are very close to mine except for the wheel size. I will get the 5000w motor because i will be using a larger wheel.
 
Thank you all very much. I am about to order i have decided on the 5000w v3 hub motor without the rim and the sabvoton 72150.
 
If you choose the 5kW motor and want to do trail riding , I would choose at least the SVMC72200 (450phase amps) or the SVMC72150 in the unlocked Version (no waranty/ but for DIY there is no real waranty), or even a controller with more phase amps.
You need the phase amps for the starting tourqe. More phase amps = more tourque.

If you do not need big starting tourque the normal SVMC72150 will be fine.

Acceleration from my scooter with the SVMC 72150 and the 5kW QS Motor
My next upgrade will be a new controller with 500-600phase amps
Acceleration_20210516-114416.jpg
 
Order a Nucular 24F now then. I have a 3.5T in a 17” rim with a Shinko 241 3.0 tire (Known for being a high traction tire and 3.5 inches wide!) and it has enough torque to break the tire loose on concrete with the front tire locked up!

It’s an amazing controller!

Tom
 
litespeed said:
Order a Nucular 24F now then. I have a 3.5T in a 17” rim with a Shinko 241 3.0 tire (Known for being a high traction tire and 3.5 inches wide!) and it has enough torque to break the tire loose on concrete with the front tire locked up!

It’s an amazing controller!

Tom

Just checked that out, for my first build that seems a bit much, if i start at the top then i don't get the joy of the upgrade chase. this is a great hobby i would like a few years out of it lol.
 
Hello can anyone offer any help or info on a belt drive setup for a qs 138 70h. I have been searching all over the net and cannot find a source for a rear belt sprocket (pulley) for a wr450. I have not come across any builds using belt drive either. I really would like to avoid noisy chains.
 
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