40kW peak from a hub motor

[dominik h]

Does anyone have already made a build with one of the 15kw or 20kw hub motors and can say something about their peak power and acceleration of the build?

At the moment I'm hitting my 5kw QS260 motor with 20kw and 600A phase current. It is doing pretty well. But acceleration could still be better. My scooter weights 183kg without me and 270kg with me. With 27kw I got in 7 seconds to 80km/h and in 9.5 to 100km/h, but the motor got really hot, i think that was to much for the motor.

In near future I want to build a motorcycle and would like to go for a hub motor. But I'm not shure if they really can be fast enough, even if they claim 15kw or 20kw continous for the newer motors and up to 40kw peak.

Or should I wait until they make axial flux hub motors with a better power to weight ratio and better efficiency than the actual radial motors?

 

[amberwolf]

Sorry I don't have the answer to your question, but I do have a question for you:

Are you only wanting to use hubmotors, or are frame mounted motors driving via chain/etc an option?

(you can get the same power in a smaller package if it runs at a higher RPM; so more power in the same size package...and you can re-gear it at any time to change the torque / RPM depending on the need you have vs other system qualities)

 

[dominik h]

I know that a midmotor can give me more power per weigth and per volume than a hub motor.
As I do not want to build the battery from 18650 ord 21700 cells, I can not easily build around the mid motor.
When there sits a 180mm or bigger motor in the space where the battery should be, I am very restricted with choosing available battery modules. I want to use the VW MEB 12S modules, or build the battery from the LG E78 cells, which are in the VW modules.

 

[pwd]

40kw peak (10 seconds or so) is no problem, you just have to have the hardware for it. I've got a QS260 50H that sees occasional peaks of 30kw. I estimate my best 0-100km time is about 5.75 seconds. If I had a larger version like the 70H; I'm sure 40kw peak would be no problem if I had the battery for that.

Here is another builder that is doing 40kw peaks on his QS260 (I'm guessing he is running the 90H):

If you look at his channel; he is planning on 60kw with the same bike. He says he does a 0-60mph in about 3.75 seconds.

I also see that you are running a Fardriver controller. There is a whole thread on those (with good tuning info) but in my experience they only deliver about 84% of the max phase current rating. Besides max phase and battery current, there are several other Fardriver parameters that may also affect your acceleration.

 

[dominik h]

The sabvoton SVMC72150 which was built in before was measured with a rogowski and a fluke scope meter and my calibrated current clamp showed the same values. SVMC72150 measurement
The sabvoton made 253Arms which is slightly over the advertised 350A peak.
I measured the phase current from my ND72680 with my calibrated current clamp meter.
The Fardriver made exactly what the manufacturer claims.
The Fardriver phone app shows Arms and not the advertised Apeak, so the app never shows more than 500A.
Line current was during my tests a little lower. I only saw 330-340A line current.

My installed motor is only 40H but I have another one with 45h which was sold as 8kw.
In the stator from the 8kw is less copper than in the 5kW stator , so I don't think it will have more power.

 

[dominik h]

Thanks for the link.
I have a 21S100Ah 8C continous battery made from 105 pieces 20Ah power pouch cells in my scooter. But it is really heavy , it weights 73kg and I had to lenghten the wheel base to fit the battery inside. Pictures were taken before the swap to the Fardriver

 

[dominik h]

The grom clone must be 50kg lighter than my scooter.
That helps to accelerate faster.

I asked QS and the only motor that fits my scooter is a 8kw 50H, the others have a wider dropout and a wider rim. This motor only has 16mm² phase wires, and I have already installed 16mm² in my motor after burning the 13.3mm² wires which were originaly installed.

 

[dominik h]

Just bought a 10kW QS 273 60H motor with 220mm dropout, located in Germany.
I have to widen the swingarm for this motor.
In a few weeks I will see, if it has 50% or 100% more power as my 5kW 260 40H motor.

 

[dominik h]

Just got it delivered.
It has 25mm phase wires and Looks really nice. Perhaps I should have installed one of the bigger Fardrivers I have .
Installation will shure take a few weeks, as I have a few other projects.

 

[dominik h]

Just bought a 10kW QS 273 60H motor with 220mm dropout, located in Germany.
I have to widen the swingarm for this motor.
In a few weeks I will see, if it has 50% or 100% more power as my 5kW 260 40H motor.

After installing the 273 60h motor and the Fardriver 721800 , I am now shure the 273 60H motor can take a lot more power than the QS260 40h without getting hot.
0-100 times is reduced from 9,5 seconds to 6,6 seconds with doubling the phase current and adding 20% more line current.

The 273 60H motor can shure take 40kw peaks. But at the moment I am limited to 33kw but the motor stays cool, even uphill for a few minutes.