Statorade in a 12" rim-integrated hub motor

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TorgueRPM   10 mW

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Statorade in a 12" rim-integrated hub motor

Post by TorgueRPM » Jan 09 2019 4:21pm

I've been looking into making an electric motorcycle for a while, and after coming across a few threads on various forums about the electric chinese grom clones (eGroms), I decided that buying and upgrading one might be my best option for now.
From what I can tell, they use these motors:
http://www.cnqsmotor.com/en/article_rea ... r/198.html
[img]http://g03.s.alicdn.com/kf/HTB1Fq5NX12C ... 50x350.jpg[/img
2kW isn't going to be enough for me, so greater cooling might be needed when I push the motor to 10kW or so. I was thinking statorade, but the motors have rims integrated into them, designed to have tubeless tires directly attached, so if Statorade ferrofluid is used the usual heat transfer path might not be there.

So I have a couple of questions:
1) Will the g-forces created by a 260mm hub motor spinning at a maximum 1200rpm even allow me to use statorade in the first place?
The statorade info page says this may not be possible without a ton of ferrofluid
2) Will the tires be damaged by a potential 100C rim due to heat passing through the magnets into the shell?

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Re: Statorade in a 12" rim-integrated hub motor

Post by billvon » Jan 09 2019 5:02pm

TorgueRPM wrote:
Jan 09 2019 4:21pm
2kW isn't going to be enough for me, so greater cooling might be needed when I push the motor to 10kW or so.
You can reduce the temperature of the windings through the use of Statorade, or you can get some more power (say 60% more) out at the same winding temperature. You are not going to get 5x the power. Statorade is great, but it's not magic.
--bill von

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TorgueRPM   10 mW

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Re: Statorade in a 12" rim-integrated hub motor

Post by TorgueRPM » Jan 09 2019 7:22pm

billvon wrote:
Jan 09 2019 5:02pm
TorgueRPM wrote:
Jan 09 2019 4:21pm
2kW isn't going to be enough for me, so greater cooling might be needed when I push the motor to 10kW or so.
You can reduce the temperature of the windings through the use of Statorade, or you can get some more power (say 60% more) out at the same winding temperature. You are not going to get 5x the power. Statorade is great, but it's not magic.
You're right about that, I guess I wasn't too clear. I'm not expecting 10kW continuous, more like 5, and even then only for hills. At 10kW continuous, my range would be terrible anyway. I'm more thinking 15kw peak, then using statorade to cool the motor down faster so I can hit 15kW peak again without waiting as long :D

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neptronix   100 GW

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Re: Statorade in a 12" rim-integrated hub motor

Post by neptronix » Jan 09 2019 7:47pm

Not sure about how well ferrofluid does at such high RPM. You might wanna search the forum and look into justin's ferrofluid tests.

But those motors have a lot of copper on them. It should take some abuse nicely, but 15kw is probably walking into beyond the saturation point where you get something like 2% efficiency.. might wanna shoot for 10kw peak for a bit longer to get the acceleration going.

I notice that your rim is extremely close to your magnet rings. Transfer of heat is actually a real concern. This would spook me off from pushing really high power into a wheel like that, then taking the additional step to send the heat over to the rim..
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TorgueRPM   10 mW

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Re: Statorade in a 12" rim-integrated hub motor

Post by TorgueRPM » Jan 09 2019 10:09pm

neptronix wrote:
Jan 09 2019 7:47pm
Not sure about how well ferrofluid does at such high RPM. You might wanna search the forum and look into justin's ferrofluid tests.

But those motors have a lot of copper on them. It should take some abuse nicely, but 15kw is probably walking into beyond the saturation point where you get something like 2% efficiency.. might wanna shoot for 10kw peak for a bit longer to get the acceleration going.

I notice that your rim is extremely close to your magnet rings. Transfer of heat is actually a real concern. This would spook me off from pushing really high power into a wheel like that, then taking the additional step to send the heat over to the rim..
I'm not really sure what satuartion means, I'll have to look into that.

I did see this motor:
https://www.aliexpress.com/store/produc ... 4a15s2RYq7

It has a 13" integrated rim and has a small gap between the rim and the outside of the motor. Do you think that gap would make a big enough difference in cooling? It's also rated for 5kW instead of 2kW.

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Re: Statorade in a 12" rim-integrated hub motor

Post by TorgueRPM » Jan 09 2019 10:36pm

So the saturation point is the point at which more amps does not give you more torque, but instead just starts creating more heat in the motor?

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Re: Statorade in a 12" rim-integrated hub motor

Post by amberwolf » Jan 09 2019 10:42pm

Essentially saturation is when the current thru the motor is so high it is making more waste heat out of the input power than it's making rotation.

it's more complicated than that, but basically once you reach this point, you're using up power needlessly, and creating heat needlessly.

Every motor has such a point; dependent on it's design.

If you go to http://ebikes.ca/simulator you can find this point with various motor / controller setups that have been tested and modelled in it, or feed in custom parameters if you know them for a particular motor to get a guesstimate of performance.

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Re: Statorade in a 12" rim-integrated hub motor

Post by neptronix » Jan 09 2019 11:25pm

The closest thing to your motor is a MXUS 4503 in the simulator.

Try this link out:
https://www.ebikes.ca/tools/simulator.h ... 96&temp=40
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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TorgueRPM   10 mW

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Re: Statorade in a 12" rim-integrated hub motor

Post by TorgueRPM » Jan 10 2019 12:12am

Thanks, makes more sense now. Would the 13" motor I mentioned above make a difference in cooling? At least the heat wouldn't all go directly into the rim.

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