An Interview With Justin

[Cyclezee]

If you have some time to spare this YouTube video offers chance to see behind the scenes at Grin which is both informative and entertaining.

For those of you who haven't heard the name, Justin Lemire-Elmore, he is the genius and all round nice guy who founded ebikes.ca , A.K.A. Grin Cyclery / Grin Technologies in Vancouver Canada.
He is also heavily involved with the Endless Sphere forum.

In hope you it as much as I did

 

[EddiePJ]

Saved for later viewing.

 

[trex]

thank you for the link. Just finished watching the entire video.
I like his passion.

 

[Cyclezee]

I think you can see why his company is called Grin

I spent a couple of days in his company when we were both staying at the eZee factory in Shanghai I can confirm what a genuinely nice guy he is.

Here he is teaching Wai Won Ching's daughter to ride a unicycle.​

 

[danielrlee]

Justin is single-handedly doing more than anyone else on the entire planet to advance electric bike technology. As time progresses we will all benefit from his research, as manufacturers products are likely to be heavily influenced by the open publication of his testing data.

 

[trex]

single-handed is the right word. Our d8veh is a bit like him.
I particularly like his ideas on making lightweight direct drive motors.
It seems that he has done a lot more research and advance on this type of motors than Rakesh ever has on his Falco motors.

 

[danielrlee]

I'm especially gripped by his current research into using ferrofluid for motor cooling. It's amazing how a few ml's of anything can aid cooling to the degree it does.

 

[trex]

ferrofluid to help with cooling? I don't think it's a good idea. It'll stick to the magnet alright, but the heat is generated by the core of the copper coils, not in the magnets, and to evacuate heat, you need to move the fluid, not encourage it to stick to one place. I understand that the Brownian movement of the magnetic fluid under changing polarity may help with heat removal but that is counteracted by the increased viscosity of such fuids. Traditional synthetic engine oil works well in this respect, I doubt he could beat that.

 

[danielrlee]

Heat is specifically required to be transferred to the motor casing, where it can then be removed into the passing air. Ferrofluid has already been proven to be many magnitudes more effective than regular oil bath cooling on a volume by volume basis and all without the downsides of oil leakage or increased drag. It's currently undergoing beta testing throughout the ES community and can even be purchased straight from ebikes.ca if you'd like to test it too.

 

[Cyclezee]

ferrofluid to help with cooling? I don't think it's a good idea. It'll stick to the magnet alright, but the heat is generated by the core of the copper coils, not in the magnets, and to evacuate heat, you need to move the fluid, not encourage it to stick to one place. I understand that the Brownian movement of the magnetic fluid under changing polarity may help with heat removal but that is counteracted by the increased viscosity of such fuids. Traditional synthetic engine oil works well in this respect, I doubt he could beat that.

You might want to have that discussion in this thread on Endless Sphere https://endless-sphere.com/forums/viewtopic.php?f=2&t=48753&p=1130620&hilit=Statorade#p1130620

 

[trex]

I don't use any high power motors that need oil cooling, hence my ignorance on the subject. However, I am fairly skeptical of any claim that depends on tuning to get to the claimed result. Isn't it correct that ferrofluid needs to be tuned to the actual condition to work their best?

 

[Cyclezee]

When it comes to DD motors the new Ansmann RM7.0 is already lightweight at 4Kg. http://www.ansmann-energy.com/en/e-bike-systems/rear-motor-rm7-0.html

Heinzmann are not far behind, the PRA 180-25 front motor is 4.5 Kg and rear 4.7Kg. Their PRA 180-30 500w is bit more hefty at 5.2 Kg.
http://www.ebike.heinzmann.com/en/systems/directpower/motor

This compares favourably to the Crystalyte H series which tip the scales at 6.5Kg.

 

[flecc]

Ferrofluid has proved very effectve at cooling loudspeakers and greatly improving their efficiency, and they work under constantly widely changing drive conditions.

It's in the worldwide market too, my 4K TV has four ferrofluid speakers handling the bulk of the sound reproduction, two per channel plus a tweeter and sub-woofer each channel.
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[trex]

You might want to have that discussion in this thread on Endless Sphere https://endless-sphere.com/forums/viewtopic.php?f=2&t=48753&p=1130620&hilit=Statorade#p1130620

In his post, Justin compared his (special mix) 'Statorade' against air cooling in a stock motor. Statorade wins, that's clear but he should also include result for stock motor with 6mL of Castrol oil and stock motor with 6mL of Ferrotec fluid for example.

 

[danielrlee]

My level of knowledge on the subject is purely theoretical and is limited to what I have read on Justin's research. Come summer, I will take the plunge for sure and try ferrofluid on my own motor, but until then I'm happy to leave it to others.

The current community testing is largely to determine if there are any longevity issues with running ferrofluid in a hubmotor. Justin has been randomly sending out samples with either a synthetic, or ester base to help him determine the best long-term formulation for the application:

http://www.ebikes.ca/shop/experimental/statorade.html

 

[trex]

I don't think that motor manufacturers are not interested by the subject of his research and indeed the result but in an environment where there are electronic PCBs, PU varnish, PVC glue, introducing an extra 5ml of fluid could cause unpredictable corrosion. The oil may corrode the components on the PCB or the varnish on the copper wire or disolve the glue on the steel laminates for example.

 

[danielrlee]

I don't think that motor manufacturers are not interested by the subject of his research and indeed the result but in an environment where there are electronic PCBs, PU varnish, PVC glue, introducing an extra 5ml of fluid could cause unpredictable corrosion. The oil may corrode the components on the PCB or the varnish on the copper wire or disolve the glue on the steel laminates for example.

This is his biggest concern and why I'm waiting until the summertime before I try it. I'm pretty sure that he has now set up a DD hubmotor running continuously on a jig to clock up as many miles as quickly as possible.

Time will reveal all.

 

[flecc]

My level of knowledge on the subject is purely theoretical and is limited to what I have read on Justin's research.

Ferrofluid doesn't just cool, it also brings a rise in efficiency and I'd most like to know how much that gain can be in DD hub motors.

For example, in loudspeakers, which are linear motors of course, the efficiency gain comes from the ferric element of the fluid directly coupling the magnetic field to the windings, rather than it being weakened in bridging an airspace. That's a side product gain in addition to the heat transfer cooling, something that oil cannot do.
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[trex]

the air gap in a high power loudspeaker is about 1mm which favours liquid for cooling but in the case of a large e-bike motor, the core is a reasonably good heat conductor in itself. Improvement in core construction and core material should be sufficient without the need for liquid cooling. But even if it did, then they can just run pipes through the core.

 

[flecc]

Improvement in core construction and core material should be sufficient without the need for liquid cooling.

True, but I suppose liquid cooling adds the potential for driving more current though, i.e. smaller motors for a given power.
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