Make a watercooled high kw motor and I'll buy it !

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Jestronix   10 kW

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Make a watercooled high kw motor and I'll buy it !

Post by Jestronix » Dec 07 2016 6:03am

The first company to make a high kw water cooled hub will get my business ! There's a market there for high end hubs, look at what people will pay for frames , controllers etc, maybe there needs to be the TRD or Nismo division for high end water cooled hubs ? I'd pay double to get a refined after market water cooled hub.

No amount of oil and heat sinks will shed heat on long climbs, or hard riding. QS was looking promising for water cooling but haven't seen anything yet in the ebike level.

As battery tech gets better we are going to be pushing more kw for longer, heat is still my number one issue for off-road ebiking .

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Samd   1.21 GW

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Samd » Dec 07 2016 6:06am

What size fella, it's kinda redundant now with ferrofluid and hubsinks. Linukas did some nice mxus mods.
And once you get over 20kw, middrives take over.
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Re: Make a watercooled high kw motor and I'll buy it !

Post by Jestronix » Dec 07 2016 6:44am

Samd wrote:What size fella, it's kinda redundant now with ferrofluid and hubsinks. Linukas did some nice mxus mods.
And once you get over 20kw, middrives take over.
Im still on the mxus v2 you sold me :) it gets nice and toasty on my rides, hubsinks and trans oil still can't remove heat on hill climbing. It helps and extends my climbs but I still have to pull over and let her cool down ferro and water cooling would be a good match , bring heat up into the cooling pipes.

Linukas did water cooling on the v1 yeh?

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Jestronix » Dec 09 2016 6:52am

I wonder if heat pipe style heat sinks will work, essentially they could be drilled into the side covers, each would be able to directly soak up heat transferred by ferro or trans oil and fed up and out via heatpipe to long flat heat sinks. Coupled with hub sinks, it could pull some serious heat away from the motor.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Jestronix » Dec 18 2016 1:09am

I guess this is where non-hub comes in. A number of mid mount watercooled motors out there.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Offroader » Dec 18 2016 2:39am

Your best bet is to just do it yourself. I was considering doing it and madin88 was able to machine a side cover and axle for the MXUS to fit water cooling hoses. Once you can get water cooling hoses you can just run some copper pipe and thermal epoxy it to the windings.

That all being said there was no reason for me to do this because I run a high speed RC EDF fan inside my motor that sheds all the heat I need. It may even work better than a water cooling setup.

It sucks cool air in and blows the hot air out of the motor like a blow dryer. I adjust the speed accordingly.

I was thinking of using ferro fluid and hubsinks for my new MXUS Turbo, but I think I'll just modify it again for EDF cooling because it simply cools the motor so well. I can't really see hub sinks & FF working better. Plus I do a lot of hills and wheelies where I really overheat the motor at lower speeds.

But don't get me wrong, if you full throttle up an extremely steep dirt offroad hill where you are at full throttle and barely moving for long periods of time you will start to overheat the motor. I don't think even water cooling could effectively remove all that heat when the motor is almost stalled like that for 30 seconds or more. However, with the EDF cooling as soon as you stop the steep climbing the temps come right back down so you never have to wait for cooldown.

If you never saw my motor modified for EDF cooling here is a pic. That little 30mm fan blows so much air. I'm actually going to be replacing it with a 35 mm EDF fan that will more than double the amount of air flow. But I usually only run the fan at 30% speed anyway.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Jestronix » Dec 19 2016 5:23am

This is why I love the sphere! Someone does something out of the box :) I bet you many people told u it couldn't be done :). So running power in is far easier than water cooling pipes, I take it no axle modification was needed?

Do u have a thread on the conversion and any stats around how well it's performed for u?

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Harold in CR » Dec 19 2016 5:59am

If I remember correctly, Doctorbass did something with copper tubing for water cooling a hub motor, several years back. You might try a google for his thread.
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Re: Make a watercooled high kw motor and I'll buy it !

Post by Offroader » Dec 19 2016 11:48pm

Harold in CR wrote:If I remember correctly, Doctorbass did something with copper tubing for water cooling a hub motor, several years back. You might try a google for his thread.
Water cooling is just way too complex to build. Especially since they don't make hub motors with large enough axles for the water cooling hoses to pass through. The other issue is you will add weight with all the copper tubing and water pipes.

In my opinion it isn't worth it if you can install a ~40 gram EDF fan that will blow air very powerful through all the copper windings. This acts the same way as a blow drying blowing through the coils. It just pushes so much hot air right of the motor. The hot air coming out of the motot is so hot that it will burn your finger if held over the vent hole. This is serious heat being blown out.

Only drawback is you will have a fan noise coming from the motor but I don't mind this noise, you can also shut it off if you are not overheating your motor and just driving around slowly.

You will also need electronics, a 12 volt DC-DC converter and tiny ESC to run the fan, but this is simple and cheap enough to buy.

The setup is very reliable also as I have run this for hours per day without any issues, cooling my motor in the extreme heat of the summer where temps are the highest.

I'm going to be modifying my MXUS turbo for EDF cooling and can show you the steps on how to do it. This motor will use a much more power and larger EDF fan which runs on 12 volts and also has a lower KV to not draw so many amps. But it is rediculously powerful in the amount of air it moves. The MXUS is also tighter which will allow better air flow through the windings. I also plan on possibly using vents on the outside of the case so that the hot air doesn't get sucked back into the intake air as easily for even extra cooling.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Chalo » Dec 20 2016 12:34am

In cases like this, I fall back on the basic principle, "if overheating, you're doing it wrong".

If you are using enough motor and enough voltage and your RPM range is right, heating simply won't be a problem. If you screw up one of the fundamental elements, then you could end up fooling around with cooling. Or you could focus on getting it right instead.

Anyway, clinging to the idea of water cooling is like doing the same with hydraulic disc brakes: It's missing the point. What you actually want is lots of dependable power, or good strong braking. Don't artificially limit your options in getting there by adding some self-imposed mental block.
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Re: Make a watercooled high kw motor and I'll buy it !

Post by nutnspecial » Dec 20 2016 7:52am

Hey Chalo? Water cooled . . . Hyrdaulic brakes
:pancake: :P

Jestronix, that internal fan idea is the best place to start for a hub imo. Offroader's approach is great, and also check out cowardlyduck's thread on air cooling for tangent methods and tests. I'd think those hubsinks would offer further cooling too.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Offroader » Dec 20 2016 12:52pm

FF fluid + hub sinks may work for you, I'm not sure how effective they cool. The problem is I don't want to try it and gum up the inside of my motor so that using a fan later on my cause issues.

But it is hard to imagine FF fluid + hubsinks working as well as high air flow through the windings.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Samd » Dec 20 2016 4:11pm

Linukas may still have some of his pipe kits!


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Re: Make a watercooled high kw motor and I'll buy it !

Post by nutnspecial » Dec 20 2016 4:47pm

FF fluid + hub sinks may work for you, I'm not sure how effective they cool.
If you're replying to me. More sink material would help regardless of FF, Air, H20, etc etc
Agree, sufficient air would outperform FF in cooling.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Samd » Dec 20 2016 5:28pm

Are you guys forgetting the data published in the cooling thread?
Real tests. Real dynos and real units of measure.
Its all there in various combinations of air and FF.

Don't forget to factor in the heat path of DD design when formulating your opinions. Don't wanna degauss those magnets and murder the torque of the motor by air cooling. Although the motor will gain a little top speed.


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Re: Make a watercooled high kw motor and I'll buy it !

Post by Offroader » Dec 20 2016 7:54pm

Samd wrote:Are you guys forgetting the data published in the cooling thread?
Real tests. Real dynos and real units of measure.
Its all there in various combinations of air and FF.

Don't forget to factor in the heat path of DD design when formulating your opinions. Don't wanna degauss those magnets and murder the torque of the motor by air cooling. Although the motor will gain a little top speed.


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Could you explain how air cooling will degauss or heat the magnets more than FF?

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Samd » Dec 20 2016 8:11pm

Probably the fastest way to do that is to say that ferro itself does almost no real cooling itself, it just bridges to a much bigger area for better air cooling given that air itself is such an awful thermal conductor. And that the case of the motor is a nice big heat shedding surface as well as a potential heat sink in the true sense.

Anyways if someone has time to crawl back thru the ferrfluid versus/and air dyno tests the data is there in the thread. The even better magic combo I observed at the tt1500 race in newcastle was ferrofluid to create the bridge and hubsinks to keep the local temp down at the magnets. Justin should be doing more dyno tests on that combo soon, Sketch sent some hubsinks I believe.

I suspect this is why the new 20mm axle front motor is very light - we are moving from storing heat bursts in ally stators to getting it from stator to rotor and out fast.
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Re: Make a watercooled high kw motor and I'll buy it !

Post by macribs » Dec 31 2016 8:29pm

There is still a untapped cooling source for the FF and heat sink combo. That is adding heat pipes to the heat sink, turning your heatsink into a closed loop phase transition cooling as well as taking the advantages of the extra large surface of the heatsink. One thing that you get as a bonus is that the phase transition cooling will help even in low speed climbing or where you would otherwise need to stop at length for the motor to cool down. Phase transition is a very effective way of cooling, and it will work even if bike is at stand still. If you ask sketch he might even take the heatsink further and add heat pipes as well.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Offroader » Jan 01 2017 4:02am

Jestronix wrote:This is why I love the sphere! Someone does something out of the box :) I bet you many people told u it couldn't be done :). So running power in is far easier than water cooling pipes, I take it no axle modification was needed?

Do u have a thread on the conversion and any stats around how well it's performed for u?
Sorry missed this post. Yes running power to the fan is easy, in the new MXUS v3 you can even just use the wires for the unused set of halls. I am also upgrading the EDF fan to a bigger EDF with much lower KV to run it at 12 volts instead of the 8 volts to cut back on the needed amps. No axle modification.

I am going to modify the Mxus V3 I have for similar air cooling, and this hub motor I believe is much easier to work with than a cromotor. I'll make a thread about doing it and will let you know.

Air cooling which brings in fresh air and exhausts the hot air out works really well. Just look at all those windings in the picture, the air flows right through all those windings at a very high speed. This works simply how a blow dryer works. It really pushes the hot air right out of the motor. Holding my finger over the exhaust air will start burning my finger, considering how much hot air is exhausting this has to work much better than hubsinks + FF.

Problem I see with FF is that there has to be a delay from the time it can transfer the heat to the hubsinks. With high air flow cooling, you are pushing a large amount of air through the windings that instantly cools them down. This is why even if I full throttle it up a huge hill and start overheating, I can just stop climbing and drive on flat ground straight away at full throttle, no way I'd ever have to stop for cooling. I could also turn my airflow up super high to get 2x-3x more air flow if needed.

I would love to try FF + hubsinks but I worry I won't be happy with it and then I have a motor full of FF fluid and now I can't convert over to air. I am not sure if you can get all of that out of the motor and it will make dirt stick inside.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Samd » Jan 01 2017 5:44am

Hey there. Ferrofluid won't prevent air cooling later as you only put 7ml in.

There was hard data taken in Feb. ferrofluid provides as much cooling as venting. Air is a lousy conductor of heat so all the ferrofluid does is provide a bridge for the heat to get out of the motor by a better path than the traditional path going via the bearings.




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Re: Make a watercooled high kw motor and I'll buy it !

Post by Offroader » Jan 01 2017 1:01pm

Samd, I heard the FF makes a mess in the motor and works itself into the stator. I worry this would work itself into the windings and block the air from flowing through. Not sure if you spray it all out. Maybe you could.

Vent cooling is one thing, doesn't work very well but better than a sealed motor. Forced air through the windings works much better than venting.

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Samd » Jan 01 2017 4:13pm

No not messy. I think a few people used the 70c flash temp stuff early in the game.

No need to force cool if you use the whole outside shell as a radiator by connecting it with ferrofluid. Did you see the data in the cooling thread? Worth a read. And it stops the mud getting in.


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Re: Make a watercooled high kw motor and I'll buy it !

Post by Matador » Jan 01 2017 11:11pm

Jestronix wrote:The first company to make a high kw water cooled hub will get my business ! There's a market there for high end hubs, look at what people will pay for frames , controllers etc, maybe there needs to be the TRD or Nismo division for high end water cooled hubs ? I'd pay double to get a refined after market water cooled hub.

No amount of oil and heat sinks will shed heat on long climbs, or hard riding. QS was looking promising for water cooling but haven't seen anything yet in the ebike level.

As battery tech gets better we are going to be pushing more kw for longer, heat is still my number one issue for off-road ebiking .

This is custom work but beautifull...
https://www.youtube.com/watch?v=2LNfDI3QUpQ

Look at 1min17 for the watercooling parts ...
This is supposedly a 45 kW rated motor !
Last edited by Matador on Jan 28 2017 12:51am, edited 2 times in total.

Jestronix   10 kW

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Re: Make a watercooled high kw motor and I'll buy it !

Post by Jestronix » Jan 20 2017 6:40pm

Yeh that's impressive , two those would make a nice electric car conversion motor.


Anyone know what motor this is ?

https://www.youtube.com/watch?v=lXkHb_uhw2Y

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Re: Make a watercooled high kw motor and I'll buy it !

Post by John in CR » Jan 21 2017 12:06am

Jestronix, you're asking for the wrong thing. The best way to deal with heat is to not make it to begin with. That means a more efficient motor. People jump thru ridiculous hoops to make crap motors disperse heat better, when for the same price they could have had hubmotors to run at up to 10-15kw in stock sealed form without unnecessary and barely effective liquid cooling of an outrunner. Sure they took some work to fit, but that pales in comparison to the effort needed to make low efficiency motors dump their heat. Ask for better hubmotors, not motors with liquid cooling.

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