Committed to liquid cooling

[DrKnow65]

I have decided, after years of pondering, to commit to finding a liquid cooling solution to my RC vehicles.

I looked seriously into doing this years ago when we used to mod the original Mamba Max's for 6S use.
Back then there were no readily available micro sized fluid pumps that would fit the bill.
It ended up going no where, mostly because of the sheer cost of the endeavor.

Today is a different story.

My financial situation has improved, the pumps seem available, and there is more reason now than ever to complete a functioning system.
My primary goals are a solution that would allow me to put an ESC in an enclosed waterproof container and use it in extremely harsh environments without damage or heat issues.
I want water cooling for the ESC, motor, servo's and be able to use the same system from 1/10 scale to 1/5 scale.
I envision this system being used on SC trucks that are ROAR limited to small motors that could benefit from high levels of cooling.

I have a few unique ideas that I have not seen done yet that I think could make this a very clean and functional proposition.
First would be using the aluminum chassis as a radiator, I mean it is a large hunk of aluminum with air flow across it when the RC is in motion.
For higher capacity cooling needs I could use a traditional fan and radiator setup.
Second would be using purpose built "negatives" of the ESC's heat sink to conduct the temps into the cooling system.
For example removing the fan assembly from a MMM and inserting a cooling sink (chunk of aluminum with liquid cooling passages machined in and sealed for coolant flow) that fits onto the MMM's sink with a fine layer of non conductive thermal paste.
I don't want to negatively affect the warranty, and have a system that is easy to remove for swapping the system to a new vehicle or ESC.

The chassis could be turned into a radiator by attaching a liquid sink that is basically a thin aluminum block with cooling channels machined into it and sealed for coolant flow.
It could be attached to the chassis with either thin thermal tape, thermal adhesive, or bolted down with a thin layer of thermal grease.
For a smooth motor a standard boat cooling coil could be implemented. And for finned motors I could develop a special coil that matches the fins better.
I'm also curios if it's possible to create sealed end bells for brushless motors that could pass the (non conductive) coolant directly through the motor to cool the inside vs the outside.
Servo cooling could be a scaled down version of the chassis sink.



I expect the project to go slowly and take the better part of 3 months to complete.
I have Autocad 2011 software (inventor, mechanical, showcase, vault, ect).
After a month or so I should have around $400 to start piecing it together... though the budget is certainly not limited to $400.
When it's all said and done I would like to be able to put together the entire system for under $200

I really want to pull this off successfully and I'm going to make it happen.
Any comments, ideas, criticisms, or wisdom welcome

[simplechamp]

I was looking into this before. I know it's not necessary or even very practical, but I just think it's a neat idea and would be a cool project.

Check out these pumps: http://www.micropumps.co.uk/

[nativepaul]

oops

[nativepaul]

If you have coolant flowing internally through the motor your windage losses (or whatever you call them when its not wind turbulence creating drag but liquid) would be huge and the IO would rise astronmically water for example is around 840 times thicker than air, and oil the traditional electrical liquid coolant is even thicker and more draggy.

Most folks stopped using cooling coils in boats when we escaped from brushed motors that had holes in the cans, coils can work if wound with the right pressure to flatten the bottoms nicely and the gaps are filled with copious amounts of heat sink grease but a typical shop bought coil fitted dry is of very little use compared to a water jacket that has water in direct contact with the can. If the fins go across the motor like castles making a water jacket is a sinch slide an "O"ring between the first and second fins and another between the penultimate and last fins then slide a tube from the plumbing store over the "O"rings and there you have a jacket, glue in a couple of bits of tube for inlet and outlet and your done.
or you can get them ready made for Nue, Castle, Leopard and Feiago from offshore electrics.

[BrianG]

Instead of dealing with the losses from another pump drawing power, not to mention adding another point of failure, I would use heatpipes. Then again, a more efficient motor (even a 1% or two) can make a huge difference.

[_paralyzed_]

fans would be a much simpler way to cool things, and much more effective.

Basically if it's running too hot and needs cooling you are pushing it too far.

People really get hung up on internal combustion technology, i.e. multiple speed trannys and liquid cooling. Electric motors are apples to the internal combustion's orange.

I don't want to burst your bubble, but liquid cooling for electric land based r/c is just very impractical.

Now, it would be very very cool to see. In the end it would be nothing more than a novelty. I for one would like to see you accomplish your goal.

Boats have a constant supply of cool water.....

The chassis idea is interesting. I'm imagining some sort of sandwich chassis with channels for coolant to flow.

If you want to do it just to do it, then by all means git 'r dun. There is no practical use for such a system however.

[DrKnow65]

Nativepaul, thanks for the info I wasn't thinking about just sealing the motor in a sleeve like that.

As for running fluid inside the motor, I think I'll pick up a cheapie throw away and do some testing since I have data logging capability now :-)

BrianG: I thought about heat pipes, but I think a forced flow could have a higher capability.

I'll post up what I've found for pumps, very small, low wattage, and plenty of flow...

[DrKnow65]

-P- I'm not arguing what fans can do :-) but they don't work very well packed full of mud LOL

The idea is to take a non waterproof ESC like the MMM, put it in a sealed foam lined box and not have heat issues.
EDIT: without voiding the warranty.

[simplechamp]

I know there was a thread somewhere around here where a guy put an MMM in a silicone oil bath in a sealed box in his Summit. Might want to look around for that, I'm pretty sure it worked out and the oil dissipated the heat (but did void warranty). Probably would be a mess if you ever had to take it out of there, but just brainstorming here. Then you could focus the water cooling on the motor.

How do those pumps I linked compare to the others you've found so far?

[brushlessboy16]

Originally Posted by DrKnow65

-P- I'm not arguing what fans can do :-) but they don't work very well packed full of mud LOL

The idea is to take a non waterproof ESC like the MMM, put it in a sealed foam lined box and not have heat issues.
EDIT: without voiding the warranty.

Either way if your going to dissappate heat you need airflow over a surface, all that energy just doesnt vanish when you have liquid cooling.

Your going to need something to move air over your radiator.. so weather a fan is directly cooling your motor, or cooling the radiator- its still a fan. and still would get covered in mud.

[DrKnow65]

good job SC, those are the same pumps I was looking at

They were actually around the last time I looked, but the company was fairly new at that point but the cost of them was INSANE!
They've come down a bunch in price since then.

[DrKnow65]

B16, that was the idea of using the chassis for cooling. No need for a fan in that situation.

[simplechamp]

What model pump were you thinking? M200P2 or M200P4 look good.

[brushlessboy16]

Originally Posted by DrKnow65

B16, that was the idea of using the chassis for cooling. No need for a fan in that situation.

Whoops, my apologies- would help if i read through the whole post

[DrKnow65]

15x16x22mm plus the fittings, 6v at 1.6w (0.27a) so it could be ran easily off the BEC. Would flow 200ml/min at 2.8psi. ~$65 usd plus shipping.

I'll try to get a few for testing purposes.

Edit: it's the M200P4, but I'll probably get one of the larger series to test as well.