# Water cooling methods and effectiveness.



## Ziggythewiz (May 16, 2010)

Does yours have any internal fan? What gear were you driving in? With my air blower I found it barely made any difference if I drove in 2nd, but was much more significant in 3rd and 4th as the delta between motor and ambient increased.


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## mizlplix (May 1, 2011)

AC50's have a built-in fan on the drive end that pulls air through the motor and exhausts radially out the end cap through 4 slots. 

I also have a ducted fan inside the intake tube. It was mostly to compensate for the air filter element restriction.

I was in low gear, about 5,100 RPM, 1.72:1 with a 6.14:1 axle ratio and a 32" tall tire. I was cruising at 100-110 amps @45 MPH.


I hope this helps.

Miz


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## Joey (Oct 12, 2007)

I've used chiller plates (in non EV applications) that have the copper tubing pressed tightly into channels on an aluminum plate. The plate is mounted with a thermal conductive paste, all in an effort to improve thermal contact with the part to be cooled. 

It was worth a try. Thanks for posting the results.


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## otp57 (Feb 7, 2012)

mizlplix said:


> I feel water cooling deserves it's own thread. It is a topic almost everyone has wondered about at one time or another.
> 
> I want to start it all out with an accomplished result...Almost everyone has seen my motor.
> 
> ...


I did the same thing to one of my motors and now I am doing air cooling on my dc motor.


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## major (Apr 4, 2008)

mizlplix said:


> *Busted:* Today I drove half way home with no water circulation, maintaining 60 Deg. C. (9 miles and 105-F. AMB.), I stopped, plugged in the pump and drove home. It was sitting on 55 Deg. C......
> 
> 5 Degrees measured at the stator windings........
> 
> My Thoughts: 5 degrees is disappointing. I believe it was because of lack of contact surface. It was not worth doing.


Hi Miz,

I wouldn't throw it out yet. It might show only 5º but that is with a fairly cool motor. 60ºC on the stator winding is hardly taxing the motor. Get it up to 150ºC and try your experiment. 

The amount of heat removed and resulting reduction in winding temperature is dependent on the temperature differential. So there was little difference between the coolant and ambient and little difference between the coolant and the motor frame. So you saw a small difference w & w/o coolant circulation.

Jacket liquid cooling works best on totally enclosed motors running continuously. Every little bit helps when you're pressing the machine to the limits. Limit on your motor is 180ºC, but use around 150 on the measurement.

I think you need to run that rod harder 

major


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## otp57 (Feb 7, 2012)

major said:


> Hi Miz,
> 
> I wouldn't throw it out yet. It might show only 5º but that is with a fairly cool motor. 60ºC on the stator winding is hardly taxing the motor. Get it up to 150ºC and try your experiment.
> 
> ...


OK I will work it hard.


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## subcooledheatpump (Mar 5, 2012)

Thermal compound (paste) might help some. I doubt the motor surface or the tubing surface is perfectly smooth, the compound could help fill the gaps

I was thinking the same thing as major, heat flow is proportional to temperature difference. It should move much more heat at higher temperatures. 


I had been thinking of trying the same thing for a while now, I'm glad you posted this.


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## otp57 (Feb 7, 2012)

subcooledheatpump said:


> Thermal compound (paste) might help some. I doubt the motor surface or the tubing surface is perfectly smooth, the compound could help fill the gaps
> 
> I was thinking the same thing as major, heat flow is proportional to temperature difference. It should move much more heat at higher temperatures.
> 
> ...


Using air cooling with water cooling will help keep the motor cooler.


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## bjfreeman (Dec 7, 2011)

you would probably do better for heat transfer to have a jacket with baffles in it.
bond the jacket to the outside of the motor with silicon thermal compound like is used for IGBT's
The Seimens 96KW 3phase uses internal liquid cooling.


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## mizlplix (May 1, 2011)

> Conclusion: Unless your motor is operating within the last 30% region, this cooling method is not effective. The only way it would be effective is if you were really marginal and it kept the motor from over temping.





> I wouldn't throw it out yet. It might show only 5º but that is with a fairly cool motor. 60ºC on the stator winding is hardly taxing the motor. Get it up to 150ºC and try your experiment.





> I was thinking the same thing as major, heat flow is proportional to temperature difference. It should move much more heat at higher temperatures


Yah, I think we all are in agreement on this point. So Maybe we could adopt a rule. Like your motor temp needs to be above 50% of it's maximum rating before water cooling even becomes viable. 


Miz


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## otp57 (Feb 7, 2012)

mizlplix said:


> Yah, I think we all are in agreement on this point. So Maybe we could adopt a rule. Like your motor temp needs to be above 50% of it's maximum rating before water cooling even becomes viable.
> 
> 
> Miz


Sound good to me.


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## toddshotrods (Feb 10, 2009)

I'm planning on experimenting with Open Revolt controllers and want to build chill plates for them, instead of finned heat sinks. Also, the motor going in my e-bike, for the first stage is a little ProTech permanent magnet, totally enclosed, deal. Even though it's not slated to be in the bike long, and will really only be used around the aisles of the shop, or at events (if we still don't have the actual Mars motor), I am planning to build a little cooler for it. It is actually the motor I bought for the big cooling blower unit on the Model E, so this motor cooler might have a purpose beyond the fist stage of the bike.

I thought about wrapping it with copper tubing, ala Miz, but had two concerns with that. One, the contact surface of the round section tubing is so small, against the motor frame - kind of like a motorcycle tire. Two, the coolant has to travel through the entire length of the tubing to get the heat away from the motor. I believe you said you used 75ft of copper tubing Miz? That seems like an awfully long time to carry heat, and if it works well the coolant is at motor temp for a lot of that journey, and unable to collect more heat from the motor. It would be interesting to shoot the tubing at different points with an infrared to see if it's cooler at the inlet side than the outlet...

One of my Team members and I came up with the idea to make two aluminum pieces that cup around the frame tightly and are clamped together. Holes will be drilled through the cooling plates, threaded, tapped, and fitted with compression nipples, on the ends; then fitted to a little hand fabricated tank on each end - like a radiator. I haven't modeled the tanks yet, and this model is just a rough sketch, but try to imagine a little half-round, miniature, tank with eleven little short flanged sections of tubing soldered or welded to it, with compression nuts on them.


I admit, it's a helluva lot of fabrication, but we're prone to this type of excess. Someone may be able to simplify this basic concept and implement it. The main point is all the water comes in cool, makes an equal path across the motor frame, and exits (hopefully) full of waste heat.









As I said, this is just a rough sketch to communicate the idea, and help me think it through. To fit in the mock-up case I made to go over this little motor, I can't have those big clamping bolts. I did those for here to illustrate the concept.


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## tomofreno (Mar 3, 2009)

My impression was that miz understands heat flow is proportional to heat transfer coefficient and temperature differential. Seems his point was that the former is low due to small contact area, so the coil only provides a small amount of additional cooling, and for his normal driving conditions it isn't required.



mizlplix said:


> Conclusion: Unless your motor is operating within the last 30% region, this cooling method is not effective. The only way it would be effective is if you were really marginal and it kept the motor from over temping.
> 
> I am in the first 30% region. I really do not need any type of extra cooling.
> It just adds extra cost, weight, complexity and ultimately draws from the pack (mileage).Miz


Heat is more of an issue with my controller than my motor, but it typically doesn't get over about 55-57 C with ambient in upper 90's. What temperature was your controller miz,and how are you cooling it?


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## tomofreno (Mar 3, 2009)

toddshotrods said:


> I'm planning on experimenting with Open Revolt controllers and want to build chill plates for them, instead of finned heat sinks. Also, the motor going in my e-bike, for the first stage is a little ProTech permanent magnet, totally enclosed, deal. Even though it's not slated to be in the bike long, and will really only be used around the aisles of the shop, or at events (if we still don't have the actual Mars motor), I am planning to build a little cooler for it. It is actually the motor I bought for the big cooling blower unit on the Model E, so this motor cooler might have a purpose beyond the fist stage of the bike.
> 
> I thought about wrapping it with copper tubing, ala Miz, but had two concerns with that. One, the contact surface of the round section tubing is so small, against the motor frame - kind of like a motorcycle tire. Two, the coolant has to travel through the entire length of the tubing to get the heat away from the motor. I believe you said you used 75ft of copper tubing Miz? That seems like an awfully long time to carry heat, and if it works well the coolant is at motor temp for a lot of that journey, and unable to collect more heat from the motor. It would be interesting to shoot the tubing at different points with an infrared to see if it's cooler at the inlet side than the outlet...
> 
> ...


 You will have the same issue as miz, small surface contact area. A gap of only tens of microinches will reduce cooling greatly, as then heat transfer is by convection rather than conduction. There is no way you will get the surfaces of two rigid parts so perfectly matched that they have more than a couple percent contact area. Even if you could, the contact area would then be limited to a few percent anyway due to surface roughness for say a 40 micro-inch surface finish. Heat sink compound will help considerably, but it won't compensate poor machining. Need to minimize that gap, maximize contact area. Turbulent fluid flow also helps, as it breaks up the boundary layer in the fluid, increasing heat transfer from the metal to the fluid. But that is a much smaller effect than reducing the heat transfer coefficient between the jacket and motor. I agree with the need to shorten the tubing length to maximize the delta T between fluid and motor over the entire length.


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## Joey (Oct 12, 2007)

toddshotrods said:


> I'm planning on experimenting with Open Revolt controllers and want to build chill plates for them, instead of finned heat sinks. Also, the motor going in my e-bike, for the first stage is a little ProTech permanent magnet, totally enclosed, deal. Even though it's not slated to be in the bike long, and will really only be used around the aisles of the shop, or at events (if we still don't have the actual Mars motor), I am planning to build a little cooler for it. It is actually the motor I bought for the big cooling blower unit on the Model E, so this motor cooler might have a purpose beyond the fist stage of the bike.
> 
> I thought about wrapping it with copper tubing, ala Miz, but had two concerns with that. One, the contact surface of the round section tubing is so small, against the motor frame - kind of like a motorcycle tire. Two, the coolant has to travel through the entire length of the tubing to get the heat away from the motor. I believe you said you used 75ft of copper tubing Miz? That seems like an awfully long time to carry heat, and if it works well the coolant is at motor temp for a lot of that journey, and unable to collect more heat from the motor. It would be interesting to shoot the tubing at different points with an infrared to see if it's cooler at the inlet side than the outlet...
> 
> ...


To get around all of the tapping and compression nipples, cut channels instead of bores, and press copper tubing into the channels. A manifold can be made so there are several parallel flow paths. You still need to figure out how to thermally couple the plate to the curved surface of the motor.


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## toddshotrods (Feb 10, 2009)

tomofreno said:


> You will have the same issue as miz, small surface contact area. A gap of only tens of microinches will reduce cooling greatly, as then heat transfer is by convection rather than conduction. There is no way you will get the surfaces of two rigid parts so perfectly matched that they have more than a couple percent contact area. Even if you could, the contact area would then be limited to a few percent anyway due to surface roughness for say a 40 micro-inch surface finish. Heat sink compound will help considerably, but it won't compensate poor machining. Need to minimize that gap, maximize contact area...


Good points. We can machine the jacket and even turn the motor frame, but your point is well taken about the tolerances. One thing about that though - the chill plates people use on controllers can't have any better contact area, even if they're machined flat and they seem to work well enough?







Joey said:


> To get around all of the tapping and compression nipples, cut channels instead of bores, and press copper tubing into the channels. A manifold can be made so there are several parallel flow paths...


That's a thought.






Joey said:


> ...You still need to figure out how to thermally couple the plate to the curved surface of the motor...


I can make the jacket thin enough to flex, and slightly undersized, so that it has to be forced around the frame; or make the jacket in smaller sections, like four, or six, instead of two...


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## major (Apr 4, 2008)

toddshotrods said:


>


I once worked on (tore apart and reassembled) an induction motor having coolant passages like you show. They appeared to be bored in a solid steel thick wall tube. It was slightly longer than the stator. Stator appeared to be heat shrunk pressed inside. No gettin' that sucker apart. Then the longintudinal passages were gasket sealed and headered (is that a word?---like a manifold) off by the end bells themselves which had a single in and single out port.

Hope that made sense 

major


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## Salty9 (Jul 13, 2009)

Check http://www.diyelectriccar.com/forum...ctric-fiat-500-r-65753p5.html?highlight=luigi

Catavolt talks of water cooling in the bike thread also.


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## mizlplix (May 1, 2011)

Like This? Except this is the housing it's self. (Copyright Ivansgarage)


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## toddshotrods (Feb 10, 2009)

major said:


> I once worked on (tore apart and reassembled) an induction motor having coolant passages like you show. They appeared to be bored in a solid steel thick wall tube. It was slightly longer than the stator. Stator appeared to be heat shrunk pressed inside. No gettin' that sucker apart. Then the longintudinal passages were gasket sealed and headered (is that a word?---like a manifold) off by the end bells themselves which had a single in and single out port.
> 
> Hope that made sense
> 
> major


It did, thanks Major - gives me even more ideas. 

That's a nice looking motor in the pic you posted Miz!


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## tomofreno (Mar 3, 2009)

toddshotrods said:


> Good points. We can machine the jacket and even turn the motor frame, but your point is well taken about the tolerances. One thing about that though - the chill plates people use on controllers can't have any better contact area, even if they're machined flat and they seem to work well enough?...


 Depends on the amount of heat transfer required, surface finish and flatness (usually dealing with flat parts), the bolt pattern (lots of bolts to clamp the parts together if that is possible), and whether something like heat sink compound is used to fill gaps -which should be very thin so there is only a film of this filler since it usually is not as good of thermal conductor as metal. In some applications there is a seal between the two parts around the edge, and helium (low mass molecule for higher heat transfer) is injected in the gap (even one due to surface roughness only) to increase convection. I would guess a controller is greater than 95% efficient, whereas a motor is maybe 80% in racing conditions, so more heat to dissipate if you want to keep the case at a given temperature after it has reached it. But yeah, if you can get the surfaces to match closely, use heat sink compound, and clamp it tightly, I would think it would work fairly well - assuming the heat exchanger connected to the cooling passages can handle the load.


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## JRP3 (Mar 7, 2008)

mizlplix said:


>


I still wonder about putting the tubing through a roller or something to flatten it out some and greatly increase the contact area compared to a round profile.


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## mizlplix (May 1, 2011)

Copper is worse than most metals when cold worked. It gets "Work hardened" and must be annealed before it can be bent again. Cold working (either compression or stretching) produces a system of uneven stresses in the matrix and the material loses what elasticity it had. (The next time you bend it, it fractures).

I would use a common sheet metal bead roller to flatten copper tubing and then reheat it with a propane torch to anneal.

The wrapping could be done by hand as I did, or in a lathe.

If you want to go all out, I would sand the motor case and "Tin" the surface. That way you could heat and solder it as you wound it on the case. Of coarse, that would mean Stator removal.But it would conduct heat nicely.

A point was brought up that the water would heat soak in the first section and leave the last half of the motor hot. My air flow is encoder end to drive end. So, my water flow is drive end to encoder. (An attempt to even out the temperature slope in the motor).

Now we are to the point of a LOT of work and added weight.

Better to just machine yourself an aluminum motor case like Ivansgarage did.

In retrospect, My AC50 has a 120C maximum temperature. Water boils at 100C. My temps are running 60C area. 

I am thinking that unless my temps reach 100C, I dont need water cooling.

At that point it would not cool the motor down, but it would slow or stop any further rise in temperature.

Miz


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## mizlplix (May 1, 2011)

I would like to throw another water cooling subject on the table.

My controller.








Curtis 1238R with a custom cold plate made by Ivansgarage.

It is of the "Bath tub" design.








It uses the thermo-siphon principal. Cold liquid in at the bottom, warm liquid out the top in a natural convection manner.

Some say it is inefficient because there are "dead" spots with no flow.
Some say it makes the upper controller run hotter than the lower.
Some say it will corrode and ruin the controller.

All are valid points.

My thoughts:



> it is inefficient because there are "dead" spots with no flow.


When a liquid is in a dynamic environment, it will react most at the point of greatest energy absorption. So while the complaint is correct, the liquid never really stands still.



> it makes the upper controller run hotter than the lower.


This is partly true, but greater water volume is a good "Band-aid" to this glitch.



> it will corrode and ruin the controller.


The heat and pressures in a conventional ICE cooling system does not exist here. Even then it takes years to do any real damage. But, careful addition of anti-corrosives will slow this down further. I am a proponent of the "direct contact" method of heat transfer.(Water contact) It is magnitudes more efficient than conduction alone.

So far, it is working really well. No leaks even when held by the 4 corner bolts alone. (Use a good anaerobic gasket compound-keep the surfaces flat)

I have about 2 GPM flow and am using a 50-50 solution of Propelyene Glycol.
It is cheapest from the Pet store. It is nice to work with and is environment friendly.

Miz


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## swoozle (Nov 13, 2011)

What kind of pump do you use?


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## Ivansgarage (Sep 3, 2011)

Hey Miz you didn't tell us what kind of temps your running on the controller..


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## mizlplix (May 1, 2011)

My controller is running 48C with an ambient of 109F. Motor was 55C /water and 60C /air.

Remember- flatland, stoplights a mile apart, light weight vehicle.

The max temp rating is low for class H. (120C)








It should be able to run as high as 180C before suffering damage. Unless there is another reason besides insulation rating..... 

Miz


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## Ryan800 (Apr 15, 2010)

I haven't seen it mentioned yet, so I just want to point out that copper pipes with an aluminum radiator is a recipe for galvanic corrosion. Use only one metal for the entire coolant loop, or expect to replace things sooner or later.

Also, if the coolant doesn't see high enough temperature it won't kill bacteria. I'm not sure how much of a concern this is in reality, but Tritium's controller manual points it out. There are biocides that can be added to the coolant.


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## mizlplix (May 1, 2011)

Last time I looked under the hood of my F150, I had aluminum, brass, copper, stainless steel and cast iron, all in the cooling system. I guess that is why the coolant is so exotic...That or FORD does not read forums.

Seriously, My degree is in Metallurgy. In a pure chemical form, you are correct, but we all must replace things eventually. I just think of it as a standard maintenance deal. No liquid cooling system lasts forever. I try to not 
"over think" the problem and accept 4 years between flushing and some parts replaced as normal, here in the alkaline South West, USA. (Other places get 5-10 years on theirs)

Miz


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## toddshotrods (Feb 10, 2009)

I smile anytime I see someone posting about using different metals or conductive materials together on the internet, because I know the galvanic FUD is coming! 

I also love, love, love, getting new engineering interns in my shop so I can teach them how we effortlessly do so many of the things in hot rodding that the books (or inexperienced teachers) say cannot be done.  Some are freshman engineering students - I know their professors are going to love me!


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## Ivansgarage (Sep 3, 2011)

Well guys, thats one good thing about DIY, you can do what ever the hell you want. galvanic FUD, and bacteria doesn't scare me.


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## toddshotrods (Feb 10, 2009)

I just like being sarcastic. When someone says something like that about certain metals in certain conditions, people with a lot of experience know that it's someone who doesn't have much, or has been indoctrinated into an unreasonable fear by someone who doesn't.

In all fairness to engineers (I really love them, almost went to school to be one), engineers are the reason I know I don't have to be afraid of galvanic reaction in most of these cases. The cars I dissect and put back together (a little differently), and that they originally designed, are full of these combinations of metals. Aluminum engine blocks full of steel sleeves, bolts, bearings, etc, are the example that come to mind first, when the subject comes up.

If one does the homework, they'll likely find (as Miz suggested) that by the time galvanic reaction/corrosion becomes an issue the part or vehicle will have exceeded its intended service life. The ones they're wrong on, have replacements at the local parts stores ready for human consumption; still no major issue, as it's usually just a slow, discernible, wear issue, not catastrophic failure.


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## onegreenev (May 18, 2012)

I would think that the aluminum would pull heat away faster than the water pool. I would opt for an aluminum cooling plate where there are tubes running through the aluminum to pull away the heat from the aluminum and the aluminum pulls heat away from the controller. Being that you now have a huge open hole filled with coolant I suspect that the flow is not so good as to pull heat away fast enough. Kinda like just using a huge block of aluminum to pull heat away from the controller with not fins or fan. Thinking that the huge block of aluminum would suffice. Boy was I wrong. That sucker heated that block up quick and then the heat had no where to go. The controller went into limp mode again. Once I put on a heat sink with fins and a fan I was able to pull the heat away fast enough to never allow the controller to over heat even in 110 degree weather doing stop and go in town with high currents. The coolant tubes within a heat sink will allow the moving water to suck out the heat fast when pushed through a good radiator. A pond will absorb heat but I bet not fast enough. When the water from your tubes hit that pond it all slows down builds pressure then gets pushed once again through a small opening. Odd that there is no track for the coolant to flow. 

Try it and see since you have it already but it does not seem to be a sound way to build a coolant heat sink.


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## lockduke (Dec 25, 2009)

Todd in response to your post about galvanic reactions in this case why not use mineral oil. We have been using it to cool our computers for quite some time and don't get any kind of bio growth in our system and once it reaches temp it tends to stabilize temperature after it runs for a while. As well it is not poisonous to the environment. And also it tends to lower operating temps better than any other type of coolant we have tried. Also a few years back I was running mineral oil in my VF1000 F Honda while club racing here in Indiana plus I did not have to remove it in the winter. I just had to wait for a little while for it to warm up before I turned on the pump.And if my memory doesn't fail me it is inert with almost all materials like aluminum, copper, brass and with steel it tends to be a rust inhibiter. As well it has no problem with teflon, rubber or silicone tubing as far as I know. Just a little bit of homegrown technology from an old hot rodder.


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## mizlplix (May 1, 2011)

During the US depression of the 1930's, my grandfather used Turpentine in his car radiator because he could not get anti-freeze coolant.

Mineral oil...Yah, I can see that would work well.



Bear in mind, I have only got 66 miles on my car. Most of the time, My controller was sitting between 45C-49C. I really had to do a lot of stop light to stop light driving and 400+ amp accelerations (with sitting at a light again) to get it above to 50C. All of this was in 105F to 113F ambient.

My inlet and outlet are the same size and the controller will not push enough heat to boil water, so I doubt if there is any pressure involved. 

The Blacksmith dunks his metal in the slack tub,he does not spray water over it, he is in a hurry. If this were a steam boiler, then multiple tubes are king. 

Granted that a metered flow along sufficient length of tubing is a perfect match for efficiency. I just feel that one does not need to be that accurate, It is just water. And it is not absorbing as much heat as it is capable.(at least in our instance)

And not to put too fine of a point on my theory, but the water jacket in every liquid cooled engine ever made is just a water tank and they cool just fine. Yes they have air pockets and dead spots, but they work and deal with many, many magnitudes of heat more than a controller can produce.

Miz


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## toddshotrods (Feb 10, 2009)

lockduke said:


> Todd in response to your post about galvanic reactions...


Me?! I'm just a jerk being sarcastic when I see comments about galvanic reaction/corrosion. I have never even considered the issue of biological growth in a cooling system, until it was posted here. I would just add something to it, like a couple shots of moonshine (being sarcastic again). 




mizlplix said:


> ...And not to put too fine of a point on my theory, but the water jacket in every liquid cooled engine ever made is just a water tank and they cool just fine. Yes they have air pockets and dead spots, but they work and deal with many, many magnitudes of heat more than a controller can produce.
> 
> Miz


I don't think I can agree with you there Miz. The water jackets inside, at least modern, engines are more passages than tanks, IMO. The ratio of inlet/outlet volume to internal capacity is what I would look at, if I were concerned about this. If it would take the outlet too long to clear the room, and the inlet is constantly funneling in more, at the same rate, there's more of a chance for some fully heated coolant to wear out its welcome.

That being said, your bathtub plate is obviously doing the job, so I would file this whole concern in the same folder with galvanic so and so: got it, considered it, deemed it not critically relevant - more important things to focus on.


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## EVfun (Mar 14, 2010)

I have a thermosyphon system on my Buggy controller. The only metal in the system is the controller's internal plate, all other parts are plastic. I run a common propylene glycol based computer coolant. I haven't noticed anything growing and there is no "other metal" to cause galvanic corrosion. It mostly adds thermal mass to the system. The upper hose is noticeably warmer than the lower hose after a drive.


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## mizlplix (May 1, 2011)

(OK moving on)

The last component in my EV "cooling system" is my transmission.

I intend to isolate it and remove it from the cooling system.

REASON; 

In the last 50 miles, my pan temperature has never gone over 160 degrees even when I stopped the coolant pump for 25 miles. 

Air cooled versions of it were produced for the lighter weight GM cars.

I have removed the biggest heat producer, the torque converter.

Using my new unofficial rule (units must be operating in the upper half of their temperature range to need water cooling) my transmission is not in jeopardy. 

On the powerglide, the cooler circuit can not be simply plugged (as it can be on some Ford transmissions). The return oil is directed at several components as a lube circuit. It must be looped.

ATF operates best from 0F-230F. After 230F it starts to slowly degrade and requires replacement. For instance, it will require replacement if operated at 265F for one hour. Synthetics are way above that. 300F-350F is the flash point of ATF, but by then you have cooked everything.

My 160F (105F-113F ambient) is well within the operating range. Using synthetic would be a good plus. Lastly, my system only uses 1 3/4 Qts total.

This eliminates a pump (electrical drain), several feet of hoses and a heat exchanger, all potential future failure points.

Miz


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## Ryan800 (Apr 15, 2010)

Ok, sorry for getting the thread off track, I just figured there might be someone out there reading this that would appreciate the heads up.

I don't think it's fair to call the issue FUD though, aluminum and iron is used commonly, but copper and steel/Al is much worse and I've never seen an OEM use this combination. Oil/transimission coolers use these combinations since oil isn't conductive.

But anyway, I guess it's been done and it works fine for a long time so carry on...


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## mizlplix (May 1, 2011)

(lets see...copper and brass in the thermostat, oil cooler and radiator. aluminum in the intake manifold, heads and radiator. Cast iron block, heads and intake manifold. stainless and carbon steel in the water pump and those inner-hose springs we all love so much.)

I dont see a sacrificial anode or special grounding anywhere in an attempt to abrogate electrolysis. 

The worst cases I have seen were on cast iron cylinder sleeves, between the bores in inline diesel engines. Looks like a woodpecker got to it...and many times they leak water into the cylinders. All because they are insulated by rubber sealing bands top and bottom and dont share the same charge as the block.

I seem to remember copper, silver and aluminum used in the solution for coolant system stop leak...

*Please stop the madness now*. It will only lead to insanity, drugs and long term confinement.

Next post I will forget and start arguing on the other side...LOL

Miz


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## piotrsko (Dec 9, 2007)

the diesel woodpeckering could also be from cavitation fretting, whereby an air bubble forms and explodes once a cycle.

At least that's what Ford tells me about the $15.00 a bottle additive that I have to use every 6 months.

IMIHO, you need a sacrificial metal (one less noble than other) anode, cathode metal, and a conductive path between the two metals. The return path has to be a conducting water based liquid. water without alkali or acid components will not conduct. Careful inspection of a typical automotive factory block generally shows that all these conditions are not generally met at the same time-space continuum.

YMMV


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## few2many (Jun 23, 2009)

I like the simplicity of the copper coils. I would use a 1/2" copper coil and flatten it a bit. The evaporators of ice makers do something similar. The contact area of the copper is flattened out and the cross section looks more like a D. This greatly increases the contact area and heat absorption. Round 3/8 copper has barely an 1/8" of contact for every 5/8", roughly.


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## lockduke (Dec 25, 2009)

Why not just use square tubing I have seen it used in magnet zappers/ magnetizer's to cool the coils that send the current through the tubing and water/coolant at the same time to run this equipment all day long magnetizing cobalt, neo, and ceramic magnets they pulse 900 to 2500 Volts through these coils and they are epoxied in place and still have to be rebuilt from time to time. The tubing is flat on all four sides and is perfect for stacking side to side and on top of another row side by side and works very well for them.


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## mizlplix (May 1, 2011)

My motor is 8" in O.D. The .250" tubing I used flattened some at this radius when winding. It is heated and shrunk into the motor afterwards. I would have used a thermal paste under it, but that would have been a huge mess forever more.

My prediction is that 3/8" or 1/2" will be problematic to install and kink a lot.

I get 5C temperature reduction at 60C. Hardly useful, but if that meant 5C for every 60C, then that would be useful.

I am going to leave it hooked up, but with a 120C sensor to turn it on. (and simply forget it.)

Miz


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## ricklearned (Mar 3, 2012)

Hey Miz,

Are you still using the water cooling for your controller? I thought I read somewhere that you found that you didn't need it, but I may have confused your motor cooling issue with that. I also have a Curtiss 1238R and I have been warned by some that I need water cooling.

Rick


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## mizlplix (May 1, 2011)

Hi Rick: That is a definite Yes. IMHO,The 1238R controller does need water cooling. 

Technically it will run on air and a 4" heat-sink/fan, but as others have found out, you will run into trouble sooner or later. 

If you live in "flatville" then you are less likely to be getting into the regions where it is necessary, but even then it depends on car weight-traffic conditions and the weight of your right foot.

There are others here that have far more experience with this controller than I, I hope some will chime in. 

Crusin was one of the first that converted to water. His cold plate was only a 4 pass, but worked far superior to any air type heat-sink.

My motor is optional. As pointed out-I need to drive it harder...LOL

Miz


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## JRP3 (Mar 7, 2008)

I've been running my 1238-7501 with nothing but a 7 inch fan blowing on the 1/4 inch thick mounting plate, Tomofreno has been running his with a finned heat sink, and maybe a fan, can't remember. So I'm not sure I'd say the 1238 "needs" water cooling, though it is better.


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## CrazyAl (May 9, 2011)

ricklearned said:


> Hey Miz,
> 
> Are you still using the water cooling for your controller? I thought I read somewhere that you found that you didn't need it, but I may have confused your motor cooling issue with that. I also have a Curtiss 1238R and I have been warned by some that I need water cooling.
> 
> Rick


According to evtv.me, having a liquid cooled controller delivers better power. They have a chill plate which from what I can gather is a heat sink which has cooling liquid cooling it. They sell a kit at http://blog.evtv.me/store/proddetail.php?prod=AC50Kit


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## JRP3 (Mar 7, 2008)

If you aren't getting hot enough for the controller limits to kick in a chill plate can't give you any more power than air cooling.


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## ricklearned (Mar 3, 2012)

Thanks, everyone for the responses. I will keep my eye on my temps and try to keep my big ol size 16 foot from being too heavy. I want to finish other parts of my build first then when I upgrade to another 10kwahr in batteries, I might put one in.


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## ricklearned (Mar 3, 2012)

CrazyAl said:


> According to evtv.me, having a liquid cooled controller delivers better power. They have a chill plate which from what I can gather is a heat sink which has cooling liquid cooling it. They sell a kit at http://blog.evtv.me/store/proddetail.php?prod=AC50Kit


That is pretty expensive for a chill plate, but then they through in the motor, controller, and programmer to give it a little more value.LOL

I suppose at the right price Jack would unbundle it and sell just the chill plate.


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## tomofreno (Mar 3, 2009)

mizlplix said:


> Hi Rick: That is a definite Yes. IMHO,The 1238R controller does need water cooling.
> 
> Technically it will run on air and a 4" heat-sink/fan, but as others have found out, you will run into trouble sooner or later.
> 
> ...


I have a finned heat sink (edit: 2" long fins) on my 1238-7501 with a 5", 260 cfm fan on it. I've not seen it over 64C in the last 3 summers. Typically it gets to about 50 - 58 C. That includes driving up into the mountains where it runs an average of about 200A discharge current for about 25 minutes (4.5% average grade for 19 miles, 4500 ft elevation change). Also driving up to Truckee on I-80 at 55-60 mph for 40 miles at 180 - 260A. It actually runs cooler cruising on the highway at 60 mph than driving around town at 35 - 40 mph with frequent stopping, because the fan doesn't cool as much as air flow while the car is moving. I tested that by driving with the fan off and then turning it on. The fan is a small effect. Dropped it from something like 55 C to 53 C if I remember correctly. It does help when spending significant time sitting at stop lights. I purchased a 7" fan like JRP3, but since the controller hasn't gotten over 58C the last two summers I never installed it. The 64 C temp was when driving in ambient of 108 F. The 1238-7601 is higher peak power, but under normal driving conditions you won't be using that, so I would expect similar temperatures.

Water cooling can certainly be more effective, provided you have sufficient coolant flow and size the liquid-air heat exchanger properly (Edit: btw, if I were going to do this, I would mill the coolant channels into the existing aluminum base of the controller along with an o-ring groove and some tapped bolt holes, then bolt a 1/4" thick aluminum plate onto it and drill holes for liquid fittings through the side of the controller plate to intersect the coolant channels). I think water cooling would be a good idea if you regularly get summer temperatures in the 105 F and above range, but in that case I would be more concerned about the batteries. At ambient temperature of around 100 F, my cells get up to 105 to 115 F depending on discharge current and length of trip. They typically start at 80-85 F thanks to high desert night time lows in the mid 50's. I see the weak links in this order: cells, controller, motor. The motor has never even come close to being an issue.


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## Thumper (Nov 24, 2010)

My hot tub pump motor has a plastic water jacket wrapped around it to capture motor heat and heat the water. It also keeps the motor cool.
Seems pretty cheap at $58.
Looks like it's only available for 48 frame motors but it must spread out in order to get it on the motor so it might fit on an AC50. Maybe use two of them.

http://www.hydrothermix.com/


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## mizlplix (May 1, 2011)

> My hot tub pump motor has a plastic water jacket wrapped around it to capture motor heat and heat the water. It also keeps the motor cool.
> Seems pretty cheap at $58.
> Looks like it's only available for 48 frame motors but it must spread out in order to get it on the motor so it might fit on an AC50. Maybe use two of them.


Actually, that looks cool. LOL

I wonder the I.D. it's designed for. Maybe it can be warmed up in an oven and remoulded around the AC50....And then thermal paste.... You only need 1, the AC50 needs clearance for the motor leads on top.

As I have stated, I wouldn't even worry about it unless I was approaching 100C. motor temps.

Miz


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## mizlplix (May 1, 2011)

> That is a definite Yes. IMHO,The 1238R controller does need water cooling.


But I live in a harsh climate....Experienced Desert Dwellers know that with electronics, there is no such thing as too cool.

I have had many/many electrical heat failures, but had none freeze up.

Miz


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## ricklearned (Mar 3, 2012)

Wow, if my last name weren't Learned, I could say I have become learned from all the things I have learned from you guys. LOL 

I will add these ideas to my project bucket list. I thought that list was long when I was trying to get my bug on the road. It is even longer now that I am sitting in the drivers seat. I keep a pencil and pad of paper handy for ideas that come to mind when I am out running around. 

Rick


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## StanSimmons (Sep 3, 2011)

ricklearned said:


> That is pretty expensive for a chill plate, but then they through in the motor, controller, and programmer to give it a little more value.LOL
> 
> I suppose at the right price Jack would unbundle it and sell just the chill plate.


I sent him an email a few days ago asking what price he would sell just the chill plate for. I'll update here if he responds.

EV West has a pretty good looking one for $140, but it doesn't have the o-ring seal like the EVTV one does.


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## mizlplix (May 1, 2011)

Don't get hung up on an o-ring....

Mine is sealed by just the four corner bolts and anaerobic sealer from NAPA. It works on hydraulic systems and GM transmissions.

It works just fine, no leaks. You are not dealing with a lot of heat or pressure to need an o-ring.

Miz


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## TomA (Mar 26, 2009)

I'm not sure I understand the case for liquid cooling 6"-13" motors at all.

The small BLDC liquid cooled axial motor designs get the coolant right into the heat sources and vulnerable components in these motors, which because they can't be air cooled very well (for a variety of reasons) makes good sense.

With the bigger motors, adding a cooling jacket around the outer case (or even integrated it into the case) just isn't where the heat is. These motors are making heat _precisely_ where the air is being blown through, so it seems clear to me that no outer case-based cooling mechanism is ultimately going to be more effective or reliable than just _blowing more air _through the hot part of the motor. I understand the value for an OEM of designing the outer case as a water jacket, (with some passages right into the hot spots) but for a retro-fit, it really seems like a dead letter compared to the stock air cooling system.

The series DC motors have the higher friction brushes to deal with than the HPEVS family, but they are also right in the airstream that passes through the motor, and are only very remotely connected to the outer case anyway. In fact, these components are actually insulated from the outer case. All that liquid cooling system weight, drain, failure points and expense aside, (which actually isn't something to be put aside,) its hard to imagine how such a device could really outperform a strong auxiliary blower. 

For extreme conditions, you could carry a 10lb bottle of CO2 and meter it into the accessory blower duct just upstream of the motor. That would be ice cold, right now, and right where you want it. No cooling jacket could touch that for responsiveness or effectiveness, and you'd only use it when you needed it, like for hot laps, speed trials or sustained high power marine use.

The takeaway on Miz, TomW and JRP's observations is pretty clear: The AC motor family do very well indeed with their OEM cooling fans (no surprise, as there's over a half century of industrial development there,) and the Curtis 1238 in these applications hasn't been demonstrated to *require* a liquid cooling plate. Its really that simple, and that's damn good news.

Jack Rickard likes the chill plates because he's used to tucking 1000A-1400A DC controllers up under the folded convertible tops and hoods of some very high powered vehicles. Cooler is better, to be sure, but I think even Jack would candidly admit that the AC/Curtis family is quite different thermally from his series DC systems, and if he relocated the controller in the beige Speedster to the underbody airstream, and paid some attention to heat sinking and airflow management, he wouldn't actually *need* the chill plate, pump, radiator, tank and plumbing in that car. Just the fan...

A water jacket wrapped around the outside of an electric motor just seems to me like cooling the intake manifold and rocker covers on an ICE in order to moderate piston and valve temperatures. 

Am I missing something?

TomA


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## McRat (Jul 10, 2012)

Compressed gas when released causes water and ice buildup unless in a sealed chamber. You would need a sealed system with a blowoff valve.

If you have a target temp you do not want to exceed, you need a coolant that is capable of boiling at the target temp. The act of boiling will absorb the extra heat. Water is a heat exchanger in most applications. You don't boil it, you just move the heat from one area to another.

A gasoline car with a radiator is actually air-cooled. The water is only used to move the heat to wide area where the air can effectively remove the heat.

I would think lots of thin fins on the motor with a fan would be the best bang for the buck. Skip the middle man.


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## mizlplix (May 1, 2011)

> Am I missing something?


Well, since you asked:



> The series DC motors have the higher friction brushes to deal with than the HPEVS family


The HPEV motors don't have brushes.(I knew what you meant, just messing with you)



> With the bigger motors, adding a cooling jacket around the outer case (or even integrated it into the case) just isn't where the heat is.


The stator is the most easily injured part of an AC motor. It depends on heat conduction to the motor's outer housing, the housing is a heat sink for the stator. The housing can then be cooled by natural dissipation, forced air flow or water jackets.

The rotor is harder to injure. It can run much hotter than the stator due to the lack of copper coils. 

A stator can be T/E (totally enclosed) or ODP (open drip proof). These two options can be either fan cooled or not. It is a little difficult to water cool a rotating mass.

So, We have the AC50. ODPFC (open drip proof fan cooled). If greater cooling is needed, forcing more air through the .010" rotor to stator gap is going to cost $ for a good blower plus the rotor is not what you want to protect first. 

Why is the Thermister in the stator winding? HPEV wanted to know the stator temp. to protect the stator. To remove more heat from the stator heat sink (motor housing), you can add surface area (fins) or water cool it.

But as I have repeated: The motor has to have a stator temp of 100C minimum to even begin to need water cooling.

Most of the factory built water cooled motors have a designed in need for it. (small heat sink mass).

Ask Rommel about air cooled engines in the North African Desert. They worked well....up to a point, then they dropped like flies. The water cooled ones kept on running. 

I guess it all comes down to need. Does my application need it?

In my case, no.

Miz


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## Ivansgarage (Sep 3, 2011)

Well said Miz, and the controller, would any one realy want to take a chance on burning out a 2500$ controller?


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## lockduke (Dec 25, 2009)

I would hope not unless they had plenty of money to burn


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## tomofreno (Mar 3, 2009)

TomA said:


> Jack Rickard likes the chill plates because he's used to tucking 1000A-1400A DC controllers up under the folded convertible tops and hoods of some very high powered vehicles. Cooler is better, to be sure, but I think even Jack would candidly admit that the AC/Curtis family is quite different thermally from his series DC systems, and if he relocated the controller in the beige Speedster to the underbody airstream, and paid some attention to heat sinking and airflow management, he wouldn't actually *need* the chill plate, pump, radiator, tank and plumbing in that car. Just the fan...TomA


 He already did say that. See this post and the next few:
http://www.diyelectriccar.com/forums/showpost.php?p=177735&postcount=525

Edit: Here are the most relevant other two posts:

http://www.diyelectriccar.com/forums/showpost.php?p=177781&postcount=530
http://www.diyelectriccar.com/forums/showpost.php?p=177902&postcount=531


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## TomA (Mar 26, 2009)

McRat said:


> Compressed gas when released causes water and ice buildup unless in a sealed chamber. You would need a sealed system with a blowoff valve.


That's overthinking what I meant. I'm not talking about a CO2 _cooling system,_ just a way to pulse in a few shots of cold into the fan cooling system that would drop the air temperature enough to quickly get a motor pushed temporarily into the red zone back into the yellow. 

Not pumping gas through the motor, and not enough CO2 to form ice or thermally shock the internals, just enough to break the hysteresis of an anomalously overheating motor in extreme conditions that needs to remain in service. A pulsed light mist of methanol/water would do it, too. That's what Jozzer is doing with the Agni motors, and it would work on the controller heat sink, too, for the rare conditions and short periods I suggested.

Sort of an academic point with these particular AC systems, though, as they don't demonstrably need it, (just like none of Rommel's vehicles was electric...) which was kind of the point: The HPEVS/Curtis packages are apparently doing fine with fan cooling.

Over & out,

TomA


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## McRat (Jul 10, 2012)

TomA said:


> That's overthinking what I meant. I'm not talking about a CO2 _cooling system,_ just a way to pulse in a few shots of cold into the fan cooling system that would drop the air temperature enough to quickly get a motor pushed temporarily into the red zone back into the yellow.
> 
> Not pumping gas through the motor, and not enough CO2 to form ice or thermally shock the internals, just enough to break the hysteresis of an anomalously overheating motor in extreme conditions that needs to remain in service. A pulsed light mist of methanol/water would do it, too. That's what Jozzer is doing with the Agni motors, and it would work on the controller heat sink, too, for the rare conditions and short periods I suggested.
> 
> ...


I've used both nitrous oxide and CO2 (gas) for intercooling before. The ice forms instantly. A 1 second burst makes ice.

It is not a bad idea for racing if supercooling an electric motor shows a HP increase. It doesn't add a lot of weight, and is extremely effective. You just have to make sure water doesn't cause issues, so you'd have to run it in a sealed box (can be low pressure if the blowoff is large), and it would have be separated from the batteries. Even a reedcage for a two stroke motorcycle would work. You'd crack the valve very gently, and open the solenoid, to "purge" the enclosure(s), then have the solenoid triggered by the throttle.

One problem to consider though, steel becomes brittle when below -250F?


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## mizlplix (May 1, 2011)

OK, now we are having problems because we cooled the motor too much and have exceeded the magic -250F point and the motor will shatter. 

That means we have to make the stators and rotors out of unobtanium to stand the cryogenic stresses. 

But the controllers need to be recalibrated to compensate for the increased flux imparted by the unobtanium.

Can we maybe direct the thread a little closer to reality?

Or has it run it's useful course?

Miz


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## lockduke (Dec 25, 2009)

Next thing you know we will be using liquid nitrogen, argon, or oxygen in the lines to pre-cool the motor before we heat them up. Might need to move down south to heat things up so we can cool them down.


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## aeroscott (Jan 5, 2008)

Stainless steel stays ductile at low temps. good shaft material .


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## mizlplix (May 1, 2011)

Will someone please shoot this thread. It has degenerated into stupidity.

Miz


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## few2many (Jun 23, 2009)

On that Ac50, how about relocating the block with the binding posts to the back. So you can get a better, more consistent wrap. Or, Seal up the motor, add some fittings and a pump, and fill it with oil or trans fluid, for cooling?


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## mizlplix (May 1, 2011)

> On that Ac50, how about relocating the block with the binding posts to the back. So you can get a better, more consistent wrap.


You can. Those large wires are not really cables. Those are the actual windings brought out with no splices and then fiberglass tubing insulated and a lug sweated on. It only looks like a cable.

You would have to shorten them and re-lug the ends. I don't believe there is enough room for thru-case terminal studs (bulkhead fittings). This motor has a 7-1/2" long stator where a "normal" AC motor has a 5" long stator. All of the room is pretty much used.

As for oil cooling, it might work except for the rotor RPM's and the drive end, CNC fan unit.

Miz


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## few2many (Jun 23, 2009)

Yeah, you'd have to pull the fan and cut down, or off, the rotor cooling fins. Not sure if the rpms of the rotor would a problem or not.


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## mizlplix (May 1, 2011)

> Not sure if the rpms of the rotor would a problem or not.


With a .010 rotor/stator air gap, it would be a mini torque converter. The stator would really be a stator. The rotor would be a turbine. The oil is HOT oil by now, as this torque converter has a 7,500 RPM stall speed.

Idea discarded.

Next?

Miz


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## lockduke (Dec 25, 2009)

Hay Miz how about a vacuum. I have an acquaintance that works on very large generators, and when they are done making repairs what I have been told is they purge the systems with an inert gas then placed in a vacuum condition to eliminate moisture from the environment and to cut down the resistance of atmosphere inside the generator units would you think this might help


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## McRat (Jul 10, 2012)

Trivia (no Rommel or Supercooling, I promise):

High power avionic motors and transmissions (and cannon sometimes) are cooled with ducted high performance fans. Jet engines are ducted air cooling as well, but they use bypass air. IIRC, the M1 tank does not use bypass air, it has dedicated HP fans to provide the air driven by a PTO.

Now high performance fans aren't like your computer fans. I'd post pics, but that would be illegal for me. Others can. They are not "turbocharger" style, which can compress air. Compressed air is hot, defeating the purpose.

They have stator blades and impeller blades much like a turbojet engine. The blades have low clearance to the "tunnel", and the root dia of the impeller is about 50-75% of the major dia. One the size of an automotive starter is about 5HP and will knock you down if you aren't ready for it. The M1 units would pick you up an throw you. Final test is done in a blast chamber. 

A clever dude could use an R/C ducted fan, which might be similar. You'd only want a HP fan on when necessary, they draw significant power. A powerful example would be: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=4235

While I doubt they have the durability or efficiency of a true HP aerospace fan, they are cheaper.


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## Ziggythewiz (May 16, 2010)

Yes, vacuums are great for cooling. Just ask NASA. A good chunk of any project on the ISS deals with figuring out how to handle an extra 50W.


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## McRat (Jul 10, 2012)

Ziggythewiz said:


> Yes, vacuums are great for cooling. Just ask NASA. A good chunk of any project on the ISS deals with figuring out how to handle an extra 50W.


Thermos bottles make poor heat exchangers.

A huge problem during the Apollo program was trying to figure out how to keep the astronauts cool in their space suits. A mesh garment of small rubber hoses with water pumped through it was the solution.


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## mizlplix (May 1, 2011)

> A mesh garment of small rubber hoses with water pumped through it was the solution.


OMG! Here we are back to my original water tubing cooling system...The problem with irony is that it is ironic.

Miz


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## McRat (Jul 10, 2012)

mizlplix said:


> OMG! Here we are back to my original water tubing cooling system...The problem with irony is that it is ironic.
> 
> Miz


Good news - They are good for 500,000 miles.
Bad news - Per unit cost was $12 million in 1969 dollars.


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## njloof (Nov 21, 2011)

McRat said:


> Good news - They are good for 500,000 miles.
> Bad news - Per unit cost was $12 million in 1969 dollars.


That's just because they couldn't get Americans to buy space suits in quantity. Sure, they'll spend $4 for a jar of "Tang"...


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## few2many (Jun 23, 2009)

Vacuums are used for insulation! To prevent heat transfer, not to reject heat. A motor in a vacuum will get hot untill it melts down. Nothing to transfer, or in the case of a motor, nothing to reject the heat through. You need a working fluid(air, water, oil) to remove heat. Or, of course, something solid like aluminum. A lot of the cryogen tanks I work on use a dual tank. The one on the outside you see is just a shell, and the one inside that contains the liquid cryogen. There is a reflective barrier for convection, and a vacuum. I work on tanks in the sun that are 160*+. The inside is -130*. 
Hey Miz, how do all the other liquid cooled motors do it? A torque converter uses bladed fans/rotors against each other. The Motor rotor, at least the ones I've seen, are mostly smooth, and would only have to overcome boundary layer, or surface tension. Plus, the gaps in the motor stator aren't nearly large enough to act the way you suggest. Ever see inside a torque converter? Large, aggressive turbines, facing each other.


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## few2many (Jun 23, 2009)

Or, when it gets hot, you can get out and pee on it. Worked in Red Dawn.


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## JRP3 (Mar 7, 2008)

In the Roadster Tesla just used air cooling. 


> Though highly efficient, the motor still generates some heat. To keep within acceptable operating temperatures, specially engineered cooling fins have been integrated into the housing and a fan is employed to blow air across the fins to most effectively extract the heat. This helps keep the overall package light and tight.


http://www.teslamotors.com/roadster/technology/motor
With the Model S Tesla uses a liquid cooled motor with a cooling loop through the rotor shaft as well as the housing, they have patents on it.
http://www.freepatentsonline.com/y2008/0272661.html


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## few2many (Jun 23, 2009)

In the Tesla link, You can definitely see the little cooling fins in there. It's all about surface area. Wouldnt be hard to make that for an ac50, wrap a flat piece of alum sheet around that, use the double shaft end for the fan and you'd get a nice, ducted fan effect over the motor fins.


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## JRP3 (Mar 7, 2008)

Jack Rickard has used an external powered fan on the end of an AC50 for extra cooling, one without the aux shaft. Not really an issue though unless there is a much more powerful controller for that motor.


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## mizlplix (May 1, 2011)

Hey, I got a great idea...

Some of you obviously have a lot of nervous energy. I purpose an experiment.

Chuck the shaft of a small electric motor in a drill press. Submerge it into a small container of oil. figure out a torque arm to hold the case from rotating.

Turn it on. See how hot (or not hot)it gets.

It must be a small container just larger than the motor housing.

Get pics, a vid would be good too....

Miz


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## Ziggythewiz (May 16, 2010)

If it doesn't get hot enough you could always ignite the oil to better test the cooling effects.


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## ricklearned (Mar 3, 2012)

....and another irony is, that there are a couple of people here, who removed their air cooled engine to replace it with a motor/controller that might need water cooling. LOL


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## Ziggythewiz (May 16, 2010)

Nope, still air cooled  I don't even run the additional air cooling I had setup last summer. Peak speed limits on my commute were reduced for "Road Work" so there's no reason to bother getting out of 2nd.


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## ricklearned (Mar 3, 2012)

Ziggythewiz said:


> Nope, still air cooled  I don't even run the additional air cooling I had setup last summer. Peak speed limits on my commute were reduced for "Road Work" so there's no reason to bother getting out of 2nd.


Me too, and I haven't been out of 2nd gear either, since the first time I drove my car three weeks ago. I'm hanging in there for air cooling. KISS


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## StanSimmons (Sep 3, 2011)

ricklearned said:


> That is pretty expensive for a chill plate, but then they through in the motor, controller, and programmer to give it a little more value.LOL
> 
> I suppose at the right price Jack would unbundle it and sell just the chill plate.





StanSimmons said:


> I sent him an email a few days ago asking what price he would sell just the chill plate for. I'll update here if he responds.
> 
> EV West has a pretty good looking one for $140, but it doesn't have the o-ring seal like the EVTV one does.


EVTV only sells their chill plate in a motor kit or a cooling kit.


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## JRP3 (Mar 7, 2008)

Jack seems to like to bundle things, which means if you only want one part of a setup you're out of luck, and they don't get the sale. Strange way to do things, but that's Jack for you.


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## mizlplix (May 1, 2011)

You should ask Ivansgarage if he would make sOme. Jacks design is simple. Ivan is just sitting around anyways. 

He made mine. 

Miz


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## Elegancec (May 23, 2012)

Hi,

I also thaught about your cooling method.
My car will have a weight of 1355kg mit the K9 220V from Kostov.
When I drive 100km/h I will need about 9-12kW power. The motor has an efficiency of about 80%. So I will have about 2kW losses. I would like to use the losses for the cabin. Maybe with an air water heat exchanger and also your water tubes around the motor. Another solution could be to bend some thin copper plates and solder the tubes on it. Between the copper plate and the motor has to be a heat paste. This should dramatically decrease your temperature of the motor. At the ends you can close it with an thermal stable medium like silicon maybe?

Just an idea from an german engineer, sounds crazy no is crazy


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## mizlplix (May 1, 2011)

EL: No, that sounds OK to me.

When I wound the copper tubing on the motor, it flattened a little, which was a good thing. Then after I sweated the spot tacks around to keep it tight, I sprayed water on it to shrink the tubing to the case. Well, it is really tight on it too.

I didnt do the heat sink paste because I was going to leave it open and it would have been a mess later on from the heat and dirt.

I did clean it up some and Polyurethane/cleared it to delay corrosion.

Miz


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## ev-converter (May 24, 2012)

mizlplix said:


> EL: No, that sounds OK to me.
> 
> When I wound the copper tubing on the motor, it flattened a little, which was a good thing. Then after I sweated the spot tacks around to keep it tight, I sprayed water on it to shrink the tubing to the case. Well, it is really tight on it too.
> 
> ...


The water cooling plate for a Curtis 1238 without the other cooling parts is available from [email protected] for $125.00. All stainless steel internal tubing with brass barb fittings. Requires no extra bolts utilizing existing which may have to be lengthened.


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## Ivansgarage (Sep 3, 2011)

ev-converter said:


> Requires no extra bolts utilizing existing which may have to be lengthened.


How do ya lenghthen a bolt?


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## GizmoEV (Nov 28, 2009)

Ivansgarage said:


> How do ya lenghthen a bolt?


To do it you need two people, two bolts, and one strip of cloth or tissue which is cut or folded to be no wider than the bolts are long. You lay the two bolts across the cloth or tissue so that it divides the tissue roughly into three equal lengths. Fold one side of the tissue over the bolt and then the other side, enclosing the two bolts with the ends of the tissue overlapping on top. Have one person hold the bolt heads, one in each hand and the second person hold the other ends of the bolts and you have a bolt stretcher.

This is what we would do if we need a spoke stretcher except that we could just use a regular rag since the spokes are usually longer than a typical bolt.


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## HPEVS (Jun 6, 2012)

FYI, We run the AC50 in vehicles up to 3500 pounds with just the internal fan cooling. With a light weight vehicle like Miz has built, I'm not surprised at the motor temp. My Scion xB weighs in at 3400 and never see's higher than 80C. I'm inland from LA by 60 miles, so ambient temps of 100+ in the summer are the norm.

You can also check out our Chiller plate on the web site.


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## GuySmily (May 11, 2012)

HPEVS said:


> FYI, We run the AC50 in vehicles up to 3500 pounds with just the internal fan cooling. With a light weight vehicle like Miz has built, I'm not surprised at the motor temp. My Scion xB weighs in at 3400 and never see's higher than 80C. I'm inland from LA by 60 miles, so ambient temps of 100+ in the summer are the norm.
> 
> You can also check out our Chiller plate on the web site.


I'd still want to run some kind of forced cooling if at all possible. I figure colder is always better, right?

Are you talking about the same chiller plate as on EVWest's site? Couldn't find it on your site. I assume "ev-converter" is selling the same plate as well, considering the price is the same.


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## JRP3 (Mar 7, 2008)

It's under "accessories" and it's no the same as the EVWest unit.

http://www.hpevs.com/chiller-plate.schema.htm


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## HPEVS (Jun 6, 2012)

GuySmily said:


> I'd still want to run some kind of forced cooling if at all possible. I figure colder is always better, right?
> 
> Are you talking about the same chiller plate as on EVWest's site? Couldn't find it on your site. I assume "ev-converter" is selling the same plate as well, considering the price is the same.



Nope, we make our own. It's on the Drive Systems, Accessories tab.

Cooler is better, but trying to run lower than 80C or so tends to be a waste. The internal fan moves way more air than a small squirrel cage or box fan and building the ducting can be time consuming.


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## toddshotrods (Feb 10, 2009)

After this thread, I am probably running air cooling on my bike. It won't see any harsh usage and it's obvious from the posts here that anything above the recommended isn't really necessary. I decided to convert it to electric because the ICE had too much crap - it would be nice to *not* add it all back with the electric motor...  The race cars will get forced air and chill plates, but that's because they're going to be pushed to their absolute limits. For normal street driving, even in warmer climates, it seem like a waste...


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## piotrsko (Dec 9, 2007)

update: 103 F day in reno, 4% uphill run for 3 miles @ 45 mph posted. Pushing about 275 motor amps @ 198 vdc on Kostov 11 192v.

starting temp of Sol1 44 C ending temp of Sol1 55.4C air cooled only as from factory. Motor temps 73 C on outside of case, 

I don't see much impetus to do any water cooling anywhere.


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## JRP3 (Mar 7, 2008)

On the other hand, Tesseract recently explained that a few degrees of cooler operation for a controller can dramatically increase it's life cycle. So even if a controller is operating within it's parameters with air cooling it may last longer if you can liquid cool it another 10 degrees or so. Something to consider.



> Yes, the higher the operating temperature the faster ALL electronics will die. The heuristic, or rule of thumb, that is commonly used is that every 10C increase in temperature over 25C cuts the lifespan in half, so going from 25C to 85C cuts the lifespan by 64x. Whether that's a tolerable reduction depends on what the lifespan is to begin with, but that's not something we can practically determine without adding significantly to the cost of the product. It's unlikely to exceed 1000 hours at 85C, based on the statistical summation of the MTBF of all components at that temperature, however.


http://www.diyelectriccar.com/forums/showpost.php?p=315644&postcount=246


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## leong (Aug 22, 2012)

for induction motors, the heat mainly is on the rotor... these tubes are not effective when they are outside even for the stator. For proper liquid cooling, coolant has to run through the laminations.


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## JRP3 (Mar 7, 2008)

Jack Rickard had an interesting concept for a series DC motor, basically make a sealed pump housing for the aux shaft on the comm end and an impeller for the shaft, turning it into a water pump. The idea is that keeps the shaft cold which would draw away the heat created on the comm. Don't know if it would be worth the added complexity and expense, plus you lose the use of the aux shaft if you need it.


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## major (Apr 4, 2008)

JRP3 said:


> Jack Rickard had an interesting concept for a series DC motor, basically make a sealed pump housing for the aux shaft on the comm end and an impeller for the shaft, turning it into a water pump. The idea is that keeps the shaft cold which would draw away the heat created on the comm. Don't know if it would be worth the added complexity and expense, plus you lose the use of the aux shaft if you need it.


Might help cool the bearing but I don't think you'd find much difference on the commutator surface. Too much thermal resistance especially with the molded comms. I've always thought the shaft to be a heat source in the DC motor. It is bound to have changing magnetic fields and is non-electrical grade non-laminated steel.


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## major (Apr 4, 2008)

leong said:


> for induction motors, the heat mainly is on the rotor...


Hi leo,

There are folks who would disagree with "mainly" on the rotor. True that the rotor has loss and therefore heat, but what is the proportion compared to the stator? Can you supply a reference to support your claim, please?

Thanks,

major


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## lockduke (Dec 25, 2009)

In that respect you could make a heatsink that also serves as a pulley for the auxiliary shaft. By being made out of aluminum and hardened by anodizing you could also add a little flash of color to a drab motor compartment. Also you could make the pulley multi-grooved to use several add on accessories for whatever your heart desires. I'm quite sure most of us will find things we can run off the auxiliary shaft. We used these types of heat sinks to cool the commutators on smaller electric motors as far back as the 80's as we were running these motors at a very maximum limit. they were intended to run on 1.5 V DC, and we were running them at as high as 18 V DC. It took motors that were failing in 30 minutes  of intermittent duty and made them last to the point we were wearing out the comm brushes before lifting the comm tabs or just plane wearing out the commutator from truing / cutting them to keep a round commutator. Duke


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## JRP3 (Mar 7, 2008)

I've been toying with the idea of using a hand held wood router to cut channels in a chunk of aluminum for a controller cooling plate. Shallow passes should work, but then I thought, why mess with aluminum? (especially after pricing 1/2"-3/4" plate) The fluid is the cooling medium, not the aluminum, which is really just a vessel for the fluid. Started looking around at plastic options, and HDPE, cutting board plastic, has a continuous rating of 194F and 266F deflection. It's less than $20 for a 3/4 inch thick 12 inch square and would be easy to machine. Am I crazy?


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## onegreenev (May 18, 2012)

JRP3 said:


> I've been toying with the idea of using a hand held wood router to cut channels in a chunk of aluminum for a controller cooling plate. Shallow passes should work, but then I thought, why mess with aluminum? (especially after pricing 1/2"-3/4" plate) The fluid is the cooling medium, not the aluminum, which is really just a vessel for the fluid. Started looking around at plastic options, and HDPE, cutting board plastic, has a continuous rating of 194F and 266F deflection. It's less than $20 for a 3/4 inch thick 12 inch square and would be easy to machine. Am I crazy?


Might work just fine. Will that plastic handle the heat given off by the controller and you might consider lots and lots of channels. More fluid in contact with the bottom of the controller the better. But you don't want a huge pool. Channels are best. 

Crazy? Na! Might have sore hands after using your hand router to route out those channels. Can't hurt to try the idea. I'd like to see that. Don't forget to route out the channel around the parameter for your sealing o-ring.


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## major (Apr 4, 2008)

JRP3 said:


> I've been toying with the idea of using a hand held wood router to cut channels in a chunk of aluminum for a controller cooling plate. Shallow passes should work, but then I thought, why mess with aluminum? (especially after pricing 1/2"-3/4" plate) The fluid is the cooling medium, not the aluminum, which is really just a vessel for the fluid. Started looking around at plastic options, and HDPE, cutting board plastic, has a continuous rating of 194F and 266F deflection. It's less than $20 for a 3/4 inch thick 12 inch square and would be easy to machine. Am I crazy?


 Yep, I'd say so  You gain so much surface contact area between the liquid and material conducting the heat not to use a material with superior thermal conductivity. Plastic would be on the order of 3 to 4 times less effective IMO. If you could afford it, copper would be better than aluminum


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## dtbaker (Jan 5, 2008)

little oil coolers, transmission coolers, or a little heater core with a small circulation pump will be WAY more effective than any finned/convective chill plate... aluminum or copper does a WAY better job at heat transfer than plastic or wood. 

or are you looking at making a plate for a controller than doesn't have the fluid plate built in like the Zilla/Solitons do?

If thats what you're doing, you'll have to bite the bullet and machine aluminum probably...


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## Abel (Sep 16, 2009)

What was your water temp.? If there is not a big difference you will not get any results worth much. Did you use strait water or coolant fluid? You can try building a catch can and putting dry ice in it.


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## JRP3 (Mar 7, 2008)

major said:


> Yep, I'd say so  You gain so much surface contact area between the liquid and material conducting the heat not to use a material with superior thermal conductivity. Plastic would be on the order of 3 to 4 times less effective IMO. If you could afford it, copper would be better than aluminum





dtbaker said:


> or are you looking at making a plate for a controller than doesn't have the fluid plate built in like the Zilla/Solitons do?
> 
> If thats what you're doing, you'll have to bite the bullet and machine aluminum probably...


This is what I'm talking about, only made out of plastic:










This bolts against the bottom of the controller. I would probably use larger channels to get more fluid in contact with the controller, then it would be pumped to a small radiator. Miz used a simple bathtub version with no passages, just an open pool for the coolant, and has had no problem, in Arizona, so passages probably aren't even necessary.


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## mizlplix (May 1, 2011)

Hi. Just sticking my oar in the water, so to speak...LOL

When you use channels, you either get lucky and have water over a hot spot or wait for regular conduction to transfer the heat to the plate then to the coolant. This one takes out the guess work.

I use long bolts to attach plate to controller with a lock nut, then the remaining threads mount it to the firewall, nice and neat.
















No channels, no o-ring, Just some Anerobic gasket sealant from NAPA. It forms a tough acrylic gasket. There is virtually no pressure involved, so why add complications?

On a 109F ambient day, this plate reduces the controller temperatures from 78C to 45C. No amount of coaxing would make it go any higher.

50% Propylene glycol coolant/ water, in thru the bottom and out thru the top in the normal thermo-siphon direction.

I use a common inline fuel pump to circulate the coolant. With no pressure it draws less than 3 amps.

Miz


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## onegreenev (May 18, 2012)

If you used a set up like miz then I think the plastic would do you just fine as the coolant is the only thing really in contact with the bottom of the controller. I guess with good flow it would work.


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## JRP3 (Mar 7, 2008)

mizlplix said:


> When you use channels, you either get lucky and have water over a hot spot or wait for regular conduction to transfer the heat to the plate then to the coolant. This one takes out the guess work.


I'm thinking of making a few large channels with some thin plastic sections left in for rigidity, since it's plastic, not aluminum. Might not be needed, but it will mean a little less routing. Plus I think the thick aluminum base of the controller already conducts heat, so even if I'm not right on a hot spot it shouldn't matter much. I suppose I could run the controller for a bit and shoot the base with an IR thermometer to "map out" any hot spots, but I'm thinking the aluminum base plate would "muddy" those readings per my above reasoning.
Looking at the interior layout I guess warmer areas might be under the cap banks?


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## toddshotrods (Feb 10, 2009)

Hey you got the lid off!  I've been waiting to see inside one of those - I can do wonders with a custom cover for Scrape, hmmm...

Back on topic: I'm not too crazy about the idea of HDPE. Maybe a high-temp acrylic would be better? I would go thicker too. I'd be concerned with the HDPE warping enough to let it leak, even though the spec says it deforms at a higher temp than your coolant should be. The problem is you don't want to find out otherwise, while driving. 

If you decide to try machining the passages in aluminum, there are aluminum-cutting router bits. They are typically a single flute, up-cut, bit - so that they through the chips out of the cut area. I touched the aluminum while one was cutting and it was completely cool. Another helpful tip is have compressed air handy to keep the cut area clean.

Lastly, if you really want aluminum let me know - I can cut one of these for you (and anyone interested), no problemo.


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## JRP3 (Mar 7, 2008)

toddshotrods said:


> Hey you got the lid off!


Nope  Not my controller but a pic from someone else.


> Lastly, if you really want aluminum let me know - I can cut one of these for you (and anyone interested), no problemo.


Good to know. I suppose you could cut a plastic one as well? I'm still keen on trying it. Thinking I could clamp a bar across the middle for extra support if I need it I can heat a cutting board in the oven as a test.


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> Nope  Not my controller but a pic from someone else...


Oh, well thanks for posting the pic. 





JRP3 said:


> Good to know. I suppose you could cut a plastic one as well? I'm still keen on trying it. Thinking I could clamp a bar across the middle for extra support if I need it I can heat a cutting board in the oven as a test.


Can do plastic too. That shouldn't be too bad with the hand router, if you choose to give it a shot. Keep the spindle speed down to the lowest setting, and pay close attention to the bit. Plastics will melt onto the bit really quickly and the blob of material on it will trash your material. You can usually spot it happening though. It usually starts as a small band of color on the bit - a long shaving that wraps around it, and then it snowballs. Sometimes it will clean itself and fling it off, and sometimes I've had to stop and remove it...


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## dtbaker (Jan 5, 2008)

given that the heat transfer is pretty much thru the base plate of the controller on this setup, which is aluminum, it is irrelevant what the back plate is.....

in fact, going one step further for people not having access to milling machines, the backing 'plate' could be two pieces of plastic; a 'frame' thick enough the drill and tap fittings thru, and a backing sheet gasketed, heat welded, or glued together!

Lovely application of the KISS principal. Who needs cooling channels when it CAN be just a full coverage 'pond' !


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## JRP3 (Mar 7, 2008)

JRP3 said:


> Thinking I could clamp a bar across the middle for extra support if I need it.


Not sure what I was thinking since this won't be an issue, the plastic will be sandwiched between the base of the controller and the plate of aluminum I have it mounted on.


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## tomofreno (Mar 3, 2009)

JRP3 said:


> I'm thinking of making a few large channels with some thin plastic sections left in for rigidity, since it's plastic, not aluminum. Might not be needed, but it will mean a little less routing. Plus I think the thick aluminum base of the controller already conducts heat, so even if I'm not right on a hot spot it shouldn't matter much. I suppose I could run the controller for a bit and shoot the base with an IR thermometer to "map out" any hot spots, but I'm thinking the aluminum base plate would "muddy" those readings per my above reasoning.
> Looking at the interior layout I guess warmer areas might be under the cap banks?


 I would think that the power mosfets delivering the drive current would be the main heat source. You can estimate the heat flow for some controller efficiency, say 95%, then calculate the temperature gradient this would give through the aluminum base to the fluid for some fluid temperature on a hot summer day. Optimum heat transfer to the fluid requires high Reynolds number for turbulent flow to break up the boundary layer at the aluminum surface. A large cavity will have areas of stagnant flow where heat transfer will be poorer due to higher fluid temperature there. 

Best heat transfer would be to machine the fluid passages into the controller's aluminum base to bring them up close to the mosfets. But I think the cooling requirement is not that demanding, so just about any design will work. Plastic is fine as long as it has the mechanical strength to not deform enough to leak, and to attach fluid hose connections. As you say, almost all the heat transfer is to the fluid-air heat exchanger via the fluid. Convection from the cover should be very small regardless of material (if not, there would be little reason to use fluid cooling). I would use an o-ring seal around the perimeter myself. Buna should be fine. The small leakage between passages should have minimal effect. Then you just have to calculate the deformation of the cover plate to ensure it maintains a good seal - or you could just drill and tap additional holes in the controller's aluminum plate to ensure a good seal (Edit: Oh, I see you said you are sandwiching the plastic with an aluminum plate). I'm not sure high density polyethylene is the best material choice. You might check mechanical properties of other plastics.


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## mizlplix (May 1, 2011)

1. I do not know where the hot spots are on the controller are.

2. The basic laws of thermodynamics prevent "hot spots" or "stagnant" areas. Heat always flows up. As long as the controller is mounted verticle, there is a thermo-siphon action, drawing the heat to the top of the "pond" where it is removed by the outlet piping as the cool media is introduced at the bottom.

3. I have yet to go over 50C in actual running conditions with an ambient of 109F.

Admittedly, I have a 1.5 gallon reservoir supply and a grossly large heat exchanger.

Miz


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## JRP3 (Mar 7, 2008)

Mine will be mounted flat so I don't get any thermosiphoning, I plan on routing a big "U" shape with the fluid passages under the caps and mosfets, and a narrow band of plastic left in the middle. The idea is this will create a definitive flow path while having most of the benefits of the bathtub concept. I might even make the borders squiggly to create some mixing effect, plus that means I don't need a steady hand while routing


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> Mine will be mounted flat so I don't get any thermosiphoning, I plan on routing a big "U" shape with the fluid passages under the caps and mosfets, and a narrow band of plastic left in the middle. The idea is this will create a definitive flow path while having most of the benefits of the bathtub concept. I might even make the borders squiggly to create some mixing effect, plus that means I don't need a steady hand while routing


Pretty much planning to steal ^^^ that idea.


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## JRP3 (Mar 7, 2008)

Doing some more research on plastics it looks like the HDPE is the best choice on an operating temp vs cost basis. Nylon does have a higher continuous operating temp but it seems to be about 2.5-3 times the cost, and the operating temp of the HDPE is well within range for this application.


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## TigerNut (Dec 18, 2009)

JRP3 said:


> Doing some more research on plastics it looks like the HDPE is the best choice on an operating temp vs cost basis. Nylon does have a higher continuous operating temp but it seems to be about 2.5-3 times the cost, and the operating temp of the HDPE is well within range for this application.


If you're going to use plastic, then check carefully for the moisture absorption characteristics of that plastic, and whether it's affected by organic compounds like glycols. We had a nylon product component in our lineup that worked on the factory floor in Asia where the ambient humidity was always 80 to 100%, but became brittle and broke here in Alberta where it's dry.


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## JRP3 (Mar 7, 2008)

Here's what I'm looking at, you can check the specs and additional info, looks as if it should be OK.
http://www.grainger.com/Grainger/Sheet-Stock-1ZAH2


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## TigerNut (Dec 18, 2009)

JRP3 said:


> Here's what I'm looking at, you can check the specs and additional info, looks as if it should be OK.
> http://www.grainger.com/Grainger/Sheet-Stock-1ZAH2


http://www.matweb.com/search/DataSheet.aspx?MatGUID=814ceb20bc964b8bad817aeed2debfa8&ckck=1

Looks like it's okay with alcohols (which should mean that glycol is OK) but not aromatics, ketones, or chlorinated solvents. The coefficient of thermal expansion is 110 um/m-C, about five times that of aluminum (23 um/m-C). Also, maximum service temperature is 80 C... Putting all that together, I would worry about the longterm sealing of this material against the aluminum backplate of the controller unless you had a clamping/retention system that really held it in place.


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## JRP3 (Mar 7, 2008)

Operating temps should be well within range in this setup, and it will indeed be clamped tightly between the controller base and mounting plate. Expansion might be an issue but I'm hoping not. Glycol cleans up easy at least


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> Operating temps should be well within range in this setup, and it will indeed be clamped tightly between the controller base and mounting plate. Expansion might be an issue but I'm hoping not. Glycol cleans up easy at least


The problem I see with the differing expansions rates (between the HDPE and the aluminum controller base plate) is maintaining the seal. When the HDPE expands the material is going to move. Since you're going to have it sandwiched between aluminum plates the only place for it to go is out (laterally). That means it could, potentially, break whatever you're using for a seal. You need something "sticky" and very flexible (non-hardening).


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## JRP3 (Mar 7, 2008)

I plan to do some tests today using some HDPE and aluminum, glued together with RTV sealer. Once cured tomorrow I'll set it out in the cold, then hit the aluminum with a heat gun, repeat a few times, and see what sort of force it takes to pull it apart. Won't be perfect but if it all falls apart in my hands I'll know it's a bad idea 
I do think a grove with an O-ring would probably eliminate any problems, but I'm not confident I can hand rout a perfect groove the exact circumference needed to seat an O-ring.


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> ...I do think a grove with an O-ring would probably eliminate any problems, but I'm not confident I can hand rout a perfect groove the exact circumference needed to seat an O-ring.


Make a template from a larger piece of scrap wood. That way, as long as you keep the router firmly against the template, you won't wiggle and enlarge the groove. You can size the o-ring to the actual groove the router bit cuts, rather than vice versa.


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## few2many (Jun 23, 2009)

When mounting horizontal, is there any concern that an air pocket may form and insulate the pate? Say, between the level of the inlet/outlet fittings, and the bottom of the controller?
Also, in regards to any possible hot spots or circulation concerns some have mentioned. If routing out aluminum, or plastic, or sandwiching something, I would think it would be easy to add a simple baffle design to the bath area. A small chamber after the inlet fitting and before the majority of the bath, with a several smaller ports that span from one side, to another, to evenly disperse flow. I know it was mentioned that with vertical, thermal siphon, this was not likely an issue, but with a unit laying flat, it's possible.


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## JRP3 (Mar 7, 2008)

I suppose when filling it initially you could tip the mounting plate up to allow any air to escape. I'm not sure if there need be any concern with hot spots, even if there are areas of stagnant water they are still in contact with colder, flowing water, and I think heat transfer would still occur. Before mounting it you could stretch some clear plastic or clear packing tape over it, add some dye to the water and see what happens as you pump it through.


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## JRP3 (Mar 7, 2008)

My testing with Permatex Ultra Black sealer did not go well. It took little force to pull the aluminum off the plastic, and even after more than 24 hours some of the silicone in the middle was still not cured. Basically there was an outer ring of cured material which sealed off the center from curing, on a 3/4 inch wide piece. I sanded both the aluminum and HDPE with 220 grit to give it some tooth but most of the silicone stuck to the aluminum and not the HDPE. So it looks as if an O-ring would be needed. With the different expansion rates I'm thinking a groove in the HDPE to hold the ring but not in the bottom of the controller. This should allow the plastic and O-ring to expand laterally while still keeping a seal against the controller. Maybe? Or I just bag the whole concept and go with aluminum


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## mizlplix (May 1, 2011)

Rarely is anything on a vehicle truly "flat" or level. Even when mounted flat it will favor one end over another, so watch where you put the inlet/outlet.

I see WAY too much overthink going on about water cooling choices:

From experience, I see that water covering the controller base pulls heat away well. Almost any strategy that puts liquid on the aluminum base will work fine.

As for "hot spots", Even if there are any, I can not tell as the controller registers a 20-25 degree cooling effect from switching to water (over just a 1" finned air plate).

The flow only needs to be slightly faster than the controller can heat the liquid, which is extremely slow. Maybe 2 Qts/minute.

Even when my controller is at it's hotest, I can hold my finger along the base and not get burned....SO, a good grade of plastic might work well as a "TUB", I would use clear silicone or other gasket adhesive for a sealer, because of the 4 bolt clamping deal...

Be sure to use plastic fittings in a plastic plate. Metal ones WILL leak eventually.

AND Use paste sealant, never teflon tape. Plastic on plastic will leak and allow the fitting to become loose over time.

Miz


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## RE Farmer (Aug 8, 2009)

JRP3 said:


> My testing with Permatex Ultra Black sealer did not go well. It took little force to pull the aluminum off the plastic, and even after more than 24 hours some of the silicone in the middle was still not cured. Basically there was an outer ring of cured material which sealed off the center from curing, on a 3/4 inch wide piece. I sanded both the aluminum and HDPE with 220 grit to give it some tooth but most of the silicone stuck to the aluminum and not the HDPE. So it looks as if an O-ring would be needed.


Essentially, nothing sticks to HDPE so an O-ring is a good idea. Also, use silicone sealers sparingly. Only a thin film is needed. Too much squeezing out often will come loose and plug up fluid passage ways.


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## z_power (Dec 17, 2011)

Here's another idea, cooling plate for two IGBTs; made with table drill ("modified" with MDF plate etc.) and lengthened drill bits. I drilled from opposite sides and managed to get less than 2 mm error at meeting point - c'mon it's not a barrel of a gun ;-) Long channels are 12 mm dia., shorter ones are 7 mm with aluminium corks sealed with loctite. I still have to mill this wall flat - there's christmas break in friend's machine shop... Red lines show "routing" of coolant.


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## agazdziak (Sep 24, 2012)

Thoughts on the evtv liquid cooling kit? $1k seems to be a lot of money, are any of those pieces particularly unique / expensive? I'm looking for something to use with the AZD Siemens motors.

http://blog.evtv.me/store/proddetail.php?prod=EVTVcoolingkit


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## JRP3 (Mar 7, 2008)

I would expect you can find all the same components for less, or similar for a lot less. Hose clamps and rubber hoses have worked well for autos and boats in much more demanding applications, unless you really like the SS braided hoses and A/N fittings.


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## ruckus (Apr 15, 2009)

agazdziak said:


> Thoughts on the evtv liquid cooling kit? $1k seems to be a lot of money, are any of those pieces particularly unique / expensive? I'm looking for something to use with the AZD Siemens motors.
> 
> http://blog.evtv.me/store/proddetail.php?prod=EVTVcoolingkit


Get on Ebay. Type in 'aluminum radiator'. Choose one for a motorcycle. Get a pump and some hoses. Done.

$250 max for everything??

What controller are you using with the Siemens motor?


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## agazdziak (Sep 24, 2012)

Great to hear, that's what I figured.

We will be using a wavesculptor 200 for this motor.


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## Salty9 (Jul 13, 2009)

Check aftermarket autotrans coolers or junk yard heater cores. Generally much cheaper than radiators of any sort.


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## dtbaker (Jan 5, 2008)

jumping in late here... and not really wanting to go back thru to the beginning... what controller are we talking about? both zilla and soliton have internal pre-plumbed fluid circulation....

If the controller is 'something else', first step would be a decent finned heat-sink with good airflow. If more het needs to be dumped, then yeah, fluid circulation will be required.

rather than have an 'open' system sealed against bottom of controller, what about a 'closed' aluminum sandwich (expanding/contracting same rate) that could slap up tight to the bottom w/ thermal paste? You could then use a variety of adhesives, or even weld.....


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