# Watercooled Curtis 1238 for your AC50



## Coulomb (Apr 22, 2009)

So is this one piece that is sealed to the base of the Curtis 1238?

It looks something like one half of the one that Jack Rickard made for one of his vehicles, perhaps the electric Mini. They glued the two halves together (I hope I am remembering this right), and bolted the resultant block to the controller.

As long as the Curtis controller's base is flat enough, and doesn't warp much with the heat, a single piece glued to the controller would seem about as reliable. You seem to have plenty of bolt holes there to keep the heatsink and controller connected well.

Any time you have to take out the controller, you'd take the heatsink with it, disconnecting the two coolant connections instead of undoing a dozen or more bolts.

Do I have the right idea?


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## UBCECC (Sep 5, 2009)

this water-block is a 2 piece design. In the first picture you can see a plate in the back which will be bolted to the thicker piece and rubber is sandwiched to seal the fluid.


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## tomofreno (Mar 3, 2009)

What are the x-y dimensions of the plates? Are the two sealed by an o-ring seal, or just a flat rubber gasket? What did you use for a liquid-air heat exchanger for cooling the liquid? What fluid flow rate did you use? Could you give some typical controller/ambient temperatures you saw on your trip? For example, I am using a simple finned (5 cm fins) heat sink with small (260 cfm) fan on my 1238-7501 controller. This summer during a climb at about 67 km/hr up about 488 meter change in elevation at average 4.8% grade in 33 C ambient, max controller temperature was 56 C. During a climb at about 70 km/hr up about 1372 meter change in elevation at average 4.5% grade in about 33 C ambient, max controller temperature was 58 C. It would be nice to keep the controller cooler, but it is not close to its spec'ed max of 85 C on these runs which are the most demanding I typically do, so I'm not sure it is worth dealing with the plumbing.


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## UBCECC (Sep 5, 2009)

tomofreno said:


> What are the x-y dimensions of the plates? Are the two sealed by an o-ring seal, or just a flat rubber gasket? What did you use for a liquid-air heat exchanger for cooling the liquid? What fluid flow rate did you use? Could you give some typical controller/ambient temperatures you saw on your trip? For example, I am using a simple finned (5 cm fins) heat sink with small (260 cfm) fan on my 1238-7501 controller. This summer during a climb at about 67 km/hr up about 488 meter change in elevation at average 4.8% grade in 33 C ambient, max controller temperature was 56 C. During a climb at about 70 km/hr up about 1372 meter change in elevation at average 4.5% grade in about 33 C ambient, max controller temperature was 58 C. It would be nice to keep the controller cooler, but it is not close to its spec'ed max of 85 C on these runs which are the most demanding I typically do, so I'm not sure it is worth dealing with the plumbing.


We had two of these radiators:
http://www.koolance.com/water-cooling/product_info.php?product_id=636

and 1 of this pump:
http://www.koolance.com/water-cooling/product_info.php?product_id=858

We sealed the plate with flat piece of rubber. dimension is the same footprint as the 1238 controller. Threading is g1/4" for o-ring fittings. 

Running at 110km/hr for 2 hours on the highway, hottest temp was around 50degrees.


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## JRP3 (Mar 7, 2008)

That's a very nice looking cooler, but comparing your results to Tom's I'd say it's probably not worth it, considering the cost of the cooler, pump, fans and radiators.


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## david85 (Nov 12, 2007)

UBCECC,

Saw your team's car on the news a while back (showed up on the forum newsbot too), just wanted to pass along a congrats on that.

I didn't realize you were a member here, welcome.


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