# 1238 gets water cooling



## cruisin (Jun 3, 2009)

After a lot of trial and error, I have come up with a GOOD working water cooler for the 1238 controller. This same design can be used with other controllers with some modification. Before the installation of the water cooler, the 1238 mounted on a 3/8"x24"x24" aluminum plate would reach 80c on a warm day with some aggressive driving. Now, I haven't seen it get over 40c which is a substantial improvement. Anyone using the 1238, or any controller not water cooled, should consider something similar. If money is a excuse for not doing something to keep the temperature down, go to another thread. With all the trial and error, I found that 1/2" tubing is not necessary as some others use. The key is the dual pass cold plate 8"x12" and not the evaporator radiator with dual super quite fans. Also, the GPM of the pump made very little difference except to add some noise if using a high capacity type. The setup as shown in the pictures makes NO noise and is undetectable standing over it while running (high priority). Bay Area EV is considering marketing a DIY kit for the 1238 with other systems available later. Here are a couple of pictures to help you understand what it would look like installed.


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## DavidDymaxion (Dec 1, 2008)

Sounds intriguing, can you give more details on how you made the cold plate?


cruisin said:


> After a lot of trial and error, I have come up with a GOOD working water cooler for the 1238 controller. This same design can be used with other controllers with some modification. Before the installation of the water cooler, the 1238 mounted on a 3/8"x24"x24" aluminum plate would reach 80c on a warm day with some aggressive driving. Now, I haven't seen it get over 40c which is a substantial improvement. Anyone using the 1238, or any controller not water cooled, should consider something similar. If money is a excuse for not doing something to keep the temperature down, go to another thread. With all the trial and error, I found that 1/2" tubing is not necessary as some others use. The key is the dual pass cold plate 8"x12" and not the evaporator radiator with dual super quite fans. Also, the GPM of the pump made very little difference except to add some noise if using a high capacity type. The setup as shown in the pictures makes NO noise and is undetectable standing over it while running (high priority). Bay Area EV is considering marketing a DIY kit for the 1238 with other systems available later. Here are a couple of pictures to help you understand what it would look like installed.


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## cruisin (Jun 3, 2009)

DavidDymaxion said:


> Sounds intriguing, can you give more details on how you made the cold plate?


Cold plates are available on the internet for around $75 to about $350 depending on the size and amount of passes. I chose the *8x12"x1" with 2 passes. The size is perfect for the 1238. I sell them for $100.00 new.


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## Guest (Jul 29, 2011)

Links would be great. To yours would be great too. No radiator? How do you get the heat out of the water before putting it back into the cold plate? It will heat up if you don't have a radiator but it will just take longer. How do you radiate the heat out of the system?


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## cruisin (Jun 3, 2009)

gottdi said:


> Links would be great. To yours would be great too. No radiator? How do you get the heat out of the water before putting it back into the cold plate? It will heat up if you don't have a radiator but it will just take longer. How do you radiate the heat out of the system?


Plates are available at 925.292.8565. The Condenser that extracts the heat from the plate is in the picture with the 2 super quite fans blowing through the condenser to the under side of the car. Both the pump and the fans run whenever the controller is on.


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## 9852 (Jan 17, 2010)

gottdi said:


> Links would be great. To yours would be great too. No radiator? How do you get the heat out of the water before putting it back into the cold plate? It will heat up if you don't have a radiator but it will just take longer. How do you radiate the heat out of the system?



love the new avatar pete


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## Woodsmith (Jun 5, 2008)

That's neat.

Have you tried it with antifreeze? I can imagine the large bore clear pipe would look good with a blue fluid running through it.

I was planning on 1/4" bore pipe and windshield wash size of pump, need to find one that will run continuously though.
Maybe the larger bore pipe and pump isn't necessary but it it looks good. 

What sort of cost are you looking at for that set up? Can't be that much more then a good dry system.


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## cruisin (Jun 3, 2009)

Woodsmith said:


> That's neat.
> 
> Have you tried it with antifreeze? I can imagine the large bore clear pipe would look good with a blue fluid running through it.
> 
> ...


 
I now use a green antifreeze in the fluid to prevent corrosion. It looks real cool with the green car. The small pumps I use make no noise and are capable of running forever with hot fluids.


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## Bowser330 (Jun 15, 2008)

will the cooling affect how the controller performs? for example, would it allow for the 650A to be delivered for longer periods of time?

off topic: A higher voltage version of this controller would really take this setup to the next level!










If 85V allows this motor to peak at 3200rpm, then simple math says @ 170V the motor could peak at 6400rpm.

With the liquid cooling helping the controller supply 650A all the way to peak, thats 170V * 650A = 110kw = 148 hp!

Two of these setups would be the competitive to the Tesla Roadster's power & torque for a 1/3 the price! (4500*2 = 9K$ & 25K$ for AC Propulsion)


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## cruisin (Jun 3, 2009)

Bowser330 said:


> will the cooling affect how the controller performs? for example, would it allow for the 650A to be delivered for longer periods of time?
> 
> off topic: A higher voltage version of this controller would really take this setup to the next level!
> 
> ...


Keeping the temperature below 65c keeps the controller from reducing the output due to heat. This controller puts out 650a for 2 minutes. Who would need more than that? Remember, higher voltage requires more cells. Most using the AC-50 have 36 cells. 200ah cells are $225.00 each plus the BMS.


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## Bowser330 (Jun 15, 2008)

cruisin said:


> Keeping the temperature below 65c keeps the controller from reducing the output due to heat. This controller puts out 650a for 2 minutes. Who would need more than that? Remember, higher voltage requires more cells. Most using the AC-50 have 36 cells. 200ah cells are $225.00 each plus the BMS.


Understood, thanks.

Many are still looking forward to higher voltage versions of the controller.


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## tomofreno (Mar 3, 2009)

That graph is for the 550A controller. The 650A would give about 18% more torque, but yeah I know you want more than that. I haven't heard anything on progress on a higher voltage controller. Not sure it is going to happen. Anyone heard anything?


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## Old Goat (Jun 28, 2011)

Would it be possible for you to sketch a diagram of the coolant flow? From the picture, I'm guessing you have the intake of the pump sucking from the top fitting on the cooling plate and into the intake of the radiator. Then the outlet side of the pump returns cooled fluid to the lower fitting on the controller cooling plate. But it isn't entirely clear where you connected the reservoir. Also, is there a relief valve on the reservoir?


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## cruisin (Jun 3, 2009)

Old Goat said:


> Would it be possible for you to sketch a diagram of the coolant flow? From the picture, I'm guessing you have the intake of the pump sucking from the top fitting on the cooling plate and into the intake of the radiator. Then the outlet side of the pump returns cooled fluid to the lower fitting on the controller cooling plate. But it isn't entirely clear where you connected the reservoir. Also, is there a relief valve on the reservoir?


Bottom of reservoir to pump, pump to bottom of cold plate, top of cold plate to heat exchanger, heatexchanger to resevoir. System is open with no pressure so valve is not required. Ethlene Glycol is used and no other additives are necessary. Proplene Glycol is similar, but is approved for food by the FDA. Bacteria will not grow in the fluid as long as it does not have light.


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## cruisin (Jun 3, 2009)

tomofreno said:


> That graph is for the 550A controller. The 650A would give about 18% more torque, but yeah I know you want more than that. I haven't heard anything on progress on a higher voltage controller. Not sure it is going to happen. Anyone heard anything?


Latest news from my inside source is that not coming anytime soon. We can hope for the middle or end of 2012 at the best. HPEV is still working on the new higher voltage motor but will require the controller, so dont hold your breath.


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## Ivansgarage (Sep 3, 2011)

DavidDymaxion said:


> Sounds intriguing, can you give more details on how you made the cold plate?


 
What is the pump you used??


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## cruisin (Jun 3, 2009)

Ivansgarage said:


> What is the pump you used??


Swiftech MCP355


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## Tesseract (Sep 27, 2008)

FYI: the Curtis 1238 uses electrolytic input capacitors, and while their life is much easier in an inverter, they still get hot from ripple current. This cold plate mod will cool off the semiconductors and allow a higher continuous power from the inverter, but it doesn't cool off the capacitors and so the "weak link" is shifted from something whose temperature is monitored (ie - the semis) to something which isn't (the capacitors). It might be worth popping open the case to stick some "CelsiDots" on a few of the capacitors to see what temp they get up to.



tomofreno said:


> ... I haven't heard anything on progress on a higher voltage controller. Not sure it is going to happen. Anyone heard anything?


I had the opportunity to speak with a Curtis engineer recently and I asked him exactly that question after first mentioning that the 1238 was well-received and could easily take over the EV market if only it had a little more power. His answer was surprisingly candid: "We already sell 10,000 of these a year - why go to all that trouble to sell another 200 a year for EVs?"


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## ElectriCar (Jun 15, 2008)

Tesseract said:


> "We already sell 10,000 of these a year - why go to all that trouble to sell another 200 a year for EVs?"


It's thinking like that that opens the door for other companies. If you have the resources and knowledge as they do, they could do that for very little I imagine and dominate the market. Keeping prices down at the same time would prevent competition from ever getting off the ground. 

It's thinking like that that has allowed the Soliton to garner a large and growing share of their market because the 500A controller is the best they offer. Two years ago when I bought mine, it was the main player, the most powerful controller out there with a solid reputation. 

Now the Soliton from what I'm seeing on this site and others is by far the best DC controller out there and is priced fairly. It has so many options you can't get with the 8601, double the power and with it's pricing I suspect will if not already overtake Curtis stake in the EV market. And I'm sure EVnetics has sold a hell of a lot more than 200 controllers!


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## Tesseract (Sep 27, 2008)

ElectriCar said:


> It's thinking like that that opens the door for other companies. * If you have the resources and knowledge as they do*, they could do that for very little I imagine and dominate the market. Keeping prices down at the same time would prevent competition from ever getting off the ground.


Well there ya go... Curtis is a $200M publicly traded company and we are perhaps 1/500th that in size. In other words, we don't have anywhere near the amount of resources (nor knowledge, to be frank) as Curtis. Should we decide to make an AC inverter we will have to start off with something about the size of the Curtis and/or for much less demanding applications as a road-going EV because developing good vector control code takes a lot more knowledge (if not raw talent - Qer has that in spades) than we currently possess. 



ElectriCar said:


> Now the Soliton from what I'm seeing on this site and others is by far the best DC controller out there and is priced fairly. It has so many options you can't get with the 8601, double the power and with it's pricing I suspect will if not already overtake Curtis stake in the EV market. And I'm sure EVnetics has sold a hell of a lot more than 200 controllers!


Thanks for the kind words !

The comparison between our Soliton Jr and the 1238-8601 is even less flattering: more than 3x the power at the same price 

As for sales volume... well, that is supposedly a big secret, but suffice it to say that sales to dat is more than 200, but not "a hell of a lot more".

EDIT: sorry for derailing thread... not my intent.


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