# [EVDL] Curtis Controller Cooling



## EVDL List (Jul 27, 2007)

Hello EVDL

The Curtis manual recommends that the bottom of their controllers be 
attached to a metal surface that then becomes an integral part of the 
controller's heat sink. I don't have space on my firewall for mounting 
my controller. The only space I have available is on the system board 
along with the contactors, etc. 

What all have you used as a heat sink and how did you mount it?



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## EVDL List (Jul 27, 2007)

> Peter Eckhoff wrote:
> > Curtis... What have you used as a heat sink and how did you mount it?
> 
> It *will* get hot, and so needs cooling. Don't just mount it to some
> ...


----------



## EVDL List (Jul 27, 2007)

Lee,

I've gotten some of the best information from you over time and I totally respect you so please don't take this the wrong way but-

Where liquid cooling has been chosen, WHY is everyone so hung up on using ethylene glycol antifreeze to cool their controllers?? It's toxic and generally nasty and goes against everything EV's are supposed to stand for. During a Maryland winter, under hard use, my air-cooled Curtis barely gets warm to the touch. Why not run water during the warm months and simply drain the system during the months where the coolant could potentially freeze? I can't imagine it's that much of an inconvenience. If it really is that much of a hassle, what about windshield washer fluid? It's less toxic and has anti-freeze properties. I'd suggest some combination of sodium and water but I know that that's highly corrosive and would eat a circulating pump in short order. Or would it? A pump with a plastic impeller, plastic hose barbs and tygon tubing?

At any rate, there has to be a better method. What say you?


P.S.- I added my voice to the positive comments on your news article, Lee.

____________________________________________________________
Message: 3Date: Mon, 21 Apr 2008 14:03:52 -0500
From: Lee Hart 
Subject: Re: [EVDL] Curtis Controller Cooling
To: Electric Vehicle Discussion List 
Message-ID: Content-Type: text/plain; charset=ISO-8859-1; format=flowed 



> Peter Eckhoff wrote:> Curtis... What have you used as a heat sink and how did you mount it?
> 
> It *will* get hot, and so needs cooling. Don't just mount it to some thin piece of sheet metal or worse, an insulating panel. If you don't cool it enough, it cuts back the current it delivers to the motor (poor performance). Heat also shortens its life. A typical heatsink will occupy about the same number of cubic inches as the controller itself. If airflow is very good, or you have a fan blowing on it, you can use a smaller heatsink. If airflow is poor, an even larger one is needed. I had a space problem mounting the Curtis 1231C in my present EV. I mounted the controller to a 1/8" thick aluminum plate about 15" x 24". The contactors, fuse, shunt, and other high voltage components are also mounted to this plate. The plate is mounted about 1" above the fender well. A piece of lexan plastic goes over the top and sides to form a box. A fan blows air through this box lengthwise. The air goes over both sides of the plate, and all sides of the controller itself. This has been ade!
> quate so far. If you are really tight for room, you can liquid cool the Curtis. One way is to make a "cold plate". Mount the controller to a copper or brass plate about 1/8" thick. Bend a piece of copper tubing to zig-zag across the plate 3-4 times. Solder it to the plate. Use a pump to circulate antifreeze through this tubing, and to a small radiator (like a car's heater core) that is positioned out the breeze, or has a fan to cool it.
> ...


----------



## EVDL List (Jul 27, 2007)

Another option might be propylene glycol. This is what most boiler
systems use for freeze protection, and all modern closed loop solar
thermal systems that I am aware of. I believe there are even some new
automotive antifreezes that use it. And, it's non toxic. Or at least
is it listed as an ingredient in some toothpaste and cheap ice
cream... so it better be...

Z



> Richard Acuti <[email protected]> wrote:
> >
> > Lee,
> >
> ...


----------



## EVDL List (Jul 27, 2007)

There are non (or low) toxic antifreezes - Propylene Glycol is one used 
in solar hot water (and I think in some cars). It's expensive though.

- SteveS



> Richard Acuti wrote:
> > Lee,
> >
> > I've gotten some of the best information from you over time and I totally respect you so please don't take this the wrong way but-
> ...


----------



## EVDL List (Jul 27, 2007)

----- Original Message ----- 
From: "Richard Acuti" <[email protected]>
To: <[email protected]>
Sent: Tuesday, April 22, 2008 5:09 AM
Subject: Re: [EVDL] Curtis Controller Cooling


>
> Lee,
>
> I've gotten some of the best information from you over time and I totally 
> respect you so please don't take this the wrong way but-
>
> Where liquid cooling has been chosen, WHY is everyone so hung up on using 
> ethylene glycol antifreeze to cool their controllers?? It's toxic and 
> generally nasty and goes against everything EV's are supposed to stand 
> for.

Where do you get this idea? It's not that bad, IMHO!
It is toxic for dogs and cats, not likely for humans,in the small quantites 
that we are likely to use in such a system, anyway. It lasts for a long time 
in an EV, and is easily recycled.

Why not run water during the warm months and simply drain the system during 
the months where the coolant could potentially freeze?

Regular antifreeze is MUCH better coolant that plain water - however, in 
your described system (below) it will probably work. I think it's too much 
hassle - besides, I want to drive some in the winter; but I guess that 
cooling wouldn't be an issue then, anyway. But freezeup would be an issue.

I can't imagine it's that much of an inconvenience. If it really is that 
much of a hassle, what about windshield washer fluid? It's less toxic and 
has anti-freeze properties. I'd suggest some combination of sodium and 
water but I know that that's highly corrosive and would eat a circulating 
pump in short order. Or would it? A pump with a plastic impeller, plastic 
hose barbs and tygon tubing?
>
> At any rate, there has to be a better method. What say you?
>
>
> P.S.- I added my voice to the positive comments on your news article, Lee.
>
> ____________________________________________________________
> Message: 3Date: Mon, 21 Apr 2008 14:03:52 -0500
> From: Lee Hart
> Subject: Re: [EVDL] Curtis Controller Cooling
> To: Electric Vehicle Discussion List
> Message-ID: Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>


> > Peter Eckhoff wrote:> Curtis... What have you used as a heat sink and how
> > did you mount it?
> >
> > It *will* get hot, and so needs cooling. Don't just mount it to some thin
> ...


----------



## EVDL List (Jul 27, 2007)

>From my experience in pc watercooling ethylene glycol actually has a
lower rate of heat conduction than water, so should be used sparingly..
iirc. 

I was researching alternatives to water for a sub-sero peltier-chilled
watercooling setup, and all the info I could find suggested that pure
water is about the best cooling medium available. Obviously the
antifreeze will stop it freezing, but does nothing positive for the
efficiency of the cooler.



-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of joe
Sent: 22 April 2008 13:55
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Curtis Controller Cooling


----- Original Message ----- 
From: "Richard Acuti" <[email protected]>
To: <[email protected]>
Sent: Tuesday, April 22, 2008 5:09 AM
Subject: Re: [EVDL] Curtis Controller Cooling


>
> Lee,
>
> I've gotten some of the best information from you over time and I
totally 
> respect you so please don't take this the wrong way but-
>
> Where liquid cooling has been chosen, WHY is everyone so hung up on
using 
> ethylene glycol antifreeze to cool their controllers?? It's toxic and 
> generally nasty and goes against everything EV's are supposed to stand

> for.

Where do you get this idea? It's not that bad, IMHO!
It is toxic for dogs and cats, not likely for humans,in the small
quantites 
that we are likely to use in such a system, anyway. It lasts for a long
time 
in an EV, and is easily recycled.

Why not run water during the warm months and simply drain the system
during 
the months where the coolant could potentially freeze?

Regular antifreeze is MUCH better coolant that plain water - however, in

your described system (below) it will probably work. I think it's too
much 
hassle - besides, I want to drive some in the winter; but I guess that 
cooling wouldn't be an issue then, anyway. But freezeup would be an
issue.

I can't imagine it's that much of an inconvenience. If it really is
that 
much of a hassle, what about windshield washer fluid? It's less toxic
and 
has anti-freeze properties. I'd suggest some combination of sodium and 
water but I know that that's highly corrosive and would eat a
circulating 
pump in short order. Or would it? A pump with a plastic impeller,
plastic 
hose barbs and tygon tubing?
>
> At any rate, there has to be a better method. What say you?
>
>
> P.S.- I added my voice to the positive comments on your news article,
Lee.
>
> ____________________________________________________________
> Message: 3Date: Mon, 21 Apr 2008 14:03:52 -0500
> From: Lee Hart
> Subject: Re: [EVDL] Curtis Controller Cooling
> To: Electric Vehicle Discussion List
> Message-ID: Content-Type: text/plain; charset=ISO-8859-1;
format=flowed
>


> > Peter Eckhoff wrote:> Curtis... What have you used as a heat sink and
> how
> > did you mount it?
> >
> ...


----------



## EVDL List (Jul 27, 2007)

circle track race cars use water, a small amount of glycol as a lube and
rust inhibitor for water pump
and red line water wetter , it breaks down the surface tension so the water
touches the surface closer and moves more heat. just adding rubbing alcohol
will keep it from freezing. test it in your refreg
On Tue, Apr 22, 2008 at 8:28 AM, Robin Lawrie <[email protected]>


> wrote:
> 
> > >From my experience in pc watercooling ethylene glycol actually has a
> > lower rate of heat conduction than water, so should be used sparingly..
> ...


----------



## EVDL List (Jul 27, 2007)

Rich

The first thing that comes to mind when I compare a Curtis (air cooled) with
my Zilla (water cooled) is the way the heat transfers. IIRC, from when I had
my Curtis open, the heat generating components are mounted on a large heat
sink that transfers the heat down to the base plate which should move the
heat out of the controller. With the Zilla, the water cooled block is in the
core of the controller. I don't know if it has the ability to transfer the
neat to the base plate in the same way. I don't relish the idea of relying
on air cooling in the winter, because the components generating the heat may
not be able to get it out any other way. The Zilla might act like a little
oven and bake the insides.

With all the ways an EV improves out impact on the environment, I'm willing
to accept the risk of running coolant in my car. Besides, my town has
coolant recycling, so there is a viable way to recycle it. It's not a
prefect option, but it's an improvement.

Dave Cover



> Richard Acuti <[email protected]> wrote:
> 
> >
> > Lee,
> ...


----------



## EVDL List (Jul 27, 2007)

I totally agree that ethylene glycol is recyclable. You guys don't think I've just been pouring it down the storm drain all this time do you?

My problem with regular antifreeze is the same problem that I have with ICE cars as a whole: Eventually, the system will fail due to neglect and it will leak. Just like engine oil seals, exhaust seals, transmission seals, catalytic converter, etc. I don't know ANYONE who maintains their automobile so meticulously that it never happens. Eventually, all that crap ends up dripping on the road and getting washed down into the watershed. Hell, I even hate brake pads because of the carcinogenic dust they give off but there are some alternatives for that too. That's one reason why I love EV's so much: They're very clean from the cradle to the grave even if you DON'T maintain them. The worst that can happen is brake fluid and MAYBE transmission fluid leaks depending on how you made your conversion. ICE's are cleanest when driven off the dealership lot and get steadily dirtier after that...until they die.

I don't own a Zilla but I read the documentation and the tone of it is that liquid cooling is definitely preferable but that you COULD get away with air-cooling, and I'm only suggesting running air cooled during the coldest months. At any rate, a couple other folks suggested a non-toxic coolant used in solar systems and I find that to be an acceptable alternative. If I lived in a year-round "hot" state though, I'd run straight, de-mineralized water.

_____________________________________________________
Message: 25Date: Tue, 22 Apr 2008 11:16:04 -0400
From: "dave cover" 
Subject: Re: [EVDL] Curtis Controller Cooling
To: "Electric Vehicle Discussion List" 
Message-ID:
Content-Type: text/plain; charset=ISO-8859-1 

Rich The first thing that comes to mind when I compare a Curtis (air cooled) withmy Zilla (water cooled) is the way the heat transfers. IIRC, from when I hadmy Curtis open, the heat generating components are mounted on a large heatsink that transfers the heat down to the base plate which should move theheat out of the controller. With the Zilla, the water cooled block is in thecore of the controller. I don't know if it has the ability to transfer theneat to the base plate in the same way. I don't relish the idea of relyingon air cooling in the winter, because the components generating the heat maynot be able to get it out any other way. The Zilla might act like a littleoven and bake the insides. With all the ways an EV improves out impact on the environment, I'm willingto accept the risk of running coolant in my car. Besides, my town hascoolant recycling, so there is a viable way to recycle it. It's not aprefect option, but it's an improvement. Dave Cover



________________________________



Rich A.

Maryland

http://www.austinev.org/evalbum/371.html

http://patriotfuel.blogspot.com/




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## EVDL List (Jul 27, 2007)

>>> If I lived in a year-round "hot" state though, I'd run straight,
de-mineralized water.<<<

Bad idea, running de-mineralized water, de-ionized or reverse osmosis
water. They are all highly corrosive. That is why when you install a
filtered water system at the home sink it is all plastic tubing. Copper
tubing would be eaten away within no time at all. At least put in some king
of anti-corrosive. Available at any local hot rod web site.

Mark Grasser

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## EVDL List (Jul 27, 2007)

Um....I beg to differ. At least on the topic of strictily de-mineralized water. The others I can't speak to. I served on nuclear submarines for 11 years where de-mineralized water was used extensively and in metal piping. Some was stainless steel piping and some was not, especially the sample sink spigots which were nickel plated copper. The submarine was 29 years old at decommisioning and the sink and spigots were the originals. (The seals were replaced with regular maintenance.)

Usually the metallic minerals in water are what cause or accelerate corrosion. Unlike metals causing galvanic corrosion, in addition to oxidation I mean. We also used pure, de-mineralized water in the oxygen generator....or rather it's pure before it's put into the individual cells and then a metallic element is added, not for the prevention of corrosion but for the conduction of electricity. We used electrolysis to split the water molecules into hydrogen and oxygen. We stored the oxygen in a bank to breathe later and discharged the hydrogen overboard because it's explosive and we generally weren't cool with having an explosive gas in a contained space with a lot of hot equipment running and A-gangers smoking cigarettes. At any rate, the cells in the O2 generator lasted for aeons and when they died, it wasn't due to corrosion.

Lastly, I'm no expert on "distilled" water, but I was under the impression that it too, was mineral-free (or at least iron-free) otherwise you could use ordinary tap water to refill your batteries. If it were corrosive, we sure wouldn't put it in our floodies.

I'm not sure where you got your information but I'd like a document or a weblink to read to back it up.
_________________________________________________________________
Message: 7
Date: Tue, 22 Apr 2008 12:21:08 -0400
From: "Mark Grasser" 
Subject: Re: [EVDL] Curtis Controller Cooling
To: "'Electric Vehicle Discussion List'" 
Message-ID: 
Content-Type: text/plain; charset="us-ascii">>

> If I lived in a year-round "hot" state though, I'd run straight,de-mineralized water.
<<< Bad idea, running de-mineralized water, de-ionized or reverse osmosiswater. They are all highly corrosive. That is why when you install afiltered water system at the home sink it is all plastic tubing. Coppertubing would be eaten away within no time at all. At least put in some kingof anti-corrosive. Available at any local hot rod web site. Mark Grasser



________________________________



Rich A.

Maryland

http://www.austinev.org/evalbum/371.html

http://patriotfuel.blogspot.com/




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## EVDL List (Jul 27, 2007)

This was the easiest to find under reverse osmosis, the water out of one of
these is very much like De-ionized water. Maybe more exotic then
de-mineralized but close enough for me not to do it. 

Here's the link,
http://www.ag.unr.edu/walker/WebPublications/FS-05-10CSREES.pdf

Here is what it says. 

SPARE PARTS AND REPAIRS
Most hardware stores carry an inventory of
plastic and stainless steel fittings that are
appropriate for use in a reverse osmosis
system. Always replace plastic lines with
new plastic tubing that is meant for drinking
water supply. >>>>>Do not use copper tubing
because this may create problems.
Water treated by a reverse osmosis system
is corrosive to copper tubing and brass
connectors, unless there is a unit in place
to add dissolved minerals back into the
treated water (known as a re-hardener). Manufacturers design
reverse osmosis systems to use plastic tubing and stainless steel
faucets to avoid contaminating the treated water with copper and
lead.

The way I understand it is that without the minerals and being pure H2O it
is corrosive to metals.
Mark Grasser

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Richard Acuti
Sent: Tuesday, April 22, 2008 3:40 PM
To: [email protected]
Subject: Re: [EVDL] Curtis Controller Cooling


Um....I beg to differ. At least on the topic of strictily de-mineralized
water. The others I can't speak to. I served on nuclear submarines for 11
years where de-mineralized water was used extensively and in metal piping.
Some was stainless steel piping and some was not, especially the sample sink
spigots which were nickel plated copper. The submarine was 29 years old at
decommisioning and the sink and spigots were the originals. (The seals were
replaced with regular maintenance.)

Usually the metallic minerals in water are what cause or accelerate
corrosion. Unlike metals causing galvanic corrosion, in addition to
oxidation I mean. We also used pure, de-mineralized water in the oxygen
generator....or rather it's pure before it's put into the individual cells
and then a metallic element is added, not for the prevention of corrosion
but for the conduction of electricity. We used electrolysis to split the
water molecules into hydrogen and oxygen. We stored the oxygen in a bank to
breathe later and discharged the hydrogen overboard because it's explosive
and we generally weren't cool with having an explosive gas in a contained
space with a lot of hot equipment running and A-gangers smoking cigarettes.
At any rate, the cells in the O2 generator lasted for aeons and when they
died, it wasn't due to corrosion.

Lastly, I'm no expert on "distilled" water, but I was under the impression
that it too, was mineral-free (or at least iron-free) otherwise you could
use ordinary tap water to refill your batteries. If it were corrosive, we
sure wouldn't put it in our floodies.

I'm not sure where you got your information but I'd like a document or a
weblink to read to back it up.
_________________________________________________________________
Message: 7
Date: Tue, 22 Apr 2008 12:21:08 -0400
From: "Mark Grasser" 
Subject: Re: [EVDL] Curtis Controller Cooling
To: "'Electric Vehicle Discussion List'" 
Message-ID: 
Content-Type: text/plain; charset="us-ascii">>

> If I lived in a year-round "hot" state though, I'd run
straight,de-mineralized water.
<<< Bad idea, running de-mineralized water, de-ionized or reverse
osmosiswater. They are all highly corrosive. That is why when you install
afiltered water system at the home sink it is all plastic tubing.
Coppertubing would be eaten away within no time at all. At least put in some
kingof anti-corrosive. Available at any local hot rod web site. Mark Grasser



________________________________



Rich A.

Maryland

http://www.austinev.org/evalbum/371.html

http://patriotfuel.blogspot.com/




_________________________________________________________________
Express yourself wherever you are. Mobilize!
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-US?ocid=TAG_APRIL

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## EVDL List (Jul 27, 2007)

Having worked with De-Ionized water in a past life (semiconductor
manufacturing) I can verify that it will corrode most metals.
Stainless it was fine on for short periods but copper had serious
issues around it. Of course, we didn't have much copper in the fab as
it could seriously contaminate the processing. Only gold was more
feared than copper from a contamination point of view.

I can't speak to nickel-plated metals but I seem to recall that the
whole reason for using nickel in the plating process is due to it's
corrosion resistance... Chrome being similar.

Trot, the squeaky-clean, fox...



> Mark Grasser <[email protected]> wrote:
> > This was the easiest to find under reverse osmosis, the water out of one of
> > these is very much like De-ionized water. Maybe more exotic then
> > de-mineralized but close enough for me not to do it.
> ...


----------



## EVDL List (Jul 27, 2007)

It would seem to me that water with ions is corrosive. Oxygen is
corrosive. But deoxygenated demineralized water should be harmless.

from (http://www.watertechonline.com/article.asp?IndexID=5230109)

"Some engineers resist the use of demineralized water because of the
common belief that is it more aggressive or corrosive than raw or softened
water. Although it is true that untreated, oxygenated demineralized water
is very corrosion, particularly at hot water temperatures, corrosion
inhibitors such as sodium nitrite and sodium sulfite passivate metal
surfaces and remove dissolved oxygen resulting in a final system water
that is noncorrosive."

>From this it sounds like the disolved oxygen is the problem.
I've liked the idea that someone presented here not long ago using a
closed loop and acetone, no pumps. If I have to liquid cool my controller,
I will probably go this route.

-Jon Glauser
http://www.evalbum.com/555

<quote who="Mark Grasser">
> This was the easiest to find under reverse osmosis, the water out of one
> of
> these is very much like De-ionized water. Maybe more exotic then
> de-mineralized but close enough for me not to do it.
>
> Here's the link,
> http://www.ag.unr.edu/walker/WebPublications/FS-05-10CSREES.pdf
>
> Here is what it says.
>
> SPARE PARTS AND REPAIRS
> Most hardware stores carry an inventory of
> plastic and stainless steel fittings that are
> appropriate for use in a reverse osmosis
> system. Always replace plastic lines with
> new plastic tubing that is meant for drinking
> water supply. >>>>>Do not use copper tubing
> because this may create problems.
> Water treated by a reverse osmosis system
> is corrosive to copper tubing and brass
> connectors, unless there is a unit in place
> to add dissolved minerals back into the
> treated water (known as a re-hardener). Manufacturers design
> reverse osmosis systems to use plastic tubing and stainless steel
> faucets to avoid contaminating the treated water with copper and
> lead.
>
> The way I understand it is that without the minerals and being pure H2O it
> is corrosive to metals.
> Mark Grasser
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf
> Of Richard Acuti
> Sent: Tuesday, April 22, 2008 3:40 PM
> To: [email protected]
> Subject: Re: [EVDL] Curtis Controller Cooling
>
>
> Um....I beg to differ. At least on the topic of strictily de-mineralized
> water. The others I can't speak to. I served on nuclear submarines for 11
> years where de-mineralized water was used extensively and in metal piping.
> Some was stainless steel piping and some was not, especially the sample
> sink
> spigots which were nickel plated copper. The submarine was 29 years old at
> decommisioning and the sink and spigots were the originals. (The seals
> were
> replaced with regular maintenance.)
>
> Usually the metallic minerals in water are what cause or accelerate
> corrosion. Unlike metals causing galvanic corrosion, in addition to
> oxidation I mean. We also used pure, de-mineralized water in the oxygen
> generator....or rather it's pure before it's put into the individual cells
> and then a metallic element is added, not for the prevention of corrosion
> but for the conduction of electricity. We used electrolysis to split the
> water molecules into hydrogen and oxygen. We stored the oxygen in a bank
> to
> breathe later and discharged the hydrogen overboard because it's explosive
> and we generally weren't cool with having an explosive gas in a contained
> space with a lot of hot equipment running and A-gangers smoking
> cigarettes.
> At any rate, the cells in the O2 generator lasted for aeons and when they
> died, it wasn't due to corrosion.
>
> Lastly, I'm no expert on "distilled" water, but I was under the impression
> that it too, was mineral-free (or at least iron-free) otherwise you could
> use ordinary tap water to refill your batteries. If it were corrosive, we
> sure wouldn't put it in our floodies.
>
> I'm not sure where you got your information but I'd like a document or a
> weblink to read to back it up.
> _________________________________________________________________
> Message: 7
> Date: Tue, 22 Apr 2008 12:21:08 -0400
> From: "Mark Grasser"
> Subject: Re: [EVDL] Curtis Controller Cooling
> To: "'Electric Vehicle Discussion List'"
> Message-ID:
> Content-Type: text/plain; charset="us-ascii">>
>
>> If I lived in a year-round "hot" state though, I'd run
> straight,de-mineralized water.
> <<< Bad idea, running de-mineralized water, de-ionized or reverse
> osmosiswater. They are all highly corrosive. That is why when you install
> afiltered water system at the home sink it is all plastic tubing.
> Coppertubing would be eaten away within no time at all. At least put in
> some
> kingof anti-corrosive. Available at any local hot rod web site. Mark
> Grasser
>
>
>
> ________________________________
>
>
>
> Rich A.
>
> Maryland
>
> http://www.austinev.org/evalbum/371.html
>
> http://patriotfuel.blogspot.com/
>
>
>
>
> _________________________________________________________________
> Express yourself wherever you are. Mobilize!
> http://www.gowindowslive.com/Mobile/Landing/Messenger/Default.aspx?Locale=en
> -US?ocid=TAG_APRIL
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


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## EVDL List (Jul 27, 2007)

Richard, you're in Maryland. Bring your EV to the Power of DC May 31 
to June 1. You need to start hanging out with some EVers instead of 
the those Bug people 

Dave and Bob and several other EVDL listers will be there.

As far as cooling a Curtis a friend gave me some 1 inch by 1 inch 
aluminum solid bar stock to make the walls of a maze to run water 
through.

You also get 2 thin 1/8 aluminum plates the size of the controller's 
base and cut and arrange the aluminum walls for the water to run 
through the maze and silicon caulk it altogether. Hook up a pump and 
a small tank and run water through it. It's a very simple design.

He did it for his car. I never ended up doing it since I sold my 
Curtis and bought a Raptor.

Someone else, and I think it was Bill Dube years ago (too bad he 
isn't here anymore) used some sort of gas to cool his controller. 
Bill was always going one step beyond and trying different things. 
But I believe it worked. I can't recall the gas he used though.

At the NEDRA drags, we use a coolers filled with ice water and run it 
through controller radiator type devices on hot days. So using plain 
water or ice water is common.

I would think the use of ethynyl glyecol (sp?) is to also keep the 
corrosion down if you are using straight water. But people do use 
straight water from what I've seen.

Try things out and do what works and show us what you've done at the 
Power of DC.

Chip Gribben
Power of DC
http://www.powerofdc.com










> [email protected] wrote:
> 
> > Rich
> >
> ...


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## EVDL List (Jul 27, 2007)

Here is a response from one of our local members:

I've used the Curtis controller on my Chevy S-10 truck since 2000.
Originally, I mounted it on a 1/8th inch aluminum sheet with a 5-in 
electronics fan blowing on it. It lasted for
four years, then burned up during one summer trip. Now I'm
a EE with lots of experience with semiconductors and I'm embarrassed that
I did it this way, and I paid for it.

I bought a new controller, and this time also purchased the heat sink
from Curtis, a beautiful heat sink with fins that is cut to the size
for the controller, and costs about a hundred dollars. I mounted the heatsink
about a half inch above the electronics board on standoff anchors, and
mounted the controller to the heatsink with the bolts that Curtis provided.
I had drilled two 5-inch diameter holes in the board below the
heatsink and mounted two 5-inch diameter, 12 VDC electronics fans that
blow air upwards into the fins of the heatsink. I've now been through
several summers here in central NC, and the controller is alive and
kicking, knock on wood.

As a number of people have said above, you MUST provide good air flow for
the controller. NEVER NEVER put it in a box without forcing air through
the box. The air forced onto the
controller by air movement caused by driving the EV is not enough to cool
the controller because the cooling is at its worst at low speeds.
I would guess that most failures occur at high currents at low car speeds,
which occur when the vehicle is accelerated from stopped. The high school
kids, when stopped for a traffic light on a hill, love to use the
motor and controller to just maintain position rather than to use the
brake pedal. This is a big no-no since it forces current through the 
controller for an extended period during the worst-case cooling situation.

I've rambled too long. Keep it cool, especially when going slow.





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## EVDL List (Jul 27, 2007)

While I think antifreeze is not that toxic (heck, there is a food grade
version) and would always use it for it's lubricating and antirust
qualitites as well as it's antifreeze, I was always told the opposite
of "Regular antifreeze is MUCH better coolant that plain water".

When I was racing, my truck overheated easy, the racers pointed out that
I was running a pretty dense mixture of antifreeze and that it lowers
the transfer rate. They drop back to 10% or 25% and use redline's "water
wetter" that is suppose to gain some transfer back. (I heard it was
mostly alchohol). The thing about ethlene glycol is that it serves both
as antifreeze and anti-boilover. Part of the problem we have around
here is that water evaps and sneaks out of the systems on hot days and
people top off with antifreeze and they overheat there cars.

I found this

http://www.engineeringtoolbox.com/ethylene-glycol-d_146.html

The specific heat decreases with increased concentration. Is that the
amount it can carry away?

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## EVDL List (Jul 27, 2007)

Here you can see the heat sink that I use on my Curtis 1221B.
I had a fan on it before but found it unnecessary in this part of Oregon.
http://www.evalbum.com/popupimg.php?5783
Neal



> Peter Eckhoff wrote:
> >
> > Hello EVDL
> >
> ...


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## EVDL List (Jul 27, 2007)

Standard car antifreeze is toxic. A big problem is it has a sweet taste 
so when it is spilled animals are attracted to it. I think a couple of 
tablespoons can kill a dog. Propylene glycol is what is used in the food 
industry and hot water systems - it is either non or low - toxicity.

As I recall from chemistry class (granted, it was a long time ago) water 
is just about the best heat transfer liquid around (based on specific 
heat). Things are added to lower the freezing point, lower corrosion, or 
lubricate moving parts, but I don't think any additive increases it's 
specific heat.

- SteveS



> Jeff Shanab wrote:
> > While I think antifreeze is not that toxic (heck, there is a food grade
> > version) and would always use it for it's lubricating and antirust
> > qualitites as well as it's antifreeze, I was always told the opposite
> ...


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## EVDL List (Jul 27, 2007)

> Richard Acuti wrote:
> > Where liquid cooling has been chosen, WHY is everyone so hung up on
> > using ethylene glycol antifreeze to cool their controllers? It's
> > toxic and generally nasty and goes against everything EV's are
> ...


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## EVDL List (Jul 27, 2007)

> Mark Grasser wrote:
> >> Bad idea, running de-mineralized water, de-ionized or reverse
> >> osmosis water. They are all highly corrosive.
> 
> ...


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