# how hot do controllers/motors get?



## TX_Dj (Jul 25, 2008)

Dan,

Follow the guidelines set forth by the controller manufacturer. Certainly no less than their recommended sink area.

I've seen some folks simply bolt it down to a thick Al plate like you mention, with some heat conductive grease in between, and I've seen others get elaborate with a machined finned heat sink + fans.

It probably all depends on what you can afford, how much you care what it looks like, and whether or not you want to hear fans running on it.

As for mounting the DC/DC on the same plate, I cannot comment. I would guess it all depends on how hot the controller is making your plate, and how much heat the DC/DC is adding to that plate as well.


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## Cornelius (Sep 15, 2007)

I had my Curtis controller originally mounted on an aluminum plate with a fan under it as instructed by EV America in their guide book. It worked fine, except that the Curtis became hotter than I was comfortable with during the summer months here in Florida. Last March I remounted the Curtis controller on a surplus aluminum heatsink with the fan under it. This summer the Curtis has been noticeably cooler, only warm to the touch. Last summer it would get too hot to keep my hand on it at times.

The other issue I discovered when I reworked the installation last March was that because the original aluminum plate was not a machined surface, there were air gaps between the plate and the bottom of the Curtis even with heatsink grease used. The new heatsink has a machined surface, as does the bottom of the Curtis, so the two fit very closely together. A single small tube of heatsink grease from Radio Shack was used between the surfaces.


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## madderscience (Jun 28, 2008)

if you are using an air cooled controller, definitely mount it on a good heat sink with plenty of thermal compound. often a thick (at least 1/4" aluminum plate is used which has around two square feet or more (top and bottom sides combined) of surface area to dissipate heat.

I found a heat sink on ebay that almost perfectly fits the footprint of my controller so I used that, and it and also has about two square feet of surface area, if you add up the area of all its fins.

Its also a really good idea to mount the controller somewhere where it will get some air movement when driving (but not get hit with spray and mud when driving in the rain) , or else you can attach a fan or fans to the heat sink. A couple of computer case fans would do the trick, and they run off of 12V making installation easy. Just don't install an air cooled controller in a small, enclosed area or it will overheat.


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## O'Zeeke (Mar 9, 2008)

I use this to record the actual temp of the surface of the controller 
http://search.harborfreight.com/cpisearch/web/search.do?keyword=infrared+thermometer&Submit=Go

It works great and gives an objective baseline temp rather than just feeling it with your hand. Mine was 121 F after 6 miles of normal driving, enough that I'm installing fans today. I also use it on all the battery connections/cables to determine if any are heating up more than others.


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## dtbaker (Jan 5, 2008)

TX_Dj said:


> Dan,
> Follow the guidelines set forth by the controller manufacturer. Certainly no less than their recommended sink area.


hhhmmmm, I went poking around on the Curtis website, and it shows that they are rated up to 85 deg C, which is 185 deg F.... pretty dang hot! So, I guess I am going to try a nice large AL plate, and might mount u-channel on the back side to act as fins; probably NOT add fans at first, and see how hot things get with natural air flow.

d


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## rctous (Jun 18, 2008)

dtbaker said:


> hhhmmmm, I went poking around on the Curtis website, and it shows that they are rated up to 85 deg C, which is 185 deg F.... pretty dang hot! So, I guess I am going to try a nice large AL plate, and might mount u-channel on the back side to act as fins; probably NOT add fans at first, and see how hot things get with natural air flow.
> 
> d


Installing fans is very easy very chaep probably the best insurance policy you can buy. I would invest the 30 bucks and do it from the start, save yourself tearing things apart later.

it cannot be a negative thing.


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## Cimpso (Nov 10, 2008)

You could just add fans as an emergency back-up, set to turn on when the temperature starts to rise above a comfortable level. This can work well on both hot days and/or when there is little to no air flow. Using this circuit > http://www.heatsink.info/content.php?content=control.shtml < could make the fans activate at your preset temperature, cooling the heat sink back to "safe" level and leave them off when the heat sink is cool-thus saving energy. (p.s. apparently the material for this circuit cost only 7 bucks )


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## madderscience (Jun 28, 2008)

probably the dirt simplest fan control circuit can be made by snagging the thermostatic switch off an old hot water tank. There are two (an upper and lower one), you want the SPDT one. (the one with three terminals) These are adjustable from about 120 to 180 degrees Farenheit, extremely reliable and free for the taking if you visit your local scrap metal yard or your packrat neighbor's back yard. Just wire it up in series with a 12V fan or two and mount it on the heat sink. Bobs your uncle, works great. I have two in my car, one is being used as the cabin heater thermostat and the other is a temperature idiot light for the controller (which has popped on a couple of times on really hot days)


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## TheSGC (Nov 15, 2007)

I have a 3/4" aluminum plate for my Kelly, and it wasn't really hot during a 2 mile AMP sucking run.

I am also working on a cooling system for my motor, but I am toying with the idea of making a grill around the motor so I can cook some burgers or hotdogs on my trips.


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## ww321q (Mar 28, 2008)

This is a video on how I mounted mine {Curtis 1209} in my Saturn .
http://www.youtube.com/watch?v=LlKoSNDGt8Y
My thought is to get the heat out so you can run at a higher amperage longer . J.W.


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## dtbaker (Jan 5, 2008)

ww321q said:


> This is a video on how I mounted mine {Curtis 1209} in my Saturn .


very nice.... WHERE did you get those heat sinks?! awesome


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## Jimdear2 (Oct 12, 2008)

On Ebay search Heatsink Aluminum Extrusion Large Big and you'll find the guy I bought from. He custom cuts as well. I don't know if the price is good I really couldn't find comparable.

Jim


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## dtbaker (Jan 5, 2008)

Jimdear2 said:


> On Ebay search Heatsink Aluminum Extrusion Large Big and you'll find the guy I bought from. He custom cuts as well. I don't know if the price is good I really couldn't find comparable.
> 
> Jim


what did you end up paying?


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## Jimdear2 (Oct 12, 2008)

He only discounts over 10 pieces so the only savings is on shipping up to four pieces one price, $10.00 U.S. more for elsewhere. He is is a BUY IT NOW guy, no auctions. 24.95 for a 12 inch length then hewill cut to your specs from there. I'm still waiting to hear if he send on any usable wastage from your 12 inch piece. If not I'll cut it myself.

I sorry, misrepresented myself tryiong to keep things brief,, the money is sitting waiting to be sent (I'm getting two pieces), I'm waiting for my group to see if anyone else wants some, I,m trying to get more then ten. Going to order Friday.

JimP


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## dtbaker (Jan 5, 2008)

aha, sounds pretty good... although I would need two pieces to line up fins vertically across the width of controller. I poked around a little, and found a wholesale extrusion place, and am waiting to see if they would sell retail in small quantities..... I will post followup.


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## dtbaker (Jan 5, 2008)

ok, I found http://www.mmmetals.com that has similar products. They have a $200 minimum, and seems a little higher in price per foot than the ebay guy. I got a quote for $470 for a 6 foot length of 12" wide, 1" fin extrusion.... There are probably others out there.


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## tj4fa (May 25, 2008)

A friend of mine here in Florida had a Curtis 1231C-8601 Controller from EVA with only one fan and it would overheat and go into limp mode (EVA's manual recommends two fans in hot climates).

He also pretty much sealed off air into the motor bay trying to keep water from getting to the motor.

He ducted in some air and it worked fine after that.

I'm going to reuse the old ICE air intake box and some 3" dust collection system flex hose and ram some air into it along with the single fan under the 1231C-8601 controller/heatsink plate.

If that doesn't work, I'll buy another 140 CFM fan on eBay for around $6-.


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## dtbaker (Jan 5, 2008)

very nice looking board you mounted everything on, what is it?

regarding the heat sink, it looks like maybe you just used some flat AL? I am trying to find finned stuff which will yeild LOTS more surface area and cooling. In my case its looking like I am going to have a ram air duct since I have to cut a hole in the hood for my too-tall batteries.

anyway, the direct sales guy for 8.5" wide finned sinks is at http://www.heatsinkusa.com/asfdas.html

I am hoping he'll do some 12" wide for people wanting to mount the fins crossways...


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## Jimdear2 (Oct 12, 2008)

dtbaker said:


> I am hoping he'll do some 12" wide for people wanting to mount the fins crossways...


 
Try the guy on ebay again. I beleive his stuff starts at 12 inches wide and he narrows it to 8.5 inches Then he sells the 3.5 inch reminant, 3 pieces for 24.95. I don't know why he cuts it off, I didn't ask. He might be getting seconds and is cutting the blems off.

Jim


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## ElectriCar (Jun 15, 2008)

Another option for fan control is Klixon switch. These are used in heating/cooling for hi temp limits etc. Check with a heating & air supplier and see if they have one that will "close" at a temperature of your liking. 

I think the water heater thermostat would be a good one to use but I think you'd have to use the unit for the top element as it has two contacts, one open and one closed and they switch together. You could use one contact for a normal temp indicator by running a green led or such when the fan isn't on which would extinguish when the fan came on. You could tie a yellow or red light in parallel with the fan wiring so it would come on with the fan as the green light went out.


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## tj4fa (May 25, 2008)

dtbaker said:


> very nice looking board you mounted everything on, what is it?
> 
> regarding the heat sink, it looks like maybe you just used some flat AL? I am trying to find finned stuff which will yeild LOTS more surface area and cooling. In my case its looking like I am going to have a ram air duct since I have to cut a hole in the hood for my too-tall batteries.


Thanks DT!  

I used 1/2" PVC board for the upper board that I bought at a local sign shop over top 1/2" plywood I had laying around. The PVC is easy to work with and cleans up nice.

I used the plywood for more rigidity and screwing components to as I don't think one layer of PVC board would have been stiff enough for the expanse of my board and all that stuff. 

The heat sink is about 1/8" AL that EVA sent with my order for the controller. I think they used to send thicker to customers in the past looking at a few other people's heatsinks. 

I agree with you on the ribbed heatsink as being better, but I figured with it being mounted underneath the controller might pick up a lot of the rising heat from the drive motor installed directly below it (and the ribbed heatsink being more expensive).

How tall are your too-tall batteries? Can you clear if you cut off the universal bolt at the top of the battery terminals?

My bolted-up metal-framed (3/4" plywood) battery box sits on 1/8" rubber directly on the Ranger frame for now and I cut the threaded bolts off the top of the universal battery terminals as I opted to use 2/0 crimp automotive style battery terminal clamps. I probably could put some more cushioning between the battery box and frame if I needed, but the board sits level presently.

I'm thinking the vibration shouldn't be much difference with my box compared to a steel battery rack welded to the frame.

I'll know in a few days when I take my first drive.


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## dtbaker (Jan 5, 2008)

Jimdear2 said:


> Try the guy on ebay again. I beleive his stuff starts at 12 inches wide and he narrows it to 8.5 inches Then he sells the 3.5 inch reminant, 3 pieces for 24.95. I don't know why he cuts it off, I didn't ask. He might be getting seconds and is cutting the blems off.
> 
> Jim


thats the guy who has his own sideline at heatsinkusa.com (direct instead of ebay). He has a 5.375" wide, and the 8.5 wide.... says he's going to do a 12" this spring maybe. Turns out he is a machine mechanic at a large extrusion co, and invested in these two dies himself, and buys runs of material as needed.


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## dtbaker (Jan 5, 2008)

tj4fa said:


> Thanks DT!
> 
> I used 1/2" PVC board for the upper board that I bought at a local sign shop over top 1/2" plywood I had laying around. The PVC is easy to work with and cleans up nice.


Aha, yes PVC would be a good choice as it is gluable and paintable (unlike the polypro for battery boxes)




tj4fa said:


> I agree with you on the ribbed heatsink as being better, but I figured with it being mounted underneath the controller might pick up a lot of the rising heat from the drive motor installed directly below it (and the ribbed heatsink being more expensive).


All true.... the ribbed heatsink is best off mounted ABOVE the heat source, or vertically so that convection can pull air by as heat rises, or forced air from fan or ducting while in motion. In my case... a hood scoop with heat sink mounted vertically!



tj4fa said:


> How tall are your too-tall batteries? Can you clear if you cut off the universal bolt at the top of the battery terminals?


nope still too tall, the Geo/Swift engine bay is very shallow. I am going to have a 2 or 3" tall scoop... maybe off a subaru WRX, or custom. I think this is going to work great though. Check pix on my site (link below in sig)


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## tj4fa (May 25, 2008)

Great website DT!! Looks like you're having a lot of fun too!! 

Your Geo donor car looks in great shape and a hood scoop will be cool looking improvement. 

If you make it yourself you could face it either forward or reverse. Maybe even put your gauges in the hood as well. 

I guess a challenge might be to design it to keep water from getting on the controller and other components but I imagine for you, that ain't nothing but a thing...


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## dtbaker (Jan 5, 2008)

Thanks, yes the website has been a blast to document all the fun.... first get-my-hands-dirty engineering project in years.

The scoop I plan to face forward to actually jam air in while in motion. Then at a stop, the vertical fins will continue to dissipate heat up and out pretty well I think. The plan is to create a closed duct from scoop down the back of the controller with nice heat sink fins in the middle of the aluminum sandwich. It will have over 900 sq.in of surface area, so should be more than enough. At the bottom it will flow out into the bottom of the engine bay, then hopefully around the motor and out the wheel wells; I am planning a thin ABS sheet under most of the engine bay as a splash barrier, I live on a dirt road that can get very dusty and sometimes muddy.

stay tuned for more on the website.... I am TRYING to make more work-time so I can clear at least half the garage for wife's car!


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## O'Zeeke (Mar 9, 2008)

Cimpso said:


> You could just add fans as an emergency back-up, set to turn on when the temperature starts to rise above a comfortable level. This can work well on both hot days and/or when there is little to no air flow. Using this circuit > http://www.heatsink.info/content.php?content=control.shtml < could make the fans activate at your preset temperature, cooling the heat sink back to "safe" level and leave them off when the heat sink is cool-thus saving energy. (p.s. apparently the material for this circuit cost only 7 bucks )


 
Hey Cimpso, thanks for the link. I went ahead and made one for less than $7 and it works great, I used my infrared temp sensor http://search.harborfreight.com/cpis...eter&Submit=Go
to calibrate it so no guesswork anymore.


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## noahmrogers (Nov 9, 2008)

I've lots experience with ICEs and cooling, air cooled as well. 

The most important part of any cooling system is ducting. Airflow in the engine bay is mostly useless. When productions cars spend time in the wind tunnel, it's to make sure the cooling system functions well more than anything. The best thing you can do is have ducting running from a high pressure area (say the radiator area), to your motor. Make sure you have an low pressure exit for this area as well. 

I'll straight up tell you that the best aero mod you can do to any car is a vented hood. It provides huge amounts of cooling by letting the high pressure hot air inside the engine bay escape. Also, it increases down force by keeping that air from going down under your car. It will in some cases make your car more aerodynamic by reducing the airflow under the car, where there isn't smooth bodywork. 

Take a look at this corvette. It doesn't spend time still unless it's in the pits, and that's only for a short while, so it doesn't need a fan. Designing ducting out of plastic to simply direct airflow in, around, and out of your components will be the best thing possible. It's also cheap. 

My suggestion would be good ducting and with an internal fan (that is on a temp switch) if you plan on drawing high amperage at low speeds on a regular basis. (autox, drag racing, low speed commuting possibly, hills)

Fans are dirt cheap and so are temp switches. Do it. Add ducting, and it probably won't ever need the fan. Having more than you need is how you'll get reliability.

Edit: 
I took a look around the local Tesla dealership a couple weeks ago, and they have a lot of cooling though mostly for the batteries. Their radiator system is on par with very high end sports cars and I was truly impressed. They are looking for longevity with their electric system, and I believe they'll get it. Their company would be far more successful though if they offered test drives. 5 grand down to get a ride, and 100 bucks is non refundable. Every dealer in the world knows that test drives are what sell cars. A good friend of mine was excited to check them out and was considering purchasing one, but he was totally turned off at the idea that he'd have to commit to an investment before even knowing what the car was like. Sorry for the side track, but my main point was, you'll have more fun if nothing breaks.


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## dtbaker (Jan 5, 2008)

good observations.... and on an ICE line of thinking I have very similar experience with cooling issues; I had a 1966 Sunbeam Tiger, engine bored too far over, headers, and a dual point ignition that made it run way too hot. Engine bay was so crammed that air thru the radiator had trouble getting OUT. The after-market fiberglass hood did not duct air in, it had reverse ports to let the air OUT.

My EV is a different story though....

I HAVE to have either a scoop or bubble, because two batteries are going to stick above the hoodline. The thought is to duct directly past my controller heatsink, then dump in the bottom of the engine bay to circulate, and exit by wheelwells. Without air tunnel testing.... I THINK I'll get flow because the whole front and bottom of the engne bay will be sealed up; not airtight, but much reduced from stock. The other consideration is that while an ICE engine continues to heat at an idle, the EV will not!

My initial question was mostly with regard to how hot the controllers get under full load to determine whether a flat plate would pull enough heat. Since finding http://www.heatsinkusa.com/ I feel really good about using a heatsink that will be more than double recommended spec for surface area (in still air). If I had an AC setup, or was planning to race I might be tempted to design in extra fans, but at this point I think I'm going to keep it simple and see what kind of temps I have in normal operation.


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## Cimpso (Nov 10, 2008)

O'Zeeke said:


> Hey Cimpso, thanks for the link. I went ahead and made one for less than $7 and it works great, I used my infrared temp sensor http://search.harborfreight.com/cpis...eter&Submit=Go
> to calibrate it so no guesswork anymore.


Just trying to help  I also made one, although not for an ev but for an external hard drive whose cooling fan was insufficient and needed a "controllable upgrade" To calibrate it with an infrared temp sensor, did you just raise ambient temp until you reached your desired turn on point? If not, how?

P.s. date on camera is a little off...


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## O'Zeeke (Mar 9, 2008)

Cimpso said:


> Just trying to help  I also made one, although not for an ev but for an external hard drive whose cooling fan was insufficient and needed a "controllable upgrade" To calibrate it with an infrared temp sensor, did you just raise ambient temp until you reached your desired turn on point? If not, how?
> 
> P.s. date on camera is a little off...


Yes, I just arbitrarily set it to go on at 115 F which I found takes a few miles on a warm day (Florida) to reach, so its not on all the time. I also leave it run if I have to make a short stop. I feel the cooler the better when it comes to this stuff. Thanks again for the info.


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