# When is a controller too hot?



## gsmith191145 (May 1, 2011)

Your car will cut out and stop driving when it gets to hot. 

When you start getting over 100-150 degrees the controller is getting too hot. 

Add a heat sink with a fan blowing across the heat sink or

move the controller to the front of the car and mount it where the radiator was originally. 

This will ensure that you will have enough air flow to keep your controller cool.

You can add a water cooled heat sink, but that is a bit more involved.


----------



## gojo (Feb 1, 2011)

gsmith191145 said:


> Your car will cut out and stop driving when it gets to hot.
> 
> When you start getting over 100-150 degrees the controller is getting too hot.
> 
> ...


I can easily aim a fan at the front of the controller. There are some cooling fins on the backside, sandwiched in between the controller, and the battery box (pic). I am hoping the combination of the cooling fan on the front of the controller, and the fins in the back will do it. If the controller over heats, and quits, I suspect it takes a while to cool off and start to work again.


----------



## Guest (Jul 7, 2011)

Your home made sink is not going to cut it. 99% of the heat comes from the bottom of the controller and you need a proper thick base finned heat sink attached with the proper thin layer of thermal grease between the controller and sink. It must be bolted on so it will be tight and get good contact. There is lots of heat generated and it will be bad to keep running it without a proper sink. This is the reason people loose controllers. They think that what they have will be good enough. You have to have a good one so it will pull away the heat quickly. Flat plates of aluminum won't work unless you are using almost no power but having NONE is just plain crazy. Yours is not any better than NONE. 

Pete 

The image with the big huge square block of aluminum as a heat sink did not work. Only the finned heat sink with that big 6" fan. Once those were installed the controller never ever ever over heated again. EVER. It is very very very important to install a sink like this and a big fan like this to push lots of air across those fins. Yes the fan blows onto the fins. It moves lots of air. At minimum this is what you need. This is a what we mean by putting on a heat sink with fins. Does yours look like this? Don't skimp here as you will loose a large investment and have to buy another later. It can get expensive if you skimp and try to save a quick buck.


----------



## gojo (Feb 1, 2011)

gottdi said:


> Your home made sink is not going to cut it. 99% of the heat comes from the bottom of the controller and you need a proper thick base finned heat sink attached with the proper thin layer of thermal grease between the controller and sink. It must be bolted on so it will be tight and get good contact. There is lots of heat generated and it will be bad to keep running it without a proper sink. This is the reason people loose controllers. They think that what they have will be good enough. You have to have a good one so it will pull away the heat quickly. Flat plates of aluminum won't work unless you are using almost no power but having NONE is just plain crazy. Yours is not any better than NONE.
> 
> Pete
> 
> The image with the big huge square block of aluminum as a heat sink did not work. Only the finned heat sink with that big 6" fan. Once those were installed the controller never ever ever over heated again. EVER. It is very very very important to install a sink like this and a big fan like this to push lots of air across those fins. Yes the fan blows onto the fins. It moves lots of air. At minimum this is what you need. This is a what we mean by putting on a heat sink with fins. Does yours look like this? Don't skimp here as you will loose a large investment and have to buy another later. It can get expensive if you skimp and try to save a quick buck.


Where do you get those heat sinks?


----------



## mizlplix (May 1, 2011)

Gottdi has got it right. You must have a finned heat sink. You can get one from the dealer that sold you the controller. 

As Gottdi said and it cannot be stressed enough, blow the air across the heat sink not directly on the controller. 

As it says above, the heat sink draws the heat from the bottom of the controller and is dispelled through the heat sink. 

This was worth saying twice.


----------



## tomofreno (Mar 3, 2009)

> Where do you get those heat sinks?


 Some of us have purchased them here: www.heatsinkusa.com


----------



## DJBecker (Nov 3, 2010)

A massive, thick-finned heat sink like that isn't going to be very efficient at removing heat compared to a fine-finned copper core or heat pipe design.

But with a big fan (shown), it's going to be effective.

And it has the significant advantage of large thermal mass. The high heat load during starts will slowly heat up the bulk aluminum, reducing the thermal stress.

We are using the type of lightweight, high-efficiency thermal designs you see on computers, which makes me appreciate the advantage of simple thermal mass. And look longingly at how much heat a low-tech radiator shed, if we would only be willing to deal with fluid connections.


----------



## mizlplix (May 1, 2011)

I have a small foundry and I plan to wind up some flat copper loops, place them in a cake pan and pour it in aluminum. Maybe 1" thick. Then machine it off flat and square to fit my 1238-7601 controller, to get a custom liquid cool plate.

I already have the rest of the system for the transmission and motor cooling, so this is almost mandatory...lol 


Miz


----------



## Ziggythewiz (May 16, 2010)

I'm looking for some thermal switch/relays to control my motor and controller fans, I recall seeing one similar to this a while ago, for $8ish, I think from digikey (think I got the link from someone here), but can't seem to find it now. Anyone know where these can be had? Needs to handle 6A at 12V and trip at 120-130 deg F.

I have found the button ones that would be suitable, but I really prefer this form factor.


----------



## Nathan219 (May 18, 2010)

To answer your question the human pain threshold ~130 F, is below the maximum operating temperature for most electronics, if you can leave your hand on your controller it should be fine.


----------



## gojo (Feb 1, 2011)

Nathan219 said:


> To answer your question the human pain threshold ~130 F, is below the maximum operating temperature for most electronics, if you can leave your hand on your controller it should be fine.


Good information. I like the simple practical ways of doing things. I could put my hand on the controller, and it felt hot, but I could leave it on for several seconds, and no blisters. 

I added a small fan to the front, and that is much cooler, and I am looking at ways to direct the air flow from driving to the back of the controller. 


According to Curtis the 1231C cuts back at 185F. I have an infared thermometer, and I am going to get it out and see just where I am at. If I am staying at less the 150F, I think I will be OK. 

These EV's are great for people who like to experiment, but I am glad I have my ICE S10 pickup.


----------



## Guest (Jul 8, 2011)

> ..........I think I will be OK.........


Don't think, be sure. Spend the money and time and get a proper heat sink on your controller. Your not driving a Golf Cart. You NEED to keep it cool. Just when you think your fine you blow the whole thing. 

I will say no more to you on this issue.


----------



## gojo (Feb 1, 2011)

I added a pancake fan to the front of my controller, and then used the scoop normally used for the radiator on an RX7 to channel air to the back of my controller as I drive.
I checked the temperature with a infrared thermometer after some hard driving, and the front was 86F, and the back was 93F. I failed to use the infrared prior to making the improvements, but the controller felt very hot to the touch, and now it is just a little warm front and back. 
The outside temps were in the 70'sF, and I will check it out again when I drive in the 90s, but so far I am happy with the results.


----------



## Ziggythewiz (May 16, 2010)

What gear are you driving in? My controller gets warm in 2nd, but 5 min in 3rd make it quite toasty. Heat sink got here yesterday, wohoo!


----------



## gojo (Feb 1, 2011)

Ziggythewiz said:


> What gear are you driving in? My controller gets warm in 2nd, but 5 min in 3rd make it quite toasty. Heat sink got here yesterday, wohoo!


I was driving hard at 45 to 50 in 4th just to see if it would get hot. 

The 90's are predicted tomorrow, and I plan on taking it out again. The infrared thermometer makes it more fun. I can check the motor's temp, and see how hot various other components get; controller, battery connections, cables, resistors, etc. 

I need to learn how to figure out my RPM's in different gears by what speed I am going to get the most effiecient use of my Impulse 9 motor. I think 2500 is the best speed for it. Usually I start out in 2 and shift to 4 on the highway, and just keep it in 3 driving in town.


----------

