# Alltrax AXE7245 controller heatsink?



## MBEV (Sep 28, 2008)

Just installing my new Alltrax AXE7245 controller and was wondering if an additional heat sinking should be added? I was going to just mount it on 4 standoffs directly on to the firewall (the fire wall is irregular so can’t mount flat. I could add a custom heat sink but not sure if it would be required?? Manual and website a bit unclear…. 

Any help apprectiated!

Cheers

Bruce


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## TheSGC (Nov 15, 2007)

All controllers must have a heatsink if you want them to last, so yes, definitely add a nice large heatsink.

Those who do not add a proper heatsink are asking for trouble. I have a 3/4" thick by 11" diameter aluminum plate for my Kelly Controller along with a thermal pad, and it has been working great.


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## tj4fa (May 25, 2008)

The heat sink I received with my Curtis controller from EVA is only about 1/8" thick and the controller mounts on it with some heatsink compound. The heatsink/controller combo has about 3/8" standoff from the control board for air to flow from below.

The Curtis controller itself has some heatsink finning on the controller's aluminum body.

EVA's method to disspate the heat is to use a fan (or fans) blowing from up under the heatsink to help dispate the heat.

I haven't had a problem yet as it is cool this time of year where I live. I have made provisions to connect a duct hose to ram air onto the heatsink through the old ICE intake air box and can easily add a second fan if need be later on.

There are some photos of my current setup in my sigline photoalbum link below.


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## dtbaker (Jan 5, 2008)

the thickness doesn't matter as much as the surface area... hence fins are the key. I found a good supplier at heatsinkusa.com


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## Coley (Jul 26, 2007)

I put mine on an 1/8th " alum plate twice the foorprint of the controller (7245 Alltrax) and it is fine.

I also used heat tranfer compound under it.

Last warm summer didn't bother it.


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## MBEV (Sep 28, 2008)

Thanks guys…. 


I did find a reference that states a surface area of 144 sq inches is recommended. So that would agree.


Coley are you using a PB6 pot box with your controller? Maybe you or someone else can help with this as well…..The PB6 I have received has the micro switch fitted - just wondering the real advantages of wiring it in?? The Alltrax wiring drawing (Doc100-045) shows the “foot-switch” micro switch in series with the key switch and other interlocks (pin 1 – KSI voltage on the Alltrax). That indicated the main contactor drops out every time you take your foot completely off the throttle? Is this right?? Maybe I am missing something here….

Thanks Again


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## Coley (Jul 26, 2007)

Yep, I have the same potbox and doi use the micro switch so the controller doesn't come on until you step on the accelerator.


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## tj4fa (May 25, 2008)

Coley said:


> Yep, I have the same potbox and doi use the micro switch so the controller doesn't come on until you step on the accelerator.


And when you take your foot off the accelerator and the potbox microswitch opens no power from the controller goes to the motor.

And then your coasting...


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## Bruce A (Jul 17, 2008)

I have the same controller it's been ok so far for a 30 min drive it remained cool, I need to get this thing registered an on the road.
Bruce A
http://www.diyelectriccar.com/garage/cars/72


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## MBEV (Sep 28, 2008)

Final heatsink completed.... If anyone is interested it can be checked out at:

http://www.mightyboyev.com/Fabrication of controller heatsink.htm 

Cheers

Bruce


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## Guest (Dec 29, 2008)

Check out this controller and heat sink. This is what you want. Be carful with that flat plate heat sink. I installed a sink to my controller that was solid aluminum of 1 1/2 thick x 6 x 12. I used thermal grease specific for this purpose. No cheap stuff here. On a long run of 15 miles at 60 plus mph non stop except at the light once the controller remained cool but it was also only 42 degrees out side. I then did another run into town and it remained cool until I started to do a bunch of stop and go driving in town. Every corner was a stop sign and with in a few minutes I had heated up the controller and sink enough to put it into safety mode once again. Pulling heavy amps in stop and go will heat your controller and sink if you have only a plate and no fan or fins. As for the irregular firewall issue you will have actually no problem. Just make sure you use irregular length for the legs of the standoffs and you will have a clean installation. Just leave enough room for your fans. You want your controller to stay cool even in the worst case. Be prepared to burn up a controller if you don't have a proper sink. A guy on ebay sells them and he will cut to size and will also drill mounting holes for free if you supply the correct placement and size. I got my two sink from him. Good quality stuff too. Search Ebay with Large Heat Sink. Or large aluminum heat sink. You will see. I will be posting a better photo of my sinks soon. 

http://www.evalbum.com/1798


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## ice (Sep 8, 2008)

For sure it will remain cool!


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