# How to install Heat sink to controllers



## Ziggythewiz (May 16, 2010)

Basically you get a finned aluminum heatsink about the size of your controller and fasten it to the flat part of the controller with some thermal grease in between. If that doesn't provide enough cooling, you can run a fan over it as well.


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## mechman600 (Oct 16, 2010)

What sort of "thermal grease" do you recommend?


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## Ziggythewiz (May 16, 2010)

Anything designed for use with a heat sink. It's typically used for computer CPUs, but you'll probably want a little more than that. It doesn't take much though, you don't want it to take any space between the heat sink and the controller, but to fill the microscopic gaps in the materials.

Honestly I don't know if there's a proper way to apply it in an EV. For computers you apply it, latch things together, then run it and it gets really hot really fast and melts into the pores, then hardens. For an EV I guess the best way would be to apply it, bolt everything together, drive around at the heaviest loads you can make, then retighten while still hot.


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## Ertike (Mar 21, 2012)

Thanks, I will look where I can heat sink from tomorrow, where can you usually find that type of thing? Here in the Philippines materials are hard to find sometimes.


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## Ziggythewiz (May 16, 2010)

I got a cheap one off ebay for around $20. I don't think I greased it properly as I just used an old syringe from my mobo repair days and it was pretty dried out. Sink doesn't get hot though, so I don't care and haven't bothered to add a fan.


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## TigerNut (Dec 18, 2009)

Ertike said:


> Thanks, I will look where I can heat sink from tomorrow, where can you usually find that type of thing? Here in the Philippines materials are hard to find sometimes.


This is the sort of thing you probably want, but I imagine you can probably find it cheaper locally, especially if there are surplus industrial electronics places you can go to.
http://search.digikey.com/ca/en/products/HS26/598-1377-ND/1762001

If you have access to aluminum stock in 1 to 1.5 inch thickness (say 2 to 4 cm) and a milling machine then you can machine your own heat sink. The important things are a good flat mating surface on the controller side; and lots of surface area on the other side.

If you have the ability, you could replace the whole back plate of the controller (or whatever part the power electronics are mounted on) with a custom machined heatsink.


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## Ziggythewiz (May 16, 2010)

Got mine here, they do ship internationally.

http://www.heatsinkusa.com/


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## bjfreeman (Dec 7, 2011)

Ertike said:


> Hi
> 
> I am new to this whole forum and technolgy. I am in the Philippines and we are trying to design an Electric Tricycle do combat the polution here. But it seems our controllers are heating up and cutting out. I have heard about installing heat sinks to our controllers but have no clue how or where to start. Our controller is 1500w and the motor is also 1500w. All suggestions are welcome.


Air cooled heat sinks will not do you much good when the Ambient temperature is high.
I guess you will need a heatsink that is capable of handling about 2400 watts.
or you may think about cold plate that use liquid cooling.
the power components will be mounted to the cold plate.


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## Ziggythewiz (May 16, 2010)

Heat sinks are not rated in watts. Air cooled works perfectly fine for most applications. The higher it gets above ambient, the faster it will cool. Unless you live at over 125 F, it should work well enough for typical applications.


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## Duncan (Dec 8, 2008)

Ertike said:


> Thanks, I will look where I can heat sink from tomorrow, where can you usually find that type of thing? Here in the Philippines materials are hard to find sometimes.


Hi
I couldn't find anything locally so I made my own

I cut some copper sheet (0.6mm thick) into rectangles - about 300mm by 400mm

I cut a piece of aluminium (6mm thick) into a piece about 200 x 60 
This covers the area on the baseplate of my controller that is next to the switching parts that need to have the heat removed
I then cut another piece of aluminium the same size as the base plate

The 200 x 60 piece and the second baseplate were then drilled so that I could clamp them together - with the copper pieces sandwiched in between 

Then I bent the copper sheets outwards - different amounts like a flower

On my car the heat sink is under the LHS front wing - behind the tire where it should get a lot of air flow but the controller is in the front battery compartment sealed off from the outside world


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## Ziggythewiz (May 16, 2010)

Duncan said:


> behind the tire where it should get a lot of air flow but the controller is in the front battery compartment sealed off from the outside world


Nice approach, what other material is in between there?


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## Duncan (Dec 8, 2008)

Hi Ziggy

There is the controller baseplate (aluminium)
The "second baseplate" - 
The four copper sheets
The sandwich plate - clamping the copper to the baseplate


The second baseplate - really a mounting plate bolts onto the bulkhead which has a hole in it.
Mounts over the hole - 

The copper plates and sandwich plate go through the hole - they are too big to go through the hole so they are mounted from the other side

I've only had a trial assembly so far - final assembly will use some thermal grease

The heat will flow 
From the controller - through the aluminium mounting plate - into the copper - down the fins and away into the air flow


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## Ziggythewiz (May 16, 2010)

Ok, thanks. It looked like the sandwich plates were on opposite sides of the bulkhead, with that joining the sandwich as well.


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## Duncan (Dec 8, 2008)

Ziggythewiz said:


> Ok, thanks. It looked like the sandwich plates were on opposite sides of the bulkhead, with that joining the sandwich as well.


I did think about doing it that way - I decided not to

Reasons 
- The bulkhead is steel so it will will end up painted
- The sheet steel is not super flat (distortions due to brazing)

I would love to have two side by side to see if the differences would be measurable


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## bjfreeman (Dec 7, 2011)

Ziggythewiz said:


> Heat sinks are not rated in watts. Air cooled works perfectly fine for most applications. The higher it gets above ambient, the faster it will cool. Unless you live at over 125 F, it should work well enough for typical applications.


so what do you think they are rated in? have you looked at a heat sink spec sheet?
De-rating starts at 70C or 158F. if the ambient temp is 32C 90F the insides can quickly 90C or higher.
why do you think they put fins and some time water cooled devices on CPU's. especially the over clocked ones.

I have a an 2KW inverter, and a 960 W charger.
they both go into thermal shutdown about 32C ambient. 

However my 10KW inverter is water cooled and has a large radiator and it operates fine in 32C ambient.


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## Ziggythewiz (May 16, 2010)

bjfreeman said:


> so what do you think they are rated in? have you looked at a heat sink spec sheet?
> De-rating starts at 70C or 158F. if the ambient temp is 32C 90F the insides can quickly 90C or higher.
> why do you think they put fins and some time water cooled devices on CPU's. especially the over clocked ones.
> 
> ...


They're usually rated in surface area and thermal conductivity.

I've never heard of a heat sink derating, especially at 158F. And CPUs run much hotter than that.

Sounds like your inverter and charger aren't heatsinked properly. Maybe you should do some research on that front.


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## Ertike (Mar 21, 2012)

All this information is great, I have been in contact with my manufacturer and explaining to them what you have been telling me and they are going to take the info i gave then and make something for me. I will let you know what they have come up with. My e-trike gets about 98km per 8hr charge but the controller heats up so that seems to be the only issue we have.


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