Help with heat sink size

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George2324

Well-Known Member
I'm about to order heat sinks for my LEDS.

I think I have everything correct but I could use some help if someone doesn't mind double checking that this heat sink will be enough for 100W of led to run cool.
I plan to run 4 citizen CLU 048 1212 per heat sink.
I believe they are 28mm wide and long chips and I hope I have the holes in right place

Heat sink details are:

181 pins
Pin diameter Diameter 5mm
Pin height 70mm
Base thickness 10mm
Heatsink diameter 152mm
The drawings are below

IMG_3599.PNG IMG_3600.PNG IMG_3601.PNG


Cheers for any help
 
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George2324

Well-Known Member
The guy on alibaba is saying these heat sinks will dissipate 100w of LED... which seems far fetched?

If I worked it out correctly each pin has 1138 square mm.

181 pins = 200,000 ish square mm
Which is only 310 ish sq inches? That's massively too small isn't it?
I believe I read 17 square inch per heat watt?
 
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George2324

Well-Known Member
verticalgrow said:
150 x 80 heatsink should be good for 100W-110W of COBs but your prolly gunna have to drill & tap holes for 4 COBs per heatsink.
Click to expand...
He's doing the drilling for me on the diagram it shows the holes I asked for.

I am just confused how it is good for 100w?

Growmau5 video states u need 17 inch2 per heat watt?
 
CobKits

CobKits

Well-Known Member
George2324 said:
He's doing the drilling for me on the diagram it shows the holes I asked for.

I am just confused how it is good for 100w?

Growmau5 video states u need 17 inch2 per heat watt?
Click to expand...

is he talking about pin fins or extruded bars?

you could always throw a fan on them
 
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George2324

Well-Known Member
I need 80 heat sinks fans would be a killer in extra watts
Where he says 17 inch he's talking about heatsink USA profiles.

Are they different?
 
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George2324

Well-Known Member
I could get larger heat sinks if needed 220mm by 100mm?

Cost is more though and it's extra wieght so if I don't need them I will avoid

But if I can cool passively then would be great
 

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George2324

Well-Known Member
I plan on mounting two heat sinks back to back vertically for a vertical grow not sure I'd be able to put fans anywhere
 
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George2324

Well-Known Member
I can put fans blowing down from
Above across all the pins ? Would have to be 20 inch box fans though

If these heat sinks cover 100w tho do I need a fan then?
 
waynejohn

waynejohn

Active Member
I have the 150-77 and it's good for 70watts max i presume...mine runs at aproximately 62w and it's warm i'd say around 50-60 celsius
 
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George2324

Well-Known Member
Holy crap so the 150 is way to small for the 100w then... good job I double checked I was wanting it to run at like 30c for efficiency
 
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George2324

Well-Known Member
The guy above said he uses that and his heatsink is running hot. Do you really think that heatsink will run 100w cob efficient?
 
waynejohn

waynejohn

Active Member
Also from EU...i ordered from kingbrite...13.5$ each predrilled and tapped

Edit:i think if you would put a decent 120mm fan on top of it there should be no problem runing it cool even at 9v
 
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