Heatsink size

[primo21]

Is there a rule of thumb for how much surface area is needed to mount 3w LEDs? For example, if I wanted to use 60 3w LEDs, what size is the minimum heatsink I would need?

thanks.

 

[twilliard]

Depends on if you have forced air cooling.
I run 50w Diy leds on 3X3 heatsink fan cooled

 

[primo21]

I do plan on running fans. Did you choose that size for a reason or did you just get the largest that would fit your setup

 

[twilliard]

I used to own a computer business so I learned a lot about extracting heat from surfaces
A 3X3 heatsink fan cooled with the proper thermal compound will keep heat to a minimal on a pushed CPU.
This is where I have obtained my knowledge about heatsinking

 

[primo21]

It's that 3 feet? If so, that is way too large for my setup. I have a 75 and was going to put about 100 3w split on 2 heatsinks.

 

[twilliard]

It no 3" sorry about that :-)
Also the size of the cooling fins matters.
If the heatsink has all parallel fins grab a dremel tool and cut cross slits to add more surface area