Help with heat sink size

I'm designing a custom vertical system with the heat sinks pin to pin with leds going left and right with plants all the way around them...

I'm thinking of mounting 10 55w axial fans at the bottom blowing up through all the pins

I can't put a fan directly on the heat sink due to mounting them back to back

I think it should still work...as long as there is constant airflow through the pins

George2324 said:

The guy on alibaba is saying

Click to expand...

Never believe anyone from Alibaba.
They are all liars and inflating the parameters usually by at least 100%.

But cobkits confirmed that his heatsink can do 100w? But then another guy said it doesn't run 70W so I'm baffled lol

DaveInCave said:

Never believe anyone from Alibaba.
They are all liars and inflating the parameters usually by at least 100%.

Click to expand...

I have to completely disagree with that...The one i bought 150x77mm was rated for 60-70w and it does exactly that...if i lower the chip to 1400mA aka 50w it's about the same as room temp...at 1050mA it's just a cold piece of metal

P

waynejohn said:

I have to completely disagree with that...The one i bought 150x77mm was rated for 60-70w and it does exactly that...if i lower the chip to 1400mA aka 50w it's about the same as room temp...at 1050mA it's just a cold piece of metal

Click to expand...

well my guy is adamant that his 152mm by 100mm is perfect for 100w

I want to work out what size I need for my heat sinks to be running at room temp :/

waynejohn said:

I have to completely disagree with that...The one i bought 150x77mm was rated for 60-70w and it does exactly that...if i lower the chip to 1400mA aka 50w it's about the same as room temp...at 1050mA it's just a cold piece of metal

Click to expand...

That's not physically possible, or your margins for "about" are quite wide.

DaveInCave said:

That's not physically possible, or your margins for "about" are quite wide.

Click to expand...

Do please explain why not?

George2324 said:

P

well my guy is adamant that his 152mm by 100mm is perfect for 100w

Click to expand...

This is the data i have:
120mm - 40-50w
133mm - 50-65w
150mm - 60-70w
160mm - 75-85w
180mm - 95-105w
Those are all for 150mm diameter 70mm height...152x100 i don't know man...you have 30mm more in height so it could work but if i was you i would go for just a bit bigger diameter

Those heat sinks are 9.50 usd each..

Next size up is 220mm diameter 100mm deep...

Will double my cost but if it's needed I will

Maybe ask him for a sample to test and see if it will do the job, they are usually willing to do that especially if you gonna buy 80 of them

I'm not entirely sure about passive sizes but I went with iceled xtra ultra for my vero's, you can see them on this linked page, but it's way overkill for what I'm running at 73 watts. The iceled xtra 550 would have been perfect and might be good for you too. It's an active cooler rated for 109 watts power dissipation with 99mmx55mm dimensions and a 12v 50ma fan. Only thing I don't like about it is the star design, the bottom doesn't seem to cover the entire die on the cob but my ultra's are completely cool at least. Something to look into at least. I saw them for $12.50

Can't Fit those fans on unfortunately.

I think I'll have to go for the 220 diameter ones and put big fans blowing across them all