Led heatsink question

Cacopepo

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Am I able to use the aluminum channels that they sell at home depot as a heatsink for led chips 5 watt cree? I would love to get a regular heatsink but it's so expensive, at the end it would be much cheaper to just buy the led fixture... just trying to save a few bucks. Thanks everyone
 

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Yes and no, although anything can be used as a heatsink given you apply thermal paste those L rods won't be very efficient as they don't have a large surface area. It might work for a few widely spaced chips but nothing high density. Will depend on the amount of chips per foot and how hard you're going to run them.

Shop around for small heatsinks like these
20200115_172036.jpg


They can be found pretty cheap and will be much more efficient when you run a fan over them
 

SALTYMOPAR

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Yes it possible i used a u channel from home depot. I built a down and dirty led fixture out of u channel bought it through an online distributor
IMG_20200229_134818_01.jpg

20200229_192803.jpg

I used 3watt led. The big thing to remember is the warmer the led is the shorter the life expectancy.

20200229_192803.jpg
 
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Ok, thanks for the response guys, I am trying to re-create 2 strips 36" similar to these... I found them to be nice and simple design and it looks like no fan needed for this particular ones.

Screenshot_20200521-153844_Chrome.jpg Screenshot_20200521-153901_Chrome.jpg Screenshot_20200521-153934_Chrome.jpg
 
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Cacopepo

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Yes and no, although anything can be used as a heatsink given you apply thermal paste those L rods won't be very efficient as they don't have a large surface area. It might work for a few widely spaced chips but nothing high density. Will depend on the amount of chips per foot and how hard you're going to run them.

Shop around for small heatsinks like these
20200115_172036.jpg


They can be found pretty cheap and will be much more efficient when you run a fan over them
Where did you get that one?
 
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Cacopepo

Cacopepo

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Yes it possible i used a u channel from home depot. I built a down and dirty led fixture out of u channel bought it through an online distributor
IMG_20200229_134818_01.jpg

20200229_192803.jpg

I used 3watt led. The big thing to remember is the warmer the led is the shorter the life expectancy.

20200229_192803.jpg
That's led on steroids lol
 

Copingwithpods

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Where did you get that one?
The light panel is a grow light (eBay) and the heatsinks I believe I found on Amazon for around $10 for 40 of them, they have multiple sizes available.

This light panel does not "require" heatsinks relying solely on the aluminum plate for heat reduction but I noticed it got quiet warm so I decided to add them plus a 120mm fan to extend diode life and decrease heat transfer to tank. Runs a few degrees above ambient now, heatsinks for the win.
 
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The light panel is a grow light (eBay) and the heatsinks I believe I found on Amazon for around $10 for 40 of them, they have multiple sizes available.

This light panel does not "require" heatsinks relying solely on the aluminum plate for heat reduction but I noticed it got quiet warm so I decided to add them plus a 120mm fan to extend diode life and decrease heat transfer to tank. Runs a few degrees above ambient now, heatsinks for the win.
Thank you, any chance you have a direct link for that heatsink? Can't find it
 

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Thank you, any chance you have a direct link for that heatsink? Can't find it
Just type in "heatsinks" in either Amazon or eBay search bar you'll get a ton of options to choose from. I'm hesitant to give you a direct link to just one because your needs will be different than mine. Calculate in mm the amount of space you have available for a heatsink and go from there. My diodes were very small so I choose 1 15x15mm sink for each one.
Capture+_2020-05-21-14-00-04.png
 
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Just type in "heatsinks" in either Amazon or eBay search bar you'll get a ton of options to choose from. I'm hesitant to give you a direct link to just one because your needs will be different than mine. Calculate in mm the amount of space you have available for a heatsink and go from there. My diodes were very small so I choose 1 15x15mm sink for each one.
Capture+_2020-05-21-14-00-04.png
Thank you very much for that.
 

oreo54

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Yes they are

Well.. common recommendation is 2-3 sq inches per watt (calculate real watts, not chip rating) if passive cooled.
thus all the fins vs just bulk.
W/ fans that is way less..see heat sinks on "165W" black boxes (actual wattage more like 110).

Anodizing or even a thin coating of paint increases surface area and transmission of heat.
mostly for passive cooling. Not really needed for fan cooling but doesn't hurt.

Also be aware of your environment. Heat transfer is much more efficient w/ an increase in the temp differential between heatsink and ambient.
Like 110f heatsink.. air 72 vs 110F and ambient 95F

Calculating junction temp is practically impossible for mere mortals. "Common useage" though seems to imply about 110F on the heatsink should be a fair approx of safe zone..

Heatsinksusa carries fairly cheap real heatsinks. Unfortunately closed (sort of) atm from Covid-19

Those Orphek strips are run around 500mA and prob. are only about 2W per chip.
Keep that in mind.
Good thing is CREE is relatively robust regarding heat though efficiency loss would be expected at higher temps.

12" = $6..
https://www.ebay.com/i/251934243617...MIk42IjYHG6QIVy8DACh07vAWWEAQYAyABEgJLWvD_BwE

1" wide 1/2" fins, Roughly 11sq inches per inch..
Recommend a thin layer of black lacquer on fin side if passive cooled.
Sounds counter intuitive but IR is color invisible..

Need to do some more crunching but heatsinks like this/ on a sq inch basis isn't really that expensive..

opps forgot link and of course expensive if you only need one row..
 
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Well.. common recommendation is 2-3 sq inches per watt (calculate real watts, not chip rating) if passive cooled.
thus all the fins vs just bulk.
W/ fans that is way less..see heat sinks on "165W" black boxes (actual wattage more like 110).

Anodizing or even a thin coating of paint increases surface area and transmission of heat.
mostly for passive cooling. Not really needed for fan cooling but doesn't hurt.

Also be aware of your environment. Heat transfer is much more efficient w/ an increase in the temp differential between heatsink and ambient.
Like 110f heatsink.. air 72 vs 110F and ambient 95F

Calculating junction temp is practically impossible for mere mortals. "Common useage" though seems to imply about 110F on the heatsink should be a fair approx of safe zone..

Heatsinksusa carries fairly cheap real heatsinks. Unfortunately closed (sort of) atm from Covid-19

Those Orphek strips are run around 500mA and prob. are only about 2W per chip.
Keep that in mind.
Good thing is CREE is relatively robust regarding heat though efficiency loss would be expected at higher temps.

12" = $6..
https://www.ebay.com/i/251934243617...MIk42IjYHG6QIVy8DACh07vAWWEAQYAyABEgJLWvD_BwE

1" wide 1/2" fins, Roughly 11sq inches per inch..
Recommend a thin layer of black lacquer on fin side if passive cooled.
Sounds counter intuitive but IR is color invisible..

Need to do some more crunching but heatsinks like this/ on a sq inch basis isn't really that expensive..
You my friend are a genius lol
 

John Smith

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You can harvest heat sinks from old electronic devices like amplifiers, VCR's, computers... They are free.
 
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Cacopepo

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So I have 2 of these laying around.... can these run some 3 watt cree led or do i have to get another driver?

20200521_203717.jpg
 

oreo54

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So I have 2 of these laying around.... can these run some 3 watt cree led or do i have to get another driver?

20200521_203717.jpg
150-1400mA <60 v out max 30W

Picking like say XP-E royal blue w/ 3.1-3.9V @ 350mA
soo on the high end..1.37W each you could run 21 of them and stay below the 30W BUT.. you can't...:(

21 x 3.9V =81.9v.. you have <60V w/ that driver

soooo go another way..

60/3.9 =15.38 soo 15
now you have a limit of 30W

Sooo you need to drive each to 2w..
2= 3.9V x A... 512mA (,5A)

Bottom line in this example 15 @ 500mA
3.9 x 15 x .5 = 29.25W
3.9 x 15 = 58.5V

Every diode will be different btw and some you just need to sort of etinmate.
That's kind of an odd driver btw..
 
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Cacopepo

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150-1400mA <60 v out max 30W

Picking like say XP-E royal blue w/ 3.1-3.9V @ 350mA
soo on the high end..1.37W each you could run 21 of them and stay below the 30W BUT.. you can't...:(

21 x 3.9V =81.9v.. you have <60V w/ that driver

soooo go another way..

60/3.9 =15.38 soo 15
now you have a limit of 30W

Sooo you need to drive each to 2w..
2= 3.9V x A... 512mA (,5A)

Bottom line in this example 15 @ 500mA
3.9 x 15 x .5 = 29.25W
3.9 x 15 = 58.5V

Every diode will be different btw and some you just need to sort of etinmate.
That's kind of an odd driver btw..
It was worth a try since I got them for free, I'll start looking for another one then.. thanks for the input, much appreciated
 

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