Heatsinks in Europe

CouchGouch

Well-Known Member
Hey guys wondering what you think about aluminium tubes...Would these tubes (link bottom) at 1m long be able to passively cool 2 cxb3590s running at say 50w?

£100 (including VAT, and almost free cutting to size) for: 5m long x 152mm (6") width x 50mm (2") height x 3mm (1/8th") thick.

I think 1 meter of tube works out about 625,000 mm surface area. I read somewhere 750 mm per watt for passive cooling? So 750mm x 50w = 37,500 x 2 cobs = 75000.

Also I read 2 square inches per watt (link below) 1200" (approx) surface area of 1 meter tube. 2" x 50w = 200" x 2 cob = 400"

http://forums.mtbr.com/lights-diy-do-yourself/surface-area-calculation-cooling-679495.html

It seems too easy from what I've read, and people paying crazy amounts for heat sinks...I'm probably missing something... or is this sufficient? If not I'll probably go active. Cheers. :peace:





http://www.aluminiumwarehouse.co.uk/Aluminium-Rectangular_Tube/c120_128/p2950/6_in_x_2_in_x_10_swg_:_Aluminium_Box_Section/product_info.html
 

littlejacob

Well-Known Member
Bonjour
I believe someone already ask and I am afraid it won't work....
And by the way tme is not so expensive...I bought an aluminum radiator (1000x165x35 14 fins) for 36, 50€ +vat and 7, 50€ shipping but I bought others things with so shipping cost were fair (it is a flat cost, always 7, 50 €)
You can cool 4 cxb 3590@1400mA with a 140mm fan on it at 5/7V.
Have a great day ★
 

CouchGouch

Well-Known Member
Hey Jacob, yeah I thought it sounded too easy to be true, would like to know why it can't be used though. Where did you buy the heatsink? That's like 1m x 6 1/2" x 1 " , how many fins? Can be used passively with 2 x 50w? I look at heatsinkUSA but the shipping is almost as expensive as the HS itself and most European suppliers don't even advertise cost. If need to use fans I'll just use arctics and have little extra freedom to adjust position. Thanks :mrgreen:
 

littlejacob

Well-Known Member
It is TME.com and look for rad it the price I told you and I assume that it is enough for 100w passive (5, 4kg)
Yes it is 39x6.5x1.3 14 fins big piece of aluminum...fast shipping and they have almost everything else!
CU
 

littlejacob

Well-Known Member
has only 5 mm base thickness i think that a little small to be good
Do you have one like this?
I do...and it is a perfect hs...good enough to cool 4 cxb3590 @1400mA!
And 0.5cm is more than enough!
Why you said that?...I said that because I tryed and it work...who told you that it is not thick enough!
How thick is yours?
How thick is 5.88 hsusa profile almost everybody use here?
CU
 

littlejacob

Well-Known Member
I am here to share good things with other growers...not bullshitt!
I am here to make good connection and maybe have some new friends...I fell like we all from the same big family (I know I am dreaming...lol...but it is the way I think! )
So no way for me to say bs to anyone here!
CU
 
Do you have one like this?
I do...and it is a perfect hs...good enough to cool 4 cxb3590 @1400mA!
And 0.5cm is more than enough!
Why you said that?...I said that because I tryed and it work...who told you that it is not thick enough!
How thick is yours?
How thick is 5.88 hsusa profile almost everybody use here?
CU
I didnt want to offend you :) but from reading all pages they recommend around 7 as a minimum, then i point to supra for this number :) offcourse it will work but without a good temp test of the back of the chip you have no idea how warm it is and this will influence the lumen and the life expectancy of the chip these readings cannot be done with feeling with your fingers if the sink feels hot or not so i just wanted to point out this might not be the best solution
 

littlejacob

Well-Known Member
Bonjour
A french guy who have the same tested it without fan with cxb3590 @1400mA X4 (same as mine and maaaany other EU growers too...no more in stock)with a laser thermometer behind the cob and it was 32ºc after 2H of use with a tº of 22ºC in the room
CU
 

EfficientWatt

Well-Known Member
Thicker base == heat spreads in the heatsink faster, so cooler junction temps.

We tried mentioning it to you @littlejacob .. :

Supra here : https://www.rollitup.org/t/heatsinks-for-diy-led-lamps.851907/page-46#post-11704265
I did here : https://www.rollitup.org/t/heatsinks-for-diy-led-lamps.851907/page-71#post-12080792

It does not mean it will not work, don't worry you're light won't break next week ;) and is adequately cooled to function correctly.
but you probably would have cooler Tj / higher efficiency / better heat dissipation with a thicker base .. *maybe* a little longer life span (not sure / very minimal I'd guess)

HSUSA 5.88 is 6.858mm thick (0.27" ) works fine for passive, but Supra used to favor 0.3" base thickness profiles for passive ie 7.6mm ..

I'm going for 10mm thickness, a little overkill perhaps, but I like big ass HS ^_^

:peace:
 
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EfficientWatt

Well-Known Member
Laser Thermometer on shinny metal is not a very reliable test from what I read.

Supra put some kind of sticker or something on the measuring point I believe, and temps all of a sudden were higher ..

Bonjour
A french guy who have the same tested it without fan with cxb3590 @1400mA X4 (same as mine and maaaany other EU growers too...no more in stock)with a laser thermometer behind the cob and it was 32ºc after 2H of use with a tº of 22ºC in the room
CU
 

littlejacob

Well-Known Member
Bonjour
I did not run passive...I have 1 120mm fan @4.5V over each piece of hs...4x 10x6.6x1.4in...so everything is cool I guess!
But thanks I will try one with a thicker base...if I can source one...
So you tell me it is better to have a smaller size but a thicker base...I guess it was the total amount of alu who was important!
So something like 36x6x1.6 (with 0.4 thick base) would be ok for passive cooling 4 cxb3590 @1400mA? (No fan)
CU
 

dionysus4

Well-Known Member
Bonjour
I believe someone already ask and I am afraid it won't work....
And by the way tme is not so expensive...I bought an aluminum radiator (1000x165x35 14 fins) for 36, 50€ +vat and 7, 50€ shipping but I bought others things with so shipping cost were fair (it is a flat cost, always 7, 50 €)
You can cool 4 cxb 3590@1400mA with a 140mm fan on it at 5/7V.
Have a great day ★
link??
 

EfficientWatt

Well-Known Member
Thicker base doesn't replace surface area, it helps with uneven spread of heat.

If you have a lot of small leds spread out, base thickness is less important than if you have 4 fat cxb3590.
 

littlejacob

Well-Known Member
Bonjour
It is www.tme.com + RAD-A42 (1000x165x35mm) but because the base is only 0.5mm you will need fans!
@EfficientWatt is it ok with fans?
I thought if the hs was cold then no problems...it is really cold with 120mm fans @4.5V and i tryed without fan and it is not hot just warm...i hope it will last a few years...i know i will lurk on the new one as soon as they will be available so...
I guess biggest hs would compensate thinner base...
Tme didn't give the base size for the 50mm tall
And on 60mm it is 0.8mm base but it is 125 € for 1000x262x60mm and it is 36 € for the one I have!
So I will stay active I guess...less expensive
How do we can have a better mesure of cob tº...is it some kind of probe we have to put on the tº point on the cob?
CU
 

EfficientWatt

Well-Known Member
Sorry, I thought you we're running pasive, my bad ;)
I haven't messed around with active cooling (with cobs) yet.

Supra mettait un autocollant, au dos du cob, pour prendre la mesure T°, pour eviter que la reflectivité metallique ne fausse les données.
Une sonde entre le cob et le dissipateur serrais bien .. mais dur a mettre en place peut etre (?)

++
 

dionysus4

Well-Known Member
Bonjour
It is www.tme.com + RAD-A42 (1000x165x35mm) but because the base is only 0.5mm you will need fans!
@EfficientWatt is it ok with fans?
I thought if the hs was cold then no problems...it is really cold with 120mm fans @4.5V and i tryed without fan and it is not hot just warm...i hope it will last a few years...i know i will lurk on the new one as soon as they will be available so...
I guess biggest hs would compensate thinner base...
Tme didn't give the base size for the 50mm tall
And on 60mm it is 0.8mm base but it is 125 € for 1000x262x60mm and it is 36 € for the one I have!
So I will stay active I guess...less expensive
How do we can have a better mesure of cob tº...is it some kind of probe we have to put on the tº point on the cob?
CU
0.5mm is very very thin
not just for cooling but for screws too

does that site include VAT?
 

littlejacob

Well-Known Member
[QUOTE="dionysus4, post: 12296146, member: 895]0.5mm is very very thin
not just for cooling but for screws too

does that site include VAT?[/QUOTE]

No...but I contact them and they told me that because I am not a company I do not have to pay vat...so I wait for restock and I buy 3 more with fans
@EfficientWatt merci pour le truc...oui glisser quelque chose entre le cob el le rad va pas etre simple...lol!
Sinon je pense rester avec ces rad...trop pratique et pas cher...je reste actif...mais en même temps je suis sur que si j'ai un soucis de ventilo ca grillera pas...mais ventilo @4.5V!
CU
 
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