DiY LED - Cree CXA3070

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churchhaze

Well-Known Member
I've been thinking about this for a while and I'm starting to lean toward the 3.945" at 4" length (almost perfect square) to make heat sinks for a single cxa3070.

It's not as wide of a profile, but look how freaking tall it is, including the base! 2.875 inches tall!, 2.5 inches of that being fin height. That's beastly.

Each 3.945"x4" square sink would have 10 fins, which is 200in^2 area. The area of the base is around 15in^2.

That gives a total of about 215in^2 for one cob.

The 24 inch bar at 4.85 profile for 4 cobs had an area of =967.201934 in^2 (6240 cm^2) as you calculated. Divided by 4, that's ~242in^2

I think the narrower, but taller, profile would actually be a huge advantage, and just might go this beastly route. They'd be 13 dollars a sink, but that sounds like a real bargain.





SupraSPL said:
Those are the 5.88" X 24" long. It gives 6240cm² each so that is about 30cm²/dissipation W. So in your case you would need 4560cm² which is about 23" of the 4.85" profile.

One thing to consider though, the 4.85" profile has a base plate that is only half as thick as the 5.88" profile, so that is why I decided against those for COB purposes. The thick base plate helps spread the heat along the length of the heatsink to all the fins faster which is important since the COBs are spaced relatively far apart and each is like a hot spot. So the thick plate decreases the temperature gradient which is exactly what we are after. The 4.85" might be a good option for vegging though because smaller LEDs are normally used and the heat doesnt need to be moved as far.
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SupraSPL

SupraSPL

Well-Known Member
Very cool idea churchhaze. The 3.945" profile is the same as the 10.08" that I have been so fond of. A very thick base so you can spread the COBs out with no worries about thermal gradient. I like the idea of the 3.945" profile because it would allow you to spread the COBs out more and you could cool the whole bar with one small fan, similar to the 5.88" profile idea.
 
SupraSPL

SupraSPL

Well-Known Member
SDS, less than 2% lumen depreciation after 1.5 years of 12/12, with a Tj of 85C. That is awesome! I think it was Mr Flux that was saying something about the output actually increasing over time in some cases?

RROG, the CXA3590 is available :joint: Digikey has the top bin 4000K and 5000K, and the mid bin 2700K, 3000K and 3500K! Although after consideration I still prefer the 3000K CXA3070 for flowering because of the cheap awesomeness of the Chinese 1.4A driver that only works with the CXA3070.Although the downside is limited avilability of the Z4 and AB bins. If we could find a cheap driver for the CXA3590, even if it was a 350mA driver, that would be good stuff.

When push comes to shove ($/PAR W), the CXA3070 3000K AB is still cheaper and more efficient than the CXA3590 even if we don't consider the driver difficulties, and it gives us a more even spread.
CXA3590 BB vs CXA3070 AB.png
 
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Rrog

Rrog

Well-Known Member
That is just so fantastically helpful Supra!!! Thank you! That's what I'll do, then. BTW I used that 10.08" and loved it. A 24" block
So I'll use the 3070 and that cheap driver and just make a small assembly line to pump them out for my new grow. I'll deploy everywhere in my new rooms for veg and flower.

I was working on some sort of articulated arm clamp system to be able to move these along the sides of the plants, but with this kind of output I basically could just mount them on the sidewalls.

Hmmm... maybe strips overhead and Church's blocks on the sides
 
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JavaCo

JavaCo

Well-Known Member
Rrog said:
So I'll use the 3590 and that cheap driver and just make a small assembly line to pump them out for my new grow. I'll deploy everywhere in my new rooms for veg and flower.
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Might just be a typo, but if not and you meant 3590's. They wont run off the cheap drivers. 3590 run at about 77 volts compared to the 3070's 38 volts.
 
SupraSPL

SupraSPL

Well-Known Member
You could run the Veros harder than 1.4A but since it cost so much more for drivers higher than 1.4A, these are what I would suggest.

I was able to cool 220W of COBs with a 1.6W fan, so based on that I suspect water cooling may introduce so much complexity and cost that it may be a false economy. On the other hand, I was using $50 worth of heatsink.
 
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SupraSPL

SupraSPL

Well-Known Member
So the most recent all-LED batch came up .96g/W. It may not break any records for growing, but it sure does for my electric bill. Bud quality was awesome especially considering they were not selected. As always, there is room for improvement. The batch was a bunch of test varieties from seed. The LEDs were CXA3070 3000K Z2s and Z4s. There were red/white/blue modules using XTE warm whites (only 34% efficient). As those get phased out I should get better numbers.

HSO Trainwreck
IMG_0003a.JPG

The next batch is also a bunch of test varieties from seed. Looking good so far, they are at 7 weeks. This room was the same, Z2s Z4s and RWBs with XTEs. Kosher Tangie on the left. The purple leaves in the center is Secret Sour. HSO EMDOG in the center and right. Mr Nice Shit in the back right.
IMG_0014b.jpg
 
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SupraSPL

SupraSPL

Well-Known Member
After this batch finishes up, that tent will be converted to all ABs @ 900mA with some R/W/B XTEs and all passively cooled (again) because I decided to spread them out a bit more and added some more heatsinks.

The other tent will be Z4s ABs and RWBs with some active cooling. I would like to phase out the XTEs. The Z4s at 700mA are 46% efficient and the ABs at 900mA are 47%, so that should get me over 1g/W.
 
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Bueno Time

Bueno Time

Well-Known Member
SupraSPL said:
After this batch finishes up, that tent will be converted to all ABs @ 900mA with some R/W/B XTEs and all passively cooled (again) because I decided to spread them out a bit more and added some more heatsinks.

The other tent will be Z4s ABs and RWBs with some active cooling. I would like to phase out the XTEs. The Z4s at 700mA are 46% efficient and the ABs at 900mA are 47%, so that should get me over 1g/W.
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Ya I was going to say your GPW should easily go up. That is going to be kick ass. Excellent job on the .96GPW! Buds all look dank too.
 
bicit

bicit

Well-Known Member
uzerneims said:
@SupraSPL you inspired me to make something like this too...
Great bud, great result. Problem is - can't find CREE3070 in EUROPE, don't want to go for those China led's, just one 3000k chip.
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Have you checked the availability of Bridgelux vero chips? The 29 is comparable to the 3070.
 
uzerneims

uzerneims

Well-Known Member
bicit said:
Have you checked the availability of Bridgelux vero chips? The 29 is comparable to the 3070.
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Hmm, yeah, the Veros are on Ebay, one COB - 65€ and there is no model number writen, cuz in spredsheet they have like 4 kind of bins. Crees are cheaper for my diy student budget science projects :D
 
bicit

bicit

Well-Known Member
uzerneims said:
Hmm, yeah, the Veros are on Ebay, one COB - 65€ and there is no model number writen, cuz in spredsheet they have like 4 kind of bins. Crees are cheaper for my diy student budget science projects :D
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Is there some reason you can't order from digikey?
 
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