DiY LED - Cree CXA3070

Boppa

Boppa

Active Member
AlcoholicO said:
1st a Very Nice thread - special thanks to Supra and Mr. Flux and many others for the invaluable information!

I'm located in SEA and have been given the following offer from Arrow Asia:
CXB3070-0000-000N0HAD30H @ $31.5/pcs SPQ/MOQ 100pcs
CXB3070-0000-000N0HAD30G @ $27/pcs SPQ/MOQ 100pcs
CXB3070-0000-000N0HAB30H @ $27.5/pcs SPQ/MOQ 100pcs
CXB3070-0000-000N0HAB30G @ $23/pcs SPQ/MOQ 100pcs

Buying 100 of these babies is, however, a very large expense for me and the people at Arrow Asia aren't as knowledgeable as you guys, since they don't use them to grow with.

Of the above, they're all 3000K and I was planning on the AD30G bin, as it is 80 CRI and has a high luminous flux. I would be using these almost exclusively for flowering.
I would test run at both 1000mA and 1600-2000mA and since 100 is 80 more than I need, I would be selling the rest once build. The people I'd sell them to, would not run them cold, but at the 1600-2000mA, where I would try both.

The question then is basically just if it's the right purchase for us, which I'm more or less sure it is...
Click to expand...

would be interested in purchase of some of those if you buy 100
 
AlcoholicO

AlcoholicO

Active Member
Well since Arrow Asia will only sell 100 pieces at the time, I will go with Kingbrite, UNLESS they give me a sample size - Arrow Asia mentioned they could sell me 3 pieces as a sample, but I have yet to confirm this.

Kingbrite will sell me these at 36.5$/piece for 1- pieces or below.
At 100 pieces, they would cost 34.50$ and then Arrow Asia would be cheaper, but I'm a long ways (financially) from being able to afford 100 pieces . . .

Kingbrite also had Led holders for .3$/piece I would like, so I'm not relying on the adhesive strength of thermal compounds.
Furthermore he offered me Lenses at 3.8$/piece (60/90/120 degrees).
I was thinking if Arrow Asia won't give me the sample size, I'd get 4+ from Kingbrite instead and WITH led holders and 60 degree lenses.
Then all I'm missing is another couple of heatsinks :)


pic upload


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happy75

happy75

Well-Known Member
SupraSPL said:
Unfortunately not very much, to get optimal junction temps. The space between fins is small and the height of the fins is high. So with even a very slight pressure differential the heatsink works amazingly, but with nothing but convection, it acts like a solid lump or very little surface area.

That said, in the case of a short term fan failure, its cooling ability will improve because as the temp of the heatsink rises, its efficiency increases due to the large differential between the heatsink temp and the ambient temp.

I did some testing, with a CXA3070 at 50W on Alpine 11 passive cooled, the heatsink quickly reached 57C and I stopped the test. The COB may have survived if the temp stabilized low enough, but I guess I was not willing to potentially bust one to find out. At 25W it reached 53C and I believe the COB would survive no problem.
Click to expand...
I did some "testing".....I had one 3070 5000K in a propagator, without a fan so just using the heatsink of the alpine (needed asap some light for a week or so). Running @1.4A (50 watts) the top layer of the led broke but it still works. Temperature in the propagator was about 22 degrees.
 
the dopest

the dopest

Well-Known Member
Supra, I was scared I would do the same thing on mine so I ran the fans 24hrs at first, then I got to thinking about wear and tear on them and put them on the same timer as the COB drivers. Now, they come on and go off with the lights, if there is a timer failure, I will be covered. The only downside is they shut off the same time as the lights so I need to check temps at the shutdown time tonight and see if they spike or the COB cools quick enough when it goes off. It's been hooked up a week like this.
 
Banana444

Banana444

Well-Known Member
Has anyone used the 5700k of the cxa 3070s? I have 2 3000k 3070s on artic 11s i have been very pleased with but looking to build something a little bigger. 2 lights, each with 4 cxa cobs. I finally have some time over then next 2-3 months to plan and finish this light before i need it. Thanks for any input. Gonna read up on some of this thread, its been a while.
http://www.mouser.com/Search/m_ProductDetail.aspx?Cree-Inc/CXA3070-0000-000N0UZ20E2/&qs=sGAEpiMZZMu4Prknbu83y3sOCTnhdZkGBveeSN31cCbYcDviwKOf9g==
 
Banana444

Banana444

Well-Known Member
I have already ordered 10 of the ideal cxa35 cob holders. Looking at heatsinks usa. Looking to mount 2 cxa3070s on each heatsink. How far apart are you placing your cobs? I am looking at this heatsink and would be adding a fan for each cxa.

http://www.heatsinkusa.com/4-600-wide-extruded-aluminum-heatsink/?faceted_search=0

If i got a 16" heatsink for each two cobs with 2 artic11 fans would that be enough cooling to get decent efficiency. I am hoping this would also allow me to mount one or two deep blue or something for uv light benefits. Is there a single driver that i could use to drive 2 cxa 3070s @ 1400ma. I know i can use the meanwell lpc60 1400 for each cob and may just go that route.
 
D

doz

Well-Known Member
Supra (or anyone), please help me out. So I built my LED but I have no clue as to PAR, well maybe.

Meanwell 185-1400 pushing 4 CXB3070 @ 1.4amp, 36v. Efficiency is 45.43% on AB bin.

200w X .4543 = 90.86 / 10sq ft = 9.086 PAR w/sq ft??? Just tryin to figure it out. Everyone seems to say that 14-16 is optimal yeah? Guess Ill need 1 more 200w light?
 
tenthirty

tenthirty

Well-Known Member
If your a really good grower it should be ok to start. You'll be growing shade adapted plants for sure. I think that I am at 11.9 or so and it works pretty well for me.

After thinking about it.......
I think to be safe add one more cob. That will work well.
 
SupraSPL

SupraSPL

Well-Known Member
doz said:
Supra (or anyone), please help me out. So I built my LED but I have no clue as to PAR, well maybe.

Meanwell 185-1400 pushing 4 CXB3070 @ 1.4amp, 36v. Efficiency is 45.43% on AB bin.

200w X .4543 = 90.86 / 10sq ft = 9.086 PAR w/sq ft??? Just tryin to figure it out. Everyone seems to say that 14-16 is optimal yeah? Guess Ill need 1 more 200w light?
Click to expand...
9 PAR W/ft² = 449 PPFD (minus reflector/lens/wall losses) Yes based on that I would add more to make sure you are avoiding larf (leafy/fluffy) in the mid branches, especially with certain varieties.
 
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