DiY LED - Cree CXA3070

I have every intention of getting a dedicated PSU for the fans. Money is a bit tight these days and this project will be on going for the rest of the month, the cell phone charger was just playing around with what's available at the moment.

I do have a quick question for you Supra: I'm planning on adding a toggle switch for the 3000k COBs. Would that require a DPST switch or an SPST? Looking at the single poles it seems like wiring it up would bypass the switch entirely, but this is my first project of this kind so, you know, ignorance. Also I'd like to say thanks for this thread. The information you've provided has been invaluable.

SupraSPL said:

That is an interesting COB and heatsink redcarpet where did you find that?

@ cannabare - ya I am trying to keep training to a very minimum. I fim them early if necessary and I will bend tops down when necessary or strap the stalk to the bucket if they start to flop over. I used to use LST and that is how I learned that it is too much work for my grow lol.

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Waiting back on an email with a link. They sell the cob and not the heatsink. http://www.superbrightleds.com/moreinfo/high-powered/vollong-10w-high-power-planar-cob-led/979/2386/

Dismantled a bunch of computers a few month ago. Never thought I would be looking for heatsinks shortly after. They were the nice big Pentium II sinks also. Just salvaged a couple.

nestor you can get adjustable high efficiency 12v power supplies very cheaply ~$5. I have a bunch on order for testing. I am using a cell phone charger in one of my flower rooms and it is working great lol.

You can use a single pole switch just make sure you switch the hot wire on the ac side of the driver. You can determine which is the hot if you have a voltmeter. Just check to see which has a voltage reading against the ground.

Thanks for the link redcarpet. I looked at the specs of the COB and they are not too good lol. 5500K and should not be run harder than 250-300mA (5Watts)

WDIK awesome salvage

SupraSPL said:

Thanks for the link redcarpet. I looked at the specs of the COB and they are not too good lol. 5500K and should not be run harder than 250-300mA (5Watts)

WDIK awesome salvage

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Yeah that cob is corn. I just like the heatsink. I'm going to check out an aluminum extrusion company not to far from me. They might be willing to give me a deal on some pieces.

Hey S, looking forward to 3590's at 2.7k. I think a few mixed in your 3k array would shoot off those ladies like rockets!

mtnstream said:

Hey S, looking forward to 3590's at 2.7k. I think a few mixed in your 3k array would shoot off those ladies like rockets!

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Can I ask who has them in stock??

To be determined.

PetFlora said:

There's a handful (maybe 2) of you guys who really deserve mega kudos for all you are doing with DIY

I think we would all benefit from consolidating the 411 into one thread, but then it might get too big to quick

You (thee collective you) have helped me more than I can say. I'm still dumber than a box of rocks, electrically speaking, but you don't have to be a rocket scientist to get it that cobs + reflectors are not only a huge jump in grow tech, but simplify DIY to a point where I am ALMOST ready to jump in.

Now if somebody would start putting kits together....

Anyway, thanks from me!

And I'm sure if there was a 'Like' button, the counter would spin a few times

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I made a thread before I knew about not advertising in forums. I would love to get a group buy together on the 3070 2700k from arrow(we would have to buy 100). I would want 16 LED's for a 4x4 and I would offer my design and driver connection to the people involved. I think the 3070 is the best it can get but only in the 2700k color temp.

I can build A BADASS 4x4 cob setup for 1k. If I didn't have to buy 100. Still thinking about doing it anyway.

That's my offer on the table.

Canna

I have a 5x5 tent for flower. How many cobs would I need~20? Also, what do you guys think would be the most efficient way of supplementing UV...besides HID I just shit my pants over my power bill...no more 860w CMH for me.

Maybe 3, 4 foot t5 HO floros with UVB bulbs. That would cover quite a bit of ground

RedCarpetMatches said:

I have a 5x5 tent for flower. How many cobs would I need~20? Also, what do you guys think would be the most efficient way of supplementing UV...besides HID I just shit my pants over my power bill...no more 860w CMH for me.

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Honestly if you space the cobs 12inches apart you can put a uvb CFL bulb right in the center and it will spread to every edge. No issues to date. Ill post pictures when I can. We need a general design thread.

CannaBare said:

Honestly if you space the cobs 12inches apart you can put a uvb CFL bulb right in the center and it will spread to every edge. No issues to date. Ill post pictures when I can. We need a general design thread.

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All that's just clutter to me. I know I could use floros, but I'd rather stick to the LED theme. I'll look into UVB stars. Thanks for input.

RedCarpetMatches said:

All that's just clutter to me. I know I could use floros, but I'd rather stick to the LED theme. I'll look into UVB stars. Thanks for input.

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UVB stars? as in LEDs?.....join the line to save up the dosh.....

Chronikool said:

UVB stars? as in LEDs?.....join the line to save up the dosh.....

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As in the Sun...or tanning bed lol. Just some 3watt LEDs for the 280nm range. I might just stick with the T5HOs. Anybody know the proper amount of UVB/ft'?

From my experience, UVB is not beneficial, especially for a large grow. Same with UVA for that matter. LED will give you incredible frosting and terpenes. You are better off spending those watts on PAR photons especially considering how inefficient fluoro tubes are. And I agree redcarpet it adds more complexity and clutter, reduced air flow etc. Just my 2 cents, experiment away

I've had great fat trich heads with UVB CFLs! Coulda been the strain. I've read that they produce more trichs for protection from harmful rays. I need a refresher course on the matter.

Anyway, since all this is about efficiency. Are cobs more efficient than 3w diodes?

EDIT: where's the spectrum graph for the 2700k? I only see the 3000.

RedCarpetMatches said:

I've had great fat trich heads with UVB CFLs! Coulda been the strain. I've read that they produce more trichs for protection from harmful rays. I need a refresher course on the matter.

Anyway, since all this is about efficiency. Are cobs more efficient than 3w diodes?

EDIT: where's the spectrum graph for the 2700k? I only see the 3000.

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Gotta love the Marijuana Man

https://www.youtube.com/watch?v=lfiI78uN3Ks

I saw that a long time ago and it convinced me to try UVB. It turned my trichs brown which I don't prefer and there was no magical increase in potency unfortunately.

Redcarpet the most efficient small white LED that I know of is the Cree XM-L2 U2 4C (4400K). It is 45.5% efficient at 1A (3W) and cost $1.52/Watt. Very impressive but the color temp is not ideal for growing IMO.

So for warm whites, the Cree XM-L2 T4 7A3 (3000K) is 36% efficient at 1A (3W) and cost $1.61/Watt. The Cree CXA3070 3000K that we have available to us is 42.5% efficient at .7A (25W) and cost $1.76/Watt.

So in regards to warm white, the CXA3070 COB is much more efficient than the XM-L2. The COB is also much more convenient to install.