DiY LED - Cree CXA3070

Ongaps said:

Hi guys ,im about to order some CXB3070 AD bin ,but the seller only got the 3 step.I would really like to know whats the difference between 2 step and 3 step.

Thanks for your input guys ,

Click to expand...

Be happy you can get such a high bin led....2 or 3 step makes no meaningful difference. A simple Google on the subject will clear that up if it really matters to you

Positivity said:

Be happy you can get such a high bin led....2 or 3 step makes no meaningful difference. A simple Google on the subject will clear that up if it really matters to you

Click to expand...

CRI and steps are references to our ability to perceive the colours represented by light sources.

Higher CRI and 2 step theoretically is better

Thanks guys, just purchased 10 CXB3070,I think im going to run each cob with this Mean well LPC-60-1400.

Any Good Advice ?

Ongaps said:

Thanks guys, just purchased 10 CXB3070,I think im going to run each cob with this Mean well LPC-60-1400.

Any Good Advice ?

Click to expand...

Seems like an expensive, complicated way to wire up 10x COBs. I would look at the Meanwell HLG series. They have much higher efficiency, support dimming. The only downside is the higher voltage(increases electric shock risk).

I agree HLG-185-C1400 would be a great option. But if you are planning on running individual drivers, these are 1.45A 89% efficient, power factor corrected and $13.50 shipped. Downside being possibly long time shipping from China

Ongaps said:

Hi guys ,im about to order some CXB3070 AD bin ,but the seller only got the 3 step.I would really like to know whats the difference between 2 step and 3 step.

Thanks for your input guys ,

Click to expand...

Not much. You can ignore number of steps for growing.

Each COB manufactured is slightly different. Number of steps basically tells you maximum difference in color of the light.

edit: I guess I missed some messages lol.

I'm going to get the Dt-pf1005 drivers ,the ones supra mentioned.
Hope they all work good as they will take 30 days to receive.

Thanks to you all.

Ongaps said:

Hi guys ,im about to order some CXB3070 AD bin ,but the seller only got the 3 step.I would really like to know whats the difference between 2 step and 3 step.

Thanks for your input guys ,

Click to expand...

http://en.wikipedia.org/wiki/MacAdam_ellipse
It shouldnt affect plants a lot, or at least the difference is not well studied, so take the cheapest/available.

Tolerance for variation in tint/spectrum between two cobs is not the same ...
It makes very little to no difference if you ask me.

EDIT : Woops what happened, loads of replies i hadn't seen ..

It's a data made for uniform lighting from several cobs, so I'd say we really don't care about for grow

Anyone any idea how much heat an Alpine 11 plus can dissipate passively ? i'm gonna drive them softly anyway and was wondering what would happen if a fan broke

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.

Would there be any problems mixing 2x 3000k and 2x 5000k CXB3070s on one HLG-185H-1400B? Better to keep them the same temperature. I couldn't find anything the pointed me one way or the other on the datasheet.

bizfactory said:

Would there be any problems mixing 2x 3000k and 2x 5000k CXB3070s on one HLG-185H-1400B? Better to keep them the same temperature. I couldn't find anything the pointed me one way or the other on the datasheet.

Click to expand...

Shouldn't be a problem.

Sorry if I'm breaking any forum rules here, but this is my first post on RIU. I haven't been able to find the info I need in this massive thread!

I'm building an 8 COB light in similar fashion to battlestar ganjactica. Thanks to everyone here I've been able to figure out almost everything I need to know to get started. Except dimming.

I'll be using 8 cxb3070's with 2 Meanwell HLG -185H C1400B's for each fixture.

How do I wire in a dimmer? I want to be able to dim to ~700ma and ~1050ma for different stages. What kind of dimmer should I use?

If you want to use 1 dimmer for both lights, get a 50k potentiometer, if you want to dim them seperately, get a 100k pot for each driver.

Wire them up like this (Supra posted this for me when I asked the same question)

The hlg has a category with an internal potentiometer too.... the B at the end of the name.

Scotch089 said:

The hlg has a category with an internal potentiometer too.... the B at the end of the name.

Click to expand...

B on the end means an external pot (like I described above). The A version of the drivers has the internal pot.

You're right my bad.

Thanks for the replies. So quick I had to delete my response lol. Is a potentiometer a dimmer? Will the driver have blue and white wires?