Newbie chosing COB's

robbah99

Member
Hi !

I figured I try and build a LED setup for myself to replace a 400HPS in my (2x2, pots are 10 liters) cabinet.

There is not too many ways to do this I guess. It's mainly five components.

COB, Heatsink, Fan, LED Driver, Fan Power

Everything but the cobs seems "pretty" straight forward to me. I realize that driving the cob properly etc. will benefit me.

Chinese
stuff seems of, let's say lesser quality and the spec's are overrated. Atleast thats what I see when reading. But they are readily availible and "cheap".
Cree CXA 3070 seems to be a jewel if you can get one from a good bin. This seems very hard? and they are expensive.
Bridgelux has Vero 18 and Vero 29. I've never heard any bin talk about these? They seems availible and great...

Chosing one of these three cob seems like the way to go(?).

Simple comparison around 3000K:
  • CXA 3070 Z2 bin:103lm/W 7700 lm 2.8 A $46 (in 100 qt.)
  • Vero 18: 122lm/W 3780 lm 1.05 A $13 (would need 2-3 to match the others)
  • Vero 29: 125lm/W 10100 lm 2.1 A $30
  • Aliexpress 125 lm/W 10000(?) lm $30

I understand that there are LOTS of other parameters as well like what different wavelengths etc.

To build my setup to sustain myself with the 4 plants. What would you suggest??
I'am leaning towards the Vero 29.
The Vero 18 seems good too but I'm guessing I would need about 8 of those?
I was thinking that with other 100W cobs I could settle for 4 of them (total ~400W LED).

Any advice is greatly appreciated. Telling me that I am on the wrong track is also ok :-D

:leaf::peace::leaf:
 

epicfail

Well-Known Member
400 watts (100w/sf) of Vero29 or CXA3070 or HID is too much for the space, most people are running less than half that when using high quality COBS. If you drive 4 of them at 1400ma it would run at just over 200 watts, which is still on the higher side but not really too much. I run about 30-40w/sf (dimmable) of CXA3070 AB bin and others are running as low as 25w/sf with excellent results, most exceeding 1g/w.
 

churchhaze

Well-Known Member
Imo, my experience with vero 29 is that it's too powerful for low ceilings. If you run 1.4A through it, it will have to be kept at least a foot away. The distribution is sort of poor, like a pan that burns everything in the middle. I ended up having to run them at 1.05A each, which is a very high $/Wpar setup cost, in which case I should have just went cxa3070.

The conclusion was to use less light more spread out (twice as many vero 18 driven at half the power).

Vero 29 was so powerful, the outside buds with less light did amazing while the ones in the middle turned yellow and burned.
 
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SupraSPL

Well-Known Member
Yep, I run my CXAs at 800mA so I can get closer to the canopy and more efficiency/less heat, but as CH pointed out it raises the up front cost. But there is no denying the awesome cost efficiency of running the Vero29 or CXA at 1.4A. Here is how they stack up at Tj 50C

Vero18 3000K @ 700mA = 116lm/W or 36.3%, $2.83/PAR W

CXA3070 3000K Z2 bin @ 1.4A = 119lm/W or 36.6% efficient, $1.83/PAR W
Vero 29 3000K @ 1.4A = 114lm/W or 35.8% efficient, $2.20/PAR W

Maybe a simple reflector for each COB would allow you to keep it further from the canopy without losing too much light laterally. You could do a simple test with any light meter to check the effectiveness of the reflector.
 

SupraSPL

Well-Known Member
The Veros do not offer bins, so I just go by the minimum numbers they provide. I use the minimum numbers for each Cree bins in those calculations also.

If you can find the CXA3070 AB for a reasonable price it will outperform all of the above of course. Even if you paid $60 each here is how it stacks up:

@ 1.4A 137lm/W or 42.1% efficient, $2.73/PAR W
 
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