Lets talk about "Other" COBS !

BOBBY_G

Well-Known Member
You don't need 3 of them to get the same power/lumens as a cxb. .
oh and youre right - 85W/23W = 3.7, so almost 4 cobs to replace that one..... ;)

granted some assumptions were made on bin and cct, but the fact remains, as stated a few times in this thread, all these mfrs have different techniques and it will take a real 3rd party test *and* some real world experiences before we can identify the value leaders

ill bet a CXB3070 would be good candidate up against the cheapies as theyre 160 lm/W @ 62W..... thats about 2.5 cheapies per $30 3070


its hard to beat the old adages like "you get what you pay for:" cree may be a "premium" , but i feel that the best value lies in "2nd tier" cobs by other majors like nichia, bridgelux, etc. or there will be a few dark horses that arise out of the no-names. but theres an old contractor's rule of thumb "never take the lowest bid".... we will find the "value" of these bargain cobs when you hear the stories of the guys who come home from vcation to find their grow wrecked by a bad cob that took out the whole string, or the potentially unlucky fire victim, etc. I think @greengenes said he had maybe one bad cree out of the box in several thousand, and i have yet to hear of a properly installed cob that burned out once in use. throw in the fact that the bargain chips will have a wider tolerance of luminosity and color, etc, you get where im going.

nothing like actual field data, so an exciting year for the geeks at any rate.
 
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BOBBY_G

Well-Known Member
Honestly, once you start hitting the big Cree numbers at 180-200lm+ per watt, it's hard for most cobs to match them at any current.
yeah i think thats why trippy picked 160, its reachable by most.mfrs and tops hps's theoretical max efficiency.

I think those looking for an economical alternative would be well served by looking at the A19s in the brightstik thread. Those are running 0.33-0.35/W including (marginal) drivers and heatsinks. the only thing remaining is the question of efficiency... which i hope to get a metric on soon:

https://www.rollitup.org/t/got-my-ge-brightstiks.896869/page-7#post-12584043

realistically with the better spectrum, led@ even 120-130 lm/W matches HPS's real world luminosity, and a gavita is ~$0.40/W out the door... before you ever buy your first replacement bulb
 
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alesh

Well-Known Member
For cob comparison testing without optics... do we need a tube or sphere?
All cobs have same radiation pattern... lambertian
Checked 3 diffrent cob companies ..all lambertian
Differences in LES size can be ignored if you are measuring at 12 inches and Les is smaller than 1 inch
What do you think of just center measurements at a fixed distance from cobs in a open area
I think that is how Supra made the cob comparison charts
I don't think it'd very accurate. Beside that, it's relative measurement only, very difficult (if not impossible) to compare your results with anyone else. And unless you have some advanced equip, your results will bear an unknown error caused by sensor's non-linear response. Of course, this can be lowered by a correction factor derived from SPD of the measured LED but the fact is that you don't know how much is actual SPD different from the typical one in the data sheet.
 

JorgeGonzales

Well-Known Member
@alesh I've been using your CLU056 LER figures here to estimate LER for the new CLU048/058 series...



Any idea where they end up at 4000k 80 CRI? I've been guesstimating around 340 LER based on these figures.
 

JorgeGonzales

Well-Known Member
I'd guess that it will be closer to 330 lm/W. No time to confirm, sorry.
Really? I saw the big jump from 2700k to 3000k and thought it would climb higher with CCT. No need to apologize, you've done plenty.

I just built a light with 4000k 80 CRI CLU048s, and was trying to figure out efficiency and ppfd. Either way, I'm at about 50% at 170Lm/W, so that's cool.
 

JorgeGonzales

Well-Known Member
Also 4.84 QER seems pretty respectable. I think I'll try digitizing the SPD curve and following along with the "Math behind" thread. Wish my excel chops were better.

Edit: nevermind, my excel chops don't have to be better, just saw the spreadsheet already made. Neat.
 
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JorgeGonzales

Well-Known Member
@alesh Man I couldn't have been any closer with my guess. Thanks for uploading this spreadsheet, you are #1. Overlapping lines on the SPD charts are real bitch though, and the resolution on the tails is dubious at best. But it's close enough for jazz.

CLU048-1818 @ 4000K 80 CRI

Screen Shot 2016-05-11 at 12.21.20 PM.png
 
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JorgeGonzales

Well-Known Member
It would be like freakin' awesome is what it would be like. There is a newer generation for a bit more dough http://www.digikey.com/product-detail/en/samsung-semiconductor-inc/SI-B8T342560WW/1510-1324-ND/5875178

But you could probably run 9 instead of 10, at better efficiency and the same-ish price.

Cooling would be interesting. 300W in a roughly 22" x 7" area. Let me consult the Supraspl oracle so I don't have to count fins and multiply....the oracle says 26"x10" piece of this actively cooled would do it:

http://www.heatsinkusa.com/10-000/

Actually that's not a bad way to make 40000+ lumens.
 

alesh

Well-Known Member
@alesh Man I couldn't have been any closer with my guess. Thanks for uploading this spreadsheet, you are #1. Overlapping lines on the SPD charts are real bitch though, and the resolution on the tails is dubious at best. But it's close enough for jazz.

CLU048-1818 @ 4000K 80 CRI

View attachment 3679021
Good guess, then.

Well I usually digitize graphs manually. It takes a good mouse and a low pointer speed but it can be done rather quickly and very accurately.
 

salmonetin

Well-Known Member
....@alesh or @growmau please bros do it a vid on how to digitize graphs manually...with your experience...
...thanks a lot in advance...

:peace:

Saludos
 

Growmau5

Well-Known Member
....@alesh or @growmau please bros do it a vid on how to digitize graphs manually...with your experience...
...thanks a lot in advance...

:peace:

Saludos
does Alesh have a youtube channel? i would sub to that.
-i dont know how to do the cool shit he does.

@JorgeGonzales I really like that you are breaking from the Cree mould and getting the word out about these very respectable Citizen cobs. I don't have time to educate myself about them right now, but I will. Unless you want to call me tonight at bedtime and tell me everything I need to know, lol
 

JorgeGonzales

Well-Known Member
Good guess, then.

Well I usually digitize graphs manually. It takes a good mouse and a low pointer speed but it can be done rather quickly and very accurately.
Is there a downside to doing it automatically? I can just say "make 400 points" and the software lines it up with 380-780.

The Citizen graphs just had the 4000k hidden at both ends completely, so eyeballing either way.

Oh, and one other thing, wouldn't robincnns method work fine with a quantum meter for comparing cobs relative to one another?
 
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JorgeGonzales

Well-Known Member
does Alesh have a youtube channel? i would sub to that.
-i dont know how to do the cool shit he does.

@JorgeGonzales I really like that you are breaking from the Cree mould and getting the word out about these very respectable Citizen cobs. I don't have time to educate myself about them right now, but I will. Unless you want to call me tonight at bedtime and tell me everything I need to know, lol
Thanks man. Cree is still amazing stuff in my book, especially with the CXB3070 at practically Vero prices now from Cutter. Nobody touches them running soft. But I'd take the $12 Citizen or $10 Nichia in a heartbeat over the Vero, or any of the Citizen CLU058 line running hard over anything I've seen.

160lm/W at 100W is Citizen's strong suit. They are practically the Cree of high power.
 
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