DiY LED - Cree CXA3070

happy75

happy75

Well-Known Member
Kuifje76 said:
Just went through it, great thread, thanx alot !
Yeah it's a learning curve, i went too fast and must clean again :(, it's in bits and pieces

btw can anyone advise me on what's the easiest way to power 10 Arctic alpine 11 plus fans and dim them as low as possible ?
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Hi Kuifje. I use a small powersupply for a pc. These devices give 12V, 7V and 5V. I have all my 70 units on 5V. Works very easy.
 
happy75

happy75

Well-Known Member
SupraSPL said:
We convert from lumens to PAR W using LER, which represents the calculus to convert a particular spectrum from lumens to Watts. Each different spectrum has a different LER. So the spreadsheet takes that into account and converts from lumens/W to electrical efficiency.

Example, Cree CXA/B 3000K 80 CRi spectrum LER is 325. So if the COB is rated to put out 138 lumens/W at a certain current and temp, that works out to: 138/325 = 42.4% efficient
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And I thought it was magic what you were doing with the spreadsheet... ;-)
 
C

CellarDweller

Well-Known Member
1947 Boy said:
Spectrum King makes 400W LED lights and claims 125,000 lux (??). How this compare to our CXA3070 project?
They also say that COBs have low efficiency (scroll down) compared to discrete LED diodes.

Could you please comment on this.
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Spectrum King have re-invented the wheel by re-inventing a non-COB COB style lamp.
Spectrum King re-market Alibaba lamps that are very easily discovered (put in Spectrum King to the Alibaba search box) and are in fact hi-bay warehouse lights.
Spectrum King is quite frankly full of sh*t.......but of course, I haven't owned one, tested one or validated any of this......so feel free to ignore me :)
 
C

CellarDweller

Well-Known Member
1947 Boy said:
Spectrum King makes 400W LED lights and claims 125,000 lux (??). How this compare to our CXA3070 project?
They also say that COBs have low efficiency (scroll down) compared to discrete LED diodes.

Could you please comment on this.
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PS - For the money you spend on a Spectrum King ($1300 for the 400+) you could buy:

15 Cree COBs (take your pick of the 3070/3590) and spend around $800
A variety of drivers and heatsinks/CPU coolers for $500

With that you could blow the SpectrumKing to Kingdom come. Frankly, they're turd.
 
Scotch089

Scotch089

Well-Known Member
They're just trying to up their sales with vague statements. Sure, individual leds can be more efficient... but what are they comparing? A warm white NAME BRAND COB vs a no name red led? (Crees reds are only 36% efficient compared to high 40s for the cobs) or are they comparing the NO NAME COBs to a cree cool white led.

They're full of shit without coming out and saying anything definitive because they know they could easily bury themselves.
 
C

CellarDweller

Well-Known Member
1947 Boy said:
Spectrum King makes 400W LED lights and claims 125,000 lux (??). How this compare to our CXA3070 project?
They also say that COBs have low efficiency (scroll down) compared to discrete LED diodes.

Could you please comment on this.
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PPS - apologies for the potentially "ranting" nature of my answer......but having seen the sheer volume of goodwill and knowledge spread throughout these DIY threads, watching some pseudo hippy pr*ck tout his wares "like he's just the most loveable sales guy ever" makes me want to vomit.
 
C

CellarDweller

Well-Known Member
Oh and PPPPPPPPPPPS they spend an age telling you some "LED/State Secrets" and being the nice guy in the process......then sell a grow lamp using LUX as a viable metric.

LUX is a "referential" metric at best, in that, the higher the LUX the higher the likely PAR of the lamp.....but really, you're looking for PAR, not LUX and any company that markets their lamps on LUX is doing so for a reason (please don't think they don't know all this.......they know very well, but LUX is what their warehouse lamps are designed around).
 
bicit

bicit

Well-Known Member
Supra, i have a very basic question for you. what amount of par w per square foot do you recommend for flowering?

For trained plants as opposed to wild bushes.
 
Scotch089

Scotch089

Well-Known Member
XPEPR.png Thanks guod I'm glad to see you're still silently watching. What do you have to say about the 670s efficiency? And sorry about the 36 number I was just pulling a number I vaguely remembered.
 
happy75

happy75

Well-Known Member
Kuifje76 said:
I'm gonna recover 1 psu 5V 1,2a, it's a d'link something and can run 5 alpine coolers for sure, i'm gonna look for another one like that, need to power 10
Thinking of using a computercase controler with display to keep temperature in place, in and output are 2 noctua fans (4-pin), find it strange nobody using them, any reason ?
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Look on the internet for "pc voeding" and you will find many for a few euro's. You have to adjust them, get the casing open and put color by color. It is all explained in youtube videos or in some sites:

http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

I am no expert with electricity, but I have done it. And it works! You only have to connect some wires to get the 5V or 12V or 7V. I have one ATX (thing is about 300 watts) of 25 euro's for 70 fans on 5V. Works perfectly and 5V is plenty to cool the cxa that I have running.
 
K

Kuifje76

Well-Known Member
happy75 said:
Look on the internet for "pc voeding" and you will find many for a few euro's. You have to adjust them, get the casing open and put color by color. It is all explained in youtube videos or in some sites:

http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

I am no expert with electricity, but I have done it. And it works! You only have to connect some wires to get the 5V or 12V or 7V. I have one ATX (thing is about 300 watts) of 25 euro's for 70 fans on 5V. Works perfectly and 5V is plenty to cool the cxa that I have running.
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It's to difficult for me at the moment to do stuff like that and it would take too much time, it has to move forward, but interesting none of the less :)

and to be honest, electricity scares me a bit :roll:
 
happy75

happy75

Well-Known Member
Kuifje76 said:
It's to difficult for me at the moment to do stuff like that and it would take too much time, it has to move forward, but interesting none of the less :)

and to be honest, electricity scares me a bit :roll:
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Lol... Me too at first. I did only half what they did on the video. I took it apart and put each of the colours in a "kroonsteentje".. and it works! It costs me less time than use a special driver for each of my lightunits.
 
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