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LED FAQ) Building and DIY
- Thread starter Dion
- Start date
Maybe i can answer.
Just today i changed my power supply for the fans because one fan had trouble starting with a 5V adapter. Later i checked it and output was 4,7V.
Now they run with an adjustable power supply, currently at 6V and it's perfect.
Meanwhile i left the cobs(@35W) without running fans and the temps of heatsinks were not high.
Now with 6V and fobs at 50W there is no heat.
Just today i changed my power supply for the fans because one fan had trouble starting with a 5V adapter. Later i checked it and output was 4,7V.
Now they run with an adjustable power supply, currently at 6V and it's perfect.
Meanwhile i left the cobs(@35W) without running fans and the temps of heatsinks were not high.
Now with 6V and fobs at 50W there is no heat.
Dion
Active member
I also have an adjustable power supply i run at 6v because the setting lower is 4.5v and they dont always start at that voltage
5v is enough for sure though
12v is unnecessarily loud and wasteful of watts i think
firetech89
Active member
What's going on Dion. First off awesome thread packed full of info. With its thread started over a year ago the tech might have changed a little and I'm am overwhelmed and confused with all the options of setting up my leds. I'm currently running a 250w HPS and want to change it out for a led setup. This is for my flower cab, if everything work well I'll plan on changing the veg over second. My question is simple, if you had the dough whats on the market that you would build today. I'm lookingoing for a setup to cover a 2x3 canopy. A list of what COBs and driver is really all I need. The heat sink and fan I have an idea to place sinks in a duct and pull air out of my cab across the sinks and then to the outside. More of a passive system using the existing fan that I already have. Is that a good idea? Thank you for your research on LEDs I wish I had more time to read all of this thread and do a parts list on my own, but I would love to easy help if youre willing to share. Thanks mate.
Dion
Active member
firetech89
Active member
Only have access to 120
Dion
Active member
without concern for cash and a 2x3 canopy im doing this:
option 1
10 cxb3590 3500K CD bin (2 rows of 5)
and im running them on a HLG-240H-C700 (i prefer the B version but thats just me)
that will be: 229 watts of 64% efficient light and give you a ppfd of around 850
A more realistic approach still very high end but better value would be
option 2
6 cxb3590 3500K CD bin( 1 per sq ft)
run on a HLG-240H-C1050
that will be:
213 watts of 61% efficeinct light and give you a ppfd of around 760
Now this second setup can fit 1 more cob on the driver so if you added a 6500K or whatver highest cold white K in the highest bin available DB etc (i only have data for the 5000K CD bin so thas what im going off)
option 3
that will be:
248 watts 61% eff and 850 ppfd
so in summation
I would go for option 2 or 3 myself-obvioulsy option 1 will get you the most street credit
option 2 has absolutely even canopy values
Dion
Active member
why?
I figured it out I can run them at 1.6a / 58w and get 7787lm, 132 lm/w.
I could have just bought the AB 3070's for $40 each and ran about the same looking at the numbers.
The difference is running chips at 1.6mA/1.9mA or 1.6mA/2.4mA.
Dion
Active member
dunno where u got those numbers from but if u are talking cxa BD bins
its lower
check here
http://pct.cree.com/dt/index.html
From the Cree tool that you select chip and type.
http://pct.cree.com/dt/index.html
3590 cxa and BD 10000 lumens.
I read through the entire thread, knowing virtually nothing from scratch, and I've kept coming back as I've been learning - beginning to get a pretty good grip now ...
First, thank you for running this thread! It's one of the best resources for current COB tech.
My question is about PAR watts/sqft and ppfd. (BTW, a new quantum PAR meter has appeared on the 'bay at a lower price - sub-$200 - tempting.) Anyway, I've been trying to find a rough formula for COB wattage and ppfd. Efficiency of COBs varies, but it shouldn't be that hard to set a range. I'm looking at 30 Vero18s at 1000-1400ma in a 4x4.5 space and I figure I'm at 1400 ppfd maxed out, and 1000 at 1000ma.
But you say that 229 watts of 64% efficient Cree at 700ma in a 2x3 is only 850 ppfd. That's 25 PAR watts/sqft isn't it? That's closer to 1100 ppfd when I calculate it.
How do you derive PAR watts? Then it's just a matter of the PAR/sqft and ppfd ratio, right?
First, thank you for running this thread! It's one of the best resources for current COB tech.
My question is about PAR watts/sqft and ppfd. (BTW, a new quantum PAR meter has appeared on the 'bay at a lower price - sub-$200 - tempting.) Anyway, I've been trying to find a rough formula for COB wattage and ppfd. Efficiency of COBs varies, but it shouldn't be that hard to set a range. I'm looking at 30 Vero18s at 1000-1400ma in a 4x4.5 space and I figure I'm at 1400 ppfd maxed out, and 1000 at 1000ma.
But you say that 229 watts of 64% efficient Cree at 700ma in a 2x3 is only 850 ppfd. That's 25 PAR watts/sqft isn't it? That's closer to 1100 ppfd when I calculate it.
How do you derive PAR watts? Then it's just a matter of the PAR/sqft and ppfd ratio, right?
Dion
Active member
par watts is the electrical watts x eff % and then also i take away 10% for reflector losses
so
(229 x .6401) x 0.9= 131.92461 par watts(so thats 13 par watts per sq ft)
par watts(131.92461)/ (60cmx90cm/10000)= par watts per m2
par watts per m2 x 4.65(the conversion for par watts to ppf for the 3500k cree)= ppfd=852.01
Dion
Active member
well yeah like i said lower than that
the orginal numbers i suggested were for cxbs
but you are planning on running cxas(which as ive already told u wont work on that driver) at 1750mA
even in ur pic we see that at 1700 its 130L per watt(lower than ur suggested 132
and u can actually refine that tool to get more exact numbers so you can see it at 1750 or changing the temp to 50c which is realistic
but anyway, some people have to learn the hard way and i guess you fit that catagory
Whoa big boy.....
I laread RMA'd the 3 CXA's 3500's and order the 3490 CXB's 3500k from Pacific Lighting Concepts and figured all the wattages out with the 2700k which I did keep and will be mounting in the middle. It's all good The Price was just too good good to pass up at $42 a pop for those 3500k's plus it changed everything witht he voltages and wattages that things were even better I can now run all 4 cobs at 1750 and still be under the Drivers specs!
