Switching to LED

Growroom Design
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#1

I’ve decided to switch to LED at last, after seeing some truly amazing yields under that kind of light.
Here is a specific question about my setup:

I plan to run Cree3590 3500K 36W CD bin at as much as 2100 mA, so they will produce considerable heat. I’ve decided to cooltube them - placing a COB onto radiator and enclosing the radiators (4 in a row) into ventilation channel. That, in my opinion, combined with proper air circulation, should do the trick.

Of course I would not run them at 2100the whole grow, only in late veg - early flower (not sure yet) and mid-late flower (pretty sure).

Will it be safe for COB’s to run at such power? Will it shorten their lifetime, cause them to degrade?

I never tried to count the heat exchange by the way (drivers should be cooled the same way, with radiators), but I am guessing that 900 square ft2 / hour of air should be able to keep 12 COB’s and their 3 drivers nice and cool. Any opinions about that guess? Any experience on running COB’s at 2/3 of their capacity?

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#2

what voltage are they 48v/100w ? they are 36w so thats like 18v?

i ran my leds at max for the whole round last time… this time i did 50% for veg and ramped up late veg and got to max around 1/2 way to 3/4 done flower. so i only got 3 years instead of 5, whatever… a COB costs what 20$ to replace? the tech moves so fast in 3 years i’ll probably want to replace my fixture even if it still works. and HLG drivers have a 7 year warranty.

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#3

They are 36W/18V. Thanks for sharing your expertise.

What do you mean you run them at max? My planned 2100 mA isn’t even close to max, so you saying it’s possible to even up the amp’s on COB’s all the way to datasheet max without considerable decrease in their lifetime? That’s great news, really. I am going to need that lumens in late bloom for sure.

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#4

oh lol no i meant i run max HLG recommends for their quantum boards, i don’t think it’s diode datasheet max. i’m running my boards ~118v @ 1400ma or something

#5

the Cree CXB3590 COBs are 36 volts not 36 watts.

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#6

Yeah, my bad. I’m kinda new to LED.

#7

here try out this driver selection tool it should help out a bit.

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#8

What’s you driver amp’s max? If it’s 1400 mA then your max will be only a half of datasheet capacity of diode.

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#9

for the LM561C diode? its because i’m 115v qb304s. if i was running 55v qb288s i would be at 2800ma no problemo…

ok the data sheet says forward current of 200ma w/ max forward voltage of 2.9 and i actually run them over 0.58w, about 0.61w each

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#10

My rig is running at 75 watts per cob at the moment.

cant . get . pictures . to . upload .

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#11

Thank you, I’ve already done that selection tool. It’s good to know that it trustworthy from a fellow grower. I’ve come up with HLG-480H-C2800A for 4 CreeCXB 3590 36V to reach desirable lumen output on bloom. Now I want to know if it is OK to overdrive COB’s a little, using proper cooling.

#12

20180517_110003.jpg4249×2390 1.64 MB
20180517_110016.jpg4249×2390 2.63 MB

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#13

Can you be a little more specific? I’ve seen your rigs at Pedro’s Garden thread, that some serious light you packing! I assume that you using COB Cree CXB3590 3500 36V CD bin, then it will be (75W, 36V per COB) 2.08 amp per COB? Is that right? That means that your driver is almost not dimmed, running full blown, right?

#14

My oh my that some very serious grow going on there!

#15

Yep thats at full boar.

How many square feet are planning to light ?
I do wish I had done what you are suggesting with channeling the air past the heat sinks in a cool tube type setup.

#16

Wow! That’s actually ever more than datasheet says it can do!

#17

About 21 square feet. I digged my LED setup from approximation that optimal lumens are 23000 per square feet, at least that how it was with my HPS setups and it always worked well.

So they are heating up well? You can do so by slightly reworking your rig. I’m not sure the needle type of radiators are good for encasing. Ah, I can get wait to get my hands on my setup, certainly you will be interested!

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#18

No they do not heat too much, it is just that with a cool tube type setup I would be able to run carbon dioxide.

I will watch eagerly how your rig gets built :slight_smile:

Edit: I will still turn them down to 50w per cob in summer (or before)

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#19

Personally I think COBs are old tech already. All the cool kids are using LM561C diodes this week. Seriously though consider SolStrips or maybe ChilLED logic 100w PCBs.

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#20

Absolutely right. the LM561C’s can be spread out more for more even lighting and next to zero shadows.

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