Cheap and Cheerful DIY using Citizen cobs

CobKits

Well-Known Member
Hi Bobby, actually all of my five 1212 may be in the same situation(some seconds plugged unmounted from any heatsink or fan), I've got a cheaperdigital luxmeter but because all cobs could be damaged i think would be useles, is there any test could I do to be sure my cobs are at there 100% of efficency? I think a killawatt can t help me Isn' t it?.any suggest Please?
thanx!!
if you have a way of applying lower adjsutable voltage and current you can look at the dies ans see if any strings are burnet out.

needs to be like 10-50 mA for you to look at them
 

1212ham

Well-Known Member
I stumbled on an easy method if you have a LOW VOLTAGE driver..... Connect one driver wire to the COB, hold the other driver wire in your hand and touch the other COB terminal. Your body will conduct a few mA to slightly light the COB. Not a good idea over 50 volts or so. If you don't have a low voltage driver a few 9v batteries can be snapped together in series.
 
I stumbled on an easy method if you have a LOW VOLTAGE driver..... Connect one driver wire to the COB, hold the other driver wire in your hand and touch the other COB terminal. Your body will conduct a few mA to slightly light the COB. Not a good idea over 50 volts or so. If you don't have a low voltage driver a few 9v batteries can be snapped together in series.
Yes electrocution urself is way easier :shock:
 

CobKits

Well-Known Member
Every single handling guide from every manufacturer specifically prohibits handling the cob by the LES. Yes they can be damaged this way but in general they are pretty robust and can take a little abuse
 

KonopCh

Well-Known Member
Every single handling guide from every manufacturer specifically prohibits handling the cob by the LES. Yes they can be damaged this way but in general they are pretty robust and can take a little abuse
Yea I know that. But I touched them because on surface was dust. I waiting for driver, hope they'll work.
 

BobCajun

Well-Known Member
A way to look at COBs without blinding yourself is to put 2 layers of mylar together as a filter. One layer's not enough but 2 works. You just hold it up in front of your face. You can also tape it over sunglasses for hands free viewing.
 

G84

Well-Known Member
Here again...I am not able to use calculator, so is there a mmol/w list at different wattage for 1212 gen 6 in 3500k(80 and cri)?thank you
 

CobKits

Well-Known Member
not that im aware of. the gen6 spectrum is slightly different and nobody has taken the time to digitize it yet
 

BobCajun

Well-Known Member
I doubt you'd be able to tell the difference from the same wattage of a Cree COB, for instance, maybe slightly higher. I think you're over analyzing things though. Just hit em with about 50w/ sq ft of any brand of COB and you're gonna be alright. It's not really a precise science, just blast the fuckers with as much as they'll take without ill effects or excessive heat, is my advice. I guess the figures would be good for reference purposes though, to to know. I dimmed my lights from 50w to 75% with PWM and I just got reduced yield. Now I put em back on full power. So what if the top parts get a little bleached? The bottom parts also get more light, so you take the bad with the good. I wouldn't go over 50w though, because that's actually pushing it, at least in an enclosed chamber lined with mylar.

Actually, since I read in one report that pulsed light avoids light saturation I may try a duty cycle of something like 99%. Same amount of light, virtually, but never on for more than a few hundred microseconds at a time. Probably make no difference, the plants used in report were lettuce, as I recall, which probably saturates a lot easier than weed. Worth a shot though.
 
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CobKits

Well-Known Member
I doubt you'd be able to tell the difference from the same wattage of a Cree COB, for instance, maybe slightly higher. I think you're over analyzing things though. Just hit em with about 50w/ sq ft of any brand of COB and you're gonna be alright. It's not really a precise science, just blast the fuckers with as much as they'll take without ill effects or excessive heat, is my advice. I guess the figures would be good for reference purposes though, to to know.
i generally design for 35W/SF if cobs are being run soft (1212@3W5, cxm or 1818@50W, 1825@75W), and would use 45W/SF if run hard (1212@75W, cxm or 1818@100W, 1825@150W). Its never a bad thing to buy more light and dim it its pretty easy to bump up 10% power every other day and watch the response. so thats pretty much the same conclusion, "design for 50W/SF and dim"

people like the science but unless youre spec'ing out a warehouse, rule-of-thumb is gonna work well for most people
 

BobCajun

Well-Known Member
i generally design for 35W/SF if cobs are being run soft (1212@3W5, cxm or 1818@50W, 1825@75W), and would use 45W/SF if run hard (1212@75W, cxm or 1818@100W, 1825@150W). Its never a bad thing to buy more light and dim it its pretty easy to bump up 10% power every other day and watch the response. so thats pretty much the same conclusion, "design for 50W/SF and dim"

people like the science but unless youre spec'ing out a warehouse, rule-of-thumb is gonna work well for most people
That sounds like a good way, 50w then dim as required. I'm trying my revised PWM system now. I went with 98% duty cycle, 500 mics on and 10 mics off. I'll see how that turns out. Good thing about dimmers/Arduinos is that you can connect several drivers to one, you just parallel them.
 

Metacanna

Well-Known Member
My growing space is 4.5 sq ft, I'm using 5x 1212 driven at 1.4A. That gives 55W per sq ft. Initially I had some problems since the plants weren't big enough to handle it, after a few weeks my plants now seem to handle that amount happily, distance 10"-12". Once I realized my plants couldn't handle so much light, I dimmed the lights to a third and every two days I would increase by 5%-10%, they are now full blast, this way plants could adapt. PPFD is 1210, which in theory is bearable for MJ plants.

My 5pcs 1212 draw 260w from wall, drived by a hlg-240h-c1400B considering a 94% driver efficiency at full power your test seems different from mine..my 1212 should run at 48.8w each oneatfull power.
Are you actually measuring the draw from wall? I have exactly the same gear but I'm reading 240W from the wall when full blast.
 
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