Cheap and Cheerful DIY using Citizen cobs

J

John MacDonald

Member
I've been a lurker for a long time. Started watching @Growmau5 videos about a year ago. Great inspiration. Then I saw the build by Jorge on the front page of this thread and wanted to build something similar.

I built a light using
four CLU048-1212C4-403M2K1 cobs
Moduled 9980-B heatsinks
HLG-120H-C1050B driver
Ideal 50-2204CT holders

$140 before wire, aluminum, shipping.....

Its bar style just like @OldGrower (hadn't gotten past the first page until yesterday). 10" spacing on the cobs using 3/4" aluminum channel, 1/8" thick (does the job but would have preferred 1/4" thick, couldn't find any).

The Citiled cob simulator shows each cob pulling 36.8 w @ 1050ma, Tc=50, so 147.2 watts total. Before I added the potentiometer to dimming lead my kill-a-watt read 163 watts. After I wired up the dimmer I got the same reading 163 watts, is this right? I thought adding the dimmer would limit the light by 10 watts. Also the light dims down to 7.7 watts. I thought I needed to add a low limit resistor (10k ohms) do prevent the light completely shutting off but apparently not. I've looked around but simply don't understand how the driver operates.

Meanwell's pdf shows 155.4 watts and 148V for the driver. Can someone help me understand why my kill-a-watt is reading 163 watts? Is it ok that its over the 155 watts? I just don't want to have an unsafe setup that is over driven. Also the driver is 94% efficient but It appears I'm only getting 90-92% depending on emitter temperature. Is this normal, is my math off? Can I do something to improve this or is it because of my combination of cobs and driver.

Needless to say I am amazed at the par numbers I am getting. Currently running at 110 watts which is just over 700ma after efficiency losses right (24.2/.92)*4=105.2w)?

Thanks to Robin, Bobby, and Supra for all the graphs and spreadsheets that helped me grasp the math with cobs. Can someone check my PPF at 700ma, I'm guessing its around 231? Thanks

 
wayward1

wayward1

Member
Hi. Does anyone know if I can run 2 X 1212 90cri on a hlg 185h c1400. I intend to add 2 more cobs at a later date I'm just not sure if 2 cobs would reach the vf of 71-143
 
pop22

pop22

Well-Known Member
Well there is a new reason coming to consider efficiency over cost, at least if you grow canna. States are already talking limiting power to home growers.........so they tell you to grow indoors, then tell you you can use the power.....

wietefras said:
I wouldn't compare them at wattage levels though. The 1212 does 2.1PAR/W at 50W, but then the 1825 does 2.5PAR/W. Completey incomparable and this is what leads to the nonsensical notion of "this COB is more efficient than the other".

Efficiency is simply a parameter which detemines the overall cost of a fixture. Wanting a higher efficiency/efficacy means you need more COBs. In the end really the only relevant metric is price. You can run all these COBs at 2.3 PAR/W efficacy up to say 2.6PAR/W, but the question is which gives you the cheapest fixture at your preferred efficacy. Or perhaps which gives you the nicest uniformity if the price difference is small.

Trouble with the smaller ones is the cost of cooling them though. Indeed the CLU048-1212 is nice and cheap at less than a third of the price of a CLU058-1825. They are also a third of the "size" of a 1825 so you need three times as much of them a lot of them to fill a room too. If you put each COB on it's own CPU cooler you'd pay about as much for the coolers as for the COBs. Which would completely negate any price advantage on the COBs.

On the other hand, I kinda like the 1825 being able to fill a square meter with only 4 COBs (90W each) while still maintaining good efficacy at around 2.36PAR/W. At $35 per COB that's 6 PAR/$. Which should make it possible to build fixtures costing around a dollar or euro per Watt.
Click to expand...
 
Moflow

Moflow

Well-Known Member
Very cheap and cheerful Citizen build.
Kapton tape.
3 x CLU048 C4 403M2K1 1212s on a cheap chinee driver - 55-110v 580mA.
Approx 67 watts (22.3 watts each) on a 400mm x 150mm x 3mm - 16" x 6" x 0.118" heatsink with a 120mm 12v fan.
Runs cool although I've noticed there appears to be more heat at front of cobs compared to the Cree 3590 - just an observation, nothing scientific......
Should be good for a veg light or side lighting for flowering.
 
wietefras

wietefras

Well-Known Member
pop22 said:
Well there is a new reason coming to consider efficiency over cost, at least if you grow canna. States are already talking limiting power to home growers.........so they tell you to grow indoors, then tell you you can use the power.....
Click to expand...
How is that a reply to what I wrote? You should still compare the COBs at the same efficiency level and then see which offers the cheapest solution or best light distribution (ort whatever you deem important).

My point was, it's nonsense to state that the CXB3590 is the most efficient Cree COB. It isn't. The CXB307 is the exact same tech. Neither is the Citizen 1825 the most efficient Citizen COB. The 1212 is just as efficient. Don't compare them all at 50W, but first find the amperage where they perform the same in efficacy and then go from there.
 
pop22

pop22

Well-Known Member
hell, I don't know what question I was answering honestly........and it disturbs me. I was over dosed with Ketamine at the hospital as they used it as an anesthesia. I spent 10 hours in recovery halucunating and thinking I was going to die. I still have occasional blanks and dis-associated thoughts.
Sorry if I was confusing

wietefras said:
How is that a reply to what I wrote? You should still compare the COBs at the same efficiency level and then see which offers the cheapest solution or best light distribution (ort whatever you deem important).

My point was, it's nonsense to state that the CXB3590 is the most efficient Cree COB. It isn't. The CXB307 is the exact same tech. Neither is the Citizen 1825 the most efficient Citizen COB. The 1212 is just as efficient. Don't compare them all at 50W, but first find the amperage where they perform the same in efficacy and then go from there.
Click to expand...
 
M

morvis

Well-Known Member
What is the difference between the Xtra and non-Xtra 9980 heatsink? Is it the width of the fins around the circumference?
 
J

John MacDonald

Member
Last edited:
M

morvis

Well-Known Member
Cool. I hope the non ultra is suitable for the clu048-1212 because I'm about to grab a mess of them.
 
CobKits

CobKits

Well-Known Member
ultra = citi clu048, 058
xtra ultra =vero 29, cxb 18xx/25xx/30xx
ultra vs = cxb 18xx.25xx.30xx

always check datasheets carefully!
 
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