I am a compleate new to growing and buy the cob fixture based on the result of forums and umols that this light give.
So I buy 4 clu048-1212 3500k 80cri gen 6 mounted on passive 133mm heatsink rated up to 70watt, full agro spectrum.
with meanwell HLG 185H-C1400A
So i dont know much about difrance between CREE,CITIZEN,VERO
But just want to know did I buy solid light compare to other cobs at the market...or is there any thing better?
And can I run it at max 240 w dim ?
Citizen COB's are as good as Cree, BLX or Luminous..
The 1212 is not the biggest, powerfulst one but it will grow you some bad ass weed, mate!
You can also use an HLG-240H-C1750 for 250w max., no problem!
But I would not drive the COB's at 65w because you'll probably need +20" distance and they run ~48% effiency.
I would rather take 8 or 10 Citi1212's and an HLG-185H-C700B(8 COB's) or an HLG-240H-C700 for 10 Citi1212's.
Much better spread and you can use the light at half the distance.
Side effect, yoiu get much better effiency when running the COB's at only 700mA(min. +5% or ~55%), you can take smaller heatsinks(only 25w per COB) and you'll get better yields(5% more light = 5% more yield, each time - again and again!)
You could use two big 40x 50x 40x 3mm alu c-channels(a x b x c x d) instead of expensive pin fin heatsinks. A 1100mm long c-channel would be enough for 4 or 5 COB's driven low, especially when there is anyway some air movement inside the tent.
C-channel looks like this and is available online, from e3ay or from the next metal store or even Walmart should have them.
You save a lot because you do not need the fin pin heatsinks and can invest the money in more COB's to make a better, more efficient light. If you already have an 1,4A driver, that's not a problem, simply make two strings of 4 or 5 COB's in series and connect them in parallel to the driver. The current will be splitted between the two strings.
So instead to invest in expensive heatsinks, I would rather invest in more COB's and run them low.
You can also increase the cooling capabillity of the c-channels when you use a 2nd smaller c-channel and stick in between the two fins to increase the surface area of the bigger channels. Would look like this:
My heatsinks above are made from a bigger channel (30x 40x 30x 2mm) and a smaller one (25x 20x 25x 2mm) glued together using cheap doublesided thermal tape. Each 1150mm "heatsink" has 4 COB's(BLX V18's, 3000°k/CRI93) running at 525mA(~70w total) and the heatsink temps stabilize at 42-46°C depending on ambient temps(26-30°C).
Two of them has cost me less than 20 bucks because I found the channels for cheap at the scrap yard. Simply call the next one and ask them for cheap aluminum channels, you can get it based on kilo price.
You can also make something like this:
It's a 600x 350x 2mm aluminum sheet with 8 added c-channels on the backside to increase the cooling surface. I'm using it with up to 150w strips and COB's currently. With the full 150w the temps stabilize at around 55-60°C.
You can calculate with around 50-55cm² surface area per 1 LED watt (or 100-110cm² per heatwatt if you know the COB effiency), for 100w you need ~5000-5500cm² cooling surface for passive cooling. If it's a sheet, a c-channel or an extruded heatsink really doesn't matter in the end, as long as it's thick enough to spread the heat, it will work.
My tablet has a 10w SoC and use only a thin copper foil to spread the heat acoss the backside.
