Finally building my cheap 120V COB light

I am finally getting to building this light setup. I bought a bunch of 50W driverless COB chips about a year ago and I haven't had the opportunity to work on them until recently. Now I am finally getting them assembled and a suitable fixture created for them. So far I have them mounted to a piece of aluminum bar stock, but I plan to add cooling fins/tubes to the back of it via aluminum brazing rods.



If anyone knows what the heck these pins are for that would be awesome

Manufacturing/assembly date, June 2017

I hadn't really paid attention to that, but these chips must have been sitting in stock for almost a year before they were sold and shipped

This kind of light has been out of date now.

QB design light is the one that most people love.

I realize its not top-of-the-line LEDs or anything, but its a step up from my current light in that area which is just daylight household bulbs. At 1.70 per COB, its probably more expensive to buy the power supply for most grow lights than it was to build this entire one. Everything on it is salvaged except for the COBs themselves. The huge heatsink was part of a peltier based mini-fridge cooler, the square tubing part of a server rack, the aluminum body pieces were left over scraps.

The power supply for the fan is what really cracks me up. I had a roof leak and a tidy cat bucket full of laptop and other power adapters got filled with nasty water. So I dumped the whole thing outside about 2 months ago now. After finding that fan in an old computers, I needed a power adapter that I could locate. So I went out to that pile and literally pulled that adapter out of mud. Works fine now, but it definitely needed some cleaning!

Anyway, here is the more-or-less finished light:

Nice. What are the color temps of those cobs?

Good job.

brickweeder said:

Nice. What are the color temps of those cobs?

Click to expand...

The two outside COBs are 50W blurples and the center is a 50W bright white of some kind(I honestly can't remember). The white light really cuts down on the weird blurple light in the work space and makes it a lot more comfortable. It also picks up some of those needed yellowish wavelengths for the plants. I have the outer two wired out of phase to the inner COB. The reason is that they are direct wired to the mains and thus they oscillate at 60Hz. Wiring them out of phase means that it greatly reduces the flicker of the fixture. Looking directly at them, you'd never realize it, but if you see the light from the corner of your eye or catch it on video and you can totally see it; this fixes that.

starke said:

Good job.

Click to expand...

Thanks! I think I overbuilt this thing kind of insanely on some levels, but it keeps nice and cool and so far the plants are absolutely loving it. My next model is going to be much simpler, have a better reflector, and its going to cost a lot less. I think next prototype is going to be a bit longer. I think about 18 inches would be preferable to the current 8 inches, but maybe I will go with 12. I really haven't decided yet. If I hadn't had all this aluminum scrap laying around I would have been more practical in my building strategy. The next version should be more waterproof, but this fixture is at least capable of having water sprayed directly into the reflector/COB area and not shorting out.