Fanleaf's Huge 42 COB Array Build Plus Other Builds

instead of a concentrated area of light you spread it out ... nice :bongrip:

hey if you are really in space then NASA wants to talk to you, they need help getting past the Van Allen Belts !! :smoke2:
 
OK so today I started the frame for the first section. I had to re-configure dimensions because the Mars Hydr 8x8x7 tent dimensions were false advertised. The actual size is 92"X92"X78" high. What a joke.

This just means our COBs will be spaced a little closer than originally planned.

So to have the outter cob's 6" from the tent walls as I want I have to make the frame sections at 86"X19" wide.

It was a nice day outside so I figured I would do this outside on my old back deck.
So first I took my 1/8" X 1" X 8' sections of aluminum angle and cut 2 sticks to 86"

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Then I cut 2 sticks at 18 3/4". These will be the ends that the light is hung from so they get tucked under the 2 long sticks for strength. They are then squared up and riveted into place with very large 1/4" wide aluminum rivets. 2 per each corner.

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Now after the outside of the frame is together and square I installed 1 eye bolt at each corner for hanging. They are 10-24 X 1 1/2" eye bolts.

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Well. Depending on how this turns out I may be adding eye bolts in the center of the frame sections for weight relief as well. Soon I will be adding the last 2 remaining aluminum sticks and we will get the 14 cobs assembled and wired into and on this first frame section.
 
So I was doing some weight calculations today to get an idea of what the whole finished light will weigh in total with all 3 frame sections. Looks like I will be about 105 pounds hanging weight. Actually lighter than I thought.
That does not include the drivers which are pretty heavy but those aren't going to be located on the fixture anyways.
 
odinsmaster said:
Do you think that frame will support that, or are you going to add some more eyelets?
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The frame will have a few more runs of aluminum to strengthen it. The rough testing I have done tells me that it will but it is still a concern that it may bow over time. I will either be adding 2 more eye bolts towards the center or strengthening with an added lip of aluminum the length of the fixture.

That first frame section isn't finished yet though. Before we can add the cob's to it I still need to add the 2 pieces of 86" C-channel down the middle. I'll get some pics and get that part done quickly so you guys can see it. Those alone will add a ton of strength.

Either way, by the time I'm done, one way or another there will be no question about the strength. But at only about 35 pounds per section finished and running, I think it will be good.
 
Why not just use angle iron instead of angle aluminum for the longest side, or bolt a flat piece of iron to the aluminum angle for support? I've seen angle/flat iron in the same section of Home Depot that I see the aluminum angle.
 
415friendly said:
Why not just use angle iron instead of angle aluminum for the longest side, or bolt a flat piece of iron to the aluminum angle for support? I've seen angle/flat iron in the same section of Home Depot that I see the aluminum angle.
Click to expand...

Because the frame section shown above is 5 pounds. If I used angle iron it would weigh a ton. The aluminum is lighter, looks better without paint and much easier to work with. I probably could have broke out the welder and built the whole thing from iron but I have to make these manageable. The weight is important. All 3 panels are going in a tent of 92"X92" so the weight for the tent support has to be considered.
 
Well I got the frame section #1 ready for COB mounting. I first added 2-86" sections of 1/2" C-channel.

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Next I added 2 cross members at 19". Each are 3/4"X 1/8" aluminum angle. This really made the frame strong. So strong in fact that I'm sure the frame is now plenty strong to handle the load all on it's own.

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Then I placed some heat sinks where they will be once I permanently get them mounted just to get an idea of what she will look like.
Here is about half of the sinks that will be on it. The COBs will be on 13" centers with the outer COBs 6 inches from the tent wall so the par levels stay up around the outside edges.

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If I have time tomorrow I will start putting the first 14 Cree chips on the heat sinks to get this panel closer to done.
I will be sure to take many detailed pictures on the chip/heat sink/holder and reflector assembly.

Oh yeah and 1 more thing. This whole assembled frame is roughly 10 pounds :thumb:
 
I wanted to draw a few distinctions for those who have questions about a build like this. I wanted to address the size and scope of this build for those who have considered building their own but think looking at this that maybe they either can't afford what I'm doing or they don't want to spend what I'm spending here.

I want to be clear. There are mainly 2 ways to build one of these. The first is very expensive like I'm doing and the second is much much cheaper.
The route you choose should depend on what your looking for. My route costs a whole lot of money up front. Roughly $4600 but I'm building this light for all out efficiency later on. With this many lights this close together it will allow me to run all of the cobs at a much lower power down close to the canopy and at the lower power level I can run at is where guys are getting 2 grams per watt with a similar rig.

Now, in my setup there is 42 cobs @ very low drive. The other way you can go is with far fewer cobs at a higher drive power. These cobs are still going to be very very efficient at a higher drive. Far more efficient than red,blue LED panels by far.

Let's look at it like this. While my room will be running 42 of them I could just have easilly covered the same area thoroughly with probably 12-13 of them. You have to remember, these Cree chips are capable of 135W each! In my panel I will only be running them at a maximum of 50W each but most of the time 30W-35W each or so.
So I wanted to be sure that some of you who may be interested in building your own cob setup understand that mine is NOT what a typical setup would cost.
 
So for today's update we started some fun stuff. Here I will show those who are

curious how I put together the heart of the system. Well, I got 10 of them put together before I ran out of thermal paste anyways.:thumb:


My heat sinks are a premium 140mm X 80mm design. They have the ability to disapate a lot more heat than these CXB's will give them and that's good because the cooler the chips run, the better. These sinks can passively (with no fan) dissipate 50W of pure heat. That's way more than needed. These run very efficiently and don't produce a lot of heat waste to be dissipated. I have ran a chip at 100W without the sink getting very warm just as a test.

So without further wait.....Let's get started.

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Parts are;
Heat sinks
Ideal metal Chip Holder 50-2303CR
50-2300AN reflector Adapters
LEDiL F13838_ANGELINA-XW 92 degree reflectors
Cree CXB3590 Chips in 3000K CB bin
Cree CXB3590 Chips in 5000K DB bin
M3 X 8mm screws
Arctic Silver 5 thermal paste

Now, the first thing is to look at the chip and the holder. Can you see how the chip has a + sign? Look at the holder and you will see that it too has a + sign. Be sure you lock the chip in the holder with the correct polarity.

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Now, for me it's easiest to get the thermal paste on correctly with the chip in the holder so I went ahead and locked them in....

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Now, adding the correct amount of thermal paste is important. This stuff goes a long ways guys. I can assemble exactly 35 of these chips with 1 full 12 gram tube of paste. How do I know you ask? Because I did 25 that are in my current grow room and I ran out after 10 more today.

Thermal paste is important. Don't skimp on cheap stuff here. I use what I feel is the best stuff on the market. I build electronics for a living so I do know a little something about it. Don't go cheap on this.

That being said, it takes very little. You just want a paper thin layer on the back of the chips. It's also VERY important to get it flat with a razor blade so there will be no air bubbles between the heat sink and the chip.

I start with a thin outline...

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Then with a good flat razor blade I start working it in like a putty knife. It takes a bit to thin it out enough to cover the whole chip.

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Now I go ahead and flip it over and into place. I very lightly snug the 2 screws down. I leave it loose enough that I can rotate the chip and holder back and forth a few times to make sure the paste is seated. Then I tighten the screws.

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Now I go ahead and add the reflector adapter and snug it down with the next 2 screws.

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Now just put the reflector into place and twist lock it on.

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Now repeat the process until you are done with all of them or until you run out of paste and have to order more..

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Are you going to just eyeball the current settings, or hook up an ammeter? I'm curious because I've been ordering the parts for a similar project, but the budget version. :)

I'm only doing a 400W version for a small grow cabinet (2' x 4').
 
Well said, fanleaf. I purchased 4 cob kit and mounted the lights on 16 in centers ( as basic a setup as possible, lol.) and set rheostat at about 25% and will finish vegging and flower stage probably around 60%, just to see what happens. BTW, even at 25%, they are really bright. I think they'll be fine for my needs, a medicinal grower. Very nice lights!
 
415friendly said:
Are you going to just eyeball the current settings, or hook up an ammeter? I'm curious because I've been ordering the parts for a similar project, but the budget version. :)

I'm only doing a 400W version for a small grow cabinet (2' x 4').
Click to expand...

I always put an inline meter with every driver. That makes it very easy to tune the room however you want. I use digital meters that read out line voltage, wattage, current and Watt hours. Heres a small picture.
I run 1 of these on every driver. That way I know how much Blue (5000K) and red (3000K) I'm running and I can keep the whole panel perfectly even from end to end.

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I just came upstairs from the growroom I have going already. Heres a few shots.
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Sent from my android from outer space!
 
You gave us a parts list, do we get supplier lists where you ordered most of the parts? It would take longer for me to hunt down the parts than it would take me to build a 6 cob light... The way you're laying it out, a light will be an easy build..... One thing i can do is follow directions, and I've got the monkey see, monkey do, down pat..
 
Dr Fish said:
You gave us a parts list, do we get supplier lists where you ordered most of the parts? It would take longer for me to hunt down the parts than it would take me to build a 6 cob light... The way you're laying it out, a light will be an easy build..... One thing i can do is follow directions, and I've got the monkey see, monkey do, down pat..
Click to expand...

No problem.
In the next day or two I'll get the list/s together for where I bought all the stuff. I shop and shop and shop around until I feel I've got about the best deal I'll get. For several items I have a few places I'll buy from. It just depends on who's got stuff in stock at that point. :thumb:
 
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