Help with cob

[eLite_gRowr]

Ladies and gentlemen, I come to u tonight for help with a new COB setup in the flower room. Currently I’m in a 10x10 room running 4-1000w Hps. All the talk and research I have done has me very interested in making the change, kinda one of those out with the old in with the new deals. At the same time, never would knock hps cuz they’ve got me this far and quite frankly they work well, I just want change. Definitely looking into DIY COB cuz I’m always up for the challenge and from researching it seems to be a bit cheaper than prebuilds. I see so many different cob lights, heat sinks, Cree, this is where I need help lol. The part actually choosing what to run. I could read some more but I wanted to turn to the experts (YOU) and get first hand advice. Any information/help is very appreciated.

 

[GrowLightResearch]

I would recommend making an 11'x11' fixture which would give you very good coverage over a 10'x10' area.
Use between 60 and 78 44" Bridgelux Gen2 BXEB-L1120Z-30E4000-C-B3
Make the fixture with 20/26 rows of three 44" strips.
Make the distance between rows all the same.
Use one Mean Well HLG 185 watt driver for every two rows. (buy with free shipping e.g. Arrow)
Run the supply wires to the strips through a 0.01Ω 1% resistor to measure current with a voltmeter. Vishay Dale part number: SR3R0100FE66
Run the same amount of current in each set of 6.
If you want to use a 48V supply and wire them in parallel, measure the forward voltage (Vf) of every strip and match the Vf in sets of 6.
Otherwise wire them in series. Series is best for uniformity but uses high potentially fatal voltages.
In parallel one 0.01Ω resistor for every strip, in series one for each set. For me this is a MUST. Especially with parallel wiring as the currents through each strip will be unbalanced. You need to know they are not unbalanced by too much. The only way to know is to measure.

Why?
A single row strip needs no heatsink.
Four 1000W HPS is about 400,000 lumens (I like very round numbers)
Each strip is about 4,700 lumens.
Times 60 = 282,000 lumens @ 700mA
Times 78 = 366,600 lumens @ 700mA
You can just about double the output as these strips can be run up to 1400 mA without getting hot.

You could scale it back to less strips but I would not use less than 51.

Why not CoBs?
Too much work to build.
Cost is higher per lumen
Heatsinks make a significant increase in cost and weight.
CoBs have shitty uniformity, strips will give you ±5% uniformity across the entire 10x10 area.

 

[wietefras]

Four 1000W HPS is about 400,000 lumens

You're comparing lumens? Seriously?

Samsung has double row strips which means you need half the number of strips. Which makes it a hell of a lot quicker to build a fixture for such a large room. You need to hang the light a bit higher when you use less trips, but for a large room you wouldn't want to hang the strips at 5" above your plants anyway.

 

[1212ham]

What he said. ^ I would be inclined to make 4 independent lights, 4x4 or 4x5.
Lots of good info here. http://ledgardener.com/diy-led-strip-build-designs-samsung-bridgelux/

 

[GrowLightResearch]

I would be inclined to make 4 independent lights, 4x4 or 4x5

I agree. It's difficult to make a 11x11 with 98" angle brackets. The size of the actual fixture(s) depends on the size of the strips and materials used.

Probably more practical to use 88" and 44" dimensions. My head hurts thinking about it. But you are right, multiple smaller fixtures.

 

[eLite_gRowr]

Thanks for all the input! I definitely will begin looking into strips. Honestly, I didn't pay them much attention due to not knowing much about them and I was stuck on cobs cuz well, that's what most ppl are talking about right now. It's crazy that these strips can pack that much of a punch! Again, Thank you guys! I'm sure once I dabble into strips ill have some more questions

 

[GrowLightResearch]

Samsung has double row strips which means you need half the number of strips.

Which also means you need a heatsink to run them at the current of a single row strip that does not need a heatsink.
Or you can run them with less current so they don't get too hot. But then you have the output of a single row strip that you paid twice as much for.

 

[wietefras]

So what? You need to mount those strips to something anyway. Might as well be an aluminium U-channel.That's your heat sink done. Boom! Put some aluminum angle on both ends and you have a frame.