Lighting Building 2 racks of three 35W COBs (for low ceiling)

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I am building two racks, each with three 35W COBs and dimmable drivers.

I tried out one 55W Autocob in my 5' tall room, and it was too strong and bleached the top leaves of my plants. I spoke with @BigSm0 at Autocob.net, and he suggested 35W COBS, so I'm giving it a shot with his helpful guidance. The two racks of 3 COBS will come in at under $250 each, cheaper than the LED panel I was looking at, and more versatile.

My room is in an unheated area. It is 4'x4'x5". In cold months I will still be using my 600W HPS for heat, which means I will need to dim my COBs for lux and heating reasons. My HPS has 25/50/100% settings, so with dimmable HPS and COBs I can play with the two to control both heat and light intensity. In summer, I was often going over 100F in the summer, this should help with that issue. I am excited about the possibilities this configuration will lead to.

I originally was going to do one rack, then realized two will give me more flexibility. Each rack will have it's own dimmable driver. @BigSm0 spec'd out the drivers for me, and sold me the six 35W partial COBs (cobshop.net). The partial COBs have Citizen version6 1812 3500k 90cri. Today I attached the COBs to aluminum L brackets. I cut the L brackets with my reciprocating saw with a metal blade (took 6 seconds to cut two at a time). I attached the COBs with 3/8" long 10-32 round head machine bolts and lock washers. These bolts fit perfectly (fyi - had trouble with longer ones). Originally I had planned to put a strip of L bracket on the ends, but they seem so sturdy I decided to skip it. So I just cut the L brackets and screwed the COBs on---very easy.

I am waiting for the MEAN WELL HLG-120H-48A drivers that were spec'd out for me, then I'll post the final pics. (Amazon product ).

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Oh baby! What a Beautiful light. So happy you went for this option instead of giving up on the cobs for being to intense. Can’t wait to see the final!
Me too! What spacing to you have between the cobs?
 
The racks are wired and working. I used 18 gauge solid core doorbell wire and wired them in parallel. The racks are bare bones, just two L-brackets with the COBs and a power supply bolted on, but they should meet my needs. I need to rearrange some things in my grow room to hang them, and I'll be doing a grow with them this spring.

The dimmer buttons on the Mean Well power supplies do not seem to be working, perhaps someone has a suggestion. Don't know if I'll need them, but I would like to have the option.

Thanks to BigSm0 at cobshop.net for help with, well, everything. He spec'd out my lights and power supply, sold me the partial COBs, and helped with my wiring issue. His partial COBs and quick responses to my many questions made this an easy DIY project.

Here are the completed pics.

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The racks are wired and working. I used 18 gauge solid core doorbell wire and wired them in parallel. The racks are bare bones, just two L-brackets with the COBs and a power supply bolted on, but they should meet my needs. I need to rearrange some things in my grow room to hang them, and I'll be doing a grow with them this spring.

The dimmer buttons on the Mean Well power supplies do not seem to be working, perhaps someone has a suggestion. Don't know if I'll need them, but I would like to have the option.

Thanks to BigSm0 at cobshop.net for help with, well, everything. He spec'd out my lights and power supply, sold me the partial COBs, and helped with my wiring issue. His partial COBs and quick responses to my many questions made this an easy DIY project.

Here are the completed pics.

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My pleasure. Very happy things worked out and seems you ended up with the best option. It also looks like a nice clean job too.
The dimmer is under the black rubber plug. You would remove it and stick in a small Phillips screw driver. Some I have seen have a set start and stop where others just spin continuously. A wall watt meter should help fine tune the wattage if you need. Can’t wait to see some ladies below it.
 
The dimmer is under the black rubber plug. You would remove it and stick in a small Phillips screw driver. Some I have seen have a set start and stop where others just spin continuously. A wall watt meter should help fine tune the wattage if you need. Can’t wait to see some ladies below it.

I was pushing the rubber 'buttons'.

What Wattage should I be at?
 
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I was pushing the rubber 'buttons'.

What Wattage should I be at?
I’d stay around 50-75 watts for the space and see how the plants react. Would be nice to crank them up but I don’t think that’s going to happen. Something that’s really beneficial here is driving the 50v cobs at 830ma and even dimming on top of that is giving you great efficiency.
 
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