Renfro's 760 Watt COB LED Build -> 1kW DE HPS Replacement

Hey folks, I didn't know if I should put this here or in grow room design and setup so I chose here.

My flowering room that run during the daytime gets a little warmer than I wish when it's 90+ outside. I have two rooms on a flip so I can't run this room at night.

I currently have about 10kW of HPS in there with 6 overhead DE HPS lights as the primary light source, the rest is side lighting (vertical HPS)

So I am building these 6 LED lights to replace the DE HPS lights.

I intend to use Luminous CXM-22 Gen 4 3500K 90 CRI COBS. Here is a chart showing the gen 4 compared to some other cobs.


I will be using 12 cobs per light and I will drive them at 60 watts each using Meanwell HLG-240H-54B drivers. The DC output from the drivers totals 720 watts, the input wattage is about 760.

The lights will be dimmable and I intend to dim each driver (row) individually, may be overkill but it's not that much more cost.

BJB Holders, 133mm pin fin heatsinks, bunch of wagos, Angelina Reflectors for BJB Holders, Arctic MX4, wire...

I am planning to experiment with a DROK Power Meter so I can see what the numbers are for dimming. This again may be overkill. I will experiment and see if I can run the positive output conductors from all three drivers thru the sensor coil on the DROK and have it accumulate the readings. That would be what I am after and if it works I will order 5 more of those and some project boxes to mount them in and put the dimmer knobs on. I am not concerned with monitoring the power on the AC side, just the DC output.

I intend to purchase an Apogee MQ-500 meter so I can tune the light, COB spacing and dimming.

I will be using these lights over a 4x4 foot area but the plants do get a little wider so I allowed a few extra watts. If I calculate by 16 square feet I get 45 watts per sqft. If I decide I want to go bigger in the future I could add another row of cobs and another driver but lets see what this does as I really would like to believe that I can replace 1150 watts of HPS with 760 watts of LED while reducing the heat load by at least a ton.

I am considering a frame built of aluminum T- Slot channel so I can easily adjust the cob spacing. I may only do this on the first light so I can tune the COB spacing to get the light spread how I want it. If the cost isn't insane it would be cool to build them all that way but chances are the other 5 lights would be made of aluminum angle and pop rivets. Probably save a couple bills a light.

I am thinking of starting with the outer cobs being about 40 - 42 inches apart, any thoughts on that for a 48 x 48 inch coverage?

So I have a lot on my plate with this project. Any ideas, thoughts, positive motivation and whatnot are welcomed. Please tag along for the ride. I am ordering the first round of parts tomorrow from @CobKits so we can get this party started and build some lights!

Subbin

Why cobs cuz and not LED?
Interested to see how this manoeuvre of yours gos!
Good luck man

Frank Cannon said:

Why cobs cuz and not LED?
I

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Definitely be paying attention to the results that a grower of your caliber will achieve with quality COB LED emitters...

Renfro said:

I intend to purchase an Apogee MQ-500 meter so I can tune the light, COB spacing and dimming.

I am considering a frame built of aluminum T- Slot channel so I can easily adjust the cob spacing. I may only do this on the first light so I can tune the COB spacing to get the light spread how I want it. If the cost isn't insane it would be cool to build them all that way but chances are the other 5 lights would be made of aluminum angle and pop rivets. Probably save a couple bills a light.

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Sounds like a good plan. Will you run a grow with the 1st light before building the others? I'm thinking you may be satisfied with a 480w driver.
I suggest experimenting with the reflectors, I think you'll find that you don't need them or maybe just on the outside rows. Never forget, VPD rules with LED!

1212ham said:

I'm thinking you may be satisfied with a 480w driver.

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Well I would still need a 240 watter for the last row of 4 cobs. May as well make them all the same since the price is a wash pretty much, plus I can dim each row individually this way and that could be handy if a plant had taller branches under part of the light. If nothing else it's cool as hell.

1212ham said:

I suggest experimenting with the reflectors

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This is my intention and the Apogee MQ-500 will help test and see what the best configuration is. Thats gonna be the fun part! I will be sure to document my findings here for everyone to see.

Frank Cannon said:

Why cobs cuz and not LED?

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COBs are LED. And why not? I like them. They performed so amazingly well in tent and that light was built with the gen 3 cobs. Here is a comparison of the gen 3 and gen 4 CMX-22. So I am getting even more light per watt with the gen 4 chips. Never know, in 3 or 4 years after the lights have long paid for themselves in energy savings the chips may have advanced so far and I could just pop new chips in the holders and have a new light that puts out even more light per watt and perhaps even less heat. The big appeal to me is the potential of a future upgrade that costs 250 - 300 bucks and brings the light up to date with current tech.

One thing I noticed about the DROK meter is it only has 0.1 amp resolution. That would let me tune in 5.4 watt increments running at 54 volts. Should be good enough for what I am doing with it.

Should I power the DROK off one of the 54v COB strings or provide it with it's own power supply? Working current is 10ma with backlight and 4ma without. Supply voltage is 5 - 90 vdc. I am leaning towards powering it off one string.

Just for ease of reference I am posting some data sheets here:

https://www.meanwell.com/webapp/product/search.aspx?prod=HLG-240H

https://download.luminus.com/datasheets/Luminus_CXM-22_GEN4_Datasheet.pdf

Here is the material I am considering for the frame on the adjustable rig.

https://8020.net/1010.html

If I use the right fastners I can set it up so I can adjust the row spacing pretty easy. If I can mount the cobs so they can be moved on their rails then I would have total adjust ability of the spacing. I can also mount the project box with the DROK meter, dimmers and female power cable connector. It might be such a clean setup that I won't be able to resist making them all that way. Plus like legos I could easily add cobs, make lights bigger or smaller by simply adding more rows each with it's own driver. I am kinda digging this LED thing and it appears that I have ventured deep down the rabbit hole. Never saw this coming 5 years ago. LED tech has come so far. I can't wait to see what the next 5 years brings.

that first graph is the gen 3s

last graph is gen 4s vs gen 3s

as with the gen 3s, nothing in its price range touches it, you gotta get up over $30 a chip to get any better

CobKits said:

that first graph is the gen 3s

last graph is gen 4s vs gen 3s

as with the gen 3s, nothing in its price range touches it, you gotta get up over $30 a chip to get any better

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Ahh thanks for that, I was thinking that first graph was gen 4. So the gen 4 would rank even better on that graph than I suppose.

correct

Yeah sorry boys, I mean't why cobs and not LED panels or strips, was not aware of the interchangeability factor of cobs!

This should be good.......cobs get the job done.

Good luck grower

Frank Cannon said:

Yeah sorry boys, I mean't why cobs and not LED panels or strips, was not aware of the interchangeability factor of cobs!

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The LED panels like quantum boards are what I am considering for the future side lighting upgrade. They would be perfectly suited to the close distances that I am working with. If I run them at the right wattage I think I can get them pretty close. As it stands my 400 watt HPS lights on my row ends get pretty close at about 6 inches sometimes but with fans blowing between the plants and lights I keep them from burning. A more even light distribution would be awesome. I can see a future where most of my lighting is LED. A bright future lol.

Renfro said:

The LED panels like quantum boards are what I am considering for the future side lighting upgrade. They would be perfectly suited to the close distances that I am working with. If I run them at the right wattage I think I can get them pretty close. As it stands my 400 watt HPS lights on my row ends get pretty close at about 6 inches sometimes but with fans blowing between the plants and lights I keep them from burning. A more even light distribution would be awesome. I can see a future where most of my lighting is LED. A bright future lol.

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hey renfro did you do a thread on ya tent with led what did you end up pulling

Interested to see what you make of them Ren.

Nice to see a COB build too, don't see so many these days.

ozziebud said:

hey renfro did you do a thread on ya tent with led what did you end up pulling

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Out of a 2x4 I pulled 15.5 zips with 3 runts (open canopy space). Nugs were very dense and terpene production was greater than my big rooms. Needless to say I was impressed with the combination of flood and drain with the LED. No complaints.

coreywebster said:

Nice to see a COB build too, don't see so many these days.

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Right?

maybe people dont post about them as much, reasonably steady over here though it seems its shifted more toward larger grows

I am definitely already planning to build 3 more lights, each with 16 cobs for my veg room, cover a 5x5 with each fixture. That will save some watts and lighten the load on that AC as well. I only have a 14k BTU/hr portable in there. Used to handle 3 x 1kW SE MH just barely but adding the tent in this winter made for extra heat load in the summer that it can't handle so I have only been running the two 1kW CMH in there for vegging along with the LED tent. So I am only lighting 50 of 75 sqft of veg canopy due to the heat.