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


New Member
Luminous CXM-22 Gen 4 3500K 90 CRI COBS. I will be using 12 cobs per light and I will drive them at 60 watts each using Meanwell Horticulture Lighting Group-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 have an Apogee MQ-500 meter so I can tune the light, COB spacing and dimming.

I am using a DROK Power Meter so I can see what the numbers are for dimming. This may be overkill. I am not concerned with monitoring the power on the AC side, just the DC output.

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.


Bearer of the Golden Afro
Super Moderator
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.
Awesome thread!
I totally believe that you can do that.
I'd like to pick your brain sometime about that LCD. I'd like to put one on all of the lights I have that dim. Just a cheap basic one so I can read watts on the light as I turn them up or down. Thanks!


Vapor Master
Staff member
Super Moderator
Impressive build man. Looks like you have your own LED grow light mini factory. Very curious to see the numbers on your Apogee in a 4x4. :p


Being a complete fng to growing and grow lights, you might as well be posting pics from inside nasa. I’m slowly learning though.

Cute dog, guessing rott or rott mix, I’ve got 2 rotts now, and have had a number of rotts since I was a kid. Hard headed creatures but they’re lovers.

Desert Plants Genetics

The Collector
Super Moderator


LED Specialist
Solid build on your DIY light @Renfro (y)

We are currently developing a new COB with onboard driver. It will feature our 6-band RGB white spectrum and 0.5W chips. We are shooting for a 35W LED to cost about $35 with shipping for all the DIY builders out there. Just slap it on a heatsink, connect your power cord and you're done! :)


LED Specialist
Actually I'd like to offer you some to test free of charge when the first samples are ready. I'd love to get some feedback from some DIY guys like yourself. If interested let me know, but either way I'll follow along per your request :)


LED Specialist
Nah, I have my own forum for that. I really like what you're doing with your DIY setup. It's a very high-end DIY rig and I can tell you take a lot of pride in your work. I'm finalizing details on the COBs now with the manufacturer and am about to order up some test samples. As long as they check out just fine, how many would you want?