Hadez411
Well-Known Member
TLDR: I need some cheap veg lights for Ma's greenhouse. They need to reach 4-6 feet and provide supplemental sprout/veg light until the summer sun is in full swing. Does anyone know from practical experience if these CXM-9 cobs will effectively throw light that far? Also, 4k is my best guess for an all-around light that is slightly more blue oriented for early growth.
Hi all,
Dear old Ma saw that I had some pretty bitchin pot lights and wanted some for her greenhouse full of garden seedlings which is attached to the the side of the house. Issue is she can't have a bunch of EB strips hovering right over her plants, as the idea is to supplement the sun in the spring and fall, not replace it. Also, she waters liberally with a hose and has some headspace, but not enough to get around a ton of hanging lights. I want to do something that can beam down from near the ceiling which is about 4-6 feet above the canopy.
I'm making a COB build with 10 CXM-9 COBs in parallel, 4000k, each running at about ~430 ma and ~15W. Powered by an HLG-150H-36A.
Running slightly over their "typical" 370ma and 12W. So I figure some big aluminum U-Channel should suffice to cool them with a bit of ambient fanning and a good thermal paste .Costs 140$ for 150W, before adding aluminum channel. wires, etc which I already have from a previous build. Going to make two 4ft U-channel bars with 5 cobs each and 75W per bar. I may solder on some scrap aluminum around each COB to make for some more surface area right next to the cob. I find that U-channel has lots of surface area but can be a bit too long of a distance for the heat to travel efficiently.
Anyhow, every year in her greenhouse her plants get fairly leggy. I suggested she go with about half the watts per square foot that I'm using to flower (120W per 2 sq. ft.), so about 150W for a 4x8 shelf. Also, due to her plants leggy-ness I'm suggesting she go with a 4000k color temp to keep those bastards squat. She's growing a huge variety of plants so I figured "neutral white" was a good choice. An agriculture student told me that the sunlight in Canada during the winter months is super weak and blue-dominant. So I figured, add some more blue and a bit of everything else in the white spectrum, especially since these plants will go outside before they need much red, that or the sun will provide it in another month or so.
The reason I chose these COBs is that they are powered low enough that I don't think they'll need a serious heat sink, their light reaches a bit further down in a tighter beam before spreading out and they're quite cheap, even when compared with the EB strip build I did.
I'm going to use either a styrofoam or red solo cup with a few layers of white paint on it as a reflector cone. The idea being to keep it from beaming anyone in the eyes and collimate the beam a little more. I think I'll put spacers under it or some 1/8" holes along the top edge, so that there's a flow of convected air past the COB. Maybe cobs are different, but I found that my EB strips cooled faster being fanned on the SMD side than on the heatsink side.
Hi all,
Dear old Ma saw that I had some pretty bitchin pot lights and wanted some for her greenhouse full of garden seedlings which is attached to the the side of the house. Issue is she can't have a bunch of EB strips hovering right over her plants, as the idea is to supplement the sun in the spring and fall, not replace it. Also, she waters liberally with a hose and has some headspace, but not enough to get around a ton of hanging lights. I want to do something that can beam down from near the ceiling which is about 4-6 feet above the canopy.
I'm making a COB build with 10 CXM-9 COBs in parallel, 4000k, each running at about ~430 ma and ~15W. Powered by an HLG-150H-36A.
Running slightly over their "typical" 370ma and 12W. So I figure some big aluminum U-Channel should suffice to cool them with a bit of ambient fanning and a good thermal paste .Costs 140$ for 150W, before adding aluminum channel. wires, etc which I already have from a previous build. Going to make two 4ft U-channel bars with 5 cobs each and 75W per bar. I may solder on some scrap aluminum around each COB to make for some more surface area right next to the cob. I find that U-channel has lots of surface area but can be a bit too long of a distance for the heat to travel efficiently.
Anyhow, every year in her greenhouse her plants get fairly leggy. I suggested she go with about half the watts per square foot that I'm using to flower (120W per 2 sq. ft.), so about 150W for a 4x8 shelf. Also, due to her plants leggy-ness I'm suggesting she go with a 4000k color temp to keep those bastards squat. She's growing a huge variety of plants so I figured "neutral white" was a good choice. An agriculture student told me that the sunlight in Canada during the winter months is super weak and blue-dominant. So I figured, add some more blue and a bit of everything else in the white spectrum, especially since these plants will go outside before they need much red, that or the sun will provide it in another month or so.
The reason I chose these COBs is that they are powered low enough that I don't think they'll need a serious heat sink, their light reaches a bit further down in a tighter beam before spreading out and they're quite cheap, even when compared with the EB strip build I did.
I'm going to use either a styrofoam or red solo cup with a few layers of white paint on it as a reflector cone. The idea being to keep it from beaming anyone in the eyes and collimate the beam a little more. I think I'll put spacers under it or some 1/8" holes along the top edge, so that there's a flow of convected air past the COB. Maybe cobs are different, but I found that my EB strips cooled faster being fanned on the SMD side than on the heatsink side.
