2.75 x 2.75 cabinet. Critiques/ suggestions before ordering cobs

[bytal]

So I've got a cab which is just under 8 square feet, which to my understanding means I need around 275 watts for ideal PPFD in and around 1000. I'm going to be using two large extruded heat sinks which I got super cheap off craigslist. They are 24" x 6.5" x 2" According to my calculations they should be able to passively dissipate 144 heat watts combined.

I'm trying to decide which COBS and driver would be best for my application. I feel that I dont need to get all the way to 275 watts with the cobs as I have a couple old Kessil 150 magentas (34w watts) which I used to supplement my T5HO lights and I plan to integrate at least one of them into the build. I'm growing 4 plants which is our legal limit, and intend to do veg and flower in the same cabinet, so I'm planning on using 3500k for the color temp. All the walls in the cabinet are reflective so light will be bouncing all over the place so I figure I will run the COBs without reflectors, that way I can also keep them a bit closer to the canopy. I will also add in an small IR circuit for lights out.

6 x cree CXB3590 @ 1.05A = 210 W
HLG 240H-C1050B
Cost of Cobs & driver = $264

6 x cree CXB3590 @ 1.4A = 285.6W
HLG 320H-C1400B
Cost of Cobs & driver = $284

4 x vero29 @ 1.7 = 250 W
HLG 320H-C14750B
Cost of Cobs & driver =$221

We have pretty cheap power where I live so I'm not overly concerned about my electricity bill, however I do like things to be efficient, and the crees @ 1050 would definitely be the most efficient. I couldn't find lumen info for the crees at that low a drive current so I couldn't estimate how it would compare lumen-wise to my other two options, but I imagine it would be quite good, especially if I supplemented it with both of my Kessils. It would also be operating at the lowest temperatures, putting the least strain on my heatsinks.

Recommendations or critiques?
Thanks.

 

[Airwalker16]

The HLG "B" version drivers have external dimming when you add a potentiometer. So get the most power you possibly can from your driver/cob combination. You can just dim it if it's more than needed. Better to have it and not use it, then not have it and need it later.

 

[Airwalker16]

Also, Vero's and crees are great. But expensive options when there's alternatives like Citizens.

https://cobkits.com/product/citizen-clu048-1212-80cri-gen6/

@CobKits

 

[Dave455]

So I've got a cab which is just under 8 square feet, which to my understanding means I need around 275 watts for ideal PPFD in and around 1000. I'm going to be using two large extruded heat sinks which I got super cheap off craigslist. They are 24" x 6.5" x 2" According to my calculations they should be able to passively dissipate 144 heat watts combined.

I'm trying to decide which COBS and driver would be best for my application. I feel that I dont need to get all the way to 275 watts with the cobs as I have a couple old Kessil 150 magentas (34w watts) which I used to supplement my T5HO lights and I plan to integrate at least one of them into the build. I'm growing 4 plants which is our legal limit, and intend to do veg and flower in the same cabinet, so I'm planning on using 3500k for the color temp. All the walls in the cabinet are reflective so light will be bouncing all over the place so I figure I will run the COBs without reflectors, that way I can also keep them a bit closer to the canopy. I will also add in an small IR circuit for lights out.

6 x cree CXB3590 @ 1.05A = 210 W
HLG 240H-C1050B
Cost of Cobs & driver = $264

6 x cree CXB3590 @ 1.4A = 285.6W
HLG 320H-C1400B
Cost of Cobs & driver = $284

4 x vero29 @ 1.7 = 250 W
HLG 320H-C14750B
Cost of Cobs & driver =$221

We have pretty cheap power where I live so I'm not overly concerned about my electricity bill, however I do like things to be efficient, and the crees @ 1050 would definitely be the most efficient. I couldn't find lumen info for the crees at that low a drive current so I couldn't estimate how it would compare lumen-wise to my other two options, but I imagine it would be quite good, especially if I supplemented it with both of my Kessils. It would also be operating at the lowest temperatures, putting the least strain on my heatsinks.

Recommendations or critiques?
Thanks.

Luminus cxm22 from cobkits would be great efficiency/cost option.

 

[InTheValley]

4 luminus, 1- hlg-320-c1400B, with reflectors, and holders,

$203

Get the lidl angelina reflectors, that would rock your area, 800 PAR is the magic value for these at 21 inches, @ 300watts.

 

[Airwalker16]

4 luminus, 1- hlg-320-c1400B, with reflectors, and holders,

$203

Get the lidl angelina reflectors, that would rock your area, 800 PAR is the magic value for these at 21 inches, @ 300watts.

Do not use reflectors or lenses in a closed area like a can or tent. They are for open spaces to contain the light.

 

[InTheValley]

Do not use reflectors or lenses in a closed area like a can or tent. They are for open spaces to contain the light.

i thought so too, because i was told i didnt need them, and i did endup getting them recently, and they help tremendously. the amount of reflection from the walls is overrated, HIGHLY. To each their own tho,. I got an additional 30% PAR boost from them, and it cut SOME of the walls reflection, but not to an extent that was was being lost without the reflectors. It would be different if your plants grew ABOVE the light, but in a 3x3 area, it helped ALOT,

 

[bytal]

The HLG "B" version drivers have external dimming when you add a potentiometer. So get the most power you possibly can from your driver/cob combination. You can just dim it if it's more than needed. Better to have it and not use it, then not have it and need it later.

I was thinkung of doing that, but I wasnt sure how much that affects the efficiency. I know a resistor creates heat so it does use some energy. I assume not as much energy is used by the resistor, as is saved by not running the LEDs as hard..

 

[InTheValley]

the yellow line is the shadow cuttoff from the reflectors. there was no need for photons to even go there, so, in my case anyways, reflectors work perfectly.