Ha, answered my question as I was writing it. Cool, you won't regret doing those COB's. You'll need the thermal paste in any config, imo it's better than thermal glue, specially if using those COB holders. Anything goes wrong or you want to change/upgrade and the thermal paste is doable, thermal glue and you'll likely destroy anything attached to it. Good luck, will look forward to your first COB grow!
The combo will be awesome, good plan
Not familiar with those, get/check that through the seller before buying it, had a quick look, looks like you could adapt the holders or maybe use their mounts. Ask them what the options are for mounting 3070 COBs.
Not an expert in this but the standard high end is 1400ma or 50%, you're thinking like 2000/2A, they'll run hot, you'll need good cooling driving them that high.
Blue Dream is exploding under the CMH, here she is at Day 20 12/12, Day 6 under the CMH. It's massive after the stretch, second pic shows a 20" fan sitting on top of a cooler, the seam between the reflective walls just behind it sits at 48". Bud sites popping everywhere, I can see why this is a popular strain, beautiful smell too, not sure what pheno I pulled but this things's going to produce some nice bud...
Thanks Bubba, this one PPP with the high cola wasn't in my main flower room or under CMH. It was in a 3Gal fabric pot, in my 2x2x4' breeding tent under 200w of a cheap Alibaba 3000k COB warehouse LED spot light, plus a DIY "panel" with 3x 13w 2700k CFL's and 3x 10w 4000k LED bulbs, 270w of mixed white spectrum, blew me away what it produced by just adding some CFL's and LED bulbs that I threw in there for heat. Wasn't expecting anything close to what it yielded or I would have had a tomato cage or trellis for support. By the end of the run I just had that large cola leaning against the wall of the tent for support, as soon as I took it out it just flopped over with weight, and that main cola wasn't pollinated so it's just some extra smoke
Cheers...
Not sure which light you're referring to, in the tent I had the COB light and CFL/LED bulb panel close, like 8-10" from the canopy, the main colas were almost touching the CFL/LED panel.
Are you planning the COB's in addition to the LEC unit? If so you could start with 2 for supplemental that's 100w actual @1.4A or 150w @2A (you were taking about driving them higher). See how they fare and the heat, go from there. If you're running them at either one of those amperages you could cover 18x18" well I think, maybe a little more lie 18x24" but stretching footprint has diminishing returns. Consider footprint in sq. feet covered vs. number of plants, then fill that footprint with either more/smaller plants, or less larger plants. I think you want around 25w/sq. ft. minimum, I'd go 30w/sq. ft. for flowering on their own, 20-25w for supplemental if you plan to mix them with the Elite Agro bulb. I haven't run those COB's yet, just going from reading stuff in the DIY forums, perhaps someone can correct me if I'm off on this.
If you go 8-9 sq. feet and throw in the CMH, then 1x 50w COB running at 1400ma on each end angled to cover the canopy, you're going to have a very nice setup. If you can, allow some height to dissipate the heat and you'll be good to go with that in an 8-9 sq. ft area. Both would be too much in 4 sq. ft. imo. Start popping beans, that'll drive you to get the builds done quicker