qb 648 questions

So, I have a diy 2 board diablo lamp. Originally i had it in a 2x2.5' tent, but i picked up a 3x3 for alittle more space.
I foolishly went and just bought the recommended driver on hlg's site without double checking specs, and just assumed the 320h-2100 would give me 320w or so.
I am sure some of you already know the problem here.

So now that its all rigged up with some seedlings under it, my range of dimming is 25 to 250w.

My questions are
Do you think roughly 28w per square foot will be adequate?
Should i just bite the bullet, and try to source 320h-c2800? Dont see any availability at mouser or digikey during my quick search

thats roughly my wattage with my cob diy it may be even slightly lower with driver losses etc. tho i think i make that up by running them at half the max amperage so the efficiency goes up. anyway here is a photo of a prior grow near the end of flowering. i think 25w and above works fine especially if not supplementing with co2.

That looks to be adequate for my needs.
With my old driver in the small tent, i kept it between 135-150w throughout the grow, and all worked out.
Is that tent a 3x3?

Boatguy said:

That looks to be adequate for my needs.
With my old driver in the small tent, i kept it between 135-150w throughout the grow, and all worked out.
Is that tent a 3x3?

Click to expand...

4x4 with 16 cxb1830s driven at 700ma

Before picking up these boards i had a cob lamp with some gpu coolers and cmt series cobs. It was a beast, not super efficient but grew nice plants.

before diying this light i was using a board type light with blue red and white diodes. kinda like a blurple but not actually, the light produced a blue-white hue rather than pink from those cheap blurples which i had when i started growing 5 years ago. anyway it grew really nice plants until some diodes burned.

so i thought about combining the power of cobs with the superior distribution offered by board designs and went with cob bars. i’m very happy with them i’ve seen many designs using cobs mostly a couple of huge cobs driven at stupid wattages to meet a w/sqft ratio which is stupid. you can hang an actively water cooled single cob led in the middle of your grow tent and run it at 400 or something and get the same w/sqft ratio i do but what its gonna do is its just gonna cook your plants in the middle and not gonna provide good multidirectional lighting to the rest. so cobs are good because they are powerful but boards provide much even distribution and i get that benefit with this design.

and if you have even distribution i think 25w and up is gonna provide satisfying results for most growers. especially if not providing co2.

With good LEDs efficiency is the key.
With a diablo at an efficiency of 3, that is enough wattage.

40w x 2 efficiency = 80
32w x 2.5 = 80
26.6w x 3 = 80

You can see with the math how these new high efficiency boards can match the higher wattage less efficient boards of the past.