LED

Good Answer by Numbers.

1.5*1.5 = 2.25 m^2 Assuming 18 hour operation 600PPFD gives you 38.9DLI ('at the diode'). this may be 5-10% too much, but it is better to err on the high side. From a typical hanging distance of 18", give or take, you get nice even coverage and don't sacrifice overall average intensit across canopy -- the bar/strip style being better distribution than a quantum board. The more spread out the diodes are the better. 2.25 m^2 * 600 PPFD = 1350 umol/S of PAR. Any light that produces 1350umol/s of par is strong enough to 'max' out daily photosynthesis given ambient CO2 levels. Any combination of lights that add up to this is good too. Common sense applied as far as distribution of diodes and how evenly you can cover the area with 'good' light. If you want the option to grow photoperiods... 1350 / .67 = about 2000 umol/s of PAR is your target. When you do autos or vege phase you'd run this light at 67% from normal hanging distance. Being off by 50-100 umol/s for either of these numbers is not the end of the world. As i said it may be about a 5% overshoot. Local co2 levels, temperatures and such will all make a slight difference as to how much a plant can handle per 24 hours. Efficacy of the light will impact how many watts you need. Beware, most light manufacturers lie on their spec sheet. Compare to info from samsung.com. Any deviation in watts per diode compared to how they were tested reduces longevity, reduces efficacy in a fairly significant way very quickly. Another trick they pull is using the specs for a diode that isn't even used on the grow light. When you see "3.14umol/J" you know it is a lie because only a 6500K CCT diode hits that efficacy, or maybe it was a 5500k, in either case tthis should not be the bulk (and zero of 6500k) of the diodes let alone the only one used. They lie like crazy. So, if you do a rough estimate of dividing total watts by total number of diodes and it is larger than .20watts/diode, be skeptical of any high-end specification, because it's likely bullshit. That'll tell you if it is a high-end light or a bunch of marketing nonsense. Efficacy is what you 'should' pay for and not empty promises based on lies. Unless they made a typeographical error on their website, the new 2024 FC4800 models have been cheapened up. If the diode count is proper, i am wrong, but last i looked they turned an awesom 'pro' light into mediocre trash. Hope it was a mistake on their website. do the simple math and if the watts per diode is sky high compared to .2watts/diode, then it was no mistake.

Autos tend to like slightly less light than photos in my opinion. Covering the full area is better than going for a wattage. Then turn down the light to suit your ppfd. Ideal coverage for the 480w is a 4 x 4 or 120cm x 120cm. Those lights will more than do a job. I don't tend to turn the lights up to full power when growing autos. Less is more kind of thing. I have run that many autos in that size space and had good results. What size pot do you plan on using? Good luck with whatever you choose. Peace up