711w Vero 29 gen 7 DIY fixture, do I use reflectors or nah?

Some quick stats on my light im building

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9x Vero 29 Gen 7 3500k 80 CRI COBs driven at 2100mah 38.7v 79W x 9 = 711W



48" x 48" = 1.49 m²
711W @ 49% efficiency = 348.39 PAR watts
348.39 PAR W x 4.75µmols = 1654.85PPF

Accounting for 10% reflection losses = 1489.37 PPF

1489.37 PPF / 1.49 m² = 999.5 PPFD

Plan on driving with 2x Mean Well HLG-320H-C2100B drivers, and I will use ample pin heatsinks for cooling and the rapidled 4x4 canopy substrate.


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My question i am having right now is if I should use Angelina 90 degree reflectors or not.

I was thinking either running the light at 12"-14" height with no reflectors to allow a lot of light diffusion off the sides of my 4x4 tent so I can get the most even light possible, or I could run it at 18"-24" height using the angelina 90 degree reflectors and run it like that instead.

Which would you guys pick? I am leaning for the 12" height with no reflectors rn.

I made the same unit using hlg 240h-c2100b, and run 3000k 90 cri about 8-12" without reflectors....happily.

What'd your PPFD at with that set up? I know i calculated the ppfd of my light bt real work testing at 999.5PPFD but i'd expect more like 900-920PPFD with an actual par sensor of you measured PPFD manually.

Id be willing to drop to 850ppfd to run 90 CRI instead of 80 CRI but any less PPFD at 711w and I would like to avoid it.

just curious why you'd choose the 36V veros at that wattage.... the 68V veros are considerably more efficient in that range

I have gotten better results in tents with no reflectors on my cobs.

I had no idea, i'll use the other veros then!

CobKits said:

just curious why you'd choose the 36V veros at that wattage.... the 68V veros are considerably more efficient in that range

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At what wattage are the 36v more efficient than the 68v? And by considerably, do you have a rough idea of what kind of % gains would be had with the 68 over the 36 at OPs wattage of ~80?

frigginwizard said:

At what wattage are the 36v more efficient than the 68v?

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none. 68V is more efficient across the board (but less so at lower wattages)

frigginwizard said:

And by considerably, do you have a rough idea of what kind of % gains would be had with the 68 over the 36 at OPs wattage of ~80?

Click to expand...

~5%

https://www.rollitup.org/t/led-vs-cmh.937211/page-2#post-13437735

note they are called "72V" in that chart

great chart, thanks

CobKits said:

none. 68V is more efficient across the board (but less so at lower wattages)


~5%

https://www.rollitup.org/t/led-vs-cmh.937211/page-2#post-13437735

note they are called "72V" in that chart

Click to expand...

I have one more question if you dont mind.
If I was going to put 4 of the 36v cobs in series on an HLG-320H-C2100, is switching to the 68v cobs as simple as wiring 2 sets of 2 cobs in series and wiring those 2 sets in parallel on the same driver?