Quantum Build opinions

[fujiyama]

Would these be too bright in a 2x4' space? Will I notice a difference using separate lights for vegetation and flower?

Vegetation light:

3x QB304 4000K
Slate 2 Triple Heatsink
HLG-480H-3500B Driver

&

Flower light:

3x QB304 2700K
Slate 2 Triple Heatsink
HLG-480H-3500B Driver

[sdfoster22]

It does seem a little overkill to me. In a 2x4 35w a sq/ft would be 280w. You would be close to 380w with that driver.

You could go with the hlg-320h-2800b and get around 300w according to hlg's spreadsheet.

You could do separate veg/flower lights, or you can do an all in one with 3000-3500k diodes. A lot of people have great results using those spectrums for veg and flower. Some people even have good results with 4000k for veg and flower. You can look up people's results on various forums.

[DaveJonesFan]

I would certainly stick with 1 multipurpose light for the space. 3000-3500K, as sdfoster22 has said will do you very well all around. Having the 80cri floor on white LED is a true game changer vs the abysmal 20cri HPS or 65cri MH lights when 2 lights were beneficial for swapping. Not to mention the real reason to swap in the HPS for flower wasn't even the exclusively yellow/red spectrum, but just the massive increase in light output and efficiency HPS provided. Having 2 HLG setups (even just the boards) for swapping between in the same 2x4 space sounds like an exorbitant expense in today's lighting landscape.

As for brightness, I second sdfoster again on the downsized 320H driver likely being enough, but pushing quanta with LED's is fun and much softer on plants than HID, so the 480H in flower running higher than the 320H but lower than full blast is likely where I would position myself if it were my build. I would run active cooling solution on the slate 2 triple with that sort of power as well, if you haven't taken that into account, you may be able to more easily passively cool on the 320H. Potentiometer would be a must, to facilitate that you'll be able to dim during veg as well. You certainly wouldn't need anywhere near the 480H level power for that space for vegetative growth!

[fujiyama]

Thanks for sharing your thoughts

I'm currently running 8x 3500K 80CRI Cree COBs in a 2x4' area

I want to try the same light with 2700 and 4000k Cree COBs eventually, but the quantum boards caught my eye.

Assume you have multiple 2x4' areas and require multiple lights..

Tent one: 3x QB304 Vegetation light
Tent two: 3x QB304 Flower light
Tent three: 8x Cree COB (Both)

I like overkill I just don't want to do any harm to the plant. Potentiometer is a given for all of these lights

What if I were to use an HLG-320H-2800B for the veg light, and a HLG-480H-3500B for the bloom? Would this give me a maximum of 300W for veg and 380W for flower? Do the quantum boards take well to being dimmed, like COBs do?

[DaveJonesFan]

COBs are still pretty great. The QB stuff is just pulling away from them in the peak efficiency and has some simplicity of design and implementation stuff going for them. The strips with mid power diodes being another popular choice these days.

If you are having multiple areas for veg and flower, then of course multiple lights would make sense, and fine tailoring the color temperature and wattage for each space's function makes sense as well.

You are not likely to do much harm to the plant with lots of photons as long as the heat is managed, the extra light will help penetrate more energy deeper down to lower sites, but the canopy will only be able to use as much of the energy as the other potential limiting growth factors will allow, and beyond that will be wasted, and therefore potentially contributing to a loss of efficiency in terms of creating actual organic matter. CO2 is a key first amendment for increased photosynthesis in the presence of luxury light levels. Higher transpiration rates can cause nutrient to water ratios to need be more fine tuned according to the different input parameters to push peak growth rates.

The 320 for veg, 480 for flower would make for a nice bit of overkill to play with in those spaces and with a good true 100K ohm potentiometer for each driver, the drivers will dim the quantum boards admirably.

[fujiyama]

Thanks! You've given me a few things to think about, including possible cooling and CO2 additions. I see these two builds in my future along with two more COB builds. Absolutely, the COBs are great! I was able to achieve even coverage using 1 COB per 1 square foot. I just have the bug and want to try a board. Heat (thankfully )isn't a problem here.

Realistically I'll be pressed to see a difference using 2700, 3500 & 4000, but the inside wants to know!

[DaveJonesFan]

I have a flower space with 3500K Vero COBs and recently QB's were added to push me into the silly overkill levels, QB288 V2 at 3000K. The 3000K is just yellow enough to sort of ruin the amazing work environment the closer to neutral white balanced 3500K lights were giving me so I dim them down when I want to get that more accurate look at the colors of the plants.

[sdfoster22]

You need to measure the resistance of the 100kohm linear taper potentiometer. They range between about 90k-110k. If you get a natural 110k you can push the driver beyond max. The same goes with if you find a 100k ohm and add a 10kohm resistor in series. You'll only have 10%-110% dimming though. But you could get even more than 380 and 300 potentially.

At least this is what people reported on riu when I asked about it.

[fujiyama]

I have a flower space with 3500K Vero COBs and recently QB's were added to push me into the silly overkill levels, QB288 V2 at 3000K. The 3000K is just yellow enough to sort of ruin the amazing work environment the closer to neutral white balanced 3500K lights were giving me so I dim them down when I want to get that more accurate look at the colors of the plants.

That's good to know . Hoping the differences will be noticeable.

You need to measure the resistance of the 100kohm linear taper potentiometer. They range between about 90k-110k. If you get a natural 110k you can push the driver beyond max. The same goes with if you find a 100k ohm and add a 10kohm resistor in series. You'll only have 10%-110% dimming though. But you could get even more than 380 and 300 potentially.

At least this is what people reported on riu when I asked about it.

Question.. if I push the driver beyond max with a 110k pot, can harm be done to the boards or the driver?

I'd be happy with dimming capabilities of 30%-95%, so 10%-110% is more than enough.

[DaveJonesFan]

Is that how that is? I don't know exactly how that works, but I think my understanding was a bit different on the pots. I thought it was the 0-100% 1:1 with 0-100k ohm pots on the driver, however some of the common inexpensive pots with the higher tolerances of up to 10% (even on some data sheets I was looking at) can indeed come up short of the full 100k ohms the driver leads need to reach 100%, so some add the 10k ohm resistor as the 10% tolerance coverage. This would potentially put an up to 10% deadspot near the top end of the dial, and increase the bottom floor of the dial similarly. The HLG series drivers under 320H level I understood to only dim to 10% on the bottom end even if pot bottoms out to 0 ohm, with the larger drivers allowing the units to dim to turn completely off at 0 ohm. I thought the 'extra current' the CC drivers have been known for is available at the 100% point of the dimmer, provided you can get there. I guess I should go back to LEDG's guides and check all that.

Either way I don't think you'll be doing any harm to the drivers by getting the most possible current out of them when you crank that dial, and the boards would only face threat of harm if that current was surpassing some limit of the board or the cooling solution for the setup.