DIY with Quantum Boards

pop22- Thanks very much for the reply. First time using the Lux app on a Samsung phone. I was mainly using it to compare the QB to the 150w cmh I had in the cab. I have three new 150w cmh bulbs - all three measured 32K lux at 10" from bulb. I slid the new QB into the cab and get the 52K at 10".
I know the app could not replace a LUX meter but just using it for comparison it appears I putting much more light to the plants. Both with app and my eyes. Here's the deal- I used the QB briefly a couple months ago and just ruined a batch within days at 120w. I may have been a little to close but I am one gun-shy kinda guy right now. How close can you get your tops to a board ? I have 18-19" soil to QB

ianc4990 said:

Chain is fine if you arent going to raise or lower your lights. But if you are going to adjust them, ratchets are better. You dont have to remove a ratchet to adjust like you do a chain. And if you have trust issues with 4, 150lb rated holding your light of MAYBE 30lbs, I feel sorry for any woman in your life hahaha (I kid, I kid)

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O I would feel sorry for any women in my life too, very true words lol.

ianc4990 said:

If you have enough room, I would put another qb288 in there and run them both as low as the driver will push. It should help with your hotspot and lack of intensity on the edges

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this was the logic I went with when I got my qb288s

Hi all
Question for you knowledgable guys.
I have a spider farmer sf1000 and it has a MEANWELL XLG-100-H-A driver.. I want an external dimmer pot.. so can I just swap the driver straight over for a MEANWELL XLG-100-H-AB ?
If that worked would I then just need a 100k potentiometer and would that need a resistor on it?
Thanks

Ianc4990 - no room for that.

no its from being hot the light doesn't go out until after I go to bed so I shut the doors and the light is one for another 45 minutes or so. And if they do have a bit of light stress, its because i've done no plant training the tallest one is about 8 inches from the light. I just stuck them in there and let them grow.

ianc4990 said:

Those plants look to already be showing signs of light stress. All the serrations on the fan leaves from halfway up your plant are curling up

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HLG's tests show a 288 V2 rspec board has a PPF of 1256. Using the HLG conversions for the V2 board a 1250 PPFD is 80,000 lux. I climbed into the bilge and did a few measurements to compared to the HLG site. Cranking the driver to 135w, using a Kill-A-Watt, at 12" from QB the app said 85K lux, not so far from the 80K Going to the max of 161w the lux climbed to 99K lux or 15000 ppdf. It appears that the phone app may not be that far off. 5-6% At 55W and a 52K lux reading at 10" would have a PPFD in the 850 range. Does any of this sound close ?

Snafu34 said:

HLG's tests show a 288 V2 rspec board has a PPF of 1256. Using the HLG conversions for the V2 board a 1250 PPFD is 80,000 lux. I climbed into the bilge and did a few measurements to compared to the HLG site. Cranking the driver to 135w, using a Kill-A-Watt, at 12" from QB the app said 85K lux, not so far from the 80K Going to the max of 161w the lux climbed to 99K lux or 15000 ppdf. It appears that the phone app may not be that far off. 5-6% At 55W and a 52K lux reading at 10" would have a PPFD in the 850 range. Does any of this sound close ?

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Measurements are anecdotal. A few degrees off of perpendicular, and your measurements are skewed. Every plant is different and can take different intensities. The only time I really measure intensities, is when I'm changing the layout of my boards and want to make sure the spacing isnt causing dim spots in the center of crossover

pop22 said:

no its from being hot the light doesn't go out until after I go to bed so I shut the doors and the light is one for another 45 minutes or so. And if they do have a bit of light stress, its because i've done no plant training the tallest one is about 8 inches from the light. I just stuck them in there and let them grow.

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You're absolutely right, it's heat stress. There is actually no such thing as light toxicity, as long as you have the correct CO2, VPD, etc. you can go to 2000ppfd if you want. If you had a bad environment and too much light you would see tacoing and twisting of the leaves to reduce transpiration.

Snafu34 said:

HLG's tests show a 288 V2 rspec board has a PPF of 1256. Using the HLG conversions for the V2 board a 1250 PPFD is 80,000 lux. I climbed into the bilge and did a few measurements to compared to the HLG site. Cranking the driver to 135w, using a Kill-A-Watt, at 12" from QB the app said 85K lux, not so far from the 80K Going to the max of 161w the lux climbed to 99K lux or 15000 ppdf. It appears that the phone app may not be that far off. 5-6% At 55W and a 52K lux reading at 10" would have a PPFD in the 850 range. Does any of this sound close ?

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Regarding the PPF of one QB288 V2 R-Spec board the 1256 figure is incorrect.


According to HLG, the total output of the HLG550 V2 R-Spec is 1293 PPF.

You can figure out an approximate PPF for your one board set-up by multiplying your wattage by efficacy in μmol/joule. Since there is no flux chart for the R-Spec, you can use the flux chart for the QB 288 V2. I would add 5% to the QB288 V2 μmoles/joule at Board figure for the drive current you are closest to now (you're around 1000mA , right?). From that resulting figure subtract .15 μmoles/joule and that will give you a rough efficacy at system level, barring any additional losses. What driver are you using, an HLG-120H-54A? Is your driver mounted to the back of your heatsink or do you have it remote mounted?

Snafu34 said:

Seems I did not do sufficient home work prior to purchasing my Q.B. 288v2 Rspec. It's total overkill for my space. 20" dia x 28" tall. Perhaps a DIY strip lighting setup would have been a better choice. Anyway- I have the 135w capable driver turned down to 55w which is giving me 52K Lux (cell phone app) at the center tops which are 10" from the board. I find that the light spread is not ideal with a significant lux drop on the sides. Is there a small light strip I can add to the sides and tie them into the HLG 120-54a ? Am I better off starting over with strip lights ? The 20 di. is not too user friendly for 1ft strips. Shameful cab photo on page 769 Any thoughts ?

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Just raise it up a little and there will be less dropoff in the corners. The most efficient hanging height for QB's always destroys your spread, so you have to hang them a little higher unless you can afford to cover the entire space in quantum boards... which I absolutely recommend doing. I have 4 V2 boards, 4 Diablo boards, and 2 QB18 strips in my 5x5.

Edit: just realized you have height limits. I would either reduce the height of something else in the cab to lower the canopy, or just get a second quantum board and run them dimmed down to 50%. It will pay for itself in reduced electric bills.

RamenToppings said:

do you just attach hooks or do you use a pulle?

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I have some hooks I use so I can shorten the chain anytime , they are just an S shape.

But I use something like these


Just try and get them small enough so you can fit it through your chain and your heat sink, but if they don't then nylon tie wraps are a life saver and wont fail.

Federucci said:

From my understanding having studied physics, filaments that are smaller in surface area, given the same energy run through them, will have to run hotter due to the nature of thermodynamics and it is based on resistance. Now these are solid-state LEDs from what I understand, so finding the resistance of different Kelvin solid-state LED semiconductors will yield the answer, and I think the easiest way to find out for sure is to measure the each board temp with an IR thermometer. Here is a chart I found with voltage drop which should correlate to resistance:

Color​	Voltage Drop (V)​
red	2
green	2.1
blue	3.6
white	3.6
yellow	2.1
orange	2.2
amber	2.1
infrared	1.7
other	2

This just made me more confused lol.

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The led is the same in each cct. The difference is the phosphorus mix.

coreywebster said:

I have some hooks I use so I can shorten the chain anytime , they are just an S shape.

But I use something like these

Just try and get them small enough so you can fit it through your chain and your heat sink, but if they don't then nylon tie wraps are a life saver and wont fail.

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I wouldn't bet my plants on that, lol! Heat, and light takes it's toll, and usually when it's not expected!

about 8" with my light at 130 watts. I'll probably get a little light burn but this grow was just for the sake of something to do lol. If it had been serious, I'd have use one plant and scrogged her. The QB 288 Rspec produces 196.1 lumens per watt at 50 watts. So multiply 196.1 x 50

So unless you are measuring within an inch of the board, there is no way the app is even close to accurate

here are the specs for the QB



What I'm not sure of is at what distance the measurement were taken at. I'm assuming this is sphere data so I'd say 12".

Snafu34 said:

pop22- Thanks very much for the reply. First time using the Lux app on a Samsung phone. I was mainly using it to compare the QB to the 150w cmh I had in the cab. I have three new 150w cmh bulbs - all three measured 32K lux at 10" from bulb. I slid the new QB into the cab and get the 52K at 10".
I know the app could not replace a LUX meter but just using it for comparison it appears I putting much more light to the plants. Both with app and my eyes. Here's the deal- I used the QB briefly a couple months ago and just ruined a batch within days at 120w. I may have been a little to close but I am one gun-shy kinda guy right now. How close can you get your tops to a board ? I have 18-19" soil to QB

Click to expand...

Stephenj37826 said:

The led is the same in each cct. The difference is the phosphorus mix.

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FlakeyFoont said:

I wouldn't bet my plants on that, lol! Heat, and light takes it's toll, and usually when it's not expected!

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Withstands 85 degree C with a 250 degree C melting point. With 18kg load per 3.6mm wide tie.

The heat shouldn't be a problem but I take your point on the light, especially if there's UV.

I add a safety chain the lights heavier than a pair of QBs. I don't know what crap the Chinese use to make string and rope, but I have had both rope on a ratchet pulley and a drying wrack simply disintegrate like some kind of dry rot. In fact, I have one of those 4Ft. long, single T5 light stands. The rope just disintegrated on that and dropped the light onto my plants! So, he is quite right to be cautious!

RamenToppings said:

O I would feel sorry for any women in my life too, very true words lol.

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Its a good thing they are cheap, I replace mine every two years after dropping a 32 pound light in my 2 weeks into flower planst and crushing them! That also when I added a safety chain!

coreywebster said:

Withstands 85 degree C with a 250 degree C melting point. With 18kg load per 3.6mm wide tie.

The heat shouldn't be a problem but I take your point on the light, especially if there's UV.

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Stephenj37826 said:

The led is the same in each cct. The difference is the phosphorus mix.

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My "hypothesis" is that if the phosphorous mix has slightly different thickness/densities, the thicker/more dense one would probably run slightly hotter. There's only one way to find out!