Bridgelux EB gen2 DIY light - add supplemental 660+730 (deep&far) LEDs there?

Hello, I have DIY grow light, based on LED strips BXEB-L0560Z-35E2000-C-B3 (3500K, CRI80). 16x strips & HLG-320H-42A driver, each two strips in serial, 6 pair in paralel connection. I'm using this light for veg & flowering cycle, during veg phase powered only on 50% output. Box size 80x100cm. It 'works' without any problem, but you know, it's always better to make it better!

Now I'm thinking about supplemental spectrum, because of 3500K and CRI80 spectrum of the light. I suppose that I will need only red spectrum, so I'd like to add some far and deep red LEDs there. Here is my idea:

• 9x Cree XP-E2 660nm + 6x XP-E2 730nm
• three additional alu U-profile bars as coolers, each bar with 5x deep + 2x far XP-E LEDs. LEDs are on 20mm cooper star (Aliexpress) - ratio 3:2 in red, appr. 10:1 in total
• one ELN-30-48D driver (3 ~ 48V, 0.63A)

And because I'm not 100% sure if it ill be a good idea, here are some questions:

• is it a good idea, or keep the light as it is and save some cash?
• could I use far & deep spectrum LEDs in flower phase with the main lighting period (powered and timed with the same timer)?
• is there a big difference between XP-E and XP-E2 diodes?
• is that 30W of supplemental light enough, will be there some "possitive effect" in result at all?

Thank you for info!

slightly faster flowering, slightly more stretch and slightly better gr/w. Do it if you have the money and time, and think it’s fun!

Fiveleafsleft said:

slightly faster flowering, slightly more stretch and slightly better gr/w. Do it if you have the money and time, and think it’s fun!

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Hello, thanks for your answer! So if I'd like to have NO faster flowering, NO longer girls and MUCH better g/W result , what supplemental lights do you suggest? Or just keep it as it is now?

spachal said:

Hello, thanks for your answer! So if I'd like to have NO faster flowering, NO longer girls and MUCH better g/W result , what supplemental lights do you suggest? Or just keep it as it is now?

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If you want to increase g/w just lower the total wattage.

@Rocket Soul : How about faster flowering and higher g/sqft? (Without the stretch, due to severe height restriction).

eminiplayer said:

@Rocket Soul : How about faster flowering and higher g/sqft? (Without the stretch, due to severe height restriction).

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The million dollar question and how to beat all growlight companies at their own game....

If you want to play around with supplementation why not go all in: 660 red, wide blue/violet and far red? This should give you the parts your after; 660: flower response, blues: stretch control and transpiration, and finally far red for end of day treatment and possible supplementation (this would cause stretch unless combined with some blue).

But remember that spectrum is only part of the story. Plant training and strategic pruning plays a part, along with veg time and size of roots, climate and nutes etc. Also for faster flower you can try shorter day hours in veg.
For better total yield; why not try a little bot more white light?

Finally the discussion is going on here, thanks for that! :]

Rocket Soul said:

If you want to increase g/w just lower the total wattage.

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This is, of course, true, but also the undesirable direction of the result ). I saw this video, the reason for my idea of red supplemental spectrum is clarified here:

Rocket Soul said:

The million dollar question and how to beat all growlight companies at their own game....

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It's not my point, I don't want to beat them, I just like to create things and I'm able to build my own light. And I want to build it as well as possible, that's why I post my questions here, to find answers from the more experienced of you.

Rocket Soul said:

If you want to play around with supplementation why not go all in: 660 red, wide blue/violet and far red? This should give you the parts your after; 660: flower response, blues: stretch control and transpiration, and finally far red for end of day treatment and possible supplementation (this would cause stretch unless combined with some blue).

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I tought that if I'm using 3500K light, there is already enough blue spectrum there. I'd rather to buy EB gen2 2700K strips, but they were unavailable a few months ago and I suppose that it's the same situation today. My point was to build quality light with reasonable budget. And these strips costed $4.80/piece.
But you're right, I can try also to add some UV LED's there too..

Rocket Soul said:

For better total yield; why not try a little bot more white light?

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I thought that 320W per 80x100cm (appr. 37W/sqf) of light with high efficiency LED's is good. On the contrary, I already had problems with light overexposure last round ..

And the rest is obvious, good all other conditions lead to good results. Well genetics, good soil/coco (I can't use hydro/aero because ambient humidity), nutients, watering etc. What can I influence is the quality of light, additional 30W is not too expensive to buy and use, if the result will be +20-30% bigger yeld (explained in video). Right?

If youre already at 37w/foot it might be hard adding more light no matter what color.

As for the video: yeah, adding more far reds (when theres already almost none!) may increase yields due to activating both photosystems. But if i understand correctly, the extra yield he quotes are from leafy greens. This is not the same as bud and quite possibly due to photomorpological effects and not extra photosyntesis as far reds will tend to stretch and increase leaf size. But far reds also seem to have a positive effect on flowering.
Blues: yes 3500k has enough blues but no violet. Thats why i quote wide blue/viollet. As you approach 400nm you have more action from photosystem 1, just like far reds. But the violets will inhibit stretch, and make shorter, less yieldy but more potent plants. More blue/violet : less yield (generally) so you have to match blue/violets and reds.

To be honest this is quite a hard question to answer and i doubt there is one answer for every plant. We ran test adding 630nm , 630/660nm 660 phosphor coated reds in flower and didnt have any definite standout conclusions. In fact straight white did better than the 90cri fixtures with red but there was several confounding variables. The whole cannopy was a multi strain clusterfuck wrapped in a hot mess.

Also, OP: you may get more use out of good environmental controls and more heat than tweaking spectrum. +81F for flower

I knew it wouldn't be that easy, thanks for your support!

I can always lower down the otuput of the main driver, so I get better efficiency of white Bridgelux strips light and I can add there some supplemented light.

In this case, what about this:
- still three LED strips of XP-E Cree diodes, evenly spaced in the main light
- on each strip there will be 5 LEDs on stars, in this combination: 660nm -- 400nm -- 730nm -- 400nm -- 660nm
- all three strips connected in series, 48V / 0,65A in total (1.4W each LED)

If there will be more green and healthy leafs, it will be benefit for flowering phase, buds can take all this comulated energy in themself. Still there will be some Emerson effect and in the light spectrum there will be also some viollet/UV part.
Right or wrong way of my thinking?

Btw, I plan to order these Cree LEDs from Aliexpress from reliable supplier, do you have any tip where to order them in EU, also at reasonable price?

spachal said:

I knew it wouldn't be that easy, thanks for your support!

I can always lower down the otuput of the main driver, so I get better efficiency of white Bridgelux strips light and I can add there some supplemented light.

In this case, what about this:
- still three LED strips of XP-E Cree diodes, evenly spaced in the main light
- on each strip there will be 5 LEDs on stars, in this combination: 660nm -- 400nm -- 730nm -- 400nm -- 660nm
- all three strips connected in series, 48V / 0,65A in total (1.4W each LED)

If there will be more green and healthy leafs, it will be benefit for flowering phase, buds can take all this comulated energy in themself. Still there will be some Emerson effect and in the light spectrum there will be also some viollet/UV part.
Right or wrong way of my thinking?

Btw, I plan to order these Cree LEDs from Aliexpress from reliable supplier, do you have any tip where to order them in EU, also at reasonable price?

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For good reds try led-tech.de
They dont have very good prices for uv/violet. Try aliexpress, i think @nachooo bought some which we was happy with. In any case i recommend you have a look at his setup if you wanna go all in on spectrum tweaking as he has the most comprehensive setup i know of.

I disagree with your setup idea: i think you should do separate channels (with accurate dimming) for red / far red/ blues-violets.
My guess is to use up to approx 10% of output each channel but you can do 15 if you want for kicks. Try to use low current on your monos, theyll last longer but its a pricier setup.

Hey, I know that shop, it's near, but prices and shipping fees are not so pleasant.. OK, nevermind, I will order it on Ali. I believe in Cree quality, so I will order them and hope that I will not receive a fake :].

I saw some posts from nachooo, probably this is the post you mentioned: https://www.rollitup.org/t/whats-new-led-growers.1007044/post-15340337
I can see that he is ordering also from Ali, digi-key, cutter.. And his posts are good, thanks!

It's a good idea to put there some PWM dimming on each color. In this case I have to change suitable driver.. I will calculate it and see.

spachal said:

Hello, thanks for your answer! So if I'd like to have NO faster flowering, NO longer girls and MUCH better g/W result , what supplemental lights do you suggest? Or just keep it as it is now?

Click to expand...

You could definitely ad some 630 and 660 and dim it down a bit to increase gr/w I would go with a slightly higher ratio of 660 since that’s where your 3500 are a bit weak. As you write driving the Leds low and keeping them cool helps with efficiency.
For good efficiency I would go with ~30 % extra red to dim up during flower.

I have a set up consisting of 4000k cxa 2530 Driven at 350-700ma with a big portion of 630 and 660, and a few 440 for the sake of it.

if you want to up the efficiency of your hole setup I recommend a tightly packed perpetual garden with clones or 12/12 from seed. I do this and have extra blue leds over the seedlings younger plants in order to manage unwanted stretch.

best of luck!

Hello, small update, I finally decided for a solution of supplemental lights, I will keep design as simple as possible.. For the main light with 14x Bridgelux EB gen2 560mm (10x 3000K, 4x 4000K), powered by MW 320W (22W per bar, appr. 1.16A each one) I will add three LED bars with this combination:

- each bar with combination of 4x 660nm + 2x 730nm + 1x 430nm LEDs on 20mm stars
- all LEDs in serial connection, powered by MW APC-35-500 (constant current 500mA, 25-70V). I know that it's not ideal, there are different voltages on LEDs and in the case of one fault LED the circuit will going down. But the only possible solution if I want to keep the price low. If the auxiliary lights prove to be very useful, I can rebuild it
- LEDs are placed on alu bar as cooler
- in the case of 3 bars (21 LEDs) placed on growing light it"s 56V voltage at 500mA, 27W of total output
- they will be shining together with the main light, no extra timing - powered on only during flowering phase

I will not power and control them separately by 'light colors', it's only supplemental light with low output power. The results with Bridgelux EB strips without supplemental lights are impressive already :], so I will see if adding supplemental spectrums will be useful or not. The price for additional lighting is acceptable, driver, LEDs and alu coolers are already ordered, total price per set is appr. $40 (I ordered two sets), so wish me luck!