Bridgelux EB-series on a 2' x 4' SCROG

[graying.geek]

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Week 6 of 12/12. Predictably, after getting my wiring corrected (thanx, all!) I burned some of the pistils in the middle of the scrog where the light was too intense. Here’s a quick shot:

Not a big deal at this point. Only about half of the buds were affected and less than 50% of the pistils on the affected plants were toasted. Nevertheless, I raised the lights to about 10” off the canopy and dialed the drivers back to ~75% power. Still awfully bright in there, but hopefully that’ll make the girls happier. I assume part of the burning was due to the plants suddenly being inundated with so many more photons, but I suspect they’ll recover and continue to fatten up. We’ll see.

Anyone who uses these EB strips, any input on how high above your canopy?

 

[BuddyColas]

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Week 6 of 12/12. Predictably, after getting my wiring corrected (thanx, all!) I burned some of the pistils in the middle of the scrog where the light was too intense. Here’s a quick shot:
View attachment 3967804
Not a big deal at this point. Only about half of the buds were affected and less than 50% of the pistils on the affected plants were toasted. Nevertheless, I raised the lights to about 10” off the canopy and dialed the drivers back to ~75% power. Still awfully bright in there, but hopefully that’ll make the girls happier. I assume part of the burning was due to the plants suddenly being inundated with so many more photons, but I suspect they’ll recover and continue to fatten up. We’ll see.

Anyone who uses these EB strips, any input on how high above your canopy?

I say get a LUX meter. There is a good LUX to umols conversion thread in this section. That way you won't be guessing.

Until then, now that you have dialed it down, how many watts are going to your EB panels?

 

[Danielson999]

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Anyone who uses these EB strips, any input on how high above your canopy?

If you harden your plants off properly, you can keep an EB strip or cobs within inches and have no problem. In 2 or 3 more days you can probably lower your light back down and keep it on 100% power.

 

[graying.geek]

When I noted the burn to buds and leaves primarily in the middle of my scrog after my lights were corrected, I loaded a lux app on my phone and recorded readings at the 4 corners and in 1 ft increments. Since Lumens will be variable by height above the canopy, I simplified the readings by dividing each reading by the lowest in the group. Here are the relative readings:

1.0 2.3 2.6 2.2
2.3 4.8 4.8 3.1
1.7 2.9 2.6 2.2

Obvious, even before I took the readings, was that the way my lights are arranged (0.75" spacing between strips), the middle of the scrog was getting significantly more photons than the corners or edges -- like DOUBLE. Applying a bit of reasoning to the design, I pulled out my light, replaced the 12" end cross members with 22" lengths of Al angle, and worked out the spacing between the strips to increase logarithmically to the middle thereby pushing more of the light out to the edges. If you look closely you can see that the spacing decreases as you move from the middle to the edges:



It worked nicely. Here are the new ratios:

1.2 2.0 1.7 1.5
1.2 1.5 1.5 1.2
1.0 1.2 1.1 1.0

Much better. This should give me a much more even photon distribution, and more even bud growth. Now I need to get the height above the plants optimized.

 

[canadian1969]

When I noted the burn to buds and leaves primarily in the middle of my scrog after my lights were corrected, I loaded a lux app on my phone and recorded readings at the 4 corners and in 1 ft increments. Since Lumens will be variable by height above the canopy, I simplified the readings by dividing each reading by the lowest in the group. Here are the relative readings:

1.0 2.3 2.6 2.2
2.3 4.8 4.8 3.1
1.7 2.9 2.6 2.2

Obvious, even before I took the readings, was that the way my lights are arranged (0.75" spacing between strips), the middle of the scrog was getting significantly more photons than the corners or edges -- like DOUBLE. Applying a bit of reasoning to the design, I pulled out my light, replaced the 12" end cross members with 22" lengths of Al angle, and worked out the spacing between the strips to increase logarithmically to the middle thereby pushing more of the light out to the edges. If you look closely you can see that the spacing decreases as you move from the middle to the edges:

View attachment 3967812

It worked nicely. Here are the new ratios:

1.2 2.0 1.7 1.5
1.2 1.5 1.5 1.2
1.0 1.2 1.1 1.0

Much better. This should give me a much more even photon distribution, and more even bud growth. Now I need to get the height above the plants optimized.

thats great info man, thanks!!!

 

[graying.geek]

If you harden your plants off properly, you can keep an EB strip or cobs within inches and have no problem. In 2 or 3 more days you can probably lower your light back down and keep it on 100% power.

Thanx, Dan! This is what I was hoping for. Your experience validates my hypothesis.

 

[graying.geek]

I say get a LUX meter. There is a good LUX to umols conversion thread in this section. That way you won't be guessing.

Thanx, Bud. I assume you're also using LEDs. What reading do you look for on your LUX meter?

Until then, now that you have dialed it down, how many watts are going to your EB panels?

Haven't had a chance to check and my girls are down for the night, but now you have me curious. I'll check tomorrow.

 

[HalfBee]

Much better. This should give me a much more even photon distribution, and more even bud growth. Now I need to get the height above the plants optimized.

Dude, you're killing me here... adjusting the spacing to even out the PPFD/lux across the canopy.
This is the kind of thing you can't get from a datasheet. Just got mine today... playtime...

 

[Randomblame]

Thanx, Bud. I assume you're also using LEDs. What reading do you look for on your LUX meter?

50.000-60.000lx(~750-900μMol/s) in flower,
10.000-15.000lx(~150-220μMol/s) early vegging
25.000-30.000lx(~350-450μMol/s) late vegging

Conversion factor rounded up 0.015.
BTW, Cree CXB conversion factor for 3.500°k is 0.014152!

 

[graying.geek]

50.000-60.000lx(~750-900μMol/s) in flower,
10.000-15.000lx(~150-220μMol/s) early vegging
25.000-30.000lx(~350-450μMol/s) late vegging

Conversion factor rounded up 0.015.
BTW, Cree CXB conversion factor for 3.500°k is 0.014152!

Perfect! Thanx. You folks are making me lazy.

 

[BuddyColas]

Thanx, Bud. I assume you're also using LEDs. What reading do you look for on your LUX meter?



Haven't had a chance to check and my girls are down for the night, but now you have me curious. I'll check tomorrow.

I am using the 3000/80 EB strips and I like to see 50000 LUX. Which converts out to about 720ish umols. I've had great results with 50K LUX at the top of the canopy.

https://www.rollitup.org/t/par-multiplier-thread.928907/

Every time I think about dropping some serious bucks on a good PAR meter, I just come back to the LUX meter which comes close...I'd say +/- 10% or so. Close enough for a hobby grower.

And I agree with Randomblame's figures.

 

[graying.geek]

I say get a LUX meter. There is a good LUX to umols conversion thread in this section. That way you won't be guessing.

Until then, now that you have dialed it down, how many watts are going to your EB panels?

The numbers are not so odd. Running both drivers (2 x HLG-185H-1050A) at full power, here's the data on the input:

453w
113v
4A

Better. The wattage is obviously in line, but assuming everything is wired and running correctly, I still can't make sense of the amperage. IANAEE but seems like it should be higher, like more than double. Either there's something wrong, or the drivers are doing something I don't know about.

 

[BuddyColas]

The numbers are not so odd. Running both drivers (2 x HLG-185H-1050A) at full power, here's the data on the input:

453w
113v
4A

Better. The wattage is obviously in line, but assuming everything is wired and running correctly, I still can't make sense of the amperage. IANAEE but seems like it should be higher, like more than double. Either there's something wrong, or the drivers are doing something I don't know about.

If you are running those drivers wide open, then that is about 45w per strip. I'm saying you are getting in the vicinity of 95ppf per strip or 95 umols square foot or about 1000umols or so to your canopy if you run them close. OK, Randomblame...give us a second opinion!

 

[graying.geek]

Always interested in build specs, that would be great if you have time

I regret that it took so long. Got wrapped up in my wiring issues.

On my 2.4 grow areaI cut 1 angle-AL into 2 x 22" inverted cross members to the top of which I bolted each end of the 48" angle-AL lengths through my pre-drilled holes using 1/4" bolts, nuts and a lock washer. I calculated the spacing between the 8 angle-AL lengths -- and hence, between the strips -- on a logarithmically expanding scale from the sides to the middle to provide a MUCH more even light coverage.

2 of the bolts on each end were replaced with loop bolts for hanging/carrying. The double-sided tape was used to affix each strip to the bottom, flat surface of the 8 48" angle-AL lengths. Here's a shot of one end of the frame from the top. Sorry for the poor lighting.

I used 14 AWG 2-wire between the drivers and the strips and 18 gauge single conductor to hop from strip to strip. Here's a diagram of the serial wiring pattern:

Were I to order again, I'd get both the strips and drivers from Arrow. Prices are better and shipping is free. Digikey usually has better stock, but overall significantly cheaper from Arrow.

I also really recommend the 1 x 1 x 0.125 angle -Al from onlinemetals.com. It's sufficiently substantial that it makes a great frame and heatsink, and their prices are excellent compared to the likes of HomeDepot.

 

[graying.geek]

Dude, you're killing me here... adjusting the spacing to even out the PPFD/lux across the canopy.
This is the kind of thing you can't get from a datasheet. Just got mine today... playtime...

You're in for some fun. These strips are fantastic!

 

[Serva]

These strips are awesome! And also your light/grow looking good! It's nice to see someone else also did some exponential (what I did)/logarithmic spacing! I just followed my intuition, and it seems to work out great!

 

[Serva]

I am supporting your opinion!

 

[algebraist]

I also really recommend the 1 x 1 x 0.125 angle -Al from onlinemetals.com.

Agreed about onlinemetal -- a great resource. When I ordered from them they gave me a great discount on shipping as a first time customer, and have emailed me other good offers since -- worth checking out.

Also, good call with the thermal tape! I recently finished my build and used bolts and thermal paste, which I will never do again -- the paste is tricky to work with, and although in theory it can give better conductivity, in practice it's hard to get the strips to lay flat enough for the paste to be in contact everywhere. And the bolts are a terrible idea -- it seems not all the holes are okay for mounting, and I shorted out a couple of strips by overtightening.

 

[Warpedpassage]

Looking nice. Thanks for posting.

 

[vertnugs]

Great build GG.....and great help you received in your thread.Nice to see threads like this.

I'm looking at doing some thing along these lines for a new veg light.