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

Serva said:

These strips are awesome!

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I'm loving these things more every day, but they've proven dangerous in the hands of Noobs. BuddyColas had warned me that I'd better raise these up when I got the wiring corrected, but while I doubled the height, it wasn't enough, and the tripled output light-burned the middle 1/3 of my scrog -- yellow leaves and toasted pistils -- after just 1 light cycle. They appear to be recovering with some new pistil growth, but I'm sure I affected my yield and potency. Oh well, the other 2/3 look pretty good. Lesson learned. Grow #3 will be better.

Not surprisingly with the drivers dialed up to 100%, heat has become an issue. I've moved the drivers outside the grow space and shifted the light cycle to take advantage of our cooler evenings, but my room temp still holds pretty steady at 29'C, a bit above optimal temp for bloom, but within reasonable limits. Going forward I plan to forego indoor grows during the summer months and take advantage of free sunlight, lighting up the grow room again in October.

serva: said:

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!

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Thanx, Serva. There hasn't been as much comment on my earlier post re: this topic as I'd expected, so maybe it's already been discussed ad nauseam and generally accepted by all indoor growers, but if not, anyone who grows an indoor sog or scrog under DIY LED strip lights might want to pay attention to this.

Making your light frame big enough to cover 90% of the canopy and shrink the spacing between strips as you move from the middle to the outer edge can yield consistent coverage across the entire canopy. When I had my all of my strips spaced at 1" apart and the total frame width of 15", my Android lux app gave me ~65k lumens in the middle, and 25K-30K at the edges of my scrog. No wonder I burned my girls when the lights were correctly wired. After applying the log spacing to nearly the full width of the scrog, I was getting 50k lumens across the entire canopy. BTW, the fact that you CAN futz around with spacing and coverage is a real advantage with these strips. Try that with a canned LED, irrespective of the perceived quality of the light.

As you assumed, you don't have to dust off your calculus and trig skills to calculate the integrals under the inverse square law. WAGging it will give good results. Just start from the middle and decrease the space between the strips by 30% of the previous space in both directions, making sure the width you start with will yield nearly full coverage of the expected canopy size. That'll get someone close enough.

vertnugs said:

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

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Absolutely. These Rollitup forum folks have been great!

vertnugs: said:

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

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You're gonna love these strips..

Very nice!

algebraist said:

Also, good call with the thermal tape!

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Yeah, the tape is sweet. It literally took me 5 minutes to get all 8 strips attached to my frame and it's holding up great.

I'm experiencing watering anxiety. I've 2 plants in 7-gal air pots, and 2 in 5-gal buckets with several sizeable drainage holes in the bottom. Sticking with the principle of waiting to water until the soil is dry 2" down, I find that I'm watering the air pots 2L every 2 days, and the buckets every 4-5 days. They've been chugging along on this schedule OK, but I noticed today that the leaves are looking a bit droopy. Am I just being an anxious father? Any input or thoughts?

graying.geek said:

I'm experiencing watering anxiety. I've 2 plants in 7-gal air pots, and 2 in 5-gal buckets with several sizeable drainage holes in the bottom. Sticking with the principle of waiting to water until the soil is dry 2" down, I find that I'm watering the air pots 2L every 2 days, and the buckets every 4-5 days. They've been chugging along on this schedule OK, but I noticed today that the leaves are looking a bit droopy. Am I just being an anxious father? Any input or thoughts?View attachment 3971869

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Pick up your Potts. If they're dead light then theyre dry. Feed then.
Once you do this a few times, you'll know how many days apart on average. I do 3 days.

graying.geek said:

I'm experiencing watering anxiety. I've 2 plants in 7-gal air pots, and 2 in 5-gal buckets with several sizeable drainage holes in the bottom. Sticking with the principle of waiting to water until the soil is dry 2" down, I find that I'm watering the air pots 2L every 2 days, and the buckets every 4-5 days. They've been chugging along on this schedule OK, but I noticed today that the leaves are looking a bit droopy. Am I just being an anxious father? Any input or thoughts?View attachment 3971869

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Which ones are droopy?
Btw...very nice looking buds!

BuddyColas said:

Which ones are droopy?
Btw...very nice looking buds!

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There's one about dead-center that you can see the leaves arching downward. There are many that simply don't show well in the photo.

I did tip up one side of an air pot as the previous dude suggested -- at least as much as a scrog will allow -- and it seemed pretty heavy, so now I'm wondering if they're *over* watered rather than under. I'm sure after I get a few grows under my belt, watering effectively will be more intuitive, but this is the frustrating part; trying to diagnose a problem by braille when I don't know the alphabet.

Thanx for your help.

graying.geek said:

There's one about dead-center that you can see the leaves arching downward. There are many that simply don't show well in the photo.

I did tip up one side of an air pot as the previous dude suggested -- at least as much as a scrog will allow -- and it seemed pretty heavy, so now I'm wondering if they're *over* watered rather than under. I'm sure after I get a few grows under my belt, watering effectively will be more intuitive, but this is the frustrating part; trying to diagnose a problem by braille when I don't know the alphabet.

Thanx for your help.

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A little droop...nothing severe. Having run air pots, I have noticed I had to water them more often than conventional pots...more evaporation out the holes I guess. I ran mine with rockwool cubes...which are impossible to over water...even drenched they are 50/50 air and water.

A few posts back you were talking about strip spacing. Mine are linear...like every 3 inches, and they do not have a hot spot. With reflective walls they are amazingly consistent under the light. The strips beat cobs, panels, hids as far as laying down a consistent blanket of photons.

How much longer do you think you have on your grow?

BuddyColas said:

A little droop...nothing severe. Having run air pots, I have noticed I had to water them more often than conventional pots...more evaporation out the holes I guess. I ran mine with rockwool cubes...which are impossible to over water...even drenched they are 50/50 air and water.

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Yeah, I've shifted to thinking that I might have a lot of moisture in the bottom half of the pots, so I think I'll hold off watering until either it's clear they need more water and/or the pots lighten up a bit.

BuddyColas said:

A few posts back you were talking about strip spacing. Mine are linear...like every 3 inches, and they do not have a hot spot. With reflective walls they are amazingly consistent under the light. The strips beat cobs, panels, hids as far as laying down a consistent blanket of photons.

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What physics and my measurements strongly suggest is that it's most important to do as you did and spread the strips over the entire area of the grow, but the perimeter still suffers from not having photons coming directly from strips in both directions as it is in the middle. Certainly reflective walls help, but even so, I showed much better lumen readings with graduated spacing. YMMV.

BuddyColas said:

How much longer do you think you have on your grow?

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I'll try tp post a week 7 update tomorrow. My trichomes are clouding up nicely and there are amber trichs on the sugar leaves. Right now, I'm thinking 3 more weeks.

Nice little canopy GG.

Will your next run be in the same manner as this one?

Week 7 of 12/12 and the girls are doing well despite the burn I gave them by suddenly increasing the light intensity. About 1/3 of the leaves and all of the buds in the middle of the canopy were moderately toasted -- yellowed leaves and browned pistils -- but the rest of the plants look pretty good. It looks like I let my pots accumulate too much water so I plan to let them dry out a bit for the next couple of days. I know it's a sensitive time and I plan to keep a close eye out for signs of over-dry conditions.

Here's a group shot of most of the canopy. The light-burned is easy to see in this one:



In the unaffected areas we've got some fairly nice buds for just finishing the 6th week. They appear to be much better quality, in both density and trichomes, than my first grow. Here's a couple of shots some of the sexier buds. Wish you could scratch & sniff:





Trichome development looks good, although, these plants were cloned from a parent that was a few weeks into 12/12, so it took a few weeks to re-veg them, but the late cloning really gave them a head start on their maturity level. From the outset, the plants were at least mildly smelly and all of the leaves and growth areas had trichomes. Not sure how this will affect the outcome, but seems like it can't hurt.

Here's a current shot of the trichomes. 70% are milky with the occasional amber. I'm thinking another 2-3 weeks might do it.



Here's to not screwing it up on the home stretch!

vertnugs said:

Nice little canopy GG.

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Thanx, Vert.

vertnugs said:

Will your next run be in the same manner as this one?

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Not sure what you mean specifically, but yeah, I don't see any reason to change anything -- other than the Noob screw-ups. I'm loving the scrog, I have the physical setup of my lights optimized to my liking, and the homemade organic teas have made feeding dead simple. I will be adding a 6" blower & charcoal filter to the existing 4" for the sake of my wife's sensitive nose.

The girls have seen the full power of these lights for less than 2 weeks, so I'm anxious to see how the next grow responds when they get 750+ umol for the full bloom cycle.

vertnugs said:

Will your next run be in the same manner as this one?

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Ah, looking back at your previous post I think you might be referring specifically to the EB-strips. If I haven't made it clear already, yes, these strips fill my need perfectly. There are more efficient routes to take, but at a significant cost. The fact that the aluminum frame does a good job acting as a passive heat sink obviates the need for active cooling or expensive heat sinks and since I'm getting >45W of quality light, the strip density is delivering close to the maximum PAR photons that the plants can handle, I can't see the value of adding more strips. Maybe after another grow I'll perceive it differently, for now I'll put on hold any plans for more strips.

To replace my 2 300w burple lights cost ~US$250 and doubled the photon output, giving me a nice, evenly spread blanket of light. Compare that with what you have to spend on a setup with similar output from COBs or Samsung strips. I'm admittedly a lot more cost-conscious than most -- yes, I'm a confessed cheapskate -- so if a small gain in efficiency is worth the overhead, then the EBs are not the best choice. For me, it's not, and they are.

graying.geek said:

since I'm getting >45W of quality light,

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Of course that should have been: "since I'm getting >45W / sq ft of quality light"

Hate it when people throw numbers around with incorrect units... Ahem.

I realize this is kind of late, but I don't think anyone answered and I think I can help you understand voltage/current relationship. Since you're using a constant current driver there is some room to screw up and not make shit go boom. The driver will automatically adjust voltage for you. Which is why you didn't see an overvoltage condition.

When you wire in series, the current will remain constant across all loads and the voltage will divide. In parallel, the voltage will remain constant and the current will divide among loads.

This being said, you divided your 1050ma among all your strips evenly in the beginning. Once you connected your strips in series, they received 1050ma each. Hopefully that helps you understand the E/I relationship in series vs parallel circuits.

These are the little things that the pioneers have already figured out for us, that kind of go unmentioned. Had you have tried that connection with a different style of driver it could've gotten ugly. Grow looks great btw!

BuddyColas said:

Check my math, but at 45 watts a square foot and 4000K...I'm saying you are running about 20 par watts a square foot for about 1000 umols. No wonder you toasted the tops a bit!

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Yeah, no kiddin'. Actually, those are the numbers I calc'd before ordering the strips, so I should have been ready, but my expectations were set too low due the misguided wiring I started with. Won't make that mistake again.

BuddyColas: said:

We should start a guess at your dry weight from that scrog! I'm saying 10 zips or better!

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Well, my first grow:



I netted 8 oz of fluffy little thumb-sized buds. This second grow, the buds seem more dense, and bigger than at the same stage. But keep in mind, these girls have been enjoying the full power of these lights for less than 2 weeks so we'll see after another 2-3 weeks. I'm gonna be optimistic and say 12 zees.

How long do you veg, what's size of screen?

KonopCh said:

How long do you veg, what's size of screen?

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Veg for 8 weeks, screen = 2' x 4'

Take your best guess.

dbrn32 said:

I realize this is kind of late, but I don't think anyone answered and I think I can help you understand voltage/current relationship. Since you're using a constant current driver there is some room to screw up and not make shit go boom. The driver will automatically adjust voltage for you. Which is why you didn't see an overvoltage condition.

When you wire in series, the current will remain constant across all loads and the voltage will divide. In parallel, the voltage will remain constant and the current will divide among loads.

This being said, you divided your 1050ma among all your strips evenly in the beginning. Once you connected your strips in series, they received 1050ma each. Hopefully that helps you understand the E/I relationship in series vs parallel circuits.

These are the little things that the pioneers have already figured out for us, that kind of go unmentioned. Had you have tried that connection with a different style of driver it could've gotten ugly. Grow looks great btw!

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I've gained a general grasp of how voltage and current vary with the wiring scheme but you've added a lot of clarity. Thanx! My confusion originated when I put my multimeter on the input side of the driver when I had the strips miswired. Naively assuming the diagram for serial wiring that I was pointed to was correct, I couldn't make sense of what watts going in with watts that were *supposed* to be going out. Once the RIU crew help me get the wiring straightened out everything fell into place, including the readings on the original wiring which was just some semblance of a parallel scheme, but not. Your right, I'm lucky it didn't toast all of my lights. Thank good engineering for these MW drivers.