DIY Build 16 Vero 29 in 4x4ft Frame + Testing Thread

Justin Eterovich

Justin Eterovich

Member
Hey guys and gals,

Really glad I found this forum. Have been watching lots of DIY videos from the likes of growmau5 and ChilLED and have inspired me to make my own. Pretty much all parts are from RapidLED, thanks for your guys help!

I am still pretty new to the LED community so please feel free to comment/askQ/answer Q's and tell me im full of it.

Set out to try and create a light with the most even PAR reading in a 4x4 ft space. This goal was set out after seeing how poorly most LED lights perform on the PAR chart. Some of the better LED lights do 1400-1600 in the middle but then drop to 150 at the corner of a 4x4. Since optimal growing par is between 1000-1200 (+/- Co2) and after testing some of the more popular lights on the market, I was left wondering a few things and set out to try to test it as best I could. Yes, after I take more par measurements I will be testing this. (Framework and tests conducted in a 5x5ft tent since the framework is 48in square it doesn't actually fit in a 4x4.)

Note: For the sake of keeping it simple, all questions are based upon a 4x4ft growing space/tent talking about flowering footprints.

1) Why do most LED light companies, with the exception of a few, build lights that do not reach the corners but advertise as a 4x4 flower space? If the plant is only getting 150 par in the corners, surely it will not grow as much or yield as much as if it was getting 600? Right?

2) Is it size related? Watt related, or both? Since spreading light to the corners is hard to do from a smaller 24in square light or even 30in square light, do most companies not worry about it because they dont want to build the lights 36-40in or because they know that it would make the light use much more power 30+% (My estimation) to get that extra PAR in the corners? Is this why most companies not show PAR readings?

3) Does it even matter or make a difference? Since part of the plant will be getting more light than the part facing the side of the tent, will the side closer to the light make up for the other side? Is the difference in yield between 150 par at 4ft corner and 600 par at 4ft corner so insignificant that the extra watts and overall light size to make it happen do not outweigh the benefits?

There has to be a reason for all of this? Would love to hear your theories.


Below are pics of testing and the light that I have built to do so.
16Vero29 poke in cobs
16 140mm heat-syncs
4 MeanWell drivers HLG320H 1750Ma (Dimable)
Bluefish WiFi dimming controller

Sorry for the mess of wires, I wanted to be able to move things around and using soild wire is a PIA to do that with. Also, got about halfway wired all neat and tidy and thought i probably shouldent wrap the wires until I tested everything, I'll do that before an actual grow.








PAR readings at 18in with 4 drivers at 100% 1117 Watts


Par Readings at 18in with center 4 cobs running 60% the others at 100% 1005Watts



Would love to hear some thoughts comments and maybe insight in case i am missing the obvious to the questions asked.

Cheers
Justin
 
freemanjack

freemanjack

Well-Known Member
Well first thing to realise is with the exception of LES/CoB's all light sources are radiant in nearly all directions, in practice we can reflect a portion of that light but leds emit in a pretty tight 120 deg cone with only moderate fringe emission, the result of this is that the inverse square law has a far smaller effect. You can more or less hang leds at the top of a reflective box and the vast majority of the available photons will be hitting the plants directly. Tho that being said I hang mine as low as poss without bleaching the tops (not irreversible like hps burn) or lighting the soil. In practice plants just luv em an all those light hose vero's will kill it, you'll be grand!
 
ganjamystic

ganjamystic

Well-Known Member
Justin Eterovich said:
...Set out to try and create a light with the most even PAR reading in a 4x4 ft space. This goal was set out after seeing how poorly most LED lights perform on the PAR chart. Some of the better LED lights do 1400-1600 in the middle but then drop to 150 at the corner of a 4x4.

...1) Why do most LED light companies, with the exception of a few, build lights that do not reach the corners but advertise as a 4x4 flower space? If the plant is only getting 150 par in the corners, surely it will not grow as much or yield as much as if it was getting 600? Right?
Click to expand...
I would like to see a light that creates a perfectly even spread, like 1000 PPFD at every point--center, edge, corner--every number nearly the same... seems like it shouldn't be that hard to work backwards from the uneven spread of most lights relative to their shape... in other words, every pre-built grow light seems to have the actual light emitters (bulbs, cobs, whatever) crammed toward the center of whatever the footprint of the light is supposed to be (example a 20"x20" light intended for a 3'x3' space)... and consequently every light's spread has higher PPFD numbers toward the center... it really confuses me why this seems to be the standard... it seems obvious that the way to correct this would be to make lights with nearly the same dimensions as the space they are intended to light with the cobs or diodes or whatever placed around the perimeter...

example a 33"x33" light for a 3'x3' space with 8 cobs space like this:

O--O--O
O-------O
O--O--O

or a 44"x44" light for a 4'x4' space with 12 cobs spaced like this:

O--O--O--O
O-----------O
O-----------O
O--O--O--O

... it seems to me like this would do a good job of evening out the numbers... I'm sure there is even a computer program that could be used to determine the exact spacing it would take to achieve a perfectly even spread...

I'm really curious what readings you'd get if you just turned the center 4 cobs off completely
 
Last edited:
P

Photon Flinger

Well-Known Member
Nah, these plants are fine with anything over 20 PPFD. There are a bunch of other factors at play when it comes to how a plant uses light energy like how it re-transmits light down below the canopy. Plant knows best and will adapt to whatever environment you give it. You can get a good idea of roughly what the plant will produce at a range measured at the canopy.

I am using the Vero 29c SE as well and find them very easy to work with. You can swap them out quickly and you save some by not having to buy a holder. Great for testing as I have paired each one off with its own driver and can make many more adjustments. I went contrary to the common approach for spacing and put the cobs close together (6 evenly spaced out on a 6x15" al sheet) and centered in the growing area to minimize the reflection off the walls. Plants fill in nicely and there isn't much making it through to the floor. With the 120 degree spread and 12 cobs for a 3x3, the lights are 6-10" above the tops which usually end up growing horizontally mid flower because of the weight. Temps are kept down by running low which will be most likely the biggest problem you will have.
 
freemanjack

freemanjack

Well-Known Member
ganjamystic said:
I would like to see a light that creates a perfectly even spread, like 1000 PPFD at every point--center, edge, corner--every number nearly the same... seems like it shouldn't be that hard to work backwards from the uneven spread of most lights relative to their shape... in other words, every pre-built grow light seems to have the actual light emitters (bulbs, cobs, whatever) crammed toward the center of whatever the footprint of the light is supposed to be (example a 20"x20" light intended for a 3'x3' space)... and consequently every light's spread has higher PPFD numbers toward the center... it really confuses me why this seems to be the standard... it seems obvious that the way to correct this would be to make lights with nearly the same dimensions as the space they are intended to light with the cobs or diodes or whatever placed around the perimeter...

example a 33"x33" light for a 3'x3' space with 8 cobs space like this:

O--O--O
O-------O
O--O--O

or a 44"x44" light for a 4'x4' space with 12 cobs spaced like this:

O--O--O--O
O-----------O
O-----------O
O--O--O--O

... it seems to me like this would do a good job of evening out the numbers... I'm sure there is even a computer program that could be used to determine the exact spacing it would take to achieve a perfectly even spread...

I'm really curious what readings you'd get if you just turned the center 4 cobs off completely
Click to expand...
I use a 120 degree cone to calculate spacings, if you draw a 120 deg triangle and mark it vertically to your drawing scale height yu can calculate how large the diameter of each light pool will be, from there you can calculate the overlaps which need numbering as 4 overlapping pools will have twice the light of say two pools etc but mostly aim for around a foot to 16 inches spacing for 100w cobs less for lower power as a minimum.
 
Justin Eterovich

Justin Eterovich

Member
Couldn't figure out how to add these to the thread so adding them to a comment.

I moved the cobs around and tested things again. Got the light to be more even. Attached are the configs and par readings. Not a huge notable difference from 16in to 18in. I would probably run at 18 in. All of these par readings are taken at full power 1117Watts.

I am using the Ledil Stella lens and I think they are causing me to loose 10-20% PAR rating due to their really wide angle. I am in the process of getting some glass lens to test those. If anyone had some info on this I would love to see what everyone thinks!

Will start growing in next 2-3 weeks.

Still pondering the question of if it is worth it to try to make the light spread even or if it really matters that much. Example, if it takes 1000W to make the 4x4 corners 650par and only 650W to make them 275 par (But everything else stays pretty much the same) Will it yield more? Is the extra yield worth the extra 350W spent? This is basically what I am setting out to find out.
I am tired of Kind and other LED brands with these small 20x20in lights claiming they flower a 4x4 with 150par at the edge of the 4x4.

Am I crazy?





 
V

VegasWinner

Well-Known Member
move the four center cobs one to each side between the other four cobs and you have a ring of five no center. may find some interesting numbers. ppfd falls at the perimeter so start near the perimeter and work towards the center, adding or moving one or two towards the center to create the balance you are looking for.
 
V

VegasWinner

Well-Known Member
now you can adjust the outer ring dimension to maximize your overall ppfd and not overheat the center which is what usually happens.
 
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