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PPFD Graphs and Analysis

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ConstantGreen

New Member
Hello, this will be a continuation of my last thread, where I hand-measured and plotted the PPFD of Amare and Mars LED's with a hydrofarm PAR meter. Since then, I've also measured the Mars Reflector 192, Philips CMH 315w, etc. The point of this research is to determine the optimal footprint and height to use these grow lights to get the best results. Manufacturer recommended footprints have been misleading in the past and to grow most efficiently you need to know the PPFD falling on your plants.

What the par is PPFD? PAR just means Photosynthetically Active Radiation; it's not a measurement, just defining the range 400-700nm. 400-700nm is used by plants for photosynthetic growth and is a more specific range of the light spectrum for horticulture than lumens which is the range of light visible to the human eye. PPF is the total amount of PAR photons a panel emits and is measured by the manufacturer in one of those fancy spheres. But PPF is not exactly reflective of how many photons are hitting your canopy. Handheld PAR meters are measuring PPFD, which is the amount of par photons hitting a square meter per second.


(not my graph)

This study, published in 2009, established that cannabis sativa grows best at 30 degrees celsius and will grow quicker from increased PPFD, capping off in the 1500's. There's a diminishing return however. At 300 PPFD, cannabis grows at about 45% speed. Increase that to 800 PPFD, and cannabis grows at about 85% speed. That 40% gain for 500 extra PPFD is easily achievable. But to max out at 100%, you would need to go all the way to 1500 PPFD, nearly doubling the light intensity for a small 15% gain over 800 PPFD.

The best flowers will no doubt be grown at the highest PPFD, regardless of efficiency. It's up to you to make the decision between what's important to you between cost, efficiency, and quality. These graphs will hopefully help others decide which light is best for their space and what heights they need to be at for clones, seeds, veg, flowering cannabis.

Optimal PPFD for Cannabis Stages:

(table by Fluence Bioengineering)

My testing was done in a 4x4 grow tent, taking measurements on the floor with a handheld hydrofarm PAR meter. The 4x4' testing plane was divided into 6" squares and PPFD values were measured at the center of each square. The meter sometimes swings up to 100 PPFD in either direction, particularly for the Mars panels. I just took the average in this case, but I think it was because the blue and red spectrums are different intensities and it was confusing the meter. The SE450, Spydrx Plus, and CMH were much more stable on the PAR meter, maybe because of the "full-spectrum" of white light.



Factors that may tamper with the accuracy of my data or your own results would be the quality of the par meter, positioning of the light source, age of the light, the reflectivity of the tent, the tent door being open or any other light leaks while taking data. There's a huge difference in PPFD directly below the panel, compared to just inches outside of the direct footprint. The difference on the edge of the footprint could be more than 500 PPFD across a couple inches. Even though I took data every 6", if that footprint edge fell in or outside of my data points, that could make a big difference in the graphs. But the vast quantity of data points every 6" at multiple heights should dampen those factors in the averages. The panel dimensions are included in the graphs so you can see how dramatically the PPFD drops outside of the actual footprint. Look into the Inverse Square Law to read more about why this is important.

My first light was the MarsII 1200. It is marketed for a 4x4 foot grow. I used it in a 3x3' though and I'll show you why you should too. Sadly, the MarsII 1200 is probably only good for a 2x2' space if you really wanted to push for the perfect flowers with CO2 supplementation and everything else maxed out. It will no doubt grow cannabis in a 4x4' space, but the outside 1' ring of that tent is going to be getting only 150 PPFD which is only 25% of maximum growth rate. This sparked my quest to buy a meter and different lights to answer the question: Which light can actually flower a 4x4' tent with above average results?
 

ConstantGreen

New Member


For the 2x2 averages i took the center 16 squares of the 4x4 graphs and averaged them, then the center 36 squares for the 3x3 averages. 4x4 averages are of all 64 data points per height.



At this point it should be kind of obvious from the graphs that there's only one light here that's actually powerful enough or designed properly for a 4x4' space. The SpydrX Plus is by far the top performer in a few ways. I don't think I need to make more graphs to explain why but here's a few more calculations:

Efficiency

Wattage:
Reflector 192: 387w
MarsII 1200: 490w
Philips CMH: 315w
Amare SE450: 450w
SpydrX Plus: 660w

Optimal height PPFD per Watt:
XPlus @ 6": 1.66 in 2x2, 1.62 in 3x3, 1.54 in 4x4
CMH @ 12": 2.72 in 2x2, 1.63 in 3x3, 1.07 in 4x4
192 Bloom @ 12": 2.42 in 2x2, 1.4 in 3x3, 0.86 in 4x4
1200 @ 18": 1.28 in 2x2, 0.81 in 3x3, 0.54 in 4x4
450 @ 18": 1.98 in 2x2, 1.25 in 3x3, 0.82 in 4x4
450 Lens @ 24": 2.58 in 2x2, 1.48 in 3x3, 0.88 in 4x4

Penetration

PPFD Loss per 6" in 2x2:
xPlus: 15%, 13%, 12%, 8%, 8%
CMH: 35%, 27%, 22%, 18%
192 Bloom: 22%, 26%, 21%, 21%
Mars 1200: 25%, 23%, 20%
450: 23%, 20%, 16%
450L: 14%, 15%, 13%

Average PPFD Loss per 6" in 2x2:
XPlus: 11%
CMH: 26%
Reflector 192 Bloom: 23%
Mars 1200: 23%
SE450: 20%
SE450 Lens: 14%

Price:
SpydrX Plus: $1500
CMH: $225 ($75 bulb + $150 reflector)
Amare SE450: $1200
MarsII 1200: $350
Mars Reflector192: $275

Ok now we can talk about the data. Because of the inverse square, all of the lights that were from a single center source performed poorly in the 4x4' grid. The Spydrx Plus beat this by having a massive 42" square size. The SpydrX Plus would still have the same issues of dramatically poorer performance in a 5x5' or 6x6' space, but its size happens to match perfectly to a 4x4' tent.

The other LEDs and CMH were way too intense at close heights. They have to be 12-18" high to not only spread 4 feet wide, but to simply not burn your plants. This is wasted energy because you're basically lighting 12" of vertical space for no yield. The most efficient light will be dropped directly on top of the canopy to get maximum PPFD for your power usage. SpydrX Plus wins here again by having LED's spaced wide enough that it's not too intense to bring the light within 6" of a flowering canopy.

But what about penetration? I've read that LED grows should shoot for about 18" of vertical canopy flowers. If you have to have your light 18" above the canopy already, and then account for 18" of high-par flowers, you better hope your light is still strong at 36". The Amare SE450 with lenses should have won here I think because the lenses create a spot light effect with the super powerful COB chips. But again, the coverage of the SpydrX Plus appears to be working with the reflective walls of the tent to maintain a high PPFD reading even at 36" away. Keep in mind the wattage though, the X Plus is just way more powerful than the other lights by default.

The Spydr X Plus is also the most expensive. Five times more than the Reflector 192. You should consider that the best light setup in a 4x4 may not actually be the SpydrX Plus if you can't afford it. Two CMH's in a 4x4 would probably be devastatingly good, or two reflector 192's. The CMH gets a special mention for having the most efficient PPFD per Watt in a 2x2 space, although it also had the worst penetration efficiency.

At the end of the day there's a lot more to consider besides PPFD when making a purchase and designing your grow. You should consider the spectrum, warranty, lifespan, cost, wattage, efficiency, shape, etc. But hopefully this data gives you some goals and ideas. Thanks for reading!
 

Skullman420

Well-Known Member
Thanks for publishing your results. Great work. Wish you had many more lights to test
 

Icemud

Member of the Month: July 2012, July 2014 - Nug of the Month: July 2012
Excellent post and very good analysis... it goes to show that 1 of these lights is not like the others... by design they understand how LED emitters work and what it takes for a good even canopy coverage. All of the rest are similar in design and lacking for a 4x4 area.

Great work here! I wish more people could understand that PPFD is the ONLY way to truly measure plant lighting coverage. Every time I see someone ask..."how many watts per square foot do I need" I want to slam my head into a wall...LOL like, here we go again...I really wish the LED manufactures would educate instead of emulate each other... the industry would grow much faster if they actually shared real data instead of making up coverage areas that do not agree with the PPFD.

Great post and thanks for the time you put into this!

I definitely agree with your analysis and it shows which design type is most efficient for delivering a even, high intensity lighting. :)

kudos
 

Icemud

Member of the Month: July 2012, July 2014 - Nug of the Month: July 2012
By the way... I would love to see all of the LED sponsors here at 420 mag, donate a panel to Entheogenerator so he can actually show some factual, unbiased data on the lights.

So sponsors... send this member some lights ;)
 

Skullman420

Well-Known Member
I would love to see the numbers of my mars pro series lamps. They outperform the other mars lights
 

PurpleGunRack

Well-Known Member
Super awesome work, very thourough :thumb:

Nice to see a scientific approach to this subject, few people realize that you need at least 1000w HID per m2 for total light saturation ;)

Would like to see some measurements with DIY tech, and see how spreading out the light helps ie. 1x Mars 1600 vs 4x Mars 400.
Was gonna try 4x Reflector 48x5 in 120cm x 120cm(already tried 1m x 1m), but then I got my hands on some Quantum Boards ;)

Do you have any grow journals in the pipeline? :)
 

Grassmaster

Well-Known Member
Theirs so many factors to consider. CMH at 315w. SpydrX Plus at 660w. Imagine what 2 CMH's would do in the same tent using 630 watts.

Then. Which develops the most THC, Cannabinoids, terpins etc.
 

ConstantGreen

New Member
Great work here! I wish more people could understand that PPFD is the ONLY way to truly measure plant lighting coverage. Every time I see someone ask..."how many watts per square foot do I need" I want to slam my head into a wall...LOL like, here we go again...I really wish the LED manufactures would educate instead of emulate each other... the industry would grow much faster if they actually shared real data instead of making up coverage areas that do not agree with the PPFD.
Thank you! It is strange to feel like a pioneer on this topic... maybe it's not that necessary for the home grower to know exactly how much PPFD their plants are getting. But as these better designs come out and more people take the time to apply advanced techniques, the benefits will be obvious. It is weird that more manufacturers aren't ahead of the game though. Fluence is the only company talking about PPFD and what they had to say basically taught me everything you need to know. I'm really in love with their commitment to testing, educating and producing the best lights. Such an innovative yet common sense design to spread out the LED's.

I would love to see the numbers of my mars pro series lamps. They outperform the other mars lights
I'd be interested to see those numbers too. The Mars Reflector 192 marketed for a 4x4' uses about 400w, while the 4x4' PRO models use about 700w. So the PRO series should definitely be performing better with all that extra wattage, but I think the numbers would show very high center PPFD and low numbers in the 4x4' ring because the model is barely 2' square just like the others. I'm guessing the lenses are 120 degrees which means it would need to hang at least 12" high just to cast light 4 feet wide. Probably at least 18" high since 700 watts concentrated above a 2 foot area sounds too intense to hang any lower. They have the wattage right, I think it would take about 600-800w of LED to max out a 4x4. But it's too concentrated in the center to use that light efficiently across a 4x4 area.

Super awesome work, very thourough :thumb:

Nice to see a scientific approach to this subject, few people realize that you need at least 1000w HID per m2 for total light saturation ;)

Would like to see some measurements with DIY tech, and see how spreading out the light helps ie. 1x Mars 1600 vs 4x Mars 400.
Was gonna try 4x Reflector 48x5 in 120cm x 120cm(already tried 1m x 1m), but then I got my hands on some Quantum Boards ;)

Do you have any grow journals in the pipeline? :)
Duude I'm excited for you and your quantum boards! That's some tech I'm really looking forward to testing with, but it's not even on Fluence' radar yet and I don't know anyone else manufacturing quantum panels that aren't thousands of dollars. DIY seems like the way to go once you know a bit about lighting and wiring. I do see a lot of DIY'ers using more spread out designs. I think the spread-out designs are not just better for plant lighting but conveniently a lot easier to build and cool.

That's a good idea for another test, a 1600 vs four 400's. I think the difference would be huge with the four spread out. Also I guess light movers could make a single-point light source a competitor by moving it around the footprint.

I don't have any plans to journal right now. My camera broke so I can't take good pictures. Just been laying low and doing research. My current grow is a sea of Sour D under two Reflector 192's. They're in a 12 sq. ft. rectangle tent, which matches the two reflectors pretty snug. The entire canopy is getting over 700 PPFD which I'm pretty happy with.

Theirs so many factors to consider. CMH at 315w. SpydrX Plus at 660w. Imagine what 2 CMH's would do in the same tent using 630 watts.

Then. Which develops the most THC, Cannabinoids, terpins etc.
Yea, I couldn't find any CMH reflectors that I could actually fit two of in a 4x4 tent, but I'm sure there's some out there. Would probably still be more of a rectangular spread but once it's competing on equal wattage I think 630w in a 4x4 would be perfect. I've seen that video of that one guy testing higher terps and cannabinoids from CMH, but the difference was pretty small that it could have been from a difference in PPFD between the CMH and other grows he tested. Or another factor. But yea... so many factors to consider.

I think all we can say for sure from these results is it takes 600w+ to cover a 4x4 with 1000 PPFD, and the emitters need to be spread out evenly across the entire target footprint.
 

PurpleGunRack

Well-Known Member
Duude I'm excited for you and your quantum boards! That's some tech I'm really looking forward to testing with, but it's not even on Fluence' radar yet and I don't know anyone else manufacturing quantum panels that aren't thousands of dollars. DIY seems like the way to go once you know a bit about lighting and wiring. I do see a lot of DIY'ers using more spread out designs. I think the spread-out designs are not just better for plant lighting but conveniently a lot easier to build and cool.
Thanks man, I'm quite thrilled about these lights too, and being able to control the output is so nice for full cycle growing.
People shouldn't be afraid of getting into DIY it's pretty easy and with the many kits available it's getting more and more accessible to the grower.
Check out horticulture lighting group and chilLed;) there's also the sun/wavy boards but it looks like they haven't restocked in quite a while.
So many new better and cheaper COB's are being released all the time, it's hard to keep up :)

Seriously, I truly belive that in a couple of years the LED market will have changed drastically and growers will be able to nitpick to their every need / wet dream.
The power is with the growers now, we no longer need companies to overcharge us for slapping a sticker on some sub par tech packed in a panel chosen because it's sutable for shipping, so growers start acting like the demanding little princesses we all know we are! :laugh2:



I think all we can say for sure from these results is it takes 600w+ to cover a 4x4 with 1000 PPFD, and the emitters need to be spread out evenly across the entire target footprint.
Fits the old HID rule of thumb with minimum 37w per square foot :)
 

ConstantGreen

New Member
Thanks bro! The Amare uses CXB3590, so we can see how 6 of those + supplemental red/blue performs. Never even heard of the CLU's but I haven't done much DIY research yet.

I did want to share this image I came across the other day though. A real statement on the heat difference with LED tech.



This came from a fin-heatsink manufacturer, but the rest of their research on passive vs air cooled LED's seemed a little biased. Nonetheless, the high conductive heat radiation supports the spread-out designs. Too many chips in a small area is just not cool, and the efficiency of spreading out is on our side. It's like nature is saying chill with these beastie LED spotlights.
 

PurpleGunRack

Well-Known Member
CLU is produced by Citizen and I would have went with the latest generation of CLU58-1825, but then the Quantum Boards caught my eye ;)

Chart also shows that CXB3590 is obsolete since it's the most expensive of the lot :)



Many ways to cool LED, I prefer passive because it's silent and easy, and really the only wortwhile option if you want to spread out many COB's above your canopy.

ChilLED are also making liquid cooled and hood cooled (like HID) LED lights, their lamps are too expensive for my liking but I could see myself picking up some of their parts for DIY ;)

With the kits one can buy from Kingbrite, HLG etc. DIY is getting more and more accessible to people who might not think too highly of their own electrical/technical skills - these kits are easier to assemble than LEGO sets for kids :)
 

TheMadDabber

Member of the Month: Dec 2017 - Nug of the Month: June 2018
PW is running 2 twin boards in his 4 by 4 par rating of 700 at the edges of tent and I think he said 1400 umol under the lights.

Fluence and amare may be decent lights but boards and white LED is the future for indoor gardening.

All the manufactures you mentioned as well as others will have to jump on "board" before long or they will become obsolete.
 

ConstantGreen

New Member
The XPlus was the first passive-cooled light I've tried and I love it. The silence is really nice, and it seems to work well. Haven't clocked a spot on it over 140F. Just convenient that passive is also the best way to cool spread-out, DIY designs.

I was looking at ChillLED before Fluence and was really excited about them, but yea... super expensive and production was delayed. The liquid cooling sounds interesting, especially if the heat can be piped out of the room to save on A/C. But doesn't seem as practical with spread-out designs.

I loved legos. Good to hear it's that easy, IDK what I've been waiting for.

@MadDabber Who's PW? How many watts are the boards? Haven't seen any PPFD graphs yet for the quantum boards. They probably are the future, but I'm more hesitant these days to jump on the latest bandwagon.

The XPlus really opened my eyes to why precision matters. It's so perfectly designed for the 4x4 space that I can't imagine anything better unless it was cheaper or more efficient. Can the quantum boards be dialed down? I fear they're too concentrated still where you'd need to hang them 12"+ to not burn plants. But I don't want to hang any lights more than 6" from my foliage anymore cause I see how wasteful it is. That initial 6-12 inches of illumination has a higher PPFD than the following 12-36 inches. Efficiency drops exponentially the further the light is, so even if quantum is a step more efficient, unless the design is right, it could still be more of the same. I'm trying to get Fluence to produce a dial for the XPlus so I can tune it to the exact PPFD my plants need at each stage of growth. Instead of just raising the light and burning the same amount of watts.

Even coverage is also important to me. The quantum boards are still subject to inverse square so if there's more than a 12" gap between the boards, I bet there'll be a low spot there for PPFD. In CO2, 800+ PPFD is basically 85% photosynthetic rate, so as long as that's minimum, the areas peaking into the 1400's should only be like ~10% faster growing.

Warranty is the only other reason I can think of going with the XPlus. 5 years is twice as long as I've been growing already, so if the light gets serviced that long it should be a pretty good investment. Not sure what could go wrong with a DIY quantum build but I guess you'd be paying for your own repairs. Also the Spydr is split into 8 "legs", so if one goes bad I still have a 85% operational light until a new leg comes. And the legs are plug-and-play, so no opening up a case to do wiring or soldering.
 

PurpleGunRack

Well-Known Member
If I remember correctly Meanwell drivers have a 7 year warranty, don't know about the boards though but some warranty for sure, those two are the only ''moving'' parts.
Running the boards on a dimmable driver makes it possible to drive them within a great range (mine can be set to draw from 30w - 170w @ 230v AC) However drivers lose efficiency when they are dimmed, I think I can run mine at half capacity and still stay above 90% driver efficiency (92% is max) This depends on the driver some are more dimming-friendly than others.
Dimming is stepless and on some drivers done directly on the driver using a philips head screwdriver, other drivers need a potentiometer.

Try watching the instruction videos by Growmau5 on youtube if you want to learn about DIY COB's ;)

PW is Pennywise.
 

Icemud

Member of the Month: July 2012, July 2014 - Nug of the Month: July 2012
The quantum boards are still subject to inverse square
Although light scatters with LED similar to inverse square, its not quite subject to the exact inverse square due to inverse square only applying to a single point source of light in which light scatters equally in all directions. (like a star in the vacuum of space). With LED its a directed light at a focused beam angle, therefore the inverse square doesn't exactly apply, however the ratio of light dropping off due to scattering is similar depending on how narrow of a beam angle the LED chip is set at.

This can easily be demonstrated with a flashlight with a zoomable lens, where the output of the LED doesn't change, but the throw of the beam due to the angle does... same goes for LED's, the tighter the beam angle, the longer the throw, the wider the beam angle the quicker the dispersion and less throw, but the rate of light dispersion is not constant in comparison between the sources due to the focusing of the light particles.

A very very minor detail but figured I would throw out the correction :) BTW I love legos too :)
 
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