NoWaistedSpace
Well-Known Member
So what has been the progress? From reading this thread, there was a lot of "work in progress" So what are some of your results? I am just learning about the COBs so any input will be helpful.
Thanks
Thanks
Is this a Vero 29 killer?
- Thread starter JorgeGonzales
- Start date
KushyMcKush
Well-Known Member
Id like to see this going as well. Looking to build a light or two here soon with either citi 1212, 1818 or vero29. All look good but Im leaning toward 1212 or 1818... just hard to find the right driver for the 1818 and their spreadsheets dont work on my phone to find the right current I want.
Anyone who might want to dm with me for a bit and help me figure out my best option? Im thinking of eitger 8 1212's @1400ma (185-1400) or 6 1818's @1050ma (240-1050). Haven't started researching vero yet... only so many data sheets and posts you can read in a week lol. By my very half-assed and mostly guesstimated calculations, I should be able to do either for a roughly similar price.
Anyone who might want to dm with me for a bit and help me figure out my best option? Im thinking of eitger 8 1212's @1400ma (185-1400) or 6 1818's @1050ma (240-1050). Haven't started researching vero yet... only so many data sheets and posts you can read in a week lol. By my very half-assed and mostly guesstimated calculations, I should be able to do either for a roughly similar price.
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DrMisunderstood
Member
I generally do not have anything to do with CoBs. LEDs are too heat sensitive to cram a bunch of them into a small area.
There is one I saw and found its Spectral Power Distribution Characteristics to be exceedingly of interest. That is the Luxeon Fresh Focus Red Meat.
When looking at White LEDs the first thing I look at is the spectral distribution. What I specifically look for is the wavelength of the peak to be in the Deep Red (650nm) region. And for the blue peak not to be too high.
In this case I chose Red Meat over Marbled Meat because of Marbled's Green peak at 530 nm.
The problem I saw in the post of this thread is the use of LUMENS. Lumens has NO place in a discussion regarding Grow Lighting.
I purchased two the these CoBs, and measured the PPFD (image number 2). This image was created from a data dump from a StellarNet BLUE-Wave spectrometer with an app I created to convert the data to an SVG image.
This LED has substantial Deep Red and well into the Far Red (710 nm) region.
Just for you guys that like to use Lumens I dumped the exact same data in Lumens. Notice how it does not even remotely resemble the actual PPFD characteristics of this LED. Lumens is about eyballs, not plants.
If I were to look at this CoB in terms of Lumens, it would have no deep or far red.
Lumen measurements takes the watt measurement and multiplies it by the CIE Photopic Luminous Efficacy factor. Totally irrelevant to grow lighting.
Where I saw trouble in this thread was in trying to pick a CoB based on the Lumens per Watt efficacy.
Lumens per Watt is a ballpark number that can be used to estimate the Efficacy of a series of White LEDs.
All the LEDs in a series such as the Vero 29 are made with the same Deep Blue LED. The efficacy of every LED in the series is the same. The output flux difference from one CCT or CRI to another is the phosphor wavelength converter efficiency.
If you base decisions on Lumen/Watt efficiency you will likely end up with an LED with less photosynthetic efficiency.
Most times in a series of White LEDs, the 2700 or 3000K with a CRI 90 is the LED with the best PPF.
Unfortunately the Vero 29 datasheet did not include the spectral distribution for their CRI 90. That eliminates it from my list of viable CoBs.
Even if the Vero 29 had an ideal spectral distribution I still would not use it based on its thermal characteristics. The number one characteristic when evaluating a LED should be the Thermal Resistance from junction to case. The datasheet does not specify the thermal resistance but it does show a 45° C delta between junction and case. This means no matter how substantial your thermal management, the junction will be 45° warmer than the case.
Also the datasheet specifies TYPICAL, there is nothing typical about an LED. You must look at the characteristics at the current and temperature it is going to be used at.
There is one I saw and found its Spectral Power Distribution Characteristics to be exceedingly of interest. That is the Luxeon Fresh Focus Red Meat.
When looking at White LEDs the first thing I look at is the spectral distribution. What I specifically look for is the wavelength of the peak to be in the Deep Red (650nm) region. And for the blue peak not to be too high.
In this case I chose Red Meat over Marbled Meat because of Marbled's Green peak at 530 nm.
The problem I saw in the post of this thread is the use of LUMENS. Lumens has NO place in a discussion regarding Grow Lighting.
I purchased two the these CoBs, and measured the PPFD (image number 2). This image was created from a data dump from a StellarNet BLUE-Wave spectrometer with an app I created to convert the data to an SVG image.
This LED has substantial Deep Red and well into the Far Red (710 nm) region.
Just for you guys that like to use Lumens I dumped the exact same data in Lumens. Notice how it does not even remotely resemble the actual PPFD characteristics of this LED. Lumens is about eyballs, not plants.
If I were to look at this CoB in terms of Lumens, it would have no deep or far red.
Lumen measurements takes the watt measurement and multiplies it by the CIE Photopic Luminous Efficacy factor. Totally irrelevant to grow lighting.
Where I saw trouble in this thread was in trying to pick a CoB based on the Lumens per Watt efficacy.
Lumens per Watt is a ballpark number that can be used to estimate the Efficacy of a series of White LEDs.
All the LEDs in a series such as the Vero 29 are made with the same Deep Blue LED. The efficacy of every LED in the series is the same. The output flux difference from one CCT or CRI to another is the phosphor wavelength converter efficiency.
If you base decisions on Lumen/Watt efficiency you will likely end up with an LED with less photosynthetic efficiency.
Most times in a series of White LEDs, the 2700 or 3000K with a CRI 90 is the LED with the best PPF.
Unfortunately the Vero 29 datasheet did not include the spectral distribution for their CRI 90. That eliminates it from my list of viable CoBs.
Even if the Vero 29 had an ideal spectral distribution I still would not use it based on its thermal characteristics. The number one characteristic when evaluating a LED should be the Thermal Resistance from junction to case. The datasheet does not specify the thermal resistance but it does show a 45° C delta between junction and case. This means no matter how substantial your thermal management, the junction will be 45° warmer than the case.
Also the datasheet specifies TYPICAL, there is nothing typical about an LED. You must look at the characteristics at the current and temperature it is going to be used at.
Heil Tweetler
Well-Known Member
RE V29, Ive got a rig using the old v29,4k @ 2.1 mA. Been running for more than 2 years. Never an issue, Loads of flowers.
nogod_
Well-Known Member
DrMisunderstood
Member
That's nice. I'm saying you probably would have done even better with a Lower CCT and higher CRI. More K is better for Lumens, not PPF. The bigger issue I have with the V29 is the very high thermal resistance.
Heil Tweetler
Well-Known Member
ive got an abundance of ppf in my 2 x4 using 4 x V29 and 4 x cxb3590, 3500 @1.4mA. I'm considering upgrading to the newer v29 and adding dimmers.
I though you were concerned with failure due to heat issues. Ive not heard of this type of failure from anyone on RIU
DrMisunderstood
Member
Just signed up today. Not a newbie to horticulture LEDs.
Heil Tweetler
Well-Known Member
There is loads of well informed discussion in these pages. Too many legit builders and researchers to name but the threads are jammed with learnings, data and experiments.
DrMisunderstood
Member
Really? I did not see it specified in the datasheet. I did see Tjmax 150°C and Tcase 105°C which say the thermal resistance is horrible. Good thermal resistance would be in the 0.2°C/Watt area with a delta of less than 20°C between case and junction. The reason I stay away from CoBs is there is too many Watts generated in too small an area. A CoB's view angle is usually not very good either, making uniformity very difficult.
DrMisunderstood
Member
I am concerned about failure of active cooling, not the LED itself. Everything about an LED boils down to thermal. I like to run LEDs on the cooler side. With 45° between case and junction, it would be difficult to bring the junction temp below 70°C.
I'm not saying you don't have lots of PPF. I'm saying you could have had more with a better CoB selection.
DrMisunderstood
Member
You say that like 300 Watts is a good thing.
Okay, I looked again, I see you are correct. They have very good thermal resistance.
It would be nice if they included the 3000K 90 CRI spectral distribution curve.
The 3000K 80CRI looks decent. Much better than the 4000K with the excess green. The green drives up the Lumens but does very little to improve photosynthesis. And this is the problem I saw in this thread. The higher CCT LEDs appear to be better, but its due to the green wavelength illusion that is very deceiving.
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CobKits
Well-Known Member
CobKits
Well-Known Member
welcome to the site
you'll have to dig a little, but jorge posted a lot of calculated umol/J for a bunch of different spectra and currents in this thread
https://www.rollitup.org/t/cheap-and-cheerful-diy-using-citizen-cobs.909460/
you'll have to dig a little, but jorge posted a lot of calculated umol/J for a bunch of different spectra and currents in this thread
https://www.rollitup.org/t/cheap-and-cheerful-diy-using-citizen-cobs.909460/
DrMisunderstood
Member
That was a nice post. I like Jorge.
I may have given the wrong impression. I do not use CoBs due to the nature of my projects. I understand the LED grow light market is pathetic and a DIY CoB is about the only alternative due to the low volume production. For maximum efficiency, CoBs cannot beat discrete LEDs.
I was not saying the Fresh Focus CoB was superior to a V29, the Red Meat LED data was readily available to graphically demonstrate the stark difference between Lumens and PPF. Actually I was searching for a different CoB top replace the Red Meat LED.
The reason I found this thread is I was considering using CoBs to speed up a very small inter-canopy experiment that required only five 150 µMole White fixtures. A CoB solution would shave the PCB turnaround time from the schedule. I did disqualify the V29 solely because there was no graph for the 90 CRI, even though it looked promising.
I did find the numbers you were referring to. The PPF numbers are much better to go by than Lumens. The significant thing I saw in his spreadsheet that backs up my point is where in the same series are the cases where Lumens decreased while the PPF increased when the CCT increased. Still even the PPF numbers are not enough and can be deceiving. All PPF does is count the photons. Not all photons between 400 and 700nm are equal. Counting photons does not consider the energy of the photon or the Photosynthesis Yield. The spectral power distribution chart is much more important factor than the PPF numbers and Lumens are worse than useless. using Lumens in an LED evaluation is almost as bad as using Wall Watts in a fixture evaluation where more Wall Watts is considered better like some think more Lumens is better. .
nogod_
Well-Known Member
Every single point you've made has been discussed on this subforum ad nauseam.
More reading and less typing will help you understand why the components we choose have gained favor in this community.
Welcome to RIU!
More reading and less typing will help you understand why the components we choose have gained favor in this community.
Welcome to RIU!
nogod_
Well-Known Member
DrMisunderstood
Member
Thank you.
Based on many of the comments and decisions posted in this tread, your point was not apparent. Sorry about being redundant.
I'm not sure if you are saying I am wrong, but that is what it sounds like.