DiY LEDs - How to Power Them

I made an incorrect assumption regarding the Signa supply. It is a constant voltage supply NOT constant current. Why it is labeled an LED Driver I do not know.

whytewidow said:

What about using the meanwell 24v power supply and then using inline a dc to dc booster

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That gets a little tricky. The HLG is a constant current driver. These Boost converters you picked are constant voltage.

You would need a Boost constant current driver that would be better driven by the Signa.

A Buck step down constant current driver is more efficient unless the cost of electricity is not a concern.

What I would do is use 18V CoBs and pair each with a Mean Well LDD-H, step down driver.
They cost $3.49 here: http://www.ledsupply.com/led-drivers/mean-well-ldd-l-series-cc-step-down-mode

You would power 3-4 of the LDDs with a Signa.

The Bridgelux EB strip is not a horrible idea. Except max forward voltage is greater than 24V.

The only other viable solution would be to buy a higher voltage supply. But you still have the same problem with load imbalance when driving more than multiple CoBs in parallel.

The voltage difference between 24 and 18 is too large to use a CCR or drop resistor, efficiency would be 75% minus the Signa efficiency. So most of the electricity would be producing heat. The LDDs are 97% efficient.

whytewidow said:

I just wish they were bigger cobs

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You will have better uniformity with more CoBs. Improved uniformity will allow you to reduce the distance between the CoB and canopy.

Reducing the distance from 24" to 17" will double the intensity at the canopy. 24" to 12" = 4x intensity.

NoFucks2Give said:

Reducing the distance from 24" to 17" will double the intensity at the canopy. 24" to 12" = 4x intensity.

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Wrong again. Inverse square law does not apply in a situation like this. You get 20% more light due to less wall losses when you go from 24" to 12".

wietefras said:

Inverse square law does not apply in a situation like this.

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Oh fuck, you are like a gnat. You promised to not respond to my posts. Where do you come up with this bullshit?

Wow, you get to make your own rules. How do you know I have walls? Could you call the guys at NIST that issued my calibration certificate that they are wrong. My radiospectrometer says YOU are wrong.





Source of image: https://www.intl-lighttech.com/support/ilt-light-measurement-tutorial

NoFucks2Give said:

Oh fuck, you are like a gnat. You promised to not respond to my posts. Where do you come up with this bullshit?

Wow, you get to make your own rules. How do you know I have walls? Could you call the guys at NIST that issued my calibration certificate that they are wrong. My radiospectrometer says YOU are wrong.

View attachment 3966236

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Well if it makes you feel better right now I don't have walls. Lol. My tent is still in the box. Not setup. So right now I have an open grow lol

wietefras said:

Inverse square law does not apply in a situation like this

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@wietefras, When you pull information out of your ass all you get is shit.

@wietefras,You are confused. You may be thinking of diffused radiance from an illuminated surface.
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Inverse square laws does not apply when you measure the amount of photons incident a surface in a solid viewing angle where you measure a larger surface as the distance increases.



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The image below clearly shows the the distance between a light source and surface affects light intensity.



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When the surface area remains the same (as in canopy top) and the distance changes

As you see the inverse square law is applicable. Applying the inverse square to 1 candela at 1 ft. (12") and 1 meter (39.37").
(12"/39.37")² x 1 ft = 0.0929 lm/ft² (as shown in image)



Source of images: https://www.intl-lighttech.com/support/ilt-light-measurement-tutorial

@NoFucks2Give, I saw you were misinforming people as usual and this time you were so stupid again that I though it better to break my "no reply rule" than let this dumbassery go on.

You can copy paste all want about inverse square law. What's the point? We all know what it. We know you are really good at copy pasting things, but the problem is that you never really understand what you are copy/pasting. This time it's no different.

The inverse square law says that the light gets DISTRIBUTED over 4 times the area when you increase the height by 2. So the light is not lost, it's still there, only more spread around. Since COB growers have multiple light points, the lights will overlap more and the overall intensity won't change at all if the grow area is big enough.

Green houses have their lights at 3 meters above the plants. You'd get practically no light from those at all if the inverse square law would actually apply for the whole lighting system.

First of all, a sane person would hang the light(s) so that the whole grow area is lit to begin with. It makes no sense to hang a single COB close to the plants and light up only a tiny circle in the middle of the grow room.

So when you have hung the light at some reasonable height, the only thing that then matters is wall losses. NOT inverse square law. The less reflective your walls are the bigger those wall losses will be. Biggest if you have no walls at all, but even then the COBs in the center of the grow will still have hardly any losses since their light would not have reached the sides.

Then there is Malocan who actually measured the average light intensity at 12" and 24" and he measured a 20% loss in light from that move. 596 vs 744umol/s/m2 average. If you had been right then he would have found 75% light loss and 186umol/s/m2 at 24". It's not even close to that.


Also, why can't you at least learn from the fact that you keep getting these basic things wrong? Why do I need to waste my time again on something so basic and so obvious? I have corrected you on at least a dozen major mistakes. It might be annoying that you need to be corrected, but at least learn from this. So when I tell you you are wrong again, at least be sensible enough to think and see why I'm right again and you are wrong again. Just copy/pasting some physics principles is not going to make you right.

wietefras said:

Also, why can't you at least learn from the fact that you keep getting these basic things wrong?

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And why can't you understand that the actual experts do not agree with what you say because it is you that is wrong.

Where in your warped view of lighting does inverse square work for you? My radiospectomometer measures the different in distance within 1% of the calculated values. My radiospectometer is NIST calibrated with their LED calibration profile.

wietefras said:

The inverse square law says that the light gets DISTRIBUTED over 4 times the area when you increase the height by 2

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No it does not. It says the point intensity quadruples when the distance is halved.

wietefras said:

Green houses have their lights at 3 meters above the plants

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And the light intensity at the canopy reflects the height. It's supplemental lighting.

wietefras said:

It makes no sense to hang a single COB close to the plants and light up only a tiny circle in the middle of the grow room.

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I agree with that.

wietefras said:

So when you have hung the light at some reasonable height, the only thing that then matters is wall losses.

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That I will not agree with. The gains in uniformity by accepting wall loss is more than compensated for when the increased uniformity allows the fixture to be closer to the canopy.

wietefras said:

s Malocan who actually measured the average light intensity at 12" and 24"

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There are 20 CoBs in these measurements. The measurements show dreadful uniformity from center to the edges so no surprises the poor performance. Without knowing the position of the 20 CoBs, the instruments used, and the procedure, I can only guess what went wrong. Uniformity, lack thereof.

I do not need your "corrections", you are WRONG!!

All I wanted to know was how many I should put on the one driver or if the dc to dc booster would work.

NoFucks2Give said:

The Signa are constant voltage power supplies, not LED drivers.

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The signa is an led power supply. But it's for different type of leds. It's for leds like street fighters. I work for a sign company. Those are the drivers we use for led mods inside signs to retrofit from fluorescent bulbs. I have multiple cases of these. 96 mods per case. I thought about using them mounted to a sheet of aluminum for cooling. Although these type of leds don't need cooling.

This one has constant current and constant voltage. Plus is adjustable up to 120vdc

For CoBs you will need constant current. And you will lose another 15+ percent efficiency.

So I am assuming you are going to run them all in parallel. If that is the case, then put a 0.01Ω resistor in series with all or some of the CoBs power leads so you can measure the current with a volt meter where 10mV will = 1 Amp. The 0.01Ω resistor will only waste 10mW of power.

I ran some experiments with 2 strings of 16 Luxeon Rebel White run in parallel between 125 and 410mA with and without a 5Ω series resistor.
One string is in the yellow the other in the blue.

This was a quick and dirty experiment, at least one of the PPFD values was incorrectly recorded. Just ignore the PPFD values.
As the experiment progressed the LEDs got hotter
I had planned to re-do the experiment but have not found the time.

The thing is how when connected in parallel with forward voltages almost matching, the currents in each string were very different.

Please forgive me for asking a question on your thread I do not want to be considered as hacking or spamming I would like to ask a question if possible with most of them LED boost converters if they are called LED drivers usually it's because they have led displays telling the voltage then use LED driver as abbreviation which is stupid I spoke to eBay seller about this subject and there are many boost inverters that have constant current and constant voltage with two potentiometers on it but they're not digital because I was told most All Digital LED boost inverters DC to DC if digital have to be set every single time power up to the correct voltage but with a manual potentiometer boost inverter it's preset set if you have one in mind that works for you I would like to see it in and if I am wrong please correct me and forgive me for writing on your thread

Growcob5 said:

Please forgive me for asking a question on your thread I do not want to be considered as hacking or spamming I would like to ask a question if possible with most of them LED boost converters if they are called LED drivers usually it's because they have led displays telling the voltage then use LED driver as abbreviation which is stupid I spoke to eBay seller about this subject and there are many boost inverters that have constant current and constant voltage with two potentiometers on it but they're not digital because I was told most All Digital LED boost inverters DC to DC if digital have to be set every single time power up to the correct voltage but with a manual potentiometer boost inverter it's preset set if you have one in mind that works for you I would like to see it in and if I am wrong please correct me and forgive me for writing on your thread

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The ones I posted have memory sets. So you don't have to reset at every power up.

whytewidow said:

I think I'm gonna go with the cree 3000k.

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I found this very new 18V CoB. It is very interesting and it looks excellent. I*t is a CXM-9 It also has bigger 36V too. I could not find one in stock.
Luminis Part Number: CXM-9-30-80-18-AC30-F4-3 Datasheet attached.

I did get one that is older in a similar CLM-9 same series, Gen 3 PN: CLM-9-27-90-36-AC30-F4-3

This image is an SVG image I created with an app I wrote that imports the data from my radiospectromoter.
This is a PAR Spectral Distribution. The datasheet has a radiometric that is very similar. sometimes I create a radiometric as well and superimpose the datasheet's SPD over mine and they match almost perfectly.

whytewidow said:

I think I'm gonna go with the cree 3000k.

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Here is another very interesting Luxeon CoB. It uses a violet LED to push the phosphor. This is made for retail clothing stores and called Crisp White. Their claim is it emits no UV.

I like the red peak is to the right of 600nm.

If if the violet 407nm peak could have shifted where it lined up with the 425 absorption of chlorophyll peak and the 455nm were at the 465 chlorophyll peak it would be perfect. But it still looks good for the action spectrum. And I like two different blue and violet wavelengths for the plant.





The below images are from the 2014 graduate level textbook Plant Physiology and Development 6th edition I added the vertical lines.

Who cares about chlorophyll only or some random collection of pigments? Why must you post nonsense? Seriously why must you keep on trolling?

McCree demonstrated a much wider absorptance and action spectrum for actual leaves. That's what actual growers work with and that's what "PAR" is based on.

If you can't debate without calling names log out

wietefras said:

McCree demonstrated a much wider absorptance and action spectrum for actual leaves. That's what actual growers work with and that's what "PAR" is based on. .

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Aw man, TW just turned in his grave.

Some of the first action spectra were measured by T. W.
Engelmann in the late 1800s (Figure 7.9). Engelmann used
a prism to disperse sunlight into a rainbow that was
allowed to fall on an aquatic algal filament. A population
of O2-seeking bacteria was introduced into the system.
The bacteria congregated in the regions of the filaments that
evolved the most O2. These were the regions illuminated
by blue light and red light, which are strongly absorbed by
chlorophyll.

Ever hear of Emerson and the Emerson effect????

In 1932, Robert Emerson and William Arnold..

Emerson and Arnold were surprised to find that under saturating conditions, only one
molecule of oxygen was produced for each 2500 chlorophyll molecules in the sample.

By the late 1950s, several experiments were puzzling the
scientists who studied photosynthesis.
One of these experiments carried out by Emerson, measured the quantum
yield of photosynthesis as a function of wavelength and
revealed an effect known as the red drop

Another puzzling experimental result was the enhancement effect, also discovered by Emerson. He measured the
rate of photosynthesis separately with light of two different wavelengths and then used the two beams simultaneously

But if you want to give all the credit to McCree I'm okay with that.

wietefras said:

That's what actual growers work with

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That is what is called anecdotal bullshit. Your opinion is not fact. Why is it you use very few facts from reliable sources. Wikipedia is not a reliable source. Peer reviewed papers works for me.

wietefras said:

Who cares about chlorophyll only or some random collection of pigments?

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I do. And thousands of scientists. And those that have to pay for the electricity to feed photons to their plants. Electricity doe not grow on trees, or so I have heard.

I want to feed my plants a healthy supply of photons with out paying more than I have to for them. Why is that so wrong?

Random? How so?

NoFucks2Give said:

Aw man, TW just turned in his grave.

Some of the first action spectra were measured by T. W.

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So what? There were many people who measured action spectra for individual pigments. McCree was the one who measured the action spectrum of the entire leaf. That is what most closely resembles actual photosynthesis in real live.

ps Please refrain from barfing a deluge of irrelevant crap in a post to try hide that you are utterly clueless. It's not working.