Are LEDs Misunderstood?

[secondtry]

unthing, the fans on the LED units from hydro grow are very quiet - almost silent.

So are good centrifucal fans like the kind I use for my 600w.

habeeb - yeah its not a problem to me but may be to other people who want a super stealth setup.

This is a big problem I have with you VG, you make claims about stealth as if that makes LED better for growing plants and it does not! Plants could care less if they are stealth or not, what plants care about is irradiance and SPD (in terms of lighting). That is my whole point, YOU want to grow plants and make them fit your needs, I want to grow plants and make MYSELF fit THEIR needs...do you see the difference? I try to grow the best plants no matter what, while you do not.

 

[secondtry]

Um, I have the 126w and it's not silent at all so I'm confused even more. Imagine 6 fans of overheated laptop blasting at full speed, that what it sounds like.

That is just what is sounds like at the grow store too, those LEDs they are LOUD and the sales people refuse to suggest people buy them because they call them "eye candy" but not great for growing plants, the 600w and 400w HID sitting right next to the LEDs grow healthier plants are are less loud then the LEDs.

 

[secondtry]

MB makes a good point. the 250 hps cab in my loft has a temp controlled 4" fan which has 4 speeds. even having used sound damping tape to isolate vibrations i can still hear it on it's lowest speed in my bedroom which is on the floor below.

VG

That is why I suggest using a 6" centrifugal fan! It's quiet; all you do is put a step-down adapter to the 4" flange on the hood and use a 6" hose...

 

[draco]

i have a hid AND a led on the front of my vehicle and i like them both very much.

 

[VerdantGreen]

Um, I have the 126w and it's not silent at all so I'm confused even more. Imagine 6 fans of overheated laptop blasting at full speed, that's what it sounds like. Not that it cannot be hidden but there's no stealthy advantage.

wow that surpsises me, i think the noise from my 63watt is nothing compared to the sound of my inline fan ( and for the avoidance of doubt the brand of fan i have is regarded as the best in the UK/europe and is also the most expensive )

perhaps all my years of DJ'ing sent me deaf

VG.

 

[GrnMtnGrwr]

MB makes a good point. the 250 hps cab in my loft has a temp controlled 4" fan which has 4 speeds. even having used sound damping tape to isolate vibrations i can still hear it on it's lowest speed in my bedroom which is on the floor below.

VG

Like others have said... that's your problem. I've got a 4" with a 400w, my temps are fine, and I run my fan on low. If I wanted to be even more stealthy, I'd get a 6" and run it on low. Just because you can't stealthify your setup, doesn't mean others can't.

 

[VerdantGreen]

Like others have said... that's your problem. I've got a 4" with a 400w, my temps are fine, and I run my fan on low. If I wanted to be even more stealthy, I'd get a 6" and run it on low. Just because you can't stealthify your setup, doesn't mean others can't.

whats my problem? it's not a problem to me, i was just saying that i can hear my fan. my temps are fine too as my fan is temperature controlled. (no A/C in my house either)

do you use an aircooled hood with your HID?? - i dont because i dont want glass between my light and plants, also i like to use an ecotechnics diamond reflector as i believe it is the most efficient for my required footprint - i dont believe aircooled hoods (available to me) are the most efficient at reflecting light down (and my plants and yields seem to bear that out). a 6" fan wouldnt work for me as the fan is inside my cab above the light and i need all the height i can get. i cant even stand up in the loft that my cab is in - and yes that is my problem - but i get round it as that is the only place i have to grow.

VG.

VG.

 

[VerdantGreen]

nothingbut, i guess you might call both of my grows 'shoeboxes' lol - although i get 1 to 1.6 gpw from my 250HID cab so if a 205LED can match that or better it i will be happy. (if you call those results mediocre then please post some pics of your grow )

but look around the site - there are a few test grows going atm with great growers who are testing 205LED against 400hid and other comparisons - the results of those as they come in should be interesting.

VG.

 

[PetFlora]

I think what 2ndTry is saying is When the LED mfgs start with the correct parameters, and design their lights to them, the yield will take care of itself.

Even though I get a pretty decent yield with my Sunshine Systems UFO 90, I paid $370 for it. That's a lot of $$$$. The CFL side has 950 watts equivalent, at a total light cost (including fixture) of under $100.

In my current journal I am doing a side-by-side CFL v LED. Both sides are fed from the same hp aero system/reservoir. Comparing the two sides, the CFL side is probably double the yield at 1/4 the price.

 

[GrnMtnGrwr]

whats my problem? it's not a problem to me, i was just saying that i can hear my fan. my temps are fine too as my fan is temperature controlled. (no A/C in my house either)

do you use an aircooled hood with your HID?? - i dont because i dont want glass between my light and plants, also i like to use an ecotechnics diamond reflector as i believe it is the most efficient for my required footprint - i dont believe aircooled hoods (available to me) are the most efficient at reflecting light down (and my plants and yields seem to bear that out). a 6" fan wouldnt work for me as the fan is inside my cab above the light and i need all the height i can get. i cant even stand up in the loft that my cab is in - and yes that is my problem - but i get round it as that is the only place i have to grow.

VG.

VG.

Like you, I don't want glass between my bulb and my plants. I don't have AC either. Saying a fan is loud is like saying a HID bulb is hot. That's how they work. You just have to make them work for your situation.

 

[unthing]

Verdant,

It might be that the little model doesn't require as much cooling. Have you tried the 205 w on? Tell me what you think about it in regards of noise.

 

[VerdantGreen]

LOL....too bad you weren't able to pull that off with the LED and that's my point isn't it? I have seen all these grows plus all the one's that the manuf. of your light won't post up because they couldn't minipulate the results to suit their agenda....BTW I have some panels for sale, Only used once! Cheap! And HID's are fine in a shoe box too...http://www.icmag.com/ic/showthread.php?t=157863

hi again nothingbut - the 63watt grow was my first LED grow so i was happy with 1g/watt from what is a low-medium yielding strain - and i learnt a lot from it, the main factor being that LED's dont give out nearly as much heat which made the temps a bit cool - but during the summer when the temps get quite high it will be a great bonus to have cooler lights. i think i can do better than my initial results with the 63 - and bear in mind that the 63 has a lower watt/sqaure foot than any other of HG's LED units.

i am just as interested in you as to how well the bigger units can do - so far i have satisfied myself that the quality of smoke from LED is just as good if not better than HPS - and just as good as CMH. my grow with the 205w unit (replacing the 250HID) will start next week. i have quite a few documented grows in my present grow diary and will be running some of the same strains, growing them in exactly the same way so we will see.

cheers

VG.

p.s. thanks for the link - thats a nice setup but near in mind no-one has got 1gpw yet on this site with a 70w hps.

 

[VerdantGreen]

Verdant,

It might be that the little model doesn't require as much cooling. Have you tried the 205 w on? Tell me what you think about it in regards of noise.

hi unthing - i have switched the bigger unit on and didnt notice the noise because i was jacking off at how bright it was at the time
but i'll be sure to post up a comparison of that in the diary.

V.

 

[PetFlora]

VG: I can be as crude as anyone, but there is a time and place for it, and this thread is neither. Please PM your rude/crude comments to 2ndTry, and vice versa.

I have a 90 watt UFO with 3 fans-they make a lot more noise than I would have thought. Another example of Chinese mfg specs, or a mfg buying on the cheap? I can only guess that 200 watt+ LED with considerably more fans, would be much noisier. By us bringing fan noise up, hopefully led mfgs will source quieter fans.

Sadly, if they are reading this thread, they probably view it as just another a'hole pissing contest. So again, please keep it civil and support any position with data, which to me at least, DOES include yield.

2ndTry If you create a Journal (as opposed to a Thread), you can control via Editing or Deleting crude/rude comments.

IMHO, yield is most def one aspect of data. Let's say all the scientific light data has been validated (I think there will always be arguments on what is/isn't important) the only way to verify is to grow.

Chances are there will be at least two somewhat opposing arguments. It is only by growing them side-by-side, using one nutrient control, as well as same room (RH, room temp, etc.) that you can prove which is closer to the truth. I think my True Aero Pod Grow Journal provides the proper control (2 tables running off the same hp pump/rez).

 

[unthing]

My friend modded china ufo and replaced the 3 fans with one big one. As rpms are lower so is the noise. The mesh that they have hotglued those fans and drivers in also contributes to noise. We were wondering what function it has other than keeping trash, hair and fingers out, but you could do it less noisy and still be safe for your fingers.

Passive cooling via big heatsink is the best option IMO, but I quess it's the most expensive one, but also more fail proof than fans or water cooling which I've also seen on certain models.

Petflora, sorry if this fan issue is bit offtopic

 

[PetFlora]

Unthing- no problem. Good input, actually.

 

[secondtry]

I think what 2ndTry is saying is When the LED mfgs start with the correct parameters, and design their lights to them, the yield will take care of itself.

Yea! But you wrote it much more elegantly then I was able to. Thanks for summing it up so nicely!

 

[knna]

Hi, Ive just found this thread.

Its large and I havent time right now to read it full, but Ill do. I think many interesting topics has arisen along it and worth to examine it deeply.

To start with some of them, I would like to give my opinion about two.

One is if its better to analyze a bulb by PPF or PPFD.

PPF is the total photon flux emitted by the lamp, PPFD is a light density (photons falling on a given area for unit time) measured on a given point of the plant (usually, its measured at top canopy). PPF is a parameter that refers to the lamp and is absolute, while PPFD refers to the area being lit and is relative.

PPFD is relative because although its related to the light being thrown on the area, the figure depends strongly on the distance you take the measurement and its relative position to the light source and how the light source distribute lights, that depends of optics/reflector used.

Its true that plants response is dependent of PPFD. But as it refers to the lighted area and is very relative, we cant use it to compare bulbs, because is almost impossible they mean the same for two different types of light sources.

The only way of comparing different types of lights is by PPF. That can gives us an insight of the potential of a bulb for growing. Actual results in regards of its potential depends it is used on the right way in order to translate it to PPFD as homogeneous as posible along the grow, on the 3 dimension axis. But that is something related to how a grower uses a given light, not related to the light itself.

One thing is true: almost any LED lamp in the market says its PPF. I only know Procyon states it and unfortunately is a figure low compared to any HID. Other vendors dont give PPF figures,probably because they dont know what is it, because dont have the equipment to measure it or because they dont want to give it because actual lamps have poor PPF figures.

In this situation, the only way to know how much light a given lamp emits will be that an independ source measure and report them.

Recently I buyed an spectroradiometer and Im building an integrating sphere (IS), that is the equipment required for such measurements. Ths IS Im building now is an small one, able to measure single LEDs, that is my priority now. But when Im done with it and have caracterized the emission al all LED models I can get, Ill build a larger IS able to measure full lamps. Its a complex task (IS able to do that cost over 40000€), because a full lamp measurement requires to eliminate light self absortion from the lamp's body, but I hope to be able todo it. I have the spectroradiometer and the calibrated lamp for absolute emission, so probably it will take many time configuring the system, but once done Ill be able to measure accurately absolute light emission from any lamp, aswell as its spectrum.

I hope a table with absolute emission of all lamps in the market will definitively clear many unclear things about LED lamps.

 

[knna]

The other topic I would like to discuss is the average PPFD to use on a grow.

Based on same studies, secondtry and me think different. He thinks 1500 uE/m2 is optimal, as MJ continues increasing photosynthesis up to that. Indeed, MJ does well close to 30ºC up to 2000uE. If a grower is looking for max production (g/m2) of a given grow area, I agree this would be the optimal, specially if there is CO2 enrichment.

On the opposite, me, as a grower, Im more interested on the productivity of the light (g/W). As irradiance increases over 400uE/m2 or so, light productivity starts to drops. Slowly first, faster as irradiance level increases. So when we look to get the highest yield with the lower watts input, we try to find the lower irradiance point where yields are good,so getting the best productivity.

Notice that average PPFD is a concept very different to actual PPFD. While PPFD is a measured figure only valid for the conditions and situation of the point where the measurement were performed, average PPFD is calculated by dividing the PPF by the area to be grown. Its just a reference for configuring setups, to know how much light we need to install depending on our priorities. In general, growers looking the best light productivity uses about half light that growers looking for max production of grow area, for any type of light.

For example, HPS growers looking for max light productivity uses about 40-50W/ sq ft, and growers looking for max total production uses 75-100W/ sq ft. For reference, that means than on a 10 sq ft area ( al ittle less than 1 sq meter), a grower using a 400W HPS looking for max light productivity is aiming an average PPFD of 500uE/m2, while one looking for max production uses a 600W (825uE/m2) up to a 1000W (1300 uE/m2).

But saying that averages irradiances of 500uE dont yield is simply false. Many people uses that irradiances using HIDs. Taking into account than well designed LED lamps offer better spectral productivity (P/mol photons or g/mol photons) and distribute light way more homogeneously (PPFD measured along the grow have way lower differences that those measured on any HID grow), 500uE/m2 is an excelent average. Indeed, I know many people using 300-400uE/m2 in average with excelent results (getting over 2g/W).

Notice than an average 500 uE/m2 may obtain PPFD in excess of 1000uE/m2 on the upper canopy below the lamp. Way higher when using single point light sources (HID), that need to keep at some distance of canopy to avoid light bleaching due excessive irradiance, that means PPFD over 2500uE/m2.

 

[secondtry]

Hey KNNA,

Nice to see you here.

Hi, Ive just found this thread.

Its large and I havent time right now to read it full, but Ill do. I think many interesting topics has arisen along it and worth to examine it deeply.

Also check out this thread, I spend much more time on it with much more info: https://www.icmag.com/ic/showthread.php?t=158600 (it's 18 pages)

BTW, I wrote a good bit about your spreadsheet and why it's not really valid in terms of accuracy, I asked with Sanjay Yoshi Ph.D about it also and he agrees. Your methods are ok but the error margin is much too high at > 10% easily.

To start with some of them, I would like to give my opinion about two.

One is if its better to analyze a bulb by PPF or PPFD.

PPF is the total photon flux emitted by the lamp, PPFD is a light density (photons falling on a given area for unit time) measured on a given point of the plant (usually, it’s measured at top canopy). PPF is a parameter that refers to the lamp and is absolute, while PPFD refers to the area being lit and is relative.

PPFD is relative because although its related to the light being thrown on the area, the figure depends strongly on the distance you take the measurement and its relative position to the light source and how the light source distribute lights, that depends of optics/reflector used.

It’s true that plants response is dependent of PPFD. But as it refers to the lighted area and is very relative, we cant use it to compare bulbs, because is almost impossible they mean the same for two different types of light sources.

I don't follow you, but I also don’t agree. PPFD is the only way to measure lamps; PPF is not because as you write it is at the source, while we need measurments at the canopy. Thus one can't use PPF because it is not a measure of the light plants use, which is what PPFD is for. It's easy to compare lamps with PPFD, just use a quantum sensor. But in terms of weighted photons we need a spectroradiometer to use QFD, but QFD was made by K.McCree using a monochromatic lighting, thus it has been updated last year for bright white lighting like HID because green photons offer higher Pn (rate of photosynthesis) then red photons.

PPF is pretty meaningless because it's at the lamp, so it's isn't showing what the plant is using at the canopy.

The only way of comparing different types of lights is by PPF. That can gives us an insight of the potential of a bulb for growing.

That would be true if the lamp was touching the canopy, but it isn’t so PPF tell us nothing much useful, we need to measure the photons at the canopy.

I posted four different studies on cannabis all showing highest Pn is from 1,500 PPFD. All studies use PPFD, no studies use PPF...

Actual results in regards of its potential depends it is used on the right way in order to translate it to PPFD

There is no accurate way to convert from PPF to PPFD.

as homogeneous as possible along the grow, on the 3 dimension axis. But that is something related to how a grower uses a given light, not related to the light itself.

That is why when I test lamps I will test them from a few distances, to find PPFD of the lamps.

One thing is true: almost any LED lamp in the market says its PPF.

That is wrong of them; it should be by PPFD and include a distance too.

Other vendors dont give PPF figures,probably because they dont know what is it, because dont have the equipment to measure it or because they dont want to give it because actual lamps have poor PPF figures.

PPF tell us nothing but radiant light, we need irradiance. That is why no studies on plants that I am aware of use PPF; they all use PPFD. We want to find how well a lamp can drive Pn, which is why we need PPFD and not PPF.

In this situation, the only way to know how much light a given lamp emits will be that an independ source measure and report them.

That is what I will do with the Li-Cor LI-190 quantum sensor, and also once I get my Ocean Optics spectroradiometer.

For now I will find PPFD of lamps and use the manufacture reported SPD to weight the PPFD as well as possible. Your spreadsheet isn't valid for that very reason; the margin of error is much too large. The same goes for using PPFD and SPD, the margin of error is too large, but once I get the spectroradiometer I will make all my own SPD and weight PPFD with the updated QFD from K.McCree; which was updated just last year

Recently I buyed an spectroradiometer

What brand and model? That is a problem with your spreadsheet is that it relies on manufacture SPD, and irradiance, however, both of those are affected by the ballast and the reflector so unless the same ballst, reflector and spectroradiomter are used one can't accurelty compre the data; and for LEDs temp is a major factor…and LEDs need green yet too few offer it.

and Im building an integrating sphere (IS), that is the equipment required for such measurements.

Why bother with a IS? It isn't needed for horticulture measurements unless one is growing vertical and doesn’t use a reflector for HID.

Ths IS Im building now is an small one, able to measure single LEDs, that is my priority now.

Just use the spectroradiometer to measure LEDs, there is no need for an IS. This is spectroradiometer model I will use, Sanjay Yoshi suggested the brand, it the same he brand uses but his model is lower quality:
http://www.oceanoptics.com/products/usb2000+rad.asp

But when Im done with it and have caracterized the emission al all LED models I can get, Ill build a larger IS able to measure full lamps.

I still don't see why you want an IS...

I have the spectroradiometer and the calibrated lamp for absolute emission,

Do you mean "absolute irradiance"? Did you calibrate it or did it come calibrated? Also, is your spectroradiometer weighted with a generalized plant action spectrum like from K.McCree etc?

I hope a table with absolute emission of all lamps in the market will definitively clear many unclear things about LED lamps.

It looks like you and I should talk, I plan to test HID and LED with the quantum sensor first, then the spectroradiometer to make SPD of all lamps I test and to weight the PPFD with updated QFD equations.

All the best!