Hi Guys,

Have just come across a site Ledgrowlight
LED Grow Light Kit - 25 Watt

Over twice the output of our original 3-light kit ! Two R180XB red grow lights, one B60XB blue grow light, one 2-foot track, three track light fixtures, 25-foot power cord. 25 watts, 120 volt AC. Covers 2-4 sq.ft.

Prices: £150 each or 4 complete kits only £549.98!!



LED Grow Light Kit - 12 Watt

Two R90XB red grow lights, one 2-watt blue grow light, one 2-foot track, three track light fixtures, 25-foot power cord. 12 watts, 120 volt AC. Covers 1-2 sq.ft.

Prices: £65 each
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Red LED Grow Lights - Now Even Better - Twice The Average Output Of Our Original Red Lights

For use as primary light source. For use with blue grow light B60XB or for supplementing metal halide-HID lighting, sunlight or fluorescent lighting. Supplement with one B60XB blue LED grow light for each two R180XB.
Ten watts, 120 volts. 5.5 in wide x 4 in. deep. Fits standard light socket. Covers 1-2 sq.ft.

Prices: £50 each or pack of 10 only £454.50!!

Covers 10-20 sq.ft.





Red LED Growlight - Enhanced 5 Watt Output

For use as primary light source. For use with blue grow lights or for supplementing metal halide-HID lighting, sunlight or fluorescent lighting.
Supplement with one B60XB blue LED grow light for each four R180XB.
Five watts, 120 volts. PAR30 size. Fits standard light socket.

Enhanced 5-Watt Red LEDGrowLight only £18.75

Covers up to 1 sq. ft.

Enhanced 5-Watt Red LEDGrowLight 5-pack only £82.50

Covers 3-5 sq.ft.

Enhanced 5-Watt Red LEDGrowLight 10-pack only £156.25

Covers 5-10 sq.ft.

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Blue LED Grow Lights - Enhanced Output!
More than 3 times the output of the model it replaces! Same price!
For use with red LED grow lights. Use one B60XB for each 1-3 R180XB red grow lights or one for every for R90XB red lights. PAR30, 5 watts, 120 volts. Fits standard light socket



Blue Grow Light only £30 each

Covers 2-4 sq.ft.
Blue Grow Light 5-pack only £132

Covers 10-20 sq.ft.

Blue Grow Light 10-pack only £250

Covers 20-40 sq.ft.
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Full Spectrum Grow Lights
Item # F42XL
Uses powerful 1 watt chips. Superior appearance of plants. Provides red, blue, plus continuous full-spectrum enhancement. Designed to operate 3-12 inches from your plants. Wide angle beam for uniform coverage. Direct replacement for incandescent plant lights.



Full-Spectrum LEDGrowLight only £58 each

Covers 1-2 sq.ft

Full-Spectrum LEDGrowLight 10-pack £499.95

Covers 10-20 sq.ft.
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long lifetime Recommended useful lifetime of 50,000 hours for red lamps- the equivalent of burning a light for 18 hours a day, 365 days a year for seven years and seven months.
Energy efficient Save 50-75% on power over HID lighting, plus reduce or eliminate power consumption by extra blowers and air conditioning systems.
Better for plant growth Plants can use nearly all of the light emitted from LED lamps. Only about 10% of the power used and about 35% of the light generated by metal halide lamps is useful for plant growth.
Low heat output Warm to the touch. LED lights produce very little heat. The temperature of our growing areas is controlled by normal residential AC/heating and a ceiling fan. In most situations, no special ventilation or air conditioning is needed.
Economical Long life, low power consumption, high efficiency and cool operating temperatures make LEDs a cost effective choice for your indoor growing needs.
Light is Tunable The amounts of red and blue light can be precisely controlled. With a track light system, light is directed exactly where you want it.
More Versatile Grow peppers next to African violets or orchids - all will thrive. LEDs will not scorch young or tender plants.

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GROWING WITH LED LIGHTS
Our LED GrowLights are the best you can buy



Our solid state grow lights have been designed for one reason: To grow plants effectively and affordably. And they do, because the most important part of our design process has always been growing plants.

Which LEDGrowlights should I use?
If you want to : Then use:
Red/Blue Full Spectrum
Get the most light per dollar 1
Display plants 1
Have full spectrum supplement 1
Add lights to existing LED system 1 1
Alter the Red-Blue balance 1
Have lights very close to the plants (3-12 inches) 1

How many lights do I need?
Light Type # of Lights needed for each 4 square feet
Red/Blue 2-4 R180XB or 4-8 R90XB with 1-2 B60XB
Full spectrum 2-4 F42XL

More on red and blue lights...

How far from my plants should LEDGrowLights be placed?
Position red and blue lights 12-24 inches from the plants. Positioning red and blue lights too close to plants may result in unacceptable growth.

Full-spectrum lights may be placed as close as 3 inches to your plants.

Growing Tips:

Reducing the distance between a light and the plants by one half increases the intensity of the light reaching the plant by four times.

Use more blue light to produce sturdier seedlings and to help contain trailing, sprawling or aggressive plants.

For leaf crops, switch to all red light at the end of the growing cycle to increase yields.

Blue lights may be used alone as a supplement for HPS lighting.

Red lights may be used as a supplement for sunlight or MH lights
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Sounds like this is happening now, anyone heard or used them ?

It depends whether you have money to burn or whether you actually want to grow cannabis

QUOTE(compostverte @ Oct 21 2007, 05:15 PM)

It depends whether you have money to burn or whether you actually want to grow cannabis

So I take what you have said to mean there not much good,
if it sounds to good to be true !

There's a 70 watt LED grow on here somewhere - the best I've seen yet ... but it's an expensive indulgence... just about keeping up with a 70 watt HPS ...
Maybe one day, the price per watt will come down and long life may make LEDs start to look interesting...

But there are a lot of advantages to having all your light coming from one point.

Hi,

As Im a complete noob, I read quite a lot about the plant absorbtion spectrum and thought it would be great to deliver exactly the right light frequencies, even if at much recuded power. Its seems the current LEDs, just dont put out enough lumens with the very best i have seen (ostar from OSRAM) only firing out 1k lumens. Its the same as an 18w cfl, but maybe with a better spectrum.

I noticed that nlites have released a biotropic, purple CFL. From the specs, its seems to put out a much more usable spectrum and decent intensity.

For the money, even when considering the light frequencies, cfls seem to be better (for now).

Just my 2 cents

bAb

i built that lamp in that 70W challenge led vs. hps. it was expensive because i took the most powerful models i could find at that moment. i could buy cheap material like most of the commercial selling companies do and the costs would be much lower (and so would the light output). there are only 5mm leds used, what is just additional reason for the high price. right now i'm prepairing for my next project, which should in theory be much better. using high power leds with much higher light output per watt, and in my calculations, the price for the equal wattage system should be arround 50% lower than if using 5mm leds.

I do research in plant light (general) since a year, being into electronics since decades. I try to collect all the available data about plants needs regarding spectrum and intensity. As user of LEDs since they've got available all my planing went directly into high-power LEDs, since I believe a competitive system (equals HPS/MH) needs roundabout half the input power. You need quite some punch. Cree, Luxeon (K2 and Rebel), Seoul Semiconductor are what one has to look for. High-voltage LED-drivers (Supertex) are more for someone with electronics background, 12V or 24V for the ones who just know on which side the solder iron gets hot. With high-power LEDs you have to know how to get rid of the excess heat (with an efficiency of ~20% you have up easily 3 Watts of heat to get rid off, thermal glue and heat-sink calculations (even active cooling, like CPU) are something one has to look into in more depth.

Being new to this conversation I follow quite some threads cluttered over the Internet and am sure that the actual builders of panels generally agree to what I've said. As for now I will use red and white (6500K) Luxeon Rebel. Those white LEDs trigger both Chlorophylls at a decent rate as well as beta carotene, still emits a wee bit over 700nm and generally cover the whole spectrum to a degree (fitting very well to the standardized photosynthesis spectrum diagrams). The red ones have their peak 627nm and a spectral half-width of 29nm, meaning they have still 50% output at 658nm. They emit at an 140° angle, so with reflective surfaces you easily reach lower leaves from the side, making up for less penetration of the top leaves.

I even think about having a ~20W CFL (nature color, Megaman, adds a bit UV) hanging in. If I can't get something from the LEDs I have to get it somewhere else, right? This approach might not be the most effective, but I think I'd rather harvest because I accidentally hit some of the plants sweet-spots in spectrum, than trying long rows of experiments without the laboratory equipment (and even more: environment) I feel is needed otherwise. Too many variables in the setups I've seen so far. Maybe that's me being a technician, I like laboratory equipment and shouldn't be misunderstood: I value each any every experiment you guys do!

Any question about high-power LED-Drivers or heat-sink calculation I will gladly answer to my best knowledge and show the source I gather my information of (heat-sink and LED manufacturers data-sheets), so there will be no tradesmans bollocks. I'm certain we are at the very point, where LEDs make sense in smaller areas (power-consumption, heat, lifespan).

Gobuchul, Have you heard about the Procyon 100 LED? [SPAM REMOVED]

• 56 CREE* Xlamp high power LEDs (40 635nm, 16 470nm)
• 100W nominal LED power delivery
• 125W total power consumption
• Integrated power supply; requires no “ballast”
• Replaces 400W HID light, giving 75% power savings
• Covers approximately 10 square feet
• 50,000+ hour LED life

To be introduced on November 12, 2007
Would greatly value your opinion. Thank you, Dan

Sounds like a nice device, considering all I've learnt (hopefully) from my internetresearches.

I'd expect it to compare more to a 250W system (which will be nice enough).

I don't know why they went for the blue instead of the royal blue LEDs (where the latter hits at least Chlorophyll B head on, whereas blue doesn't hit one of them directly and is "above" them). Then again: if you are close around a sweetspot quite some light gets still absorbed (hence my choice for the 627nm instead of 660nm in the red part of my design). The red/blue ratio 2.5:1 is unusual, the original idea was 9 red for each blue. Another Lamp (the UFO) seems to go the 8:2 way. Those changes might have come from the more general approach of plant grow under LEDs to the more specific spectral needs of hemp (which I can't say anything about, this is pure speculation, based on the MH/HPS differences, a general LED growlight for both phases - veg and flower - should have more blue than 9:1 IMHO). Right at the moment you have not a lot of choices about the LEDs manufacturers, Cree and Luxeon are probably the most available ones that are known for reliability.

Now all we have to know is the price to give a final verdict. This will be more expensive than we hope for.
I'm additionally interested in the electronic background, there are quite some approaches to this, simple resistors, linear voltageregulators used as constant current sources (LM317, LT1086), or switching powersupply (e.g. LM2576) , as well as the supertex mains approach, which I doubt will be housed in a metal case.

Sounds like a load of bollocks, quite frankly ....



What the hell does that mean ?

LEDs, like all light sources are seriously inneficient., the fact that they get hot and are semiconductors, and presumably optical considerations too, mean it'll be a very long time before they replace domestic CFL lighting, (high tech mood lighting, fab, task lighting maybe, "bulk" lighting, no.) let alone growlights which benefit hugely from being point source - for cannabis anyway ... lettuce maybe... though I will be growing my indoor salads under linear fluorescent.

As I read it: the LEDs draw 100W of power, the entire unit 125W giving the power supply part an 80% efficiency.
I think the 400W are too optimistic, as I said. Maybe the coverage is more 6 square feet, again more pointing towards 250W MH/HPS than 400W.
The Crees are emitting at a 90° angle, well suited for a closet grow, which I see this unit aimed at.

There is a comparison 70W HPS vs. 70W LED going on, which looks quite even. Keep in mind that there are 5mm LEDs used, which are less efficient than the Cree/Luxeons at the same power, so maybe 35W LEDs = 70W HPS.

Interestingly enough, c_v, that's not actually true - modern LEDs are very efficient - about 90%+ IIRC. They don't actually get that hot - it's just that the heat that they do produce is contained in a tiny, teeny space at the semiconductor junction, which is encased in a plastic resin blob, which creates further difficulties as it's so well insulated in there.


They're actually making great strides in the area of using LEDs for indoor lighting applications, and we should expect to see realistic, affordable home lighting that uses LED clusters very soon.

But as far as growing is concerned, they'll be experimental for some time yet, but IMHO I think that it's do-able, and we will see semiconductor grow lighting sometime in the foreseeable future.

A royal blue Rebel PR01 0275 emits 525mW when driven with 3.4V and 0,7A (2,38W) which is roughly 22% efficiency. Since that is the only LED in the Luxeon datasheets which actually uses radiometric power (the others use Lumen) I can't draw conclusions on the other LEDs, but I believe them to be in that area, too. Always keep in mind that this power is emitted at the spectrum sweetspots, much unlike HPS/MH and CFL.

¿I take it that these high-power LEDs, although bright, are far less efficient than their older-fashioned counterparts?

Click to view attachment

It's hard (for me) to find 5mm LED data regarding radiated power in a comparable way to high power LEDs. Here is one online source. It states an ordinary 5mm LED¹ has 8 lumens per dollar and 20 lumens per watt. No color is given in this example, but I guess it's red. I get a red Rebel with 33lm/W (85lm at 3.6V and 0,7A) and 34lm/$ ($2.50pp). White would be 75lm/W (180lm at 3.4V and 0.7A) and 40lm/$ ($4.50pp).

¹ red LED, 12000mcd, 20° equals 1,44lm. To compare with the 85lm of one red rebel you need 60 of them, which will cost you 11$ ($0.2pp, quality brand). Those values are gathered by me and therefore might differ slightly to what that site claims.

this thread is fantastic so far, great to see the amount of technical information being uncovered. let's hope leds really can be the future!

what about his 14 watt kit?

It has 272 LEDs, with 3 reds to every 1 blue.

According to greenpinelane.com, this kit produces 4900 lux at "a distance of 12" from the center." I'm not sure if that 12 inches is vertical distance or mix of horizontal and vertical.

The kit is 44 US with a declining price based on quantity and a 20 US dollar assembly fee if you'd perfer to do it that way. Seems a little more pratical then his $600 light.

Or, if someone could post a parts list to rig up the same thing, the cost could be even lower.

I don't follow some aspects of this discussion. For instance, what is the concern about using a distributed light source like LEDs vs a single point HPS?

You will have a hard time to get 272 LEDs and a PCB plus components (even tho not a lot on that board, but still) for $44 if you buy somewhere. So if you want to go 5mm LED that seems to be a good offer. Worst case: it's for a mother- or clonebox. This guy at greenpinelane liked it, for what he grew.

About the Procyon-100: it's the same price (but more powerful) as the UFO - ~$600. I was hoping for less, but that's more or less what you have to ask for at the current situation. I would have to pay like 5€ ($7.35) for a Cree LED, the Procyon-100 features 56 of them. $411, plus electronics $50, casing $30, plus electrical testing to approve standards (whatever that might cost in the USA).
So we are around $500 for a selfmade system, without any warranty.
One would save >$180 a year on electrical bills replacing a 250W-system at 12/12. If it compares to a 250W-system (they claim 400W) it pays for it self after 3 years, plus you have less heat problems. Don't forget the 3 HPS/MH-bulbs you need in those 3 years.

This obviously appeals mostly to enthusiasts with a big wallet. But it still think it's a capable system, so if some of those better situated people start using it and pass on their finding I think the price will drop quite fast, especially keeping in mind that the prices for LEDs are falling at the same time, too.

What about trace light sources? Like plants need certain amounts of minerals in very small amounts for proper health, do you think they need trace amounts of light in different wavelengths?

The Procyon 100 and his 14 watt kit both have only one or two different types of LEDs.

I don't believe it'd be practical to modify the Procyon 100, but the 14 watt kit is begging for some experimentation.

Anyone have any thoughts?

I can't forget it. The decreased power use would allow me to expand my crop size by the same amount.

So if a 125 watt LED can kick out as much as a 250 watt HPS, I can double my grow.

So it's a question of whether LEDs as a pipe dream or an immature technology. If it doesn't work, that's one thing. If it's difficult and might require some research, that's another.

No, it won't.


No, they can't, and you certainly couldn't.


adj. - nominal, token, tokenish -- (insignificantly small; a matter of form only (`tokenish' is informal); "the fee was nominal"; "a token gesture of resistance"; "a tokenish gesture")

adj. - nominal, titular -- (being such in name only; "the nominal (or titular) head of his party")

The one commercial application on the planet so far as I can tell - and I would be interested to know if they paid full price for those LEDs :-

Click to view attachment

http://www.metaefficient.com/archives/hydr...eds_to_gro.html

The combination of monochromatic light and long-life may one day make them attractive, but I feel sure that point source lights are the better choice for our favourite plant.

At the moment, multiple £1 CFLs are a better choice.

I think that day is closer than a lot of the nay-sayers believe. Highpower LEDs are a different league, relatively new and a bit more complex to handle than the ordinary 5mm LEDs some people build their opinion on. Certainly a HPS/MH system is working well. And it's very hot, need a new bulb every year and eats your money via electrical bills, propably draws attention to you. Might even set your house on fire. Worst case, obviously. I can understand why people look for other ways. I can only give my opinion on the technical/scientific background and that looks good for highpower LED system around 100W. I will spend some money on parts to build my own system, designed to replace a 250W system for the reasons mentioned above. I need to see myself. To anybody else I'd recommend to wait till the ~100W systems are showing up here in the forum and then decide, especially when there is advice for 1st time growers.

http://www.patmullins.com/img/hpsspectrum.gif

Shows HPS output spectrum

http://en.wikipedia.org/wiki/Image:Par_action_spectrum.gif

Shows what plants absorb.

http://www.hebeiltd.com.cn/?p=z.pricelist.led.diode

Is a chinese vendor I found while searching for a project I was doing for work. Notice how most LED's sell for about 7p each, so, to take a specific example. Part number 980MR2C a high flux LED emitting 1800mcd at 80 degree's (equivalent to 2.64 lumens http://led.linear1.org/lumen.wiz)


But, a 70W HPS emits about 5500 lumens average over its life span. So, to match a 70W HPS in terms of brightness, you require 2000ish LED's at a cost of $0.099 (about 4.5p) means you are spending 80 quid, to match the output of a £5-10 bulb.

Now, the counter argument, is that if you look at the HPS output spectrum. You'll notice it doesn't match very closely to the PAR spectrum. So arguably, less wattage of LED's is required for the same overall effect. On and 2000 .2W LED's consume about 500W of power. So, are you doing better or worse with LED's? Its quite a difficult problem and one I don't feel fully able to answer.

But would be interested in further comment on the subject.

The proof is in the smoking I would say

*scarpers*

well the leds put out 100% PAR, and put out almost no heat, so 500watts of leds = almost 500watts PAR, much higher than hps. only problem is, they aren't very intense so like fluoro's need to be very close to the plants, you can get them close to the top of the plants, but this is no good for plants that are more than a few inches tall

is that not right then? i thought compared to hid lamps, led's put out far less heat/watt

Even the 1 watt ones need serious heat sinks or they'll fry.

I was looking at some high output 5mm LEDs the other day that have an extra wide leg that acts as a heat sink.

I think the general rule of thumb is LEDs up to a few watts (or for difficult maintenance situations), CFLs up to about 70 watts - at which point HIDs take over.

Pretty well every kind of lamp gets more efficient at higher powers... which just isn't possible with LEDs because of inherent design limitations.

Horses for courses.

ah, learn something new, think i'll be sticking with my hps anyway! if it aint broke

Exactly. I know it's boring, but I'll wait until LEDs at least compete with CFLs on the domestic front before I even consider trying to grow plants with them

I have now done what I consider serious research into this and found a few more links.
http://arabidopsisthaliana.com/lightboxes/

That guy is actively researching LED's for plant growth.

Heat dissipation for LED's worries me. I am going to ask the PCB supplier I use for the possibility of making metal cored PCB's. Because compostverte is spot on with the heatsinking requirements for high power LED's. The difference is, the maximum temperatures are still alot lower than you see with HID bulbs, so I don't think there's much of a risk of burning the plants. And for smaller grows, the distributed light output is alot better than a point source.

What bothers me is the cost, high intensity LED's may last for 100,000 hours (about 10x that of HID bulbs), but once you start factoring in a custom PCB everything starts adding up extremely quickly. Farnell supply luxeon K2's (each around 40lm) for £2.50 so, to get the full benefit, you have to assume, HPS wastes 50% of its lumen output in non-par radiation and that you can get an LED array at least 2x as close. Even then, it still works out to be £85 worth of LED's roughly!

Now, this price is reduced if you use more lower intensity LED's. But, I'm not entirely sure whether fewer high intensity point sources would work better at penetrating foliage, than a more diffuse lighting arrangement.

At some point in the near future, i'm just going to say f@ck it and spend some money, even 50 quid is nothing in the grand scheme of things. I'd blow that much in smoke in a week without thinking twice.

But it doesn't mean you should spend that money.

Maybe it's because I've to all intents and purposes never paid for cannabis, and don't drink or smoke, but my £10 an ounce suits me fine.... though it tweaks my conscience that I'm using twice as much electricity per ounce as Owderb.

I'm quite comfortably off, and I'm a lighting technology buff in several other areas (I have spent quite a few quid on disco lighting ) and am starting to use LEDs for their optimal purposes (battery power in the first instance).
If LEDs seemed remotely sensible for growing cannabis I would be using them.

You only have to look at all the bogus LED growlight manufacturer's websites to see the fairy dust. Just look at the people who are sold envirolites as "cold", and why not take a roll of "anti-detection film" while you're at it. ?

I await with enthusiasm any advance on this one single commercial (and even that is highly questionable) application on the whole planet so far as I know :-

Click to view attachment

I look at what my eight 18 watt CFLs are doing in my cupboard and I really can't imagine what would be more suitable. The heat they produce is keeping the temperature up to a comfortable 23 degrees C.

They cost me £24 and I could have got a different style for £8, and spirals are less efficient, but I love their aesthetic qualities and use them all over the house.

Click to view attachment

Horses for courses.

You do make a very fair point, I have to say, the more I do the calculations on LED's the more I think they're overpriced and overly complicated for the returns per watt. I do like the idea of 100% par, but by the time you've costed it all in, I think i'm going to go for a rack of T5 tubes in a small custom made box. Because I am lazy and like to know the fundamentals of my system are based on something which works.

After everything is said and done, I costed up a lighting system equivalent to a 70W HPS and it would require around 700 lower power LED's which is a mind boggling amount of soldering and would require custom PCB's. It can be done, it's a shitload of effort for the rewards.

I just like projects, thought experiments and research. I think there is a future in LED growing, but the technology is still too expensive for us hobby growers. For the likes of NASA, they do provide a very real alternative to conventional lighting techniques.

FWIW LED lighting is extensively used in commercial applications, including traffic lights, lighting on aeroplanes, so it is become more widespread. And it is only a matter of time before LED lighting becomes common place within the home. We are looking at the future.

Power: 75Watt HID should be possible with 35W of high-power LEDs¹, something like 14 piece. Thats 42€ lasting for 11 years (12/12) and then it's not broken, but lightoutput is down to 70%. How much would you spend in that time for HID-bulbs plus the additional power?

Temperature: A heat-sink like this will be sufficient, put a slow running fan (e.g. 12V fan at 5V) on it and you will be able to touch it, try to do that with a HID.

Works: For general plant use see here, this guy grows cucumbers and tomatoes under the HID-UFO (80W) and Procyon 100 (100W), both high power LED systems.

¹Technobabble: For 5mm LEDs a rule of thumb is HID*0.6 to have the same effect, like 100W of HID is 60W of 5mm LED. Following this findings high-power LEDs are more than twice as efficient as 5mm LEDs, so it's propably HID*0.3, the companys selling the UFO and the Procyon 100 say they are HID*0.25, quite close, propably a bit optimistic. So I say a 250W HID would need 75W of high power LEDs, 40 LEDs go for 120€. Add heatsink/thermal glue/powersupply, ~50€, more or less what a ballast for HID comes, too.

Click to view attachment Click to view attachment


He seems mostly to sell very expensive LED lamps.

And one of his links was an advertising portal that spawned a garish popup telling me I'd won a laptop.

Maybe someone who can be arsed, could check the whois records for these sites ...

I wonder if this really oughtn't to be in the conspiracy forum instead ...

I know this is slightly off topic, but i will go with it anyways

At first the PAR output of LEDs seemed attractive, specifically the tuning to the key absorbtion frequencies.

CFLs seemed good value for money, but wasteful in emmission spectra. However, someone on the forum started talking about nlites and i think i seen an ad in a mag >> looked at the purple cfls they supply. The bio-tropic spectra seems quite appealing and no doubt cheaper per lumen than LED at the moment.

I havent used these yet, but even for spectral junkies surely they rule out LEDs for the near future at least.

a thought at least

bAb

What links? Where does he sell? I never experienced a popup on his site, but very well I know that people get money for popups, or pay less for their domain, if they let the hoster have banners/popups. You wouldn't do that for a professional page where you sell your own stuff. So this guy probably pays 4$ instead of 6$ a month and that makes him a doubtful source?
BTW: the pics look nice to me, considering the variety he used.

Come on, you have to be kidding.

It simply seems to me that people are fixated on the idea of growing with LEDs and are tying themselves in knots trying to convince themselves that there's some point to spending silly money and wasting electricity growing really bad cannabis (and tomatoes)...

Commercial applications for LEDs - apart from the battery-powered sector, are largely about reliablility and longevity. Unfortunately they're not suitable for growing plants. As I've said before, my indoor salad experiments will probably use linear fluorescents.

I can't quite see what these experiments are for, and quite what people are waiting for that will suddenly turn LEDs into a sensible choice for growing. The 70 watt SCROG grow should have proved the point.

Looks more like an "X-files" fixation than a garden :-

Click to view attachment

http://www.greenpinelane.com/lights_apr15.aspx

At the end of the day though it's whatever floats yer boat ...

Sometimes it doesn't really matter. Bog standard pound shop CFLs wipe the floor with LEDs.
HIDs do the same to CFLs if you can accomodate a 250 watt lamp.
The most efficient lamp of all is a 600 watt.

Purple CFLs look interesting and there's certainly scope for using lamps other than HPS in the quest for enhanced psychoactivity.

You, on the other hand seem to be locked into the thought that LEDs will never be able to do what they do. Emit light. Of which purple CFL emit less than white CFL, btw. There are always a couple of people into exploring (and sometimes wasting money on the way) so that when they finally succeed people like you - plain consumers - can get the enhanced stuff. There is not a lot room to enhance traditional lighting (HID), but LEDs efficiency skyrocketed the last years. Even car companies use full LED headlights now. Why would they, if they still could sell you the Xenon HID? Because it's easier to handle and cheaper for them for the same light output.
The 70W scrog you refer to used 5mm, IIRC, not even half as efficient as nowadays high power LEDs and the second run yielded around 70% of the 70W HID. Anyway, it's good to have some critics voice around, since there is a lot of marketing BS with LED growlights, especially the 5mm ones. You are not a CFL salesman by any chance? Joking

Out of curiosity, which model of car is currently being fitted with LED headlamps ?

E2A:-

Audi R8 and Lexus LS

And not fitted for reasons of efficiency, but for style / reliability.

GM joins the club. Even if they chose them for design, they have to send out the same light, or wouldn't be allowed on streets. So we have small and powerful LEDs now. What voodoo is exactly missing in LED light that is in the HIDs?

Mostly its a rational cost benefit analysis. The technology is too new to be available at a reasonable cost for the volume required for cannabis cultivation. I'm sure it can be done, after all, NASA don't exactly enjoy wasting time. Its just whether it shows anything other than being able to match current and widely accepted technology. Also, remember pyschoactive chemicals produced by cannabis are at least in part created by exposure to UVA/UVB, something no commercially available LED produces currently.

Maybe in 5-10 years i'll have a successful LED cannabis farm, who knows!

I was surprised to find there are now 10 watt LEDs .... (there are 15 watt ones too but only in white.)

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http://www.rapidonline.com/productinfo.asp...;moduleno=76761

Given the effectiveness of single lamps (my plants really take off when moved from spread out fluorescent to a single 250 watt HPS), my instinct would be to assemble 20 of them on a metal tube, (£300), mount cooling fins on the inside and pass cooling air through it ...

On the other hand ....

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If the lamp was much more efficient, the 180 watt tube heater underneath would have to be on to compensate ...

NASA are hugely preoccupied with reliability and longevity and not having fragile glasswork containing mercury and other hazardous substances in zero G.

I admit I'm being unfair demanding evidence of commercial horticulture using LED growlamps in that 99 percent of applications consist of HPS lamps being used as supplemental lighting in greenhouses ... and I'm guessing that 90 percent of growlamps sold these days are not going to mainstream horticulture

The challenge faced by alternative lighting methods is that with people successfully growing our favourite herb for £5 of electricity an ounce, (£100 a batch) (mine costs twice that), the effectiveness of the alternative technology needs to improve hugely before the £30 replacement lamp cost every 3 batches and the £50 replacement ballast (every 30 ??) becomes an issue.

NASA is faced with the problem of getting rid of excess heat in space. You don't have conduction (and convection) as option, just radiation. So even if they might have looked into high-power (and I remember an article about that even), they can't use it in spacecrafts so far. They might use it in fixed stations, with pipes to transfer heat to the ground. But luckily on earth we have air and can go where NASA can't

About the Edison high power LEDs: the red 10W has a minimum of 160lm at 10W, 16lm/w, for 26€ here. 10W of Luxeon K2 or rebels equals 10 emitters, each min. 40lm/w, you get 400lm for 30€.

Couldn't NASA put a radiator on the outside and design a heat engine to work between the low celcius waste heat of a grow lamp and near-absolute zero of space ?

Hi,

I dont think you can transfer heat to what is essentially a vacuum.

For heat transfer you need to have either absorbtion of an emmission (eg radiation or radiated heat, what every you want to call it).
or
You need a mollecular collision tranfering the energy from one to the other.

Heat is (at a molecular level) the translational and rotational energy of a molecule.

So transfering heat into "space" isnt possible, but im sure they could transfer it using heatpipes to something more useful, like hot water...

bAb
edit spelling

It seems to me there are two views on this; 1: those who are adamant LEDs can and do work, and 2: those who are adamant they don't work. I've seen a couple of small grows work under LEDs but they weren't amazing - kept thinking "what's missing here is a HID"

I myself have a somewhat different view. I'm a fan of this growing under LED thing especially as LED's can be switched off and on many times a second (120+) giving approximately 50% power saving - of course the SMPSU won't be 100% efficient so would be more like 40%. This meaning you could run 140w of LED on the same power as 100w by switch moding. LEDs are not quite ready to compete with HID imo - especially with the immense set up costs. What with the new reclassification laws though, i predict an explosion of micro grows. LEDs WILL eventually compete, of that there can be no doubt - and would be terribly useful for micro growing, in conjunction with CFL.

However I do see the longer grow times, and not very attractive growing.. What i'd like to see is LED's being used to mean less of an HID array is needed - say 100w (60smp) of LEDs around the sides and perhaps even in a scrog net a-la those tube fairy lights to mean full canopy lighting, COMBINED with say 170w of HID(hps/mh) - replacing say a 250w HPS. I think we will see benefits from such a setup. I'm strongly considering getting at least 20 of these big high power LEDs (3w most likely, or 40x1w) to dot about my grow once i've had a crop to dial it in.