LED Grow Lights: Separating Fact from Fiction

TeaTreeOil said:
I'm not sure what your angle is.... :lol:

The technology is incredibly durable.

I don't know about *all* LEDs, but here's what Philip's has to say about their mortality/durability. It also explain the B/L ratings a lot more in depth. http://www.philipslumileds.com/pdfs/WP12.pdf
Page 8 has the composite graph of the LEDs by B/L ratings over hours/temperature/current.



50,000 hours is the typical minimum lifetime rating for LEDs I've looked at.



I'm not sure about these figures. As I recall most LEDs are 80-90% efficient at converting electrical energy to luminous flux. That's why they're so damn useful. They put out most heat via the resistance required to drive the low-power LEDs. 10w actual LED = 100w incandescent equivalaent. For a CFL it's 23w actual watts.

CFLs are around 80% electrically efficient. This makes LEDs... so many people already know this., as it's probably common sense if you're any sort of nerd.. but that's over 90% efficiency.

Light converted to matter? Uhm.... WTF? I can't take much more of this.

The room with 1000w HPS would be significantly hotter than the one with 1000w of LEDs. They do not convert electrical energy to thermal energy equally or similarly. The difference between the HPS vs LED room could possibly be 2-3x times hotter with HPS, watt for watt. Again, times the difference, not ambient temperature(aka measure & substract the baseline from the results).

Why? The LEDs have a surface area advantage, in addition to the aforementioned reasons. This will act as a much larger heat sink, allowing more efficient thermal(mostly convection, as our cooling source is air movement) exchange. The HPS outputs powerful radiant heat, this penetrates/strikes surfaces deeper/more intensely, warming them internally, causing higher emissivity of radiant heat(turns struck objects into heaters), increasing the amount of retransmitted/irradiated IR rays(as many surfaces absorb light ranges, and remit vastly different, often useless ranges, like FIR heat signatures, radio waves, etc.).

Even if it's as claimed, consider taking one match, or lighter, versus, say 10? Assuming HPS is "10 times better than LED." This is just an argument to make a point, and not technically accurate. Anyway, consider 10 butane lighters, individually, each lighting a joint perhaps. Now put them all together, to form one flame. It's the same energy, but certainly a more dangerous(you could torch an ENTIRE single joint), and much higher temperature ball of flame. Entropy quickly brings excitation to rest. Having a single much higher temperature source(1100C arc in the HID lamp) will also create a higher ambient temperature. And a decaying gradient from the light source, so also room temperature irregularity.



WTF, again. Voltage (E) is equal to current (I) multiplied by resistance (R). If one changes the other will change, assuming R is fairly constant.

--

Other manufacturers(CFL) who claim to out shine HID:

www.nexstarlighting.com
http://www.maxlite.com/PDFs/FocusSheets/HighMax.pdf

--

Seems to make sense that an equal wattage of CFL or LED would be superior to HID(30% vs 80-90% electrical efficency). The problem is execution, and lost light, and it's a problem in most setups.

HPS? No... not really. The best LEDs are over 150 LM/w, HPS tops out around 140 LM/w(brand new HQ bulb on a HQ ballast). Maybe low pressure sodium oxide lamps(200LM/w) are more efficient than LEDs, but not HPS. Especially if you consider 50k hours(basically 6 full years), a fairly long life when temps stay under 120C. You'd have to replace your HID bulb around 6 times to stay above 70-80% rated output. That's around $500 for hiqh quality bulbs. Then operating 1000W... what, about $900.00-$1800USD/year? So $1400.00-$2210.00 + ballast/fixture versus.... how much are these LEDs?

Versus LED, which by the numbers, well, divide $$900-$1800 (depends on your kWh) by how much better you think an LED is. A difference of a grand, maybe.
Click to expand...


nice post + rep
 
Ive seen various videos comparing hids and leds, one in particular had two clones, same age,came from the same plant,put in the same ebb and flow hydroponic system(ie.they got the same nutes at the same temps at the same times),there lighting schedule was the same.Everything was the same except for the lights,a 400 watt metal halide for veg and a 400 watt hps for budding on the hid side and a 90 watt ufo led light on the other side.He did a day by day snapshot on each.The ufo seemed to do a little better for Vegging but when it came down to harvest time(even with the led side flowering for an additionall ten days or so)the hid side produced 92 grams while the led side produced a WHOPPING 32 grams.That right there is proof enough for me.Its my opinion that leds could be used for vegging with a decent level of succes but as far as flowering....lol.
 
Could anyone speak more to a LED-CFL combo setup? I'm finally going to start up my server pc (24" high) grow and have both CFLs and a LED lamp ready to use. Can anyone speak to the synergy of running a LED-CFL combo?
 
tom__420 said:
616371d1257955536-led-grow-lights-separating-fact-2009_0816horsecreek0019.jpg


Fact, LED's do not flower plants to their fullest potential. Someday... someday
Click to expand...

leds blow and cfls make them look silly....
 
CMH and PELs aside, CFLS are superior to HID for smaller grows for the expert grower. PAR > footcandles.
 
I thought I should clear up the misinformation about the luminous efficacy of various lighting technologies. Who ever said LEDs are 80% efficient is plain wrong. The following is a list of lighting technologies and their corresponding efficiency in lumens/watt and total percent of energy efficiency:

40w Tungsten incandescent (120v): 12.6 l/w or 1.9% efficient
100w Tungsten incandescent (120v): 17.5 l/w or 2.6% efficient
White LED: up to 150 l/w or up to 22% efficient
9-26w CFL: 46-72 l/w or 8 to 11% efficient
MH Lamp: 65-115 l/w or 9.5 to 17% efficient
HPS Lamp: 85-150 l/w or 12 to 22% efficient
LPS Lamp: 100-200 l/w or 15 to 29% efficient

So to conclude that LEDs are 3 or 4 times more efficient than HPS is complete and utter nonsense.

You also have to take the following into consideration as well:

It should be noted that high-power (≥ 1 W) LEDs are necessary for practical general lighting applications. Typical operating currents for these devices begin at 350 mA. The highest efficiency high-power white LED is claimed by Philips Lumileds Lighting Co. with a luminous efficacy of 115 lm/W (350 mA).

Note that these efficiencies are for the LED chip only, held at low temperature in a lab. In a lighting application, operating at higher temperature and with drive circuit losses, efficiencies are much lower. US dept. of energy testing of commercial LED lamps designed to replace incandescent or CFL lamps showed that average efficacy was still about 31 lm/W in 2008 (tested performance ranged from 4 lm/W to 62 lm/W)
Click to expand...

So there you go, LEDs typically have much lower practical efficiency than what is claimed in a lab, whereas HPS are equally efficient in a lab or in a basement grow room (Where it counts). In fact, this demonstrates that on a practical application, HPS lighting is much more efficient than LED lighting.

One day I may be proven wrong, but I really don't think LEDs are the wave of the future when it comes to grow lighting. I honestly believe the next big thing in grow lighting will be an improvement on gas discharge lamps. Think about it, what is the brightest form of light in nature besides the sun, it's from an electrical arc (hence why welders need shades to protect their eyes, which BTW can be used to look at the sun, which also gives you an idea of the shear light producing power of an arc). LEDs will have their applications to be sure, I just don't think they'll be most efficient use is for growing plants. But, we'll see.
 
smppro said:
Well i dont know about that, i use an HID in a pretty small spot and cfls couldnt compare.
Click to expand...

The only HIDs that are better (and they are signifigantly better) in terms of par are LEPs and CMHes.

Yes it is much easier to use hids. Yes CFLs are a pain in the ass as they require movement at least once a day. The results will be there though if you put the time and effort into it when using CFLs.

I personally prefer HIDs to CFLs, but at the same time seeing people use old technology and claim superiority makes my head hurt. It's akin to people running windows XP and saying it's better than Seven or Leopard. Just isn't possible.

Sorry for the tangent :)
 
Electro-magnetic induction fluoro lighting owns and WILL replace HM and HPS and LED for that matter.... 200w LVD is equiv to 400w mh but costs $500.... well, it ALMOST owns :bigjoint:
 
Man!! THAT WAS WAY TO MUCH TO READ LOL, I AM GOING TO PROVE YOU WRONG THOUGH :) GIVEN THAT SOME LED GROW LIGHTS ARE CRAP, BUT NOT ALL LOOK WHAT IS EASILY ACHIEVABLE WITH A GOOD WELL THOUGHT OUT SETUP :) I AM LOVING PROVING PEEPS WRONG MY LADIES HAVE ONLY JUST GONE INTO FLOWER ON THE 12TH JAN BUT LOOKY HERE AT WHATS HAPPENED WITH LEDS + CFL'S!!!! I HAVE 70+ PICS IN MY FOLDER CHECK THEM OUT AND LEAVE COMMENTS ALL COMMENTS WELCOME :) Stelthy :)
 
cryppi said:
Screw LED's and MH/HPS Whatever happened to the MPS Lamps? I saw a lot about them in 2007 They seem to have faded away

Microwave Powered Sulphur Plasma Lamps
Click to expand...

they are working on them right now.

I think we might have some rly nice plasmas with long lifeline and superb spectrum and a fat price tag around 2012-2013, the tech is right now tested on cannabis in fact but in mind with at least 1 year of tweaking, and that the market is slow and working backwards to scam ppl to buy stupid leds before they release the plasma tech. i'd say 2013 something.

http://www.youtube.com/watch?v=atrKO1tnNBY

http://www.youtube.com/watch?v=DE6yLuI1NPM

http://www.youtube.com/watch?v=oTnnZ45KmZQ

Here's some teasers. I can't back any of the videos up, i mean....ofc they could have just dragged a plasma into a allrdy functioning growroom to hype things up but i doubt it...


and some forum posts taken from grasscity:
"Luxim corp. is performing tests with there Sulphur Plasma lighting systems, out- sourced to growers, on seedlings and vegitative growth of different plant species. They told me over the phone, within a year to eighteen months, they will have a lighting system for growing and available to the average joe. The spectrum will be suited for seedling and vegitative growth plus there pricing will be competative. Now, I'm sure the price will be inflated at the begining, but as everything else, it will decrease to meet market demand. I'll be the first in line."

"We will be manufacturing Plasma HID Grow Lights in March
I can help you with info if you wish
You can email me [email protected]
www.ChameleonGrowSystems.com

They are amazing and we will be selling enclosures with two Plasma HID's in them

Independant testing went very well! "

"I've done some research on the subject and I've talked with LUXIM, a manufacture of Sulphur plasma lights. A 250 watt unit costs $900.00+, for the bulb and fixture. However, they say in the next two years, the watts will go up and the price will come down. Also, the spectrum of light they produce is very good for the veg. stage of growing. Most of the comparisons are between MH and sulphur plasma."

thats all i could find for now.
 
Nver used them myself but I think you need to shell out the big bucs for the good onesif you wanna see any kind of 'good' results in flowerin stage !!
 
highpsi said:
It should be noted that high-power (≥ 1 W) LEDs are necessary for practical general lighting applications. Typical operating currents for these devices begin at 350 mA. The highest efficiency high-power white LED is claimed by Philips Lumileds Lighting Co. with a luminous efficacy of 115 lm/W (350 mA).
QUOTE]

Actually, you are wrong. The current record holder (Feb 2010) for highest luminous efficiacy is Cree with the XP-G at 131lm/W. They recently made an announcement that a lab prototype reached 208lm/W. Last year, when a similar announcement was made, the XP-G was the result.

Ignoring the fact that you are wrong, it is pointless to look at luminous efficiacy as a measure of light intensity due to the biased nature of lumens (i.e. weighted function for human vision).
Click to expand...
 
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