The myth of LED efficiency

[trueperc]

Great thread, almost about time as with LED becoming more popular and is being used more widely. One thing that I am truly concerning about is this idea that they will last 5-10-17 years before replacing and how true really that statement is. I mean no one has had a led setup that long over a tank. Some things to think about, led bulb is usually plastic and with heat plastic hazes up also heat is a factor with leds. With some of the fixture they are coming with 30w leds these are creating a lot of heat with affect lifespan. Also even just think about these two thoughts. One, when t5's first came out one of there big draw was lasting two years before needing to be replaced well now that is down to 6-10 month, before the need to be changed. Also just because the bulb fires doesn't mean its giving enough par or light for something to grow.
For me LED is almost there but still needs some tweaking. I really would like to see more studies and test doneI have seen many threads about ya growth is there but color is not or things look great for 3-5 months and then start to go down hill.

 

[ruprecht]

Plasma bulbs also look very promising, there is somebody here using them already.

Their output is impressive. I'll have to search out the thread here.

 

[steveu]

I am confused by the original posting- I thought it was (far) infared waves that I was feeling when placing my and under a light- both are outside the visible spectra but isn't UV on the opposite end?

I agree. This also confused me in the original post. Infrared is felt as heat, not UV.

 

[firereef]

Sounds like both will be equal In annual savings throughout the years is what I understand with the op. No expierience here with LEDs yet but I'm getting there.

 

[tahiriqbal]

You would also need to look in to some of the latest Cree XP-G LEDs as they could double the lumen output what you have been using as a baseline for your conclusions. From my understanding, LEDs are lot more flexible when it comes to suit and meet the needs of the reef hobbyist.

Plasma lighting, they are very interesting but if pushed at full tilt looks horrible over your tank and would give you max 6000K look. If you dial it down to get the desired blue spectrum then you start to loose lumens which defeat the whole objective of getting high PAR. Plasma lights would consume almost same amount of juice as MH bulb would (less the ballast) and give out lumen output which is very similar to plasma bulb.

Just a thought.....

 

[usefulidiot213]

That's my big question..
The bolbs might last 5 - 10 years, but will the light system it's self last that long. I have read a couple of threads where somebodies $3k LED lighting system totally crapped out. Yeah the bolbs have plenty of life, but they have nothing working them....

 

[BFG]

The OP state that he tested with a 600w mh. Is there such a thing? To my knowledge, there are 150w, 250w, 400w and 1000w mh. Is this something new?

 

[ludnix]

That's my big question..
The bolbs might last 5 - 10 years, but will the light system it's self last that long. I have read a couple of threads where somebodies $3k LED lighting system totally crapped out. Yeah the bolbs have plenty of life, but they have nothing working them....

Probably a PFO fixture. With basic electrical knowledge you should be able to repair a ballast failure in LEDS, or replace individual LEDs. It may be something to consider when choosing a fixture though, if you can't easily replace the ballast or individual lights it might not be worth getting.

 

[greenbean36191]

Well, all our corals have the same Zooxanthellae algae in them (as each other, not same as terrestrial plants), so the wavelengths should be about the same between corals....

I think that LED's would be great as a suppelemnent to a broad spectrum bulb in order to provide more "light" at those peak ranges.

Our corals actually don't all have the same zooxanthellae. The activity spectra of zoox is close enough for our purposes that you could basically ignore the differences, but you still can't come up with an ideal spectrum for corals. The problem is the pigments of the corals themselves. The light actually reaching the zoox is modified by the pigments and fluorescent proteins of the coral in such a way that the light reaching the zoox is not the same spectral composition of the light striking the coral. To make things even more complicated, the pigments change over time even within corals. As a result you could easily tune a light to be ideal for zoox, but the corals will completely undo all of that tuning and each specimen will mess with it in a different way.

It's not a lack of research that's prevented us from coming up with an ideal spectrum for corals, but the fact that there isn't one. We can go out into the field and measure the precise light use of coral across the spectrum, but it's a PITA and the results have limited applicability to other corals and even the same coral over time, so we usually just talk about PAR.

 

[MyDogIsStill#1]

Check this light out, a plasma argon driver and it's the size of a tic tac

You will have to deal with a commercial

http://www.zdnet.com/videos/tech-news/the-lightbulb-of-the-future/192842

plasma argon by http://www.luxim.com/


I work for a company that makes chips for led lighting and this technology looks to be the new light of the future.

A little info from luxim

"The tiny bulb contains an argon gas in the middle, as well as a component called a "puck." The bulb is partially embedded in a dielectric material. When electrical energy is delivered to the puck, the puck acts like an electrical lens. It heats up the argon to a temperature of 6000 degrees Kelvin, and turns the gas into a plasma that gives off light.
The plasma, whose 6000-degree temperature is similar to that of the surface of the sun, also emits a spectrum that looks very similar to the spectrum of sunlight.
The plasma bulb uses 250 watts, and achieves around 140 lumens per watt, making it very bright and highly efficient. By comparison, conventional lightbulbs and high-end LEDs get around 15 and 70 lumens per watt, respectively.
"A key advantage is that the energy is driven into the bulb without any electrodes, so you don't need any electrical connections to get the energy into the bulb," Luxim CEO Tony McGettigan explained to ZDNet.
Luxim is using different versions of its electrode-less plasma technology to develop lighting for ultra-bright projection displays, retail and street lighting, microscope lighting, and various medical applications."


And for those who want to vaporize their tank here is 1400 watts of sulphur plasma

http://www.nlites.co.uk/sulphur-plasma.htm

 

[Stephen Keen]

Its my understanding that this isn't quite an apples to apples comparison. LED's provide a directional light source so most, if not all light is directed into the aquarium. A MH is an omnidirectional lightsource which emits light in every direction. Consequently, significant light is lost to the surrounding room before it ever reaches your tank.



I take particular issue with this. How did you come to this result? I did a side by side comparison with a 250W MH SE bulb next to a 48LED (16 x Cree XR-E Royal Blue and 8 x CRee XP-G white) array (total wattage 133W). Both were mounted at the same height. Although the metal halide emitted 30% higher PAR at a 4" depth, the LEDs showed 20% higher PAR at a depth of 24".

Depth .......MH......LED
4".............744......501
12"...........498.......425
18"...........324.......361
24"...........184.......224

BTW, I do agree that plasma is probably the future of high intensity lighting. However, from this vantage point, you appear to be making some gross assumptions without doing actual testing.

Yes a MH bulb does send out light in every direction but it isn't lost in the room unless you are just hanging a bare bulb, 99% of the time the light is directed with a reflector. There is some loss of efficiency with a reflector but it isn't much, obviously the better the reflector the more efficient it is at placing the light.

My testing has been with plants, I personally can't see wasting the money to try and use it over my coral. We have tested many fixtures that have been developed for over 3 yrs. Everytime I get sucked in by "the newest LED that works!" but it ends up being the same scenario. I have worked closely with these guys trying to develop fixtures that could compete with MH, please understand that I wanted this to work. This seemed like the answer to all of our problems but I have been disappointed so many times I just wanted to warn others about them. Lots of people talk about LEDs but there aren't that many using them succesfully to grow coral...just like the gardening industry.

I'm not an engineer or scientist by any means nor have I tested them for anything but lumen output. BUT I have tested them in real world scenarios with plants, and was disapointed everytime. The last fixture that I tested ACTUALLY worked! It was $5,500 and had the same lumen output as a 600 watt lamp. This fixture actually grew the plants quite well....the only problem is that it consumed 800 watts to do it. That is why the topic of this post was "the myth of efficiency" and not "LEDs don't work". There are people out there using them I understand that, my point is that they don't live up to the hype, not even close IMO.

Yes you are right, I should have been more clear, LEDs can be made to direct light farther down in the tank (or streetlights for that matter), just like a flashlight with a small bulbs can be made to direct light farther away, but also just like a flashlight you end up having a smaller beam of light to do it. If you were to put enough of the LED's over your tank to get that reading across the bottom of the entire tank you would have to spend a small fortune, you would be using lots of power, and you would be creating lots of heat. Since LEDs are directional you would have to cover your entire canopy with them to get even light distribution with the PAR rating at those depths.

I have people tell me all the time about the newest and greatest LED's, LED manufacturers and people online mostly. I have never seen a fixture perform as advertised, so I'm still very skeptical. When told this by LED manufacturers I tell them "bring it, if you can show me a fixture that performs and doesn't create loads of heat and use lots of power I will buy thousands of them to resell".....I'm still waiting! If I ever get one I will gladly eat crow!

Here is something else to consider. None of the coral farms use them, it seems like those guys would benefit the most of anyone. This would lower their power bills for cooling and for the lighting itsself and with as many fixtures that they have this would be significant. These are the professionals that like us are prived to the latest and greatest lighting, we attend all of the related trade shows all year long. There is a reason why none of the major lighting manufacturers, like sunlight supply for example, do not sell them. You only hear about LED only companies producing these...so my point is if they truly worked there would be a Sunlight Supply brand fixture using LED technology. Please note that I'm not talking about some LED actinic strips, I'm refering to fixtures that are meant to be used alone with no supplemental lighting.

Disclaimer....I'm not arguing that LEDs aren't a great lighting choice in many situations, I'm arguing that LEDs can't grow coral or plants without being less efficient than MH lighting. I'm also arguing that b/c there has been little research on a per coral basis to know what color spectrum that each of these corals need to thrive, live long, and have the proper colors that we all are expecting from these high dollar fixtures. MH is proven and is becoming more efficient everyday, using digital ballasts and with more efficient cooling methods can lower the usage of a 400watt light by 25%.

Plasma lights could turn out to be a disappointment too....only time will tell. I didn't know that about the spectrum that someone mentioned, this is uncharted territory for us and I can only talk about what I have read about them, just like most folks with LEDs. This is a great discussion, and thanks for the comments!

 

[jdhuyvetter]

jefathome,

I have solar tubes on my main tank. I had some extra LED strips and I was going to use them as supplements, but they just don't have the spread of a MH reflector. The LED's go almost straight down. So, no supplemental light under the solar tube. My corals all browned out over the winter (none died). So, I pulled the PC retrofits and put in 250w MH with T-5 retrofits between the tubes. Only run the MH two hours now. Took the corals about 10 days to color back up. I plan on running the MH about 4 hours in the winter.

 

[Stephen Keen]

Check this light out, a plasma argon driver and it's the size of a tic tac

You will have to deal with a commercial

http://www.zdnet.com/videos/tech-news/the-lightbulb-of-the-future/192842

plasma argon by http://www.luxim.com/


I work for a company that makes chips for led lighting and this technology looks to be the new light of the future.

A little info from luxim

"The tiny bulb contains an argon gas in the middle, as well as a component called a "puck." The bulb is partially embedded in a dielectric material. When electrical energy is delivered to the puck, the puck acts like an electrical lens. It heats up the argon to a temperature of 6000 degrees Kelvin, and turns the gas into a plasma that gives off light.
The plasma, whose 6000-degree temperature is similar to that of the surface of the sun, also emits a spectrum that looks very similar to the spectrum of sunlight.
The plasma bulb uses 250 watts, and achieves around 140 lumens per watt, making it very bright and highly efficient. By comparison, conventional lightbulbs and high-end LEDs get around 15 and 70 lumens per watt, respectively.
"A key advantage is that the energy is driven into the bulb without any electrodes, so you don't need any electrical connections to get the energy into the bulb," Luxim CEO Tony McGettigan explained to ZDNet.
Luxim is using different versions of its electrode-less plasma technology to develop lighting for ultra-bright projection displays, retail and street lighting, microscope lighting, and various medical applications."


And for those who want to vaporize their tank here is 1400 watts of sulphur plasma

http://www.nlites.co.uk/sulphur-plasma.htm

Thanks for this. The only problem that I see with the lumen per watt is that its the same efficiency as a MH bulb, it's probably 10x the cost, and I'm sure creates lots of heat too.

For the ultimate in MH efficiency the trick is to be able to use the heat if possible which is the wasted electricity. On commercial projects we use air to cool the lights and then we use heat exchanger to cool the water. In the winter time we can store the hot water while the lights are on and blow it back in the warehouse when the lights are off. In doing so we can raise the efficiency by 50% even adding in using the power to run the pumps for the water-cooling.

 

[serpentman]

If you were to put enough of the LED's over your tank to get that reading across the bottom of the entire tank you would have to spend a small fortune, you would be using lots of power, and you would be creating lots of heat. Since LEDs are directional you would have to cover your entire canopy with them to get even light distribution with the PAR rating at those depths.

Again, I'm not trying to sound argumentative, however, even with the best reflectors, MH's will not give you a consistent PAR number across the tank. In fact, some of the higher end reflectors result in "hot" spots in some areas. I would agree that LED's become cost prohibitive when lighting a very large tank. Personally, I'm a fan of MH's for these applications. However, I would be shocked if 99% of the light actually made it to the tank.

I've spent considerable money testing HO LED's and was pretty impressed with the results. Electrical savings vs a comparable 250W MH was about 40%, so I still take issue with the claim that they are not more efficient. This is not based on a lumen per wattage but actual PAR readings in the tank. IMO, I agree with a comment earlier that Lumens are not a good measurement of comparison for growth applications.

However, of all the lighting I've tested, so far IMO, for even coverage, T5's still hold up as the most efficient for tanks under 24" tall.

 

[HighlandReef]

Great thread, I am also waiting to see what they do with plasma bulbs,
From what I have read the plasma bulbs are supposed to use less power than led's and be several times as bright, I also read they are going to start using plasma bulbs for the street lights
I think as plasma progresses in it's technology manufactures will develop
The technology and we will have more bulbs choices as far as k values go but I think we won't see that for some time yet

 

[mcallahan]

I can't believe people are buying the "the bulbs will last 7-10 years". They might last, but no one will keep their fixture that long.

How many pieces of equipment do you have on your tank that is 7-10 yrs old (other than the tank itself)?

We're all addicts and when the latest, greatest comes out, we unload the old and buy the new! Check the For Sale area!

 

[mcallahan]

I think Hydro has a great point that the LED technology is great, but not there yet. There is not enough data through experiments, or real world experience (which I value more).

In a couple of years, we'll probably be arguing about the latest technology and why LEDs are a thing of the past.

 

[Stephen Keen]

+1 on the t5's although I'm only a fan of the VHO's. You are right about the 24", same with plant lighting. What I really appreciate about T5's is the ability to evenly spread the light over the tank or plant canopy. The VHO's put out their fair share of heat though, Sunlight Supply just came out with an air-cooled version of the VHO which I think was overdue. I keep telling them they need to make a remote ballast for the fixtures so that you can remove that part of the heat from the canopy. I guess I will have to build and sell one myself!

 

[stanlalee]

(and the fact that many hobbyists are using LED's sucessfully)

Well thats debatable. Sure there are some nice reefs with leds but there was a thread in the SPS section asking to show any tanks with LONG TERM (more than a year) success keeping SPS maintaining colors and growth simular to MH or T5 and I cant remember any examples. I have also heard several people claim to have used LEDs without getting the same results they got from MH and T5 but I have never heard the opposite (never heard anybody switch from T5 or MH and claim their corals took off after switching to LEDs).

As mentioned in the initial post its not the absolute intensity, there have been LED fixtures with much higher measured PAR without results. Its the spectrum. something somewhere along the spectrum is missing with the LEDs used thus far.

 

[serpentman]

I can't believe people are buying the "the bulbs will last 7-10 years". They might last, but no one will keep their fixture that long.

Agreed. However depending on your situation, ROI can be 6-18mos depending on what you do with your existing equipment. So, if they last 3-5yrs, you are still considerably ahead.

The biggest pitfall I see is that LED's are increasing efficiency about every 6 mos. So similar to most electronics, they are outdated quickly.