LED lights

[naesco]

Originally Posted by Ron99

My Pico is the iReef from the last nano contest; about 2 gallons for the display portion. Here is the link to the thread where you can see the DIY LED setup:

http://www.canreef.com/vbulletin/showthread.php?t=53597

It's really not hard to build your own and is much more cost effective then buying a fixture. For a shallow Pico with easy corals you could probably get away with some of the cheaper fixtures using 1 watt LEDs but 3 watt LEDs are preferable. Avoid any of the fixtures using less than 1 watt emitters, especially the ones with the regular 5mm LEDs. They may look bright to your eye but they have very little usable PAR for the corals.




The thing I don't like about the Maxspect lights is that they use a few single 30W white emitters rather than an array of good quality 3W emitters. The 30W ones are not very efficient in terms of output and heat and not a good choice for aquarium lighting. Personally I wouldn't buy one.



Heatsinks is a problem. The few electronics suppliers I found that could get one were very expensive. I ended up buying 3 large used ones on eBay that will do the trick for me.

Maybe we should set up a local LED DIY group

Ron can you expand further on your comments on the Maxpect LED lighting. I am looking for lighting particularly blue lighting which will optimize the florescense of particularly LPS coral. On the basis of their article, it appears they would fit the bill. Why would the wattage of the emitters matter? Why would efficiency matter and wouldn't the heat sink be designed to take the heat?
Thanks

[Ron99]

Most of that comes from what I have gleaned from the LED expert at nano-reef.com. The problem with the high wattage LEDs is that if you look at their lumen/watt output it is actually far less than a good 3 watt Cree XR-E for example (not to mention the new XP-G series).

These numbers are from what I remember off the top of my head so don't take them as hard fact. The typical 30 watt LEDs produce around 300 to 350 lumens vs. well over 100 lumens for a 3 watt cree XR-E. So 3 times the light output but 10 times the power consumption and higher heat production. Very poor efficiency for the 30 watt ones.

Also, they are trying to produce a good spread of light with good PAR and penetration with 4 emitters of 30 watts with no optics which will not give as good a spread and penetration as a larger number of 3 watt LEDs spread out over your tank. Now add some optics to the 3 watt LEDS and you get higher effective PAR and penetration and they will blow away the performance of the smaller number of high wattage LEDs. They are saving money and thus producing a cheaper fixture by using a smaller number of inferior LEDs. If you want MH equivalent lighting then stick to something using Luxeon or Cree emitters with good coverage and optics to increase penetration and have higher PAR at depth. Cree are the market and technology leaders in terms of output and efficiency. The Luxeons are also quite good but a bit behind Cree from my understanding.

[Canadian]

Originally Posted by Ron99

Most of that comes from what I have gleaned from the LED expert at nano-reef.com. The problem with the high wattage LEDs is that if you look at their lumen/watt output it is actually far less than a good 3 watt Cree XR-E for example (not to mention the new XP-G series).

These numbers are from what I remember off the top of my head so don't take them as hard fact. The typical 30 watt LEDs produce around 300 to 350 lumens vs. well over 100 lumens for a 3 watt cree XR-E. So 3 times the light output but 10 times the power consumption and higher heat production. Very poor efficiency for the 30 watt ones.

Also, they are trying to produce a good spread of light with good PAR and penetration with 4 emitters of 30 watts with no optics which will not give as good a spread and penetration as a larger number of 3 watt LEDs spread out over your tank. Now add some optics to the 3 watt LEDS and you get higher effective PAR and penetration and they will blow away the performance of the smaller number of high wattage LEDs. They are saving money and thus producing a cheaper fixture by using a smaller number of inferior LEDs. If you want MH equivalent lighting then stick to something using Luxeon or Cree emitters with good coverage and optics to increase penetration and have higher PAR at depth. Cree are the market and technology leaders in terms of output and efficiency. The Luxeons are also quite good but a bit behind Cree from my understanding.

However, there's a strong argument for not utilizing optics whenever possible with LEDs. If you can get away without optics you don't have to worry about the potential for spotlighting and you get a more uniform distribution of light and blending of different colors (if your fixture employs different colored LEDs).

Here's a post on the Reefbuilders blog:

http://reefbuilders.com/2010/01/27/l...ics-explained/

Seeing the light: LED optics explained
Posted on January 27th, 2010 by Brian Blank 9 Leave a comment

LED secondary optic focussing lensLED lighting is beginning to take hold in the aquarium hobby and it can be a very complex subject to master when trying to make an informed purchase decision as a consumer. We touched on the topic of underdriving or overdriving LED’s with coralSky’s Jeff Littlejohn earlier and were fortunate enough to get a hold of some great information on LED optics by Jeff from his forum post at coralSky to share with our informed readers.

Typically, when we think of LED optics, what comes to mind in a plastic lens of some sort used over the LED itself to focus or disperse the light. We need to take a step back and realize the LED itself has a protective casing called the primary optic. The primary optic serves two purposes: to protect and to shape the light output of the diode.

Manufacturers will use the spatial distribution (or shape of the light) when describing the LED, referring to the spread of the light from the central axis of the unit. In the aquarium setting, LED’s are mounted facing down and into the tank and if we imagine a line running vertically from the center of the LED, the spatial distribution of the light is measured in degrees from this central axis. For example, a 120-degree LED will extend the beam 60-degrees to either side.

“This is one of the reasons why LED lighting is more efficient than metal halide or fluorescent light sources, which emit light in a nearly spherical pattern,” says Littlejohn. “This means that most of the emitted light is directed away from the intended subject, and a reflector must be used to redirect this light to a useful direction. Since there is no such thing as a perfectly reflective surface, this results in a loss of efficiency.”

But just because an LED is rated at 120 degrees, it doesn’t mean you get the lighting punch of the LED across the entire spectrum. Just like any other point of light source, it’s going to be stronger the closer you travel to the center. Along the central axis the LED emits 100 percent of its relative luminous intensity and will lose intensity the farther you move away from the central axis.

For simplicity’s sake, if a 100 lumen will produce 100 lumens of light at the center and a measurement taken 25 degrees from its central axis, the output of the LED will appear to drop to only 80 lumens. Continuing on the path away from the center axis a measurement taken 45 degrees off axis will yield only 40 lumens, and so on, until at 60 degrees, only 10 lumens or so are emitted.

Now that we have a better understanding of the primary optic, let’s delve into secondary optics. The secondary optic are separate components that are usually made from optical-grade acrylic or polycarbonate mounted over the primary to help further shape the beam of light. The purpose of the secondary optic is to increase the relative luminous intensity. An example Littlejohn uses is the Fraen 8 degree optic that can actually increase the intensity of the LED 27 times.

“2,700 lumens out of a 100 lumen LED sounds great, right?,” notes Littlejohn. “Not so fast. All of this extra intensity is still only achieved directly under the central axis of the LED. In the case of a narrow optic, there is a SEVERE drop off in light intensity only a few degrees from the central axis. A narrow optic creates a “pencil” of high intensity light, and almost no light is emitted outside of this very narrow beam.”

The numbers sound incredible but in your typical aquarium lighting application the light would have to be mounted so high above the tank to get any usable spread off the LEDs making them unusable from a practical standpoint. There are some more practical secondary optics for use in the hobby, Fraen wide beam or the Ledil Rocket W for example, that do increase the light output of the LED but at a much smaller scale. The Fraen wide optic increases output 2.4 times and directs it into a 58-degree come.

“Besides the obvious advantage of achieving more light from the same number of LEDs, for deeper tanks, the addition of a secondary optic will greatly benefit the light penetration through the water column,” he adds. “In my opinion, for tanks up to 24-inches deep, LEDs do not require a secondary optic to reach the bottom with a significant amount of light energy intact. For tanks over 24-inces deep, the extra light penetration provided by the secondary optic overrides enough of their disadvantages to warrant their use.”

So why aren’t optics used everywhere then? According to Littlejohn, there are disadvantages of secondary optics with some of them being pretty significant:

1. They can be expensive. They typically add between 25%-50% to the cost of each LED.
2. With few exceptions, they create a harsh transition from bright to dark. In other words, the “edges” of the cone-shaped light pattern can be very distinct. This creates a “flashlight effect”, where everything within the light beam is very bright, and everything just outside the beam is very dark.
3. They hinder color blending. Since most of us like the actinic effect of all blue lighting, and since most of us prefer a cooler color than the coolest white LED available, we must use a combination of royal blue and white LEDs in our systems. When secondary optics are added, you may see obvious white and blue spots in your tank. This effect can be reduced by reducing the center to center spacing of each LED, so that the cones effectively overlap, but it may still be very apparent as our corals grow towards the top of the tank. Also, our rock formations and corals cast shadows, which may be distractingly blue or white under secondary optics.

So what is the bottom line from all of this? For Littlejohn, there are two significant takeaways from his post.

“On shallower tanks, I’m a proponent of using straight LEDs without secondary optics,” he states. “I’ve found that achieving a sufficient amount of light for high-light corals is possible, there will be no flashlight effect, no spotting, and more uniformly colored shadows.”

What exactly is a sufficient amount of LED lights for light-intensive corals you may ask? Littlejohn recommends a LED density of around 24 LEDs per square foot for 10- to 12-inch deep tanks, 36 per square foot or 12- to 18-inch tanks and 48 per square foot for tanks 18 to 24 inches deep using a nominal drive current he outlined in the previous post here at Reef Builders.

“On deeper tanks over 24 inches, I like to add a mix of secondary optics to the LED array. I’ve observed that a relatively small number of secondary optics can provide enough extra light penetration while minimizing spotting and colored shadows,” he says. “It may take some trial and error, but I believe a good starting point is to cover 15 to 25 percent of the LEDs with a good secondary optic, and LED densities of 54 or even 60 LEDs a square foot may be required, at a nominal drive current.”

We see great potential in the hobby over the upcoming years with LEDs and other advanced lighting and we will continue to bring you more quality information on the advances in this promising technology.

[StirCrazy]

there few little bits of wrong info in that Andrew. first they say secondary optics are expensive costing between 25 to 50% of the LED.

a cree led is a shade over 6 bucks and the optic is 1 buck.. not realy expensive at all. as for spotting this is easily overcome with spacing. make you max spacing between LEDs 2" and between rows 3" and you can run 40 degree optics. I am spacing mine at 1.75" and 2.5" respectivly.

I don't know why anyone would want to run 8 degree optics but I am assuming that was just and example. 40degree optics will give you about 250 MH levels or bettwe, 60 degree will give you 150 watt mh or better and no optics will be like running T5's . now of course this all depends on the distance. on a shallow tank you might be able to use 60 degree optics and get the same PAR as a 250watt MH.

the down side to optics is simple.. the lower the degree the tighter the spacing of the LEDs must be to avoid spotting. so if you want to run the 40 degree optics you must use more LEDs to cover the same space. a good example is the system I am building. with no optics I can get away with 16 leds to evenly light a 30 gal tank. If I wanted to run 60 degree optics I would need 20 to 24 LEDs but I want lots of par so I am going with 40 degree optics so I need between 36 and 48 Leds (depending on how I arange them. so in a way optics are more expensive but not much and the extra expence isn't because of the price of optics but rather from the extra LED's needed.

Now having said this, I will probably hit 250 watt levels in my ank with no optics (tank is only 17" deep) but I want to be able to go even higher than 250 watt levels to test a couple theories

If you want to see some good info on LEDs I am going to recomend a left field place. RC has a couple good threads, but overall not much else. Nano_reef.com is the most info and support I have ever seen for LEDs. they have one guy there "the LED god" who designs lighting systems and is actualy very helpfull with questions about LED lighting. I usaly don't recomend boards other than Canreef as I generaly feel we have all the info some one needs unless they want to get way over the top, but this is one time I will say that the nano board is the board for LED questions and info.

Steve

[naesco]

My tank will likely be 18-24 inches.
It looks like to get the whiteish rather than the yellowish look these leds do it.
When the white led lights are out and the blues come on is it possible to get the overall blueish look and in addition the deep blue flashlight effect which would highlight certain flourescent corals?
What I gleaned from their website is that this might be possible because it is programmable.
Am I missing something? Am I missing lots?

I plan to restrict my new tank to florescent corals, inverts and fish. The reason is that I want to enjoy the tank when I get home after work.
I also want to 'hunt down' uber-florescent species and specimens. I want to frag the best.
Thanks

[Canadian]

Hi Steve,

I know about nanoreef being THE site for LED info. I don't really have any particular interest in LED right now so I can't be bothered to stay abreast of the ins and outs. From what I have read there does appear to be some disagreement about optimal designs (for example whether or not it is better to over, under, or normal drive them). Given the still experimental nature of LED lighting over reef tanks I'll let the manufacturers figure things out and people such as yourself continue experimenting before I get too worked up about it. I'd love to change to LED ASAP but it looks to be at least another year before we start to see some quality, reliable, readily available, and attractive LED fixtures hit the reefing market.

[StirCrazy]

Originally Posted by Canadian

Hi Steve,

but it looks to be at least another year before we start to see some quality, reliable, readily available, and attractive LED fixtures hit the reefing market.

the way the company that holds the patent is going I don't think we'll ever get anything nice.. well at least for 20 years when the patent runs out.

Steve

[Ron99]

+1 to what Steve said above. That info from Coral Sky may be slightly biased as they are obviously marketing a product without optics. As Steve said the cost of the optics is small and they help with concentrating the light so you get better PAR deeper in the tank.

As for the patent, I think all it needs is to be challenged in court and invalidated. I can't see how that patent was issued as they found nothing new or revolutionary or surprising that merits patentability. There was also a bunch of prior art that the patent examiners obviously didn't see. PFO was in financial difficulty before Orbitec went after them so they obviously didn't have the finances to fight it out in court. Hopefully somebody can do that at some point.

[Crytone]

Originally Posted by StirCrazy

the way the company that holds the patent is going I don't think we'll ever get anything nice.. well at least for 20 years when the patent runs out.

Steve

From what I read recently the company who owns the patent (Orbitec) is filing for a continuation of their patent. This is where people are stepping in and submitting a Third-Party Submission against Orbitec to hopefully stop their monopoly. If they can prove "prior art" (basically meaning someone was using this idea before Orbitec claims they invented it) then they are hoping to overturn the patent. Big problem though is Orbitec has big pockets- iirc they got money from NASA for something. I believe money speaks a lot in the patent biz.

The patent is pretty broad too. Summed up it's basically "adjustable/dimming LED lights over an aquarium". Did they invent the LED? No. Did they invent the dimming/adjusting of the LEDs? No, PWM's have been around a long while for this purpose.. Did they invent the aquarium? Of course not! So All they claim they invented was the IDEA of putting an adjustable LED over an aquarium! Orbitec doesn't seem to be doing anything substantial with this patent either- except suing everyone who infringes it.

[Canadian]

Originally Posted by Ron99

+1 to what Steve said above. That info from Coral Sky may be slightly biased as they are obviously marketing a product without optics. As Steve said the cost of the optics is small and they help with concentrating the light so you get better PAR deeper in the tank.

As for the patent, I think all it needs is to be challenged in court and invalidated. I can't see how that patent was issued as they found nothing new or revolutionary or surprising that merits patentability. There was also a bunch of prior art that the patent examiners obviously didn't see. PFO was in financial difficulty before Orbitec went after them so they obviously didn't have the finances to fight it out in court. Hopefully somebody can do that at some point.

If optics are inexpensive why do you think a company would produce a fixture without them? They obviously have reason to believe that not having them provides some type of performance benefit. I believe the new Vertex LED fixture also lacks optics. So there are obviously some companies performing some R&D that leads them to believe LEDs without optics provides a performance, efficiency, or cost advantage. The application of LED technology is still in its infancy in this hobby. Over time I guess we'll see how things pan out. It wasn't that long ago that MH reflectors were designed with the intent of focusing the light and we got to a point where fixtures were producing fairly acute hot spots. Then reflector design transitioned to providing an even spread of light without hot spots.