evilc66

Ultimate LED guide

3,107 posts in this topic

So I have been asked to do this a few (hundred? )times now, so I figured I would get it out of the way. Hopefully this will provide some education to those looking to dabble in the world of high power LEDs.

 

If you asked for this, here it is. If you didn't, well you're getting it anyways ;)

 

Go grab a cup of coffee, hit the bathroom, you are going to need it. Don't worry, I'll wait.... Back? Ok. This is a lot of information, but it's useful. Making educated decisions on how to build your LED array will save you time, money and headaches in the future. Put it this way, I did all the hard work for you. You just have to read it.

 

DISCLAIMER: This involves the use of tools that can hurt you, and electricity that can kill you. Please be careful. We would like to see you back here again showing off your new LED setup at some point. Missing limbs and burned off eyebrows won't get you bonus points. I have tried to explain everything here as clearly as possible and as safely as possible. I hold no responsibility for you hurting yourself or others.

 

 

 

 

First things first. This will be addressing high power LEDs only. 5mm, 8mm, and 10mm LEDs are just not powerful enough for most applications. There are some instances (like fuges, algae scrubbers, and very small pico tanks) where they can be used, but when it comes to most applications, they don't cut the mustard. I will be writing up another thread addressing the differences between the different sizes here soon.

 

Many of you have posted question on this forum like "I want to get into LEDs, but I don't know what to get", and "I know what parts I need, but I don't know how to wire them up". These are the kind of questions that will be addressed here. I'll divide this into three parts; "Why Use LEDs", "Parts You Need", and "How To Put It All Together".

 

This article will be updated continuously as new tecnologies and part options become available. It will also be updated to correct any goofs that I make. Hey, I'm not perfect :)

 

Update History

2-17-09 Initial Release

3-17-09 Added Recom driver to the driver list

3-25-09 Added Meanwell ELN series drivers to the list

2-16-10 Added info on Cree XP series LEDs. Added discontinuation note on Luxeon LEDs.

7-28-10 Added Rebel ES, c, and Altilon lines to Luxeon LEDs. Updated Rebel datasheet links

 

 

 

Why Use LEDs

 

We have all seen LEDs before. They are everywhere in our society in all kinds of modern technology. But why use them in our aquariums?

 

Up until recently, we weren't able to use them effectively to light up a tank. Too expensive, and just not powerful enough. But in recent years there have been great advances in the area of high power LEDs. Now, what makes a high power LED different from those that we find in our electronic devices?

 

First thing thats obvious is the amount of power used. Typical high power LEDs come anywhere from 1 watt to 3 watts, where your average 5mm LED is around 1/4 watt or less (8mm, 10mm and Superflux LEDs can go as high as 1/2W). With this high power comes increased brightness, but also increased heat. This increased brightness, which is many times more than 5/8/10mm LEDs is important for penetrating the water to greater depths. Another advantage is that they can generate more light over a wider angle. This is a clear advantage over smaller LEDs, as usually manufacturers will make the angle tighter to generate higher brightness numbers, and are usually so tight that they create what I like to call a "spotlight" effect, which it basically is. Currently, the top end high power LEDs are right behind metal halide and T5 in terms of efficiency, so you can produce almost as much light (lumens) for the same wattage.

 

But producing light, lumens in this case, is not what LEDs are all about. The real clincher is the ability to produce more PAR (Photosynthetic Active Radiation) per watt than most any other form of light. For those that don't know, PAR is a measurement of the amount of light that falls onto an area, that falls on a response curve for photosynthesis (400-700nm, ignoring UV and IR light). Basically what this means is that more PAR equals more growth out of photosynthetic corals. Because of this, LEDs do not have to produce as many lumens as other forms of light to reach the same growth potential. This also means less power is required too.

 

The next major advantage is heat. Now, I'm not going to say that these LEDs don't produce heat, as they do, and quite a lot of it. But what makes this different is where the heat is radiated from. Usually in most lights, heat is emmited from the bulb itself in the form of infrared light. LEDs do not emmit infrared from the emmiter and will not directly transfer heat into the tank like a metal halide bulb would. The heat that is generated comes off the back side of the LED. Usually, they are mounted to heatsinks to effectively control the heat, and radiate it into the air. Without additional heat placed into the tank, there is now less of a need for chillers and additional fans to cool the tank, saving you money.

 

LEDs can also save you money long term by elliminating bulb replacement. Most high power LEDs are rated to live for 50,000 hours before the light output drops to about 70% of the original rating. Thats a long time. With a light schedule of 10 hours a day, these LEDs could effectively last for over 13 years! The price you pay upfront is going to be more, but it could pay for itself within the first few years of ownership.

 

Another benefit of LEDs is the fact that they can easily be dimmed and controlled. Can you imagine being able to change your color temperature on the fly, going anywhere from 6500K to 20,000K? It's pretty cool. I realize that there have been new prducts released recently for T5 that allow dimming control, but I'm sure at quite a cost. Controlling LEDs can actually be quite simple, but also allows for some more complex setups and effects that you simply can't do with any other lighting source.

 

So as you can see, there are some very compelling advantages to using LEDs for aquarium lighting. The upfront costs will be more than most lighting setups, but the savings long term between heating and cooling costs, running costs (ie. less power to operate, less equipment to run), equipment costs (ie. removing a chiller out of the equation), and maintenance cost (bulb replacements) can make up the difference is a short period of time.

 

So how do you get this going?

 

Parts You Need

 

 

LEDs (Light Emmiting Diodes)

 

The obvious thing you are going to need here are LEDs. There are many different manufacturers, models, shapes, colors, and mounting options. Some are a little easier to work with than others, while some are easier to get. The main brands that get used the most for DIY purposes are from Lumileds (Luxeon), Cree, and Seoul Semiconductor. I'll break them down here in detail.

 

Lumileds (Luxeon)

 

Probably one of the more well known companies in the high power LED game, they practically pioneered the industry years ago with the introduction of the Luxeon I, III, and V series LEDs. While not the most efficient nowadays, they paved the way from what we have now.

 

Their models include:

 

The K2, K2 TFFC and Rebels are the LEDs that we are going to focus on from Lumileds. These are the newer generation of LEDs and have much higher efficiency and output in comparison to their older siblings. The K2 got Lumileds back in the race after Cree and SSC started cranking out some seriously high power LEDs. But they weren't without flaws. With the high drive currents used by the K2, they generated a lot of heat. The K2 TFFC fixed a lot of the problems by using technology that was developed for the Rebel. This brought output back up to where Cree and SSC are currently, and brought heat levels down.

 

Now the Rebel is the odd duck of the family, but not one to ignore. All the other LEDs are much larger in size, and are more easy to work with when they are not mounted to a pcb. The dedicated solder tabs make attaching wire much easier. The Rebels on the other hand are SMT (Surface Mount Technology). Think of all the tiny little chips that are soldered to PC motherboards and most modern electronics. They are very small, and with the solder pad under the LED itself, makes for a tricky package to work with. BUT, if you can get past that, you have the ability to create very high density arrays, that are very bright. It also gives the opportunity for great color mixing, which we will get into later. The current generation of Rebel LEDs are just about as bright as the best that all manufacturers have to offer.

 

All Luxeon LEDs are available in multiple colors to suit the needs of you application. Most of the time you will be focusing on cool white, blue, and royal blue.

 

NOTE: As of March 1st 2010, Lumileds is stopping all sales of all of their high power LEDs with the exception of the Rebel. That will be the platform that they will be using for all future products.

 

 

Cree

 

A relative newcomer to the game, Cree has made a big splash by releasing some of the most powerful LEDs on the market. They are one of the most common LEDs that we end up using for DIY projects, mainly for their cheap availability from Asia, and their high output. Their models are covered under the XLamp brand and include:

 

Most of the Cree products that we are going to use are XR-E and XR models. The XR-E series has all the new super bright white LEDs, including the P4, Q2, Q4, Q5, and R2. These are brightness bins, that I will explain in the next section, but for right now, all you need to know is that the Q5 is the most common, and second highest brightness out of the lot. The XR series is used by us mainly for the blues. Idealy, the XR-E blues would be better, but are not as common, or as cheap as the XRs. They do work out quite well though.

 

The MC-E series is new, and is king of the hill in brightness in the Cree camp, but isn't particularly practical in our application. Because of it's extreme brightness, it makes it harder to effectively raise the color temperature with blue LEDs, and still get good color blending. Using an LED like this for spotlighting certain show corals, which is a very popular approach used in Japan, could be a good application for it.

 

Just like the Luxeons, most all of the different models are available in multiple colors, except the MC-E, which is only available in white.

 

UPDATE 2-16-2010: In recent months, Cree has stepped things up in the small form factor market to compete with the Luxeon Rebel. The XP series has been around for a little while now and is making some pretty significant strides in output and efficacy. The latest LED, the XP-G is Crees highest output single die LED, capable of lumen outputs north of 400lm when driven at 1500mA. The newly released XP-E royal blue is equal in output to the XR-E royal blue, but a fraction of the size. What makes these LEDs very interesting is that they use the same optics choices that have been available for the Rebel. There are still some critical lens angles missing that are preventing these from becoming a complete replacement for the XR-E, but it won't take long.

 

 

Seoul Semiconductor (SSC)

 

SSC is in kind of a strange situation. As of late, they do not actually make the dice (the part of the LED that actually emmits light) that they put in their LEDs. They actually buy them from Cree and repackage them. This make their performance very similar to the Cree equivalents. The models that are most common are:

 

  • P4
  • P7

 

The P4 LEDs are the equivalent to the Cree XR-E LEDs. The biggest difference is in the viewing angle of the LED, which is greater on the P4. This doesn't mean it's a benefit. The smaller viewing angle on the Cree LEDs means that more light is pointing into the tank without the need for optics. The SSC LEDs are also not as common on the marketplace for DIYers to get a hold of.

 

The P7 is very similar to the Cree MC-E, and as a result, shares the same problems with using them in aquarium applications.

 

 

 

These are by no means the only companies that make high power LEDs. They are just the companies that make the highest power, most efficient and easiest to obtain LEDs that are suitable for our hobby.

 

 

Constant Current Drivers

 

This is where things take a little departure from what you normally know about electrical devices. Everyday items like incandescent bulbs, motors, electric heaters, etc. are all what are called "voltage driven" devices. What that means is that the voltage to operate the device is kept constant, but the current required can change depending on what is needed. A motor is a great example of this, as when it is running with no load, the current is quite low, but as soon as you start to load the motor, or stall it completely, the current skyrockets while the voltage stays the same. An LED is a "current driven" device. The concept is the same as a voltage driven device, but it's the voltage that now changes and the current stays the same. This is very important in the long life of the LED because when the current increases on an LED, so does the heat. Once an LED gets too hot, it can be destroyed, or have it's overall life and performance severely reduced. I will go over some of the common LED drivers.

 

Luxdrive Buckpucks

 

Buckpucks are probably one of the most versatile drivers on the market right now. On top of their really small size, they offer a wide variety of options to suit your needs.

 

  • AC or DC models
  • 350mA, 500mA, 700mA, or 1A output
  • Non-dimmable, on-board dimmer, or external dimmer options
  • Wire lead or pin header connection options
  • Up to 32v operation
  • No additional cooling required.

 

All of these will require a power supply, and will not run directly on mains power, even though some are AC rated (low voltage AC). These are a great little driver for the money. Luxdrive also has a number of other models that are good for other applications, but the Buckpucks work the best for aquarium lighting.

 

 

Advance Xitanium

 

Advance Transformer, who many of you might be familiar with their PC, T5 and MH ballast, make a line of LED drivers under the Xitanium brand. They have a good selection of different models that can handle varying amounts of power and LEDs. What sets these apart is that they are one of the few drivers that can be powered directly from the mains.

 

  • Multiple output current options
  • Dimming capabilities (only on certain models)
  • Mains power

 

 

Deal Extreme and Kai Domain Drivers

 

 

Both companies offer numerous different drivers that may fit the need for your application. The have a number of AC and DC rated units. Unfortunately, neither seems to have that one driver that does it all, none of them are dimmable, and most are low power. For smaller arrays, like fuge lights, there are some great AC drivers. There are some great small DC drivers too for you flashlight guys. While there isn't that magic driver, the super low cost on some of these can sometimes make up for it.

 

Recom RCD-24

 

A new driver on the market that seems pretty interesting. Similar in size to the Luxdrive Buckpuck, it holds many similarities, but could have some advantages.

 

  • 350mA, 500mA, 750mA, 1000mA, or 1200mA output
  • Non-dimmable, or external dimmer options
  • Seperate analog and digital inputs.
  • Wire lead (non-dimmable) or pin header (dimmable) connection options
  • Up to 36v input
  • Up to 32v output on 350mA, 500mA and 750mA models. Up to 30v output on 1000mA and 1200mA models
  • No additional cooling required.

 

These will require a power supply, and will not run directly on mains power. These are reasonably priced, and competitive with the Buckpucks. It will require a little more work to get running than the Buckpucks, as the potentiometer is not included, and does not provide a 5v reference voltage to supply the analog input. Easy to fix, but a little more work

 

Meanwell ELN-30 and ELN-60

 

A new line voltage driver that is showing some promise. Similar to the Xitanium drivers, these have the advantage of higher current capacities, and higher output voltages for more LEDs per driver. All models of this driver have an option for dimming capabilities, unlike the Xitaniums.

 

  • 30W or 60W output, with multiple options for max voltage and current
  • Non-dimmable and dimmable (via analog 0-10v or pwm, but pwm is easier to get)
  • Onboard pot for max current setting, independant of the external dimming control
  • 90-264VAC operation for worldwide usage.
  • Overcurrent and short circuit protection
  • Sealed to IP64
  • No additional cooling required.

 

While a very good driver on paper and in practice, availability is going to be the tough one here. The non-dimmable versions are readily available and can be had for a very good price. The dimmable ones require hand modification by Meanwell USA and adds a little lead time to the delivery. It also adds a good amount of cost for small quantities. Larger quantities makes the price a lot more reasonable once you get past a certain price break point.

 

 

DIY Drivers

 

Not many people are going to get into this end of the DIY spectrum, but there are options out there for those feeling adventurous. Some of these I have even used myself with varying levels of success.

 

 

 

 

These are the most common ones. There are many more that have different features including DMX control. I will update this list as more become available (or you guys tell me about them).

 

 

Power Supply

 

Not much to this one. If you are running a DC or low voltage AC driver, you need one. If you are running mains power, you don't. There are a few different types though if you do need one.

 

  • Linear Unregulated. Big, heavy, and expensive (for the high power ones). They do give some of the cleanest power output though, but the voltage can wander if the input voltage changes. Usually open frame (parts are exposed).
  • Linear Regulated. Same as the unregulated ones, but has much tighter control of the output voltage. This is what you usually find in cellphone chargers (wall wart).
  • Switch mode. Much smaller for the same power as a linear power supply. Typically found in laptop power supplies. These can come open frame, industrial, and desktop (line lump).

Different voltages and current outputs will be determined by the array that is going to be powered, and the drivers used.

 

 

Heatsinks

 

This is probably the most important support component for an LED array. Like I mentioned before, high power LEDs do produce heat, and this needs to be removed and controlled. Overheating LEDs is a sure fire way of shortening their life, so picking out a good heatsink is critical.

 

Heatsinks can come in all different shapes, sizes and materials. Small arrays, using low power LEDs can get away with something as simple as a thick aluminum plate. Larger arrays will need something considerably bigger. There are three elements that make up a good heatsink:

 

  • Material
  • Mass
  • Surface Area

 

Common materials are usually aluminum and copper. Both have advantages and disadvantages, but aluminum is the typical choice for this application. While copper has a greater ability to pull heat away from a heat source, aluminum is far better at actually getting rid of it (rejecting). Aluminum is lighter and cheaper than copper, and also doesn't corrode as easily as copper does. A large, high fin count copper heatsink would ultimately be better than most aluminum heatsinks, but the cost would be astronomical.

 

The mass of a heatsink plays into its ability to pull away and store heat. This can be important for an LED array. A heatsink with low mass can be saturated with heat very quickly, making it hard for a fan blowing air across it to keep up with the load. Think of the mass like a buffer. It takes longer for a high mass heatsink to saturate with heat, and the fan can more effectively keep the temperatures lower.

 

The surface area of a heatsink is also very important. Surface area is usually seen the easiest by high fin count. PC heatsinks are a prime example of this. The more surface area you have, the more area there is for heat to be transfered to the air, and taken away. Lot's of fins doesn't mean better in some respects. With fins very close together, it takes much more air flow to effectively remove the heat away from the heatsink, and more airflow can often lead to more noise. It also does not work well for passive cooling (no fan). At the same time though, very few fins hurts performance by not having enough surface area to remove heat. It can be a tricky ballance, but if you go on the side of caution and get a heatsink that you probably know is too big, you are probably going to be ok :)

 

Some of you that have looked into this before may have seen a measurement of heatsinks called Thermal Resistance. This is basically a measurement of how well a heatsink can transfer the heat from the load to the air. It's a combination of all the features I listed above. Lower is better in this case, but you can spend hours trying to find the right heatsink with the lowest thermal resistance.

 

Heatsinks can be found in a number of different places. PC heatsinks can work well for arrays that concentrate light into a smaller area, but are usually quite tall and can be difficult to hide in a hood. Ebay is a good source for reclaimed industrial heatsinks of all kinds of different sizes. There are also online retailers that deal with many different shapes and sizes of heatsink that can work for your application.

 

 

Optics

 

Optics are not one of the parts that you will need in every application. The whole point behind them, whether they be reflectors or lenses, it to focus the light into a smaller area. These start to become more important for tanks over 12-14" tall. The amount of light at 12" is considerably less than at the surface, and it gets exponentially worse the deeper you go. Optics can help bring the performance back up to usable levels for deeper tanks.

 

Optics come in a wide variety of angles, from very narrow (4 degrees) to quite wide (50+ degrees) and even different shapes (oval beam patterns). Most of these aren't very useful for the most part, and only the optics in the 25-80 degree range prove to be the most useful. A tighter optic will have better performance at depth than a wider optic will, so thats something to keep in mind. Conversely, a narrow optic will require closer spacing of the LEDs to get enough overlap to stop spotlighting, and may require more LEDs to cover the same area.

 

Based on recent test, I have found that 60 degree optics have the ability to reach 150W MH levels when LEDs are run at 1000mA. 40 degree optics can reach 250W levels. These tests were performed with Cree XR-E LEDs and optics.

 

All optics are designed for a particular brand of LED. A lense designed for a Luxeon K2 will not work well for a Cree Q5, and vice versa. It's important that you pick the right optic for the LED you decide to use. There are many companies that support all the big makers, so finding something that will work for you should not be hard. Some of the vendors include:

 

  • Fraen
  • Cree
  • Ledil
  • Polymer Optics
  • L2

 

 

Tools

 

You aren't going to get much done without tools. There are going to be a few basics that you are going to need. Obvious ones for basic assembly are going to include:

 

  • Soldering Iron (40W+, with a fine tip. More wattage the better)
  • 60/40 or 63/37 rosin core solder (easier to solder than the newer lead free stuff, 0.030" to 0.040" diameter is nice)
  • Wire cutter/stripper (need to be able to strip small diameter wire like 26awg)
  • Basic hand tools like screwdrivers, drills, etc.
  • 26-18awg wire in multiple colors. Use stranded, not solid core.
  • Thermal Paste/Epoxy
  • Shrink tube and electrical tape. Don't skimp on this. Get polyolefin heatshrink, and 3M Super33 vinyl tape. HD and Lowes carries them.

 

Good soldering skill is going to be important for this. Search around for some basic soldering how-to's on the web, and get some parts to practice on. It's not hard to do, but does take a little practice to get it right.

 

When looking to buy a soldering iron, I would suggest something from Weller over what you can buy from Radioshack. They are generally better quality, and have better selection of optional tips. A high wattage iron from Radioshack will work in a pinch, but if you can afford it, go Weller. The reason I recommended a 40W+ iron is because of the heatsinks. Once you start applying heat to the solder pad, the heatsink is pulling that heat away, and not getting the pad hot enough to melt solder. The higher the wattage, the quicker the pad will heat up, allowing you to solder the joint while reducing the amount of time the LED is exposed to high heat levels.

 

Some additional tools that might be required, are things like a tap set. I use screws to hold down the LED pcbs to the heatsink, and I need to tap a thread into the heatsink. These can be picked up in sets or individually for not a lot of money.

Edited by evilc66
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YAY now you wont get pm's every 5 seckonds

 

now i gotta finish reading it

 

 

edit: this needs a sticky

Edited by coralcor

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I've Been waiting for this.. for the longest time.. Thank you very much!

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There is still more to add, but it's a start. I hope to start adding pictures soon.

 

Keep checking the first post, as I will be updating that one with all the information. I was trying to split it across multiple posts, but it kept automerging.

Edited by evilc66

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Bravo, you deserve a beer.

1 person likes this

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Can I have two? :)

1 person likes this

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Can I have two? :)

beer-1.jpg

 

 

get pics. im pritty shure we all like pics

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Hopefully there aren't any glaring issues (other than there is anentire section missing telling you how to put it all together :o)

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IT'S HERE!!! IT'S FINALLY HERE!!!!

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is there any doubt this will become a sticky... bravo sir!

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Great idea and well written.

 

Keep it coming :)

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Thanks everyone. Hopefully it will be useful to someone.

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Excellent right up, thanks Evil...cant wait for the rest

 

 

...now its time to get ready for a project.....

Edited by Enzo0000

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Now it's time to start bugging Evil to post the rest! :lol:

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Keep going! I can't wait to read the rest!

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Very nice,I've been trying to stay "in" the LED craze by reading :)

I'm still wanting to do a setup,i'm going to have to ask soon :D

Edited by jm82792

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thanks for the collected info...can't wait to see the rest!

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thaaaaaaaaaaaaannnnnnk yyyyyyyyyyyyyyyooooooooooooooooooooouuuuuuuuuuuuuuu!

:bowdown::bowdown::bowdown::bowdown::bowdown::bowdown::bowdown::happydance::happydance::happydance:

your work and help is greatly appreciated.

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Bravo, you deserve a beer.

 

 

Can I have two? :)

 

 

Ha, I substituted the advised coffee for those two beers!

 

Thanks evil. Certainly worth the wait. Will be eagerly awaiting pics.

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