One can become easily overwhelmed by all the different LED Choices. Cheap Chinese Fixtures can be had for less than $200 on EBay. Other European Fixtures are well over $1000. Without being specific on the differences between Cheap Imports and more expensive Fixtures, we would like to outline what makes a LED fixture and then define the levels of quality of each part.
A LED Fixture consists of the following components: LEDs, LED Optics, Drivers/Powersupply, Heatsink&Fan and Controller. Each one of these components has a direct effect on the longevity and efficiency of the fixture. Skimping on any one will have a negative effect.
The amount of different LEDs can be daunting. One cannot say 3Watt LED and have any quantifiable idea on the quality. Many inexpensive fixtures claim that they use 3 watt Bridgelux LEDs. The Fact is Bridgelux no longer makes these 3 watt chips. They are made by different Chinese Companies. If you were to purchase these LEDs you would have no guarantee of brightness or spectrum. In fact there is no data provided at all. Mainland China is notorious for allowing counterfeits and patent infringement. This class of LEDs are best described “Like a Box of Chocolates” as you dont know what your going to get.
As of today Cree and Luxeon offer the best three and 5 watt LEDs. Modern factory fixtures offering these LEDs tend to be more efficient and of a higher quality compared to the Black Box Imports. Even then one has to ask which Cree LED? Cree Bins their LEDs by Spectrum and Intensity, Cree Binning PDF. Not all 5 watt Cree Cool Whites are the same. There are 28 different spectrum Bins and 5 different intensity Bins. The intensity bins Q5 to R5 differ by by 30%. A R5 Cool White is 30% brighter than a Q5 Cool White at the same current. The Q5 of course are less expensive. Along with Intensity Cree Bins their LEDs according to Colour with Warmer bins approaching 5K and Cooler ones close to 8K. The difference is noticeable with the warmer bins having a yellow look. The binning is also very important in the Royal Blue. This is your primary grow LED and Bins at 450nm offer much more colour pop than bins over 460nm. Companies that Bin their LEDs ensure optimal looks and performance. Companies that do not Bin their LEDs more often than not receive the most common Bins which are warmer and not as bright. For those who purchase their LEDs from ReefLEDLights we label the Bins on the back of our LED Stars so you know which colour and intensity Bin you are purchasing.
LED Optics are a force multiplier. Their quality varies greatly, ranging from generic Chinese to European precision molded polycarbonant. The naked LED has a spread of 120-180 degrees. This results in a lot of spill or wasted light. Optics optimize the light by focusing it where you want it. Generally optics are not very expensive with the highest quality one running around $1 each. This is well worth it as they are 85-90% efficient compared to to 70 % efficiency of cheaper optics. Simply by choosing a higher quality optic your fixture will be 15-20% brighter. Then add the right optic. We found that for a 24″ Deep Tank 45-60degree optics offer the best ratio of coverage and penetration with the fixture 12-18″ off the water. A 12″ LED Fixture with these optics will cover a square area of 24-30″. 90-120 degree optics are fine if you have to be close to the water but your still loosing light to the glass which means more frequent cleanings. One valuable technique is to mount the fixture slightly forward and angle it slightly to the back. This optimizes your coverage while reducing wasted light on the glass.
There are many different types of LED Drivers. Some require a separate DC powersupply, others have the powersupply built in. Overall the quality of drivers vary greatly from unlabeled mystery drivers found in many EBay fixtures. These have been the source of frustration for many reef keepers. These are not IP 67 Water Proof. This fixture was used for about 12 months and note the rust on the bottom screw. Imagine how bad it is on the electrical components inside the driver. If this fixture was placed inside an enclosed hood the corrosion would be much worse and premature failure imminent. Not only do you have electrical components exposed and not protected, you do not know the current or forward voltage range so when the obvious failure happens you cannot easily replace the driver. Another thing to consider is safety. Is this driver UL or CE listed? Quality fixtures will use components only UL and or CE Listed. Everyone has heard stories about cheap imports without any warning simply catching fire. The pictures on the right are both high quality Mean Well Drivers. The top is one of our bullet proof drivers as it has excellent reliability and is IP67. The lower picture to the right is our preferred driver as its extremely reliable, offers one of the highest efficiency ratings and is completely dimmable via common 5V PWM. It would be unlikely that the drivers on the right fail but if they do they are easily replaced. LED Fixtures are very simple and once you build one you have complete fluency with its components. If you purchase an Ebay Fixture and the drivers goes bad, you are dependent on the retailer. Some will send out a replacement with little trouble others will simply disappear as they know the quality of the fixtures they are selling. Either way the last thing you want is your corals suffering due to lack of light while you deal with warranty issues. When choosing a fixture or building one only use quality UL/CE listed IP67 Drivers.
Heat is the enemy of any electrical component. The hotter a component gets the shorter its lifespan. By reducing heat your fixture will simply last longer. High efficiency LEDs and LED Drivers produce less heat and simply last longer. Add this to a heatsink with a large mass and surface area you have a winner. The Cree XT-E Cool White LED is 13% brighter at 25 degrees C vs 85 degrees C. Cree XT-E Data Sheet In other words buy simply dissipating the heat you have a brighter more efficient fixture. This is where DIY offers a great advantage. You can simply choose a larger heatsink and cool it with standard 80mm or 60mm for a modest cost. Imports are restricted be weight not to mention they dont care about ultimate quality. If fact they believe that you would be happier with a lighter fixture that is 10 % less expensive and 30-40% dimmer. Their 30-40% dimmer is a compromise on using lower intensity Bins and only the minimum in thermal management. In addition to using a proper heatsink and fans, one must not forget the LED Circuit Board or Star and the fact its mounting surface are not perfectly smooth. A thermal paste, tape or pad is required to more efficiently transfer the heat.
Over all by simply choosing the right components you can easily build a fixture the exceeds the performance of most factory fixtures. Its rather sad that in this vibrant economy companies choose to lower the quality significantly only to save a few cents. In the long run these savings are lost to premature failures and reduced efficiency. LED fixtures are easy to build especially when using the BJB Solderless connector. When you Do It Yourself you control the quality 100%. In the real world things fail, in the unlikely event you have a premature failure you can easily swap out the part. Just remember you cannot judge the power of a LED Fixture by watts consumed or the listed wattage of the LEDs. Please reference our build threads and feel free to contact us with any questions.