Many hobbyists today are designing and building their own LED fish tank lights. Even many people with little or no background in electronics or LED lighting, can participate in such a project, by referencing books and internet how-to sites. This article will discuss several approaches to complete an LED fish tank lighting project successfully. It covers the basic design considerations that one should outline prior to starting the fish tank project. The first paragraph below with introduce concepts one should be familiar with prior to starting any new home LED lighting project.
The key to any successful project is patience. This is because many new electronics projects require trial and error. Building a simple mock-up can allow you to obtain the basic form factor and dimensions required for the final product. Chances are, the initial prototype may also require some modifications before your LED fish tank lights are ready to provide a full-service life. Understanding it is normal to expect at least two revisions for a new project, is the first step to realizing the full potential of your fish tank project. In addition to patience, it is also equally important to posses some basic mechanical, electrical, and soldering skills. Anyone who has worked with a soldering iron in the past should be able to pick up on basic soldering skills required to get the job done. Having the correct tools is also critical to the success of a custom fish tank light project. Some common tools may include a soldering iron, wire strippers, wire cutters, and a multi-meter for measuring voltage and current. Most of these tools can be purchased from a local Radio Shack, or online from an electronics distributor such as Digi-Key or Mouser Electronics.
Obtaining a clear understanding of your concept design will set a base line for your expectations. It is important to understand the potential of various LEDs and LED technologies, have at least a basic idea of the final effect you wish to achieve with your fish tank lighting project. A basic illumination theme can provide a general lighting effect to illuminate aquatic life as well as tank features. This type of illumination generally consists of white LEDs placed above or near the top of the fish tank. You may also be considering a colored theme, which would feature colored LEDs to highlight certain features of the fish tank, as well as draw peoples attention to the tank. Many reef-tank lights focus on the primary purpose of aquatic plant growth. Such LED products are often intended to replace traditional methods of fish tank lighting, such as metal halide lighting fixtures. These lighting fixtures can produce a high powered light output, and are often difficult to reproduce using modern LED lights. The next step to your fish tank lighting project is to select the most appropriate LED for integration into your aquarium light.
When most people hear the word LED, they instantly think of the famous 5mm T1-3/4 through-hole package. This LED package was the first to dominate the LED market, and become very popular among hobbyists due to availability and ease of use. Today, the 5mm LED is still a popular choice for many hobbyists. The cost of LED has dramatically decreased over the years, and can now be purchased for as little as $0.10 per unit in some cases. If you choose to work with the 5mm LED in your fish tank project, it is important to understand advantages and disadvantages associated with using this type of LED technology. As previously mentioned the LED is inexpensive and readily available from any number of LED suppliers or LED manufactures. The through-hole wire leads make the LED very easy to physically place, and solder into place. Another favorable characteristic of the 5mm LED is the narrow beam angle resulting from the integrated epoxy domed lens. A narrow beam between 10 to 30 degrees will provide a higher intensity rating, and directional characteristics that allow the designer to choose specially what areas to illuminate within the fish tank. Although 5mm LEDs have many advantages, they also feature many disadvantages over more modern LED devices. Most importantly, they lack in terms of energy efficiency and lifespan. A typical 5mm LED may offer up to a 10,000 hour life expectancy. In an aquarium tank lighting application, this may or may not be an acceptable value. Compared to modern LEDs commonly rated at 50,000 hours or more, the 5mm LED simply does not compare. But perhaps energy efficacy is an even more critical aspect of a fish tank lighting project. Many designers and hobbyists turn to LED technology due to its popularity as being one of the most efficient forms of lighting. However, the traditional 5mm LED does not typically lend itself to an extremely energy efficient final project. A typical energy efficiency rating for a 5mm LED might be around 30 lumens per watt. This does not even come close to many modern LEDs now rated as high as 100 lumens per watt when utilized in the proper electronic and thermal circuits.
Power supplies for fish tank lights may range from your typical wall transformer, to a switch mode regulator found on many common electronic devices such as laptop computers. Most power supplies are configured for a constant voltage output. This means that the designer must consider some type of current regulation through the LED circuit, or could otherwise expect to damage the LEDs. If using a traditional 5mm LED package, this current regulation may consist of simple current limiting resistors placed in series with each LED string. A more modern approach, recommended for use with all high power LEDs, is the constant current source. The constant current source will compensate for the changing forward voltage across the junction of the LED as temperature increases. A board level current source can still rely on a constant voltage power supply as the primary power input. However, is some fish tank LED lighting projects, it may make more sense to incorporate an off-line current source, which converts the AC line current directly to a low voltage constant current output. This current is then distributed to each parallel LED circuit contained within the fish tank light. Although this method can save time, simplify the design, and reduce component costs, it is not always recommended due to an anomaly referred to as current hogging. This occurs when one or more parallel LED circuits begin to draw excess current in comparison to the remaining LED circuits. This leads to uneven illumination, and in extreme cases, may damages LEDs due to overdriving.
Perhaps one of the most commonly overlooks aspects of LED lighting is thermal management. This can be increasingly important in an LED fish tank lighting application. Many traditional fish tank lights, such as metal halide lights, a chiller is almost always required. When replacing HID fish tank lights with LEDs, thermal management should be no exception. Keeping the junction temperature of the LEDs under control is one of the most critical aspects of any new design. This is often overlooked due to the popular believe that LEDs produce little or no heat. This statement is actually far from true. Depending on the circuit design, as well as the type and number of LEDs used, the fish tank light may produce as much if not more than the traditional metal halide lighting system. The most basic method for maintaining LED thermal management is natural convection. Attaching the LED board to a aluminum finned heat sink can effectively increase the system�s surface area. However in some cases, forced convection, such as a cooling fan, may be required. To determine what type of thermal management is required for your LED fish tank lighting project, you must first determine the LED junction temperature. Once the junction falls to or below the normal specified limit, you know that your method of thermal management is doing the job.