This is a great article on LED lights by our good friend and genius tech guy, Michael Blake at Palladium Technologies.
LED lighting on yachts is in great demand as the transition to phase out away from traditional incandescent lighting fixtures are occurring worldwide. The main drive towards LED lighting is from an energy savings standpoint, while on our yachts there are a number of other benefits to this evolution as well. These other benefits are, heat reduction, lower number of spares onboard, and the time taken to continually replace failed or failing halogen bulbs, which seem to only occur when an owner and/or guests are onboard.
One of the basic laws of physics is the law of the Conservation of Energy. This law simply states that energy cannot be created or destroyed; it can only be transferred from one form to another. So when we turn on a typical 25-watt halogen overhead bulb, we will see 0.875 watts converted to light and the remaining 24.125 watts converted to heat, resulting in about a 3.5% efficiency.
This low energy conversion to light ratio for a halogen bulb and the resulting heat, puts high demands on the air conditioning system of your yacht, which in turn requires more energy/electricity from the generators. All of this translates to more frequent maintenance on the electrical and the air conditioning systems. Also some of the heat from the halogen bulbs is transferred through the metal fixtures into the surrounding materials, which can discolor the fabrics and becomes a fire hazard. It is this potential for a fire from the halogen bulbs, which is one of the major worries, and a driving force to replace halogen bulbs with LED lights.
Myth #1: LED’s Do Not Produce Heat
In one sense, this is true: LEDs are cool to the touch because they generally don’t produce heat in the form of infrared (IR) radiation. It is the IR radiation, which heats the enclosures and its surroundings of incandescent bulbs, as mentioned above, resulting in the potential fire hazard.
LED’s do produce heat, with 30% of the electrical energy being converted to visible light and the remaining 70% to heat. Where is this heat from the LED being attributed to, if it is not from the conversion to IR? The heat is generated at the LED semiconductor level and it is essential that it be removed through efficient thermal management. This is usually obtained via heat sinks (sometimes seen as metal fins on the back of the LED fixture), which with air circulation will dissipate the heat from the LED semiconductor. In our lab at Palladium Technologies, we have tested a large cross section of LED fixtures, and find that there are quite a few which are designed without proper heat sinks or thermal management. The end result is that as these LED fixtures’ temperature rises, their lifetime is reduced. It not just the reduction of the LED life which is affected, but as the LED ages, it’s light output decreases as well.
Myth #2: You Can Simply Replace Halogen Bulbs with LED Bulbs
I think it might be beneficial to share some of the mistakes that we have seen in the transition from halogen to LED bulbs. One of the biggest errors is assuming that you can just replace the halogen bulb with an LED bulb (MR16, GU10, etc.). For the same lumens (light output) the LED replacement bulb typically will not come with a heat sink to remove the heat from the semiconductor. Remember in our discussion above, the halogen bulb removed its heat via IR, which radiated away from the bulb with the light. The LED must have a properly designed heat sink, which normally requires replacing the entire fixture and the halogen bulb.
Myth #3: All LED’s Are Created Equal
This myth has led me to use one of my favorite phrases “you don’t get what you don’t pay for”. Some of the very inexpensive LED bulbs/fixtures are usually poorly manufactured in Asia, with cooling fins which are not sufficient in size, thereby overheating and ultimately failing. Additionally in the manufacturing process, quality is sacrificed for price, and the soldered connectors are not properly attached to the LED semiconductor. With the inevitably heat increase and/or just normal vibration, poor solder joints at the LED semiconductor may break, resulting in a complete failure of the LED fixture.