What should I buy? Why should I buy? My friend bought LEDs for his boat and they all died in the first month, are they all like that? Those are all legitimate questions that our customers have asked. This article should clear the air on the subject.
The confusion takes root in the fact that all low voltage LED lighting products are not made equal. There is a multitude of sources for LED lights on the market, very smart led lights little honest technical information is available on them and the price range is extremely wide. The abundance of products and the lack of precise information has incited us to write this article. This document is based on information that comes directly from the engineers and manufacturer of our product line and is complemented by our own experience with LED Lighting in the Marine Environment.
This article will try to spare you the physics behind the product while giving you enough information to carefully choose what product you should install on your vessel. I apologize to all the engineers who will not find this document complete and precise, but the objective is only to provide our fellow sailors with the basic knowledge necessary to make a smart decision when purchasing LEDs for their boat.
At first, it would appear to us that LEDs were made with a boat in mind. They have a great life expectancy, don’t mind vibrations, give off much less heat than their incandescent or halogen counterparts and use a lot less energy – about a tenth of the wattage of a halogen – for a similar output. So, where is the problem you ask? Why don’t they work on my boat?
Historically, it was simple. The color output was BAD! Nobody liked the dull, low-output blue color of the early LED’s. Well, that has changed and LEDs now smart lighting have a similar light output and color to that of low-wattage halogens we find on our boats.
The problem these days is different. The marine environment with its various power sources is very hostile towards electronic components, especially LED lights. Voltage variations that we witness on our yachts are the greatest enemy of LEDs. Being VERY SENSITIVE TO VOLTAGE VARIATIONS, MOST LEDs found on the market are NOT SUITABLE for use on our boats.
I have promised not to get into the physics of powering LEDs, but let me try a few simple principles that apply to LEDs. What follows doesn’t require advanced electronics knowledge, I will call this segment BOAT LED 101.
All LED’s are semiconductor diodes. They create their light at the junction of their positive and negative sides. When power is applied to an LED, the electrons jump from one side to the other releasing light in the form of photons in the process. Different types of semiconductors produce different wavelengths and consequently produce different light colors. The warm white lights that we prefer in yachts is produced by Indium Gallium Nitride (InGaN). Add other materials, like phosphors and you get a pleasing incandescent light color.
Now, what happens when we apply voltage to this semiconductor is what we really need to look at. Apply the right voltage – in our application 12V – and the right amount of current will travel through the semiconductor and we get a beautiful, energy-efficient, bright light that will glow for thousands of hours. But, we need the right voltage, precisely 12V.
You and I know for a fact that boats do not offer lab quality power! Start the engine, the generator set or connect to shore power and your environment has suddenly become hostile to your LEDs.
Why is that? Simple! When the generator, alternator or inverter kicks in, we often see the voltage reaching upwards of 15V or higher. The higher the voltage, the more current goes through the semiconductor, the more electrons jump from one side to the other, the more light is generated and MORE HEAT is generated. And, guess what is the enemy number one of LEDs? HEAT! We need to either control the heat produced or dissipate it. Apply a lot of current to an LED and you will get a very bright light for a very short period of time. Apply to little and you get a dim, useless light. That’s what happened to you friends’ LEDs.
In this application of semiconductor physics, we know that the current measured at junction of the materials is proportional to the voltage supplied. Controlling the voltage and consequently the current is paramount to the life expectancy of your LED.
Most inexpensive 12V LED cluster bulbs being sold today use a ballast resistor which bleeds off energy to limit the current. This ballast resistor limits current according to a simple formula: Voltage/Resistance = Current. In that world, one can reach the right amount of current for an LED by using a ballast of the right resistance for the Voltage provided. Problem is, on a boat, the voltage is not always the same, it fluctuates. Consequently, the resistance being fixed, when the voltage drops, the current drops, and vice-versa. Conclusion: low voltage = dim light and high voltage = fried LED!
The result is the disappointment in LED lighting that you have heard about from all your cruising friends.
Most automotive and inexpensive LEDs are based on the ballast resistor model. They work fine in automotive because the voltage variations are smaller than those found in the marine environment and also to the fact that most LEDs in the automotive world are used for turn signals or brake lights. These signals are not on for a long period of time so heat is not a problem. One can also use a resistor that will handle 14V while maintaining an acceptable current level for the LED generate enough light. This makes automotive LEDs inexpensive, but unsuitable for the marine environment.