LED lights have become increasingly popular for boats due to their energy efficiency, longevity, and versatility. There are replacement LED lights for pretty much any existing light on a boat, but this is not as simple as replacing an incandescent or halogen lightbulb. There are several important factors that need to be taken into account.
Beam Angle and Color Temperature
One crucial aspect is the beam angle, which determines how wide the light is spread. If you need wide area lighting, you either need LEDs with a wide beam angle or multiple LEDs pointing in different directions. For cabin lighting, a wide beam angle or multiple LEDs is likely to be necessary to ensure adequate lighting.
Then there’s color temperature, which will be printed on the packaging for an LED light.
Lower color temperatures (below 3000k) provide warmer, more natural light, while higher color temperatures (above 3000k) produce cooler, bluish light. First generation LED white lights from a decade or more ago had a high color temperature with a harsh, bluish light that worked for anchor and some exterior lights but was totally unsuited to interior lighting.
Over the years the color temperature of white lights has been steadily lowered for ever more pleasant interior lighting. Today, LEDs with a color temperature below 3000k are widely available. These provide a warm, pleasant light that mimics the incandescent and halogen lights previously used on boats.
Importance of Color Rendering Index (CRI)
The color rendering index (CRI) is a measure of how accurately a light source renders colors compared to natural sunlight, with 100 being equivalent to natural light. In other words, the higher the CRI, the higher the ‘quality’ of the light. A low CRI can result in poor quality lighting with colors appearing distorted and unnatural.
Incandescent and halogen lights typically have a CRI above 90, while many LEDs in the past have had a CRI well below 90. This may not matter for exterior lighting but is important when it comes to interior lighting. Assuming you have a suitable color temperature, you also want a CRI above 90.
Radio Frequency Interference (RFI)
LED lights typically have a tiny DC to DC converter (a ‘driver’) in their base operating at a high frequency. High-frequency switching can cause radio frequency interference (RFI) that may affect navigation electronics and VHF radios. It's important to choose LEDs that are adequately RFI suppressed, especially for masthead lights next to a VHF antenna, and for lights near the nav station or electronic equipment on your boat.
Life Expectancy
On paper, LED lights have extraordinarily high life expectancies. It is not uncommon to see 20,000 operating hours or more, in which case given the low number of hours many boats are used they will outlive most of us! In practice, things are not this simple.
In general, heat is the enemy of life expectancy. The DC systems on boats have variable voltages. A well-loaded, partially charged 12-volt battery may see its voltage fall below 11 volts. The same battery with an aggressive absorption voltage for its charging devices may rise above 14.4 volts. The LED’s driver must handle these changing voltages, and the changing currents (amperages) that may result from them, without generating excessive heat and hot spots. It has to do this in a potentially high ambient temperature, and/or with heat entrapment at the location of the LED light. Some drivers handle this better than others, with a major impact on real-world life expectancy.
Choosing the Right LED Lights for Your Boat
Whereas poorly designed LEDs may result in uneven and low-quality light output with RFI issues and a short life expectancy, investing in quality LEDs with appropriate beam angles, color temperatures, and CRI ensures a pleasant and effective long-lived lighting experience on your boat.
With attention to detail, the light intensity and quality will be at least as great as with all other lighting choices with a considerable reduction in the energy consumption. If LEDs replace halogen lights, which were the primary choice for boatbuilders for many years, it is not unusual to see the lighting load reduced to somewhere between one fifth and one tenth of what it was with no loss of light intensity or quality.
For more in-depth information on LED lights and other boat electrical systems, we offer a bonus module in the Boat Electrics 101 course.
