LED Spreader Lights

When I was refitting Annabelle, I added a 40 watt spreader light to each spreader arm (four total). This provided a large amount of deck light that was very usable at night. Over time these lights have burned out and I was able to replace them with bulbs from a tractor supply company for much less than a marine outlet. But when 3 died at the same time, I decided to move away from incandescent to high power LED lights. I found 10W white LED's and the drivers for them on eBay (at the time the LEDs were ~$8 each and the drivers~ $8 each).

After much thought of how to house the new spreader lights, I finally decided to modify the existing Perko Spreader lights to accept the 10W LEDs. Usually you think of LEDs as being cool running devices. 10W LEDs are anything but cool when they are running. They produce enough heat they will self-destruct if a means of heat relief is not provided. The most common method is called a heat sink. These tend to be made of aluminum and have fins on them to increase the surface area available for cooling effects.

From a project I started sometime last century, I had a 3' piece of heat sink about 4 inches wide, from which I cut four 4" long pieces. Using my milling machine, which I have converted to CNC (computer control), I turned the square pieces of heat sink into round pieces. I then milled out the center section to provide a flat area to mount the LED. The LED is held to the heat sink with a couple of 4-40 screws. Thermal compound is used between the LED and the heat sink to assure the best thermal transfer possible. The LED driver was attached to an outside fin using thick double sided tape. This unit was then attached to the Perko housing via two screw holes already in the housing. A new lens was machined out of .25" Lexan to keep rain from the LED unit. (the incandescent lamp provided its own lens). The Lexan lens is held in place by the retaining ring that held the incandescent lamp in the housing).

The result has been nothing short of spectacular. The LED spreader lamps ran for two days while anchored out for hurricane Irene in the fall of 2011 without issues.

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