I got interested in LED lighting about ten years ago. I started making LED flashlights using red LEDs for night use. The red light would not spoil my night vision. As brighter LEDs became available in white and green, I decided to see if I could use them for Navigation lights and cabin lighting.
LEDs need a current source to operate them, typically 20ma. If they are simply connected to a voltage source, they will burn out. In my flashlights, I used a resistor to limit the current. But, for 12V boat lighting, I needed something better. I found a current regulator circuit used by Bob Pease author of a column in Electronic Design magazine. I connect 3 white or green LEDs in a series string to a source of 20ma. I use 4 to 6 red LEDs in series. The number is chosen based on the voltage required for the LED. I make the current regulators in multiples of 20ma – 20, 40, 60 and 80. The regulators can operate 1, 2, 3 or 4 LED strings in parallel. Each string needs a current equalizing resistor. The regulators are made from an LM334 regulator, a current setting resistor, and a 2N4401 transistor.
The LED reading light bulbs have 8 white LEDs arranged in a circle. A yellow LED is in the center of the circle. The yellow LED softens the color of the reading light. I potted the assembly with the current regulator in the base of an original incandescent bulb. The light draws 60ma - ¾ watt.
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An array of 6 red LEDs is mounted in the dome light fixture over the chart table. A two way switch turns on the white light or the red LEDs. This light draws 40ma – ½ watt.
The TriColor Anchor light contains four arrays of LEDs. Three arrays comprise the TriColor light. The starboard bow array has 4 columns of 3 green LEDS; the port bow sector 4 columns of 4 red LEDS, and the stern sector 6 columns of 3 white LEDs. The TriColor light draws 280ma – 4 watts.
The anchor array contains 12 white LEDS arranged in a circle. The anchor light draws 80ma – 1 watt.
The fixture is a Hella #40 all around light.
Bow sector port side
Stern sector
Anchor light
The bow light is made up to replace the bulb in a Aqua Signal Series 25 masthead (steaming light). The insert consists of the same arrays of red and green LEDs as I used in the Tricolor. It draws 160ma - 2-1/4 watts.
