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# Navigation lights for boats? 112.5 degree - Port/Starboard (red/green) side lights &amp; 360 degree white stern lights Answered

Small boats under power are required to have a 112.5 degree lighting on the sides and an all-round white light on the stern. The light on the left or port side is red, while the right or starboard sidelight is green. At night, these lights must be visible for 1 mile, while the stern (rear) white light must be visible for 2 miles (minimum). These lights indicate direction... course. Led navigation lights are very expensive. LEDs are very cheap... So, why not build 'um yourself? My small craft uses a 12 volt battery operated trolling motor for power, and therefore, the idea low power consumption LEDS is very appealing. I've never built and LED lights, but I'd love to see some ides for small electric (or gas powered) powered water craft. Thanks

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Let me see, I'm just a land lubber but, if I get problem right we need a sixteen row 'Corn Cob' LED display. Five rows of LED 'Kernels' should be red, five rows should be green and the remaining six rows should be white.

Twelve volt electrical sysyems are only 12v when the battery is about dead, and charge at about 13.5v.
All LEDs are assumed to have a maximum current draw of 20mA or 1/50 A.
For 16 rows of LEDs that is a MINIMUM of 320mA, more if you use longer rows of LEDs.
Red LEDs drop the voltage 1.8 - 2.2v for every LED in a series string.
Green LEDs drop the voltage 3.2 - 3.8v for every LED in a series string.
White LEDs drop the voltage 3.2 - 3.8v for every LED in a series string.
Thus for a string of three green or white LEDs we would see a voltage drop of around 9.6 - 11.4 volts.
For a string of five red LEDs we would see a drop of 9.0 - 11.0 volts.
If we make the 'Cob' 15 'Kernels' long each of the five red LED rows will draw 60mA and the eleven green and white rows will draw 100mA for a total of 1400mA or 1.4 Amps. (That's 240 LEDs, 75 red, 75 green and 90 white.)

Each string of five red LEDs should have a 170 ohm resistor in series with it.
Each string of three white or green LEDs should have a 150 ohm resistor in series with it.

I'm just doing the math in my head as I go along so have someone check it for you.

I think you might be able to house this light in a plastic parmasan cheese jar.

When you get this thing built you might want to have the Coast Guard take a look at it to see if it meets the regulations.