Hard to believe we hash this topic again. LED's must have a constant CURRENT supply. Constant voltage only works if ALL LEDs ont the circuit are ballanced. This makes it difficult to ever replace one or add on. Please go to this sites and read the Idiot's Guide
Marinebeam Replacement LED bulbs for your existing boat fixtures
or this site and read about regulators. Bebi Electronics-Installing Marine LED Reading, Navigation and Running Lights!
You need a current regulator to make the LED operate at the correct forward current no matter what the charging
system on your boat is doing.
You will learn that the cheap
3-dollar bulbs do a marginal job of this using a buck resistor. The problem is that the resistor circuit eats up your precious power in the form of heat. The lowest power consumption
bulbs have PWM (pulse width modulation) for current control. This is a high speed circuit that turns the current on and off at very high frequency so that the average current is the correct current no matter what voltage is applied. This means that it works when your batteries are deeply discharged or when the alternator
is pumping the heck out of them. I have some of both of the above and a lot of IMTRA Marine Lighting - Boat Lights - Yacht Lights - Imtra
replacement bulbs. (show special). Total cabin
lights is about 60. All on at once draws 0.4 amps at 28 volts. I also replaced all nav lights including my AquaSignal Tri-color from Marine Beam and installed their SOLO deck
lights on the spreaders.
I got a 3 for 2 price on these LED Navigation Lights
and added them at deck
level as redundant nav lights.
TYPICAL PWM REGULATOR
ON THE BACK SIDE OF EVERY BULB.