Now that we know that a ballast resistor is not suitable for our environment, what do we do next? Let's start with what we have learned so far. We know that a resistor is a passive device that can't maintain an even current with a changing voltage. So, what are our other options?

What if we had a type of resistor which could accommodate the changing voltage? There is such a device, and it is used by many LED cluster manufacturers. The device is called a Linear Regulator, and it is a small step up in control technology from the primitive ballast resistor. A Linear Regulator is a low-cost control method which can be thought of as a variable resistor that varies the resistance according to the load in order to provide a constant output voltage to the LEDs. Because it is still a resistive device, it controls excess energy (above that required by the LEDs) by turning it into heat. But wait a minute, isn't HEAT the great enemy of LEDs? That's right! Of course, with proper design one could dissipate some of the heat, but overall, Linear Regulator can only work for small voltage variations, which is fine for some applications, but again, not suitable for the full of battery banks, solar panels and generators and inverters of our electrically hostile marine world.

Hopefully the above makes it very clear why ballast resistor bulbs and cheap bulbs have no place on a boat. From what you have read in the previous paragraphs, you are now considerably better informed than the average person looking for LED lighting. Not only that, you are most probably better informed than most of the uninformed merchants out there selling LED bulbs to the unsuspecting boater.