A frequently asked question is how to calculate the right resistors to use when building a custom LED light set. Although the math is fairly easy we’ve made things even easier with our RC LED resistor calculator. All you have to do is fill in the battery voltage you will be powering your LED lights from, the LED’s forward voltage and the LED’s current rating. The specs of the resistor you should use with your LED will appear below. The resulting calculations are for each resistor wired (in series) to each LED bulb you want to use.
If you cannot find a resistor with the exact resistance in ohms as recommended by the calculator, just use the next size up. Also, when it comes to the power rating of your resistor, it is always better to err on the side of caution. If the calculator recommends a .230 watt resistor you are within spec to use a 1/4 watt (.250) resistor but with the numbers being so close the resistor is likely to get very hot. In that situation going with a 1/2 watt resistor would be the much better choice. You can also use higher number resistors to lower the light output of your LEDS, which also results in longer battery life.
If you have any questions feel free to post them below and we’ll do our best to help out.