What Resistor do I need for an LED light bar in a 12V Auto System?
I am wanting to build an LED light bar from dollar store flashlights to use as driving lights on my truck. There is currently a 12V wiring harness with 15A relay that I plan to tap into. As for the lights I want to use, I have no idea how many mili amps they use for voltage. There are 7 LEDs inside of each flashlight head. I know that each flash unit head draws 2.37V when I test for voltage drop. My thinking is to run 3 head units in series to reach a total of 7.11V of resistance. My question is, how big of a resistor do I need to put on the power supply in order to not fry the lights? There will be a total of 6 lights altogether, but I just planned on running them in series of 3 units. Would it be better to run all 6 in series? If this doesn't make any sense, let me know and I will try and explain it better. Thanks.