My project came about to increase visibility/safety on my motorcycle. Unable to find what I wanted I have built my own custom inserts for turn signals and brake lights. I am using 48-52 5mm leds with Vf=2 and If=20ma. I am wired into my bike's wiring and using either a 10v or 12v voltage regulator(my leds are wired in arrays) in each light assembly to smooth/restrict output of my charging system. As brake and t/s(5 lights in all) they run at 100% and work great. Now my problems: 1)Since leds are not linear how can I figure my resistors so these lights will run at 50%-60% brightness(running lights)? 2)Since leds are not dual filament when signal comes down brake and/or ts wires I think I need to disconnect the running light circuit(to prevent overdriving leds) and switch to 100% brightness(brake and ts lights). I need something simple and efficient I can can install in each housing to switch between these 2 circuits. Any suggestions?