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Last Updated: August 13, 2013

Led Brake Light

Constant current LED brake light tail light module. Ever wonder how to make your filament bulb type tail / brake light to all leds, the solution is to use a constant current led driver with additional mosfet as switch for brake light so that the usual tail light will switch from dimmed to full brightness on the leds. More often, enthusiast uses just again the limiting resistor type of controlling the brightness of the light emitting diode installed on the bike, as i had said from all of my previous post about led, in order for them to stay consistent and works longer, a constant current driver will protect your led installed.

Circuit description:

first, in order for the tail light to work. conventional stator driven path for the filament bulb needs to be rewired to battery driven, in short words, cut the path of the original then from the tail / brake light wires, just tap the tail light wire directly to your ignition switch ON wire..(this is the wire that will supply all your accessories and will only be LIVE when ignition is at the ON position.

From the circuit above, D1 and d2 are
Schottky diode that will block the two supply path so that they are independent with each other, that is the trick to isolate the tail from the brake light. VD3 is a zener that will clip the entire module to 15 volts, to protect the circuit from sudden voltage spike when charging of the bike is on use or when you are revving the engine. C1, is dc filter. Q3 is your constant current driver for leds that is controlled by R1, R2 and R3.

Q? is your mosfet switch with R4 VD4, and R5 that will illuminate your leds fully when STOP or brake light switch is pressed. VT3 will pull R3 to ground when on, turning npn transistor Q? and allowing Q3 to flow more current onto your led array..

R2 can be experimented with values...this will be your initial idle curent for your tail light.