Star LED holder for Kawasaki Vulcan 750 Turn Signals by Morpheous85

Last crawled date: 3 years, 3 months ago

This is designed to hold a standard Star LED inside the stock turn signal housing. I use Cree XL-M RGBW LEDs. They have a maximum internal temperature of 150C. The recommended maximum currents below assume use of the Cree XL-M RGBW LED. The mounting surface is designed to minimize contact with the PCB to maximize heat transfer. The housing itself has a measured temperature rise of 7.5 C/W.
Here are a few videos comparing the LED with clear lens to the factory bulb and amber lens.https://youtu.be/gn7po60E8KM (LED vs Incandescent Amber)https://youtu.be/doI2Jd8qtY4 (LED Red vs Incandescent Amber)https://youtu.be/ceSAGbNMjWg (LED Red vs Amber)https://youtu.be/5WB9jIua1uw (Front vs Rear Test)
The mounting tabs use the lens holder screws to mount. The lens needs to be modified to allow for the thickness of the mounting tabs. This is a simple cutting of the screw mounting posts by the thickness of the mounting tabs. A Dremel cutting wheel should suffice.
It is recommended to use either Red lenses with the Red or White LED, Amber lenses with the White LED, or clear lenses with Red, Red + Green or White LEDs. If using Red or Amber lenses, it is recommended that the Warm White (3000 K) LEDs are used. Neutral may suffice, but Cool White have less then half the output in the red spectrum vs Warm White.
The LEDs are designed to be secured using two bolt/nut with plastic spacers/stand-offs added to prevent shorting the pads on the LEDs. One LED faces towards the lens, and the second LED faces away from the lens. The rearward one sits in the same location as the factory bulb filament, so it utilizes the factory reflector.
You should be able to run 700mA into the Red LEDs continuously (brake lights) in 41C heat for an internal temperature of 114C. Turn signals could be 700mA Red + 310 mA Green (9:4 ratio gives amber color approximation) with an internal temperature of 133C. This temperature assumes continuous use, where as turn signals are flashing. The actual internal temperature will be lower when flashing (approximately 124C). For rear running lights, the Red should be reduced to 70mA (1/10 of brake lights).
I wired the two LEDS in series for each color. I used 150/15 ohm for red (running/brake) and 300/30 ohm for green (running/turn). The 300 is omitted for the rear running. It is only used for the front. I used diodes to separate the signals coming in. I will add a schematic when I have it finalized.
When using in the front, you can run 450 mA into the White LEDs continuously (additional forward illumination) in 41C heat for an internal temperature of 113C. If you are using the White LEDs with a Red or Amber lens, the White LED can be run at 700 mA continuous in 41C heat for an internal temperature of 146C. While this is only 4C away from maximum, the duty cycle will result in a temperature estimate of 130C. DO NOT RUN WHITE LED CONTINUOUS AT THIS CURRENT LEVEL!!! Running lights are supposed to be 1/10th of brake/turn signal brightness by DOT standards.
To run white as running lights in the front, the circuit is a bit more complex, with a transistor and a time delay element, that shuts off the white whenever the turn signal is on, and leaves it off for 1-2 seconds. The circuit is a FQPF11P06 P-Channel MOSFET with the source at 12V and the drain connected to a pair of 22 ohm resistors. 22 ohms gives 450 mA at 15V. The gate is tied to ground with a 56K resistor and a 100 uF capacitor. This turns the transistor (and white LEDs) on by default. Both turn signals connect (through diodes) to the gate. Whenever either turn signal is used, the gate is driven to 12V and the transistor turns off all the white LEDs. After 1-2 seconds of turning off the turn signal, the 56K resistor fades the white LEDs back to full power. This can be seen in one of the videos.
This piece should be printed with white material to minimize light absorption. However, the videos are done with black printed material so light absorption isn't a huge issue in practice. The picture of the two assemblies lit red shows one with a white printed piece and one with a black printed piece, both running at the same current level. If you can't see any difference, then don't worry about the color of the plastic! In my opinion, the white printed piece resulted in a more uniform light output.