I wanted to switch the bulbs in the trunk and baggage side lights, as well as all the rear brake running and turn signals to LED. I initially did this by using off-the-shelf LED bulb replacements. This is a simple way to do it - pull out the 1156 and 1157 type bulbs, and replace them with 1156 and 1157 type bulbs. However, this didn't really give me the look I wanted. The bulbs still lit up "hot spots" on the lenses, leaving large areas un-illuminated. What I wanted was for the entire lens to light up, evenly, without being able to tell that there were individual bulbs behind it. On the back, I wanted ALL of the red lights to light up as running lights, and ALL of them to light up as brake lights when I hit the brakes.
To do this requires some custom work with LED strips. I bought several reels of LED strips, in both red and amber. I wanted the brightest possible lights for my bike. I won't tell you where I found them, because as is true with a large number of Chinese LED online retailers, they appear and then disappear quickly. I used SMD 5050 LED strips. SMD 5630 LED strips are brighter - however, it's not just the brightness of the chip, it's the density. I was able to find LED strips that had far more chips per inch in 5050 than the 5630 - and the end result was that with more LED chips crammed in there, the end result was brighter looking with the 5050 strips.
The first thing that has to be done is the removal of the light lenses. I won't sugar-coat it, this is a real nightmare of a job. The lenses are stuck together with the nastiest, stickiest, gooiest adhesive Honda could devise. I found the best way to do it was to use a heat gun set on low to warm the adhesive (it's hard at room temperature) until it became gooey. Then carefully use a screwdriver to pry the lens apart from the housing:
This is a tough, tedious job. The lenses are made of a hard plastic that does not bend at all - it cracks. Apply too much pressure, and the lens will crack. These are EXPENSIVE to replace, so you really need to go slowly, and do a bit at a time. It took me about 15 minutes to remove the lens from each light, and about 45 minutes to an hour to fully clean the remaining adhesive from both the lens and the housing. There are 8 lenses to do on this bike - so yes, the disassembly of these lights takes a LONG time to do. Once the lenses were apart, I discarded the internal fresnel lenses, and covered over the light bulb sockets with scrap ABS panels, cementing them into place with ABS cement. We won't be using those anymore, so to keep the lenses weatherproof we need to close them up.
The LED strips I used were weatherproof, and covered in silicone. To gain access to the contacts, this silicone needs to be cut away, to expose the copper contacts.
I then soldered wires to the contacts:
And covered the solder joints with shrink tubing to insulate and strengthen the joints:
I soldered several strips in parallel, making several assemblies like this:
Each assembly was tested to make sure it light up properly. This one is lighting up amber, for a turn signal:
The tape was pulled off the back of each of the strips to expose the adhesive, and the strips were installed into the light fixtures. I fed the wires out through the bottom of the fixtures.
This is the view of the bottom corner fixture, with red brake LEDs in the section on the left, and amber turn signal LEDs in the section on the right.
With the lens installed, the whole lens lights up when the LEDs are activated, which is just the effect I wanted:
Here is the brake light portion of that lens being illuminated from inside:
The upper (trunk) section has one large brake section, and turn signal sections on the ends:
The next problem: I have only one set of LEDs to act as both my running lights and my brake lights. I need a way to make them appear more dim for running lights, and full brightness for brake lights. First, I thought I would light up only two of the five strips for running lights, and all five strips for brake lights. However, this looked terrible - you could see the individual strips in running light mode. So I needed to come up with a way of dimming them.
LEDs don't work the same as incandescent bulbs. You can't dim them reliably (to a preset level of output) using resistors. The level of output will vary from individual LED to LED - and what's worse, this will change over time. The only way you can guarantee a given level of light output is to use what's called pulse width modulation. This is the method used by automotive manufacturers when they put LED taillights on newer model cars. Basically, the LED is flashed at full power, really fast - faster than our eyes can discern. They are flashed in a pattern of ON for a certain percentage of time, and OFF for a certain percentage of time. The longer the LEDs are turned on, the brighter they appear to be to our eyes. I designed and built a pulse width modulation circuit capable of flashing the hundreds of LEDs I now had mounted on my motorcycle. I connected my circuit to my oscilliscope, so that I could see the output of the circuit. My circuit flashes the LEDs on and off roughly 200 times per second. You can see on the screen of the oscilloscope that the LEDs are on for about 20% of the time. This was just about right for my bike.
Below is the circuit I designed and built - feel free to use it for noncommercial purposes. (click image for full size image)
I did find that this change caused one unexpected problem that I had to fix - I detailed this in LED brake lights cause Cruise Control to stop working
And the end result? Have a look for yourself:
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The scope trace is from when I was doing the prototype development, confirming that the PWM frequency was in the range that I wanted.