Well, this won't be much of a DYI, and to be honest, I wouldn't really suggest anyone else try this, but here it is anyways:

Start with Parts:


In this case I'm using true phillips superflux lumileds as my LED's. They're nice because the package allows you to get nice, easy, consistent mounting and heat isn't an issue with these guys (unlike with the higher power LED's, 300 mah and up). These LED's are commonly used in automotive applications. I will be running the following configuration:
Turn signals: 40 LED's per side
Brake Lights: 32 LED's per side
Running Lights: 16 LED's per side running at very low current

I have only gotten the turn signals in so far. I didn't have the right resistors on hand so everything got put back together with only the turn signals in.

Build Arrays:

Here is the brake and running light array


The back side, note that all the solder helps act as a heat sink for the LEDs


With the plastic piece I built for out front of the LED's. This piece was going to be used to house a diffuser for the LED's, but the material I had on hand (a cut-up traffic triangle) was restricting output too much. Turns out this piece still did a great job of acting as a mounting plate for the LED circuit board.

I would have used more LED's for the brake lights but since the light assembly is sealed and I had to cut a hole into it, I was quite restricted by what I could get into the housing.


My calculations for LED power and resistances. This is for the turn signals only. Note that each LED is operating at 60 mah. There is a series resistor on the LED array to control power through the LEDs. There is also a parallel resistor (i actually used 2 to distribute the 13W of power to waste across 2 10W resistors) across the whole unit to ensure that the total wattage is close to the 21W bulb that came out of there originally.


Cut a giant hole in your taillight assembly. This is where things got a little hairy. I used a drill press and a skill saw to make the hole (dremel tool doesn't work and the mini hack saw method was painfully slow). Note that you will get a lot of debris into the taillight housing. Also note that it is impossible to get all of it out. I spent a few hours with an air compressor and vacuum and there's still some dust and debris in there. Once you have a hole, just glue everything into place (i used the amazing goop glue, it's great stuff).


Another pic.


To ensure that the light gets properly re-sealed, I used the existing sealing connector and soldered the leads on to the contacts that the bulb used to hook up to. Then I used a large piece of plastic and gooped it to the assembly to seal the giant hole I had just made.


End result, looks pretty good!


Just the LEDs on (it looks better in person than the pictures lead you to believe).


LED + brakelight.


From behind, photobucket really drops the quality on these pics . . .

So, as mentioned earlier, I still have the brakelights to do, but the turn signals look pretty good. The issues I have with this project are as follows:
- Dust in taillight assemblies . . . nothing I can do about that now, just roll with it.
- I'm not quite sure the intensity is there in the daytime. I have used 40 LED's, vs most OEM applications which used much less (6-10). The big reason for this is that when you have a properly designed reflector, the LED's become much more visible. It's fine for the turn signals, but I'm a little nervous about the brake lights. I will probably do a side by side comparo before I glue everything in place. Also, the lens on the taillight assembly is clearer where the brakelight is over the turn signal (turn signal lens is somewhat fresnel so it causes weird things to happen, from some angles it is super bright and from other not so much) so this should only help the situation. Also, because of the angle that the taillights are at, the LED's aren't at peak intensity because you are viewing them from say a 30º angle, arranging them facing directly rearwards would help significantly.
- Project took quite a while. This is the 4th time I've put these LED's in a car and this was by far the worst one to do. Every other time I've had access to the inside of the taillight housing and then it was simple.
- My wife isn't too happy with me for hiding in the basement all christmas holidays while our 7 month old was teething

Let me know what you think, and if you have any questions I will be happy to answer them.

Jorgen

 

Very nice! I love playing with LEDs. When I did my bumper reflector LEDs it was hard to find some that were bright enough too. Good luck the brake lights!

 

Looks cool; thanks for sharing this! I've been thinking the ILX tail end would be even sexier with some proper LEDs. Nice work.

 

Thanks for giving this a go! You are way beyond what I could do! Acura should have done these from the factory! Anyone tried using the LED bulbs in the stock sockets? I hear some of the better bulbs have the resistors built in. I had LEDs on my 2007 Accord, then they DE contented the 2008-2012 Accords. Hope Acura "sees" the LED light soon!

 

I can't say I've every seen the bulb replacement LED's that have been anywhere near bright enough. Part of the issue is that once you get off axis on LED's, the intensity drops off very quickly. Here's the plot of intensity drop-off for the LED's I used:


Since the rear lens on the taillights is at a roughly 30º angle to the back of the car, vehicles behind me will automatically get a maximum of 55% of the maximum intensity of the LED's. With the turn signal case, you normally care more about warning someone in the lane beside you so it works out well as the maximum intensity is directed somewhat off to the side. With brakelights it's a different story.