Luxeon trunk lights

In my never ending quest to put luxeons where ever I can, I targeted the trunk of my car next. The trunk of my Nissan Maxima is lit up by a single, sickly, ugly yellow incandescent bulb. According to the manual, the bulb is a 3.4W bulb, I measured it at 240mA at 12V (2.8W).

Here's what the trunk looks like under it's mighty output (I put the white plastic boxes in as subjects, since the trunk is lined in black cloth):


(camera set to ISO400, F 2.0, 1/2s exposure)

I prepped 3 1W luxeons by AA'ing them each to a 3" long piece of 1"x1/16" aluminum bar stock. The regulator is an LMS1587-ADJ linear regulator that works just like an LM317 - except the dropout voltage is 1.2V at maximum current (3A), but at 350mA (which is what I run this at), the dropout voltage is around 0.8V. In current mode, this makes this regulator have a headroom of about 2V total (much less than the 3-4V that a similar LM317 setup would need).




And *drumroll* here's the results, with all 3 luxeons running at 350mA (probably the first time I've run a luxeon at rated current /ubbthreads/images/graemlins/tongue.gif ) - the camera settings are identical to the first trunk shot above:



Notice a difference? /ubbthreads/images/graemlins/wink.gif

And just for fun, here's an in-trunk panorama of the installation. This is looking up at the trunk roof, forward towards the front of the car.
(click for a larger version)



You can see where I mounted the plates with the LEDs - I drilled small holes and used self tapping screws to secure them and the regulator board into place. The regulator board is the black/copper square with the wires coming out of it. The white boxes are the seat belts for the back seats; the rods, torsion bars that help lift the trunk lid.

The plastic dome thingy is where the original bulb was. I double-folded the wire ends, soldered them into a blob, and stuck them into the bulb socket contacts - no modification needed here. I could remove these lights, and the only thing that would be left would be 8 extra holes in the sheet metal. Finally, to protect things from shuffling cargo, all the wires are neatly zip tied up and out of harms way.

Now thats absolutely sweet. /ubbthreads/images/graemlins/smile.gif If i had a trunk worth lighting in my camaro i would surely do this. hmmm,, the posabilities. /ubbthreads/images/graemlins/smile.gif

Wow, great job!

Evan 9162,

I have a friend looking for just such a setup, he would like 5 lights, would you consider making the board and setting it up?

Bill

Nice!!! Wish I knew how to make little circuits like this. /ubbthreads/images/graemlins/frown.gif

There are lots of "easy to do it yourself" citcuits around, specially if you are not looking for the smallest package. /ubbthreads/images/graemlins/wink.gif

I havent built a circut since i was in the 8'th grade lol. Man i miss Industrial Tech class.

Woah... that's just beautiful! After looking at the first picture I expected bright, but was blinded when the final picture scrolled up!

Once I start getting into the Luxeons I'm going to upgrade my "Hatchback Light Version II" to "Hatchback Light Version III -Luxeon-".
http://www.nifty-stuff.com/gt-lights.php

Great job!!!

<by the way... I'm SO glad I don't have a reason to keep a snow / ice scraper in my trunk! My wife went to school in Idaho and I hear lots of scarry stories!>

Rob,

Your elantra lights are still a vast improvement over stock. As for the winters here, Boise is actually quite mild compared to the rest of Idaho - we might have a few days where snow stays on the ground, but otherwise, it only gets a little cold (a little being relative - I was born and grew up in Alaska). The worst part is the inversion - a low lying cloud layer that can hang over the city for weeks at a time - nothing but gray skies that can really get to you...

Just to clarify to everyone, here's more on the circuit. The LMS1587-ADJ works in a current source circuit just like an LM317 does. The only difference is less headroom (lower dropout voltage), and the 1587 can only drop 13V instead of 37V like the 317.

Here's the circuit diagram:



Originally, one of the screws holding the circuit board to the body panel was making contact through the ground plane on the PCB. This had the effect of causing the trunk light to remain on after the trunk was closed. The car also has a backup timer for the trunk light that cuts it off after 5 minutes - so the light goes off if the trunk remains open for a long time.

What I found was that the timer seems to cut off the power (+) to the light after the timeout -- but, the trunk latch actually switched the negative wire open and closed! So, by shorting the return through the car body, the trunk latch switch was being bypassed. So, I had to electrically isolate that screw from the PCB to make everything work proper - just something to keep in mind when doing something like this - keep the ground return path the same as it was with the bulb, because your car may have something similar going on.

Anyways - here's a close-up of the PCB - it's really simple to make - just 4 cuts to make 5 different planes. I broke off the center pin of the 1587 since the tab also is connected to output. The tab is soldered to the out contact area - I really wouldn't suggest doing this though, since it takes a LOT of heat to get it properly soldered by hand, and you would risk overheating the part.

Circuit board close-up

Added to LED Fixed Lighting Threads

awesome.

i put one of those high power led wedge bulb in the stock holder and mounted 2 led bar(tapped to the original socket) on the corner of my trunk. much better than stock but no where as cool as yours :thumbsup:

how about cree xre q2 reverse lights?