DIY LED tail lights

[dichotomous]

buy a couple SV650S (2003 or newer) tail lights, two rows of LED's on each, VERY bright, all set up, would probably fit each side of the jeep too, then you'd have quad lights

[trebuchet03]

I read in an earlier post about putting lights in the oven.... If you're going to do that - do it with a heated oven with the oven off.... NEVER underestimate the additional radiant heat when that element kicks on....

I've personally taken apart sealed headlights (to reseal) with a heat gun. Just some quick passes to soften the glue/sealant

That said, the drop in variety is the easiest way to go.... Probably much cheaper too (an economist would probably tell you that you'd spend more time than buying what someone already figured out). Unless, of course, you want the individual diode look - something purely aesthetic.

[captainslug]

If you don't want to have to do anything complicated you could simply wire the LEDs in parallel with one resistor per LED.

Make an array board out of plastic with holes drilled in the spacing/pattern you want.
Then you can solder the negative leads all together, or make separate circuits and lighting patterns for running and braking. I did the latter because it was easier.



Or if you want dual intensity you could simply wire the running light circuit to deliver a slightly crippled supply to power to the array, then have the braking circuit supply full voltage.

You can buy LEDs (often with resistors) in bulk lots of 50, 10, or 1000 factory direct through eBay.
http://stores.ebay.com/Chi-Wing-LED-...QQftidZ2QQtZkm

6000mcd LEDs will be more than bright enough for brake lights.

[Memorytwo]

I dunno what the tail light pattern is, but I dont think i can do the every other row thing.
http://www.truckaddons.com/images02/...98tailligh.jpg
the taillight is thin compared to most cars, and id want it to be fully lit.

i need to examine one up close, but im pretty sure its a sealed unit.

also i remember seeing a method of doing the dual intensity with 2 sets of resistors. I dont know how they did it, but 2 feeds into a resistor each, then they converge into 1 row of leds. (with multiple rows of leds) my question is how big are the resistors?

oh also, i hear you cant judge how bright the LED is simply by its MCD? I'd probably prefer wide angle leds with as bright as possible?

and if its a multi coloured tail light, should i get red for the red part, and amber for the amber part, or should i just get all white?


edit:http://keld.eu/led/index.htm found the dual intensity method.
i dont know how to read schematics so can someone explain how they did it? thanks.

[Christ]

Every other row will be plenty bright enough to light up the whole lens. Especially since you can put like 12-15 rows at least of 3mm LEDs in the width of the lens.

If you don't like every other row, you can also do every other LED, staggered in each row...

So it's like
.0 (1) 0 (1) 0 (1) 0 (1) 0 (1)
(1) 0 (1) 0 (1) 0 (1) 0 (1) 0
.0 (1) 0 (1) 0 (1) 0 (1) 0 (1)
(1) 0 (1) 0 (1) 0 (1) 0 (1) 0

And the (1)'s are running/parking lights, while the 0's are brake lights.

And in the lower red section, you can make it so the (1)'s are running/parking, and 0's are turns.

Catch what I mean?

You can get rid of the hot-spots that LEDs normally have (bright point of light) by filing the tops so they're flat instead of domed.

[Memorytwo]

oh i forget, i dont know if jeeps have mechanical or electronic flasher relays, but would an electronic relay automatically fix the flash rate in cars?

[captainslug]

Originally Posted by achang1

oh i forget, i dont know if jeeps have mechanical or electronic flasher relays, but would an electronic relay automatically fix the flash rate in cars?

Yes, you can get LED-specific flashers. Which you will need if you replace both conventional brake lights with LEDs. I have a cheap one I didn't end up using if you're interested.

Or alternatively you can solder in a 3 ohm 20 watt resistor between the B+ and common negative on both of the LED brake lights and that will solve the issue.
LEDs offer so little electrical resistance compared to incandescent bulbs that the coil in the flasher relay trips much faster. So adding the resistor fixes that issue.

Originally Posted by achang1

1. oh also, i hear you cant judge how bright the LED is simply by its MCD? I'd probably prefer wide angle leds with as bright as possible?

2. and if its a multi coloured tail light, should i get red for the red part, and amber for the amber part, or should i just get all white?

3. edit:Keld's DIY page- LED found the dual intensity method.
i dont know how to read schematics so can someone explain how they did it? thanks.

1. You can, but the LED will only deliver it's rated output at the specified voltages. 3,000mcd LEDs are fairly bright, but 6,000mcd LEDs are EXTREMELY bright (6,000mcd = 6 lumens). LEDs are just very directional, and you'll need to use a bunch of them.

2. Depends on how heavily tinted the lens is. 6,000mcd White LEDs for all three should work fine. Most yellow/amber LEDs are too dim to really work anyways.

3. The L+ is the supplied 12v+ power for the running brake light. The B+ is the supplied 12v+ power for the activated brake light.
L+ powers the LEDs through a set of resistors that end up delivering about 80% of the rated power to the LEDs so that they're not at full intensity.
The B+ delivers the remaining amount of voltage (since the L+ is always on) to bring the LEDs to their full intensity.

LED symbol

The wiring for brake lights have a common negative. So the cathode of the sets of 4 LEDs are wired to that.
That schematic should work fine for any 2.2 volt 25mA LEDs. You can increase or decrease the array size by adding or removing sets of 4 LEDs from it.

This circuit is a bit simpler: http://www.sca40.com/led/

[Christ]

when you're all done, count your flashes per minute.. I'm pretty sure NHTSA says 60-120 flashes per minute.

I know that's the rule for PA, and it applies equally to the turn signals and the hazard lights.

[Memorytwo]

what does 820 ohm *9 and
330 ohm *9 mean?

i see that the 820 is the "Bigger" resistor, but i think it means thats the running lights
and the 330 is the smaller one to provide full flow?

oh and *9 is apparently 9 total for his project.

[captainslug]

Originally Posted by achang1

1. what does 820 ohm *9 and 330 ohm *9 mean?

i see that the 820 is the "Bigger" resistor, but i think it means thats the running lights
and the 330 is the smaller one to provide full flow?

oh and *9 is apparently 9 total for his project.

Those are resistor values for 1/4 watt resistors in 820 ohm, 330 ohm, and 270 ohm ratings.
More resistance = less power delivered

I'm not sure what the spec on the LEDs he used are. But should you want to double check his resistor choices you can use an LED calculator.
http://www.hebeiltd.com.cn/?p=zz.led...tor.calculator