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Discussion Starter · #1 ·
Well, my 3rd brake light is out and I need a replacement. After reading "Outlaw's" DIY repair I've decided to give this a try with some slight alterations.

Instead of using a prepackaged LED strip, I have ordered (24) 5mm 630nm 30 Degree 8000 mcd red led bulbs online from superbrightleds.com $18.78 with shipping.

I'm planning to make my own strip. From what I've been able to learn I will need 1 resistor for every 3 bulbs and the bulbs will be spaced 1/2" apart from each other. My strip will be 12" long and about 3/4" wide.

The second thing that I want to try differently is seperating the existing housing without cutting. I was thinking of trying DR. Whistlers approach to his headlamps and cooking them in the oven. The Black material holding the cover on may seperate under heat. With any luck it is simply silicone.

I'll attach pics as I go along. I plan on doing the majority of this in 2 weeks (I'll be off work). In the meantime, I'm going to investigate some different materials for the board, including plexiglass and start crafting it. Another thought I had was to embed the bulbs in a plexiglass tube to help to refract the light across the entire length.

Any thoughts by the resident LED gods would be appreciated as I am a novice but never afraid to try something new.
 

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Discussion Starter · #2 ·
After further review, I've changed my mind. I think it would be better for each bulb to have resistor.

Each bulb is 2.2v 25ma. If I guage the incomming current at 13v I would need a minimum of 432ohm/k resistor for each.

The only concerns I have are the bulb voltage. Should I do my math based on the 'typical' voltage 2.2 or the MAX forward voltage 2.6?

And should I base my incomming current on a typical 12v car battery or should I go out and measure it under load? I'm not really concerned about excessive heat since it's the break light and won't be illuminated for extended periods.

One more question, could i reduce the entire circuit current by introducing a resistor prior to current entering the cuircuit. If this is possible I could reduce the size of the resistors that are directly connected to the bulbs.

Anyone?
 

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After further review, I've changed my mind. I think it would be better for each bulb to have resistor.

Each bulb is 2.2v 25ma. If I guage the incomming current at 13v I would need a minimum of 432ohm/k resistor for each.

The only concerns I have are the bulb voltage. Should I do my math based on the 'typical' voltage 2.2 or the MAX forward voltage 2.6?

And should I base my incomming current on a typical 12v car battery or should I go out and measure it under load? I'm not really concerned about excessive heat since it's the break light and won't be illuminated for extended periods.

One more question, could i reduce the entire circuit current by introducing a resistor prior to current entering the cuircuit. If this is possible I could reduce the size of the resistors that are directly connected to the bulbs.

Anyone?
http://ledcalculator.net/

This site will calculate which resistors you will need. I would go ahead and do source voltage of 13v and use the max voltage for the LEDs. This is a way to be safe so they won't get overloaded and force you to rip the thing apart again. This site works well, but then again using the formula would also yield the right information. Either way, you'll be good to go.

As for the resistors, if you use that site I listed, it should tell you where to put the resistors. You may have to fabricate a bit to get the resistors in the right spot.

And as for materials, I had made 2 3x3 LED boards for my old car in the reverse lights. I used 10mm LEDs with about 200000mcd luminous output. Quite bright I might say. Custom LEDing is always brighter than buying pre-fabbed bulbs. The bulbs are just more convenient.

I wish you luck sir. Hope it works out. :tiphat
 

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Discussion Starter · #5 ·
Thanks for the link. This was very helpfull in creating my design.

Yesterday I spent a couple of hours going to various stores around town looking for an acrylic rod to embed my LED's in. I went to Lowes, Home Depot, Advance Auto, Bed bath and beyond, Radio Shack and local fabric and craft store. So far I have not been able to locate any acrylic. What I did find was a 1 1/2" x 2" x 18" pvc pipe for .80 cents at Home Depot. Unless I find some acrylic, this is what I will be using.

My plan is to cut it in half on my table saw and drill holes for the Leds to sit in. I will probably paint it Pewter since this is the color of my TB. I will do the wiring on the back side where it will be hidden. I'll post a picture of the tube later - my wife took the camera and I can't find it.
 

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Discussion Starter · #6 ·
And as for materials, I had made 2 3x3 LED boards for my old car in the reverse lights. I used 10mm LEDs with about 200000mcd luminous output. Quite bright I might say.
This is great to know since my design will work out to be very close to what you have done; 24 5mm LEDs @ 8000mcd each should yield 192,000mcd.
 

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for the acrylic, look in the phone book under glass. most glass shops will do acrylic also. years ago i some acrylic rod for a car show display, so im sure they still stock stuff. good luck.
 

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for the acrylic, look in the phone book under glass. most glass shops will do acrylic also. years ago i some acrylic rod for a car show display, so im sure they still stock stuff. good luck.
Also check with the hobby shops and arts and crafts stores.
 

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You could always use lexan polycarbonate too. When I was into Hydroxy injection (also referred to as HHO) I made a polycarbonate container for my generator. The material is bulletproof and is very easy to cut and drill with a circular saw, jigsaw, and handheld drill. You could easily cut a long flat section and then put small holes for the LEDs to fit in. Then you could slide it in and get some epoxy in there.

Acrylic will definitely work but I know polycarbonate is a bit stronger (not that it necessarily matters here). Either way, both materials are easy to deal with and should be easily modifiable for your application.

Good luck.
 

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Discussion Starter · #10 ·
Thanks for everyones input so far. Lexan polycarbonate vs acrylic? Hmmm... another great idea. :hail:

After doing some reading about both products I decided to order a 3/4 acrylic rod. For my purposes I think both of these products would work out to be about the same. What closed the deal on the acrylic are 2 things. #1 It's not quite as hard as Lexan polycarbonate and may resist scratching more readily (I'm concerned that I might 'Gork' it up while working with it). :bonk: #2 It's slightly cheaper.

I'm going to use the 'clear cast' rather than the 'extruded'. I'm going to order it today so that I will have it by next week.
 

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Thanks for everyones input so far. Lexan polycarbonate vs acrylic? Hmmm... another great idea. :hail:

After doing some reading about both products I decided to order a 3/4 acrylic rod. For my purposes I think both of these products would work out to be about the same. What closed the deal on the acrylic are 2 things. #1 It's not quite as hard as Lexan polycarbonate and may resist scratching more readily (I'm concerned that I might 'Gork' it up while working with it). :bonk: #2 It's slightly cheaper.

I'm going to use the 'clear cast' rather than the 'extruded'. I'm going to order it today so that I will have it by next week.
You did some great extensive research because those are the two exact things people have said about lexan vs acrylic.

Acrylic resists scratches and is a bit more flexible. Lexan can be a bit rigid but then again that makes it stronger and more expensive, hence, your second point.

I think all will be well with your project and you will be happy. Be sure to post pics and let us know how it goes.
 

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Discussion Starter · #12 ·
Ok, I've my 3/4 acrylic rod and my led bulbs. Tonights project was to get the tail lamp assembly separated. Heres a pic
 

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I'm glad someone else is doing this at the moment. My 3rd brake light died and I took it apart as well but I used the pre-fabbed strips from advanced like in the sticky, but I wasn't real familiar with leds and used the wrong color so I am redoing it as soon as my stuff comes in. I ordered twenty 10mm red leds/holders and will be doing 4 sets of 5 with 100ohm resistors. So wish me luck as this is my first LED mod and if all goes good... well I fear my checking account will feel the mod bug's bite...:bonk:
 

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Discussion Starter · #14 ·
So wish me luck as this is my first LED mod and if all goes good... well I fear my checking account will feel the mod bug's bite
:iagree:

I hear ya, there is always that risk when you are trying something new but the upside is the experience gained and the feeling of having done something yourself that is unique.:thumbsup:

The only experience you get by going to the dealer is that stinging feeling when they first 'Bend you over'. And you usually don't even get a kiss afterward. :worried: Good Luck, keep us updated.

Today I'm going to be drilling my acrylic, inserting my LED's and soldering my resistors and wire. If all goes well I will be able to test the light out before final assembly. :woot: I will take pictures as I go.
 

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that looks AWESOME!!! I'm hoping mine turn out half that good. I'll keep this thread alive while I am doing mine so I'll just hijack it...:hijacked lol
 
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