Automotive LED Cluster Circuit

Discussion in 'The Projects Forum' started by Matt Patten, Sep 16, 2015.

  1. Matt Patten

    Thread Starter New Member

    Sep 16, 2015
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    Hello,

    I am looking into build my own LED Cluster, to replace the standard bulbs in my car.

    I have come up with a design for my PCB, but I wanted to run things past some of you guys here so as not to risk setting fire to my car as such.

    The cluster involves 8 0.5w LEDs connected in paralell as two rows of 4 LEDs. I am unsure of how many resistors I should use, whether I can use one per the whole PCB or, whether should be 2 resistors, one for each row of 4 LEDs, or even a Resistor for each individual LED.

    I am also unsure of the resistor rating I should use for my circuit, the car obviously runs on a 12v circuit, the bulb it would be replacing is a standard 21w 581 bulb.

    I am then wondering how I should do the stop/tail light bulb, could I run one circuit through the resistor as the circuit above, and then the other circuit will goes through an extra resistor? ie: Tail light circuit 2x resistor, Stop light circuit 1x resistor.


    Thank for reading, very much appreciate your thoughts!
     
  2. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    If you can draw a schematic that would help you and everyone else understand what you are trying to do.
     
  3. Matt Patten

    Thread Starter New Member

    Sep 16, 2015
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    Sorry about the rough drawing,, hopefully you can see what I am trying to portray,,

    The yellow circles are LEDs, Red wire is 12v,, Black wire to earth: Drawing.png
     
  4. gerty

    AAC Fanatic!

    Aug 30, 2007
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    You can't build one as cheap as you can buy one. I tried to cross your number, but it's not listed here
    https://www.superbrightleds.com/cat/tail-brake-turn/ you know what type you're after.
    As to your drawing, you need to put some of the leds in series with each string having its own current limiting resistor. How many in each string is determined by the led itself, we need to know the type, color, voltage and current.
     
  5. Matt Patten

    Thread Starter New Member

    Sep 16, 2015
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  6. Matt Patten

    Thread Starter New Member

    Sep 16, 2015
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    Bump
     
  7. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Connect the LEDs in pairs in series, each pair with its own 72Ω 1W resistor.
     
  8. Matt Patten

    Thread Starter New Member

    Sep 16, 2015
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    Would you be able to draw this circuit with the resistors just so I can get it clearly in my head?
     
  9. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Repeat this for all pairs of LEDs:
    [​IMG]
     
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