Custom Brakelights

Discussion in 'Electrical' started by jettblack, Jun 14, 2010.

  1. jettblack

    jettblack Member

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    I took 2 beacon 2 marker lights and put them on top of my sidemount licence plate as brakelights. it looks way cool but my problem is they are way to bright. does anyone have an idea what size resister I should use to dim them down a little?
     
  2. Hoople

    Hoople Account Removed

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    I may be able to help you but I would need more information. Are all the bulbs dual element. How did you wire it up,, did you just tie 5 bulbs in parallel? Do you now have 5 running elements and 5 stop elements? What are the bulb numbers. Are all the lamps tungsten or tungsten/LED combo?

    Free hand a schematic of what you did and upload it. A picture of what the rear looks like would also help me understand the best way to do it.
     
  3. jettblack

    jettblack Member

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    they are halogen single element 35-watt bulbs. i used the existing 3 wire led tailight wiring one light is the running light and the other light is the break light. so one hot wire to each light and they share the ground. the original tail light is not used.




    I have a pic of the lights on my public profile if you click on my name
     
    Last edited by a moderator: Jun 15, 2010
  4. Hoople

    Hoople Account Removed

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    I now see what you mean. Wow, I really like that look. Great idea.

    So all you want to do is calm down the brightness on just those Two single element 35 watt bulbs that will only come on for braking, correct?

    If so, that won't be hard to do. Do you have a soldering iron?.
     
  5. jettblack

    jettblack Member

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    yeall i really need to do is calm the inside one down it is the running light. the other only comes on with the break so it can be bright. and yes i do have a soldering iron
     
  6. Hoople

    Hoople Account Removed

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    As long as you now have 1 positive battery wire feeding Both red Halogen lamps and the other side of the lamps are going to ground, this will work. You can also turn down individual bulbs using this technique.

    Go to a local Radio Shack and pick up (2) packages of catalog # 276-1661. Each package costs, $2.49 and contains 4 diodes. You will now have 8 diodes. Look at each diode. One side of each diode has a silver band.

    What you are going to do is cut the Hot battery feed wire that is going to the Halogen Bulbs or bulb.
    Now solder the Hot battery feed wire to the NON-Banded side of 1 diode (diode #1). Now solder the BANDED side of Diode #1 to the NON-banded of another diode (diode#2) . Now solder the Banded side of Diode #2 to the NON banded side of another diode (diode#3). Now connect the Banded side of diode#3 to the 2 tail light wire that you cut earlier. Step on the brake. Still too bright? Keep adding diodes until you like what you see. Each diode you add will reduce the voltage by about 1/2 volt. So if you string 4 diodes together, you will reduce the voltage by about 2 volts.

    2 packs of diodes will allow you complete control of the brightness you are looking for. You can shorten the diode leads so a string of 4 or 5 is very short and easy to tuck away. There will be very little heat dissipated compared to using a resistor and the total string of diodes will be much smaller than the wattage resistor you would have had to use.

    That's going to look so Cool. Let me know how it turns out!
     
  7. jettblack

    jettblack Member

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    Cool! That sounds like an easy fix, I'll do it and let you know. Thanks alot for your help.

    Yeah it looks good going down the highway it lights up the back spokes bright as heck.
     
  8. glider

    glider Veteran Member

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    Hoop

    You lost me with the diodes. They are a directional current limiting part and not a resistor. How do they lower the voltage using multiple diodes ?

    At first read I thought you were building a bridge rectifier but this is DC voltage.

    Could you explain this a bit more?
     
  9. Hoople

    Hoople Account Removed

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    Glider, I know it sounds confusing but it is really a neat trick to lower the supply voltage going to a device. The banded side of the diode is the cathode. As long as the anode is more positive than the cathode, the diode will be forward bias and will conduct. Because the diode has 1 silicone NP junction, a voltage drop of appox .6 volts will exist from that junction. Now if you like, you can just daisy chain junction after junction after junction and collect each .6 volt drop together as 1 big voltage drop.

    Those Radio Shack diodes are 6 amps so you really can put a nice load on them with no worry at all. This trick works only in DC circuits. It's a quick, cheap & effective way to cut down a little or a lot of voltage going to a device.

    I ran across the tip years ago while reading a book on "Electronic shortcuts and tips". It has helped me out of a jam a bunch of times.
     
  10. Hoople

    Hoople Account Removed

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    Here you go Hobbit,,
    It is important to look at a SEMIconductor as just that. It is not an insulator (like a piece of rubber would be) and it is not a Conductor (like a copper wire would be). It is a "Semi" conductor which kinda puts it right in between. Since it's somewhat of a conductor and somewhat of an insulator, it will have some resistance or voltage drop across it. Well, it just so happens that a silicone junction has a "resistance" that yields a voltage drop of .6 volts.