How to wire LED strip as tail-light on motorcycle

Discussion in 'General Electronics Chat' started by stover954rr, Mar 26, 2009.

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  1. stover954rr

    Thread Starter New Member

    Mar 26, 2009
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    Hello Everyone,
    I was hoping that you guys could help me with your expertise. I have taken the stock tail light off my bike (12v) and it has:

    1 ground, 1 running, 1 brake wires (3 wires total)

    My LED strip has only (2) wires total

    It is just a strip of leds (9 in total)

    Basically how would I make this work?

    Also, I am using 2 seperate led strips, but I am going to tie them in together as I would like them to both run, and both brake (Not one strip run and the other one come on for a brake).

    Also, will hooking these up to the existing wires be okay for the bulbs or do I need some sort of resistor so that they don't blow.

    I really appreciate any help.

    Thank you,
    Russ
     
    Last edited: Mar 26, 2009
  2. CoolbeaN

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    Mar 26, 2009
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    LEDs do not have a low and high setting. You cannot vary the intensity (without burning them out anyway) and therefore cannot use the same set of leds for both running lights and brake lights.
     
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    We have been turning LEDa every way but loose, now we find out our flashing dimming etc is'nt possible.
     
  4. CoolbeaN

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    Mar 26, 2009
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    Edit: nevermind.. I am completely wrong. Listen to the experts.
     
    Last edited: Mar 27, 2009
  5. Bernard

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    Aug 7, 2008
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    Are the strips designed to opperate on 12V DC or are they a series/ parallel combination of only LEDs- no resistor. Operating current??
     
  6. italo

    New Member

    Nov 20, 2005
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    You will need a lot of LED there is some solution for the brake lights just pump more current on that wire how much well it depends on the LED that you buy. Or you can buy them $10 each i sugestn you buy by the time you figure it how they work and assembly making it yourself is just not cost effective
     
  7. thatoneguy

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    Feb 19, 2009
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    If the strip is to augment your brakelight, I suggest hooking it directly to the brake power wire and a 555 timer so it flashes about 3-4 times per second. People tend to notice that MUCH better than a non-flashing brakelight. Most areas will not allow you to have a flashing red light on continually though, only as a warning for stopping.

    To "DIM" the light, it gets more complicated. Again, using a 555 timer, set it up for PWM modulation. Bill Mardsen has a great post on how to build both a flasher and PWM with a 555. Depending on the current needed by your stip, an additional transistor or more may be needed.

    Combining the two (dim taillight + Flashing brake light) gets tricky, but is possible.
     
  8. stover954rr

    Thread Starter New Member

    Mar 26, 2009
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    Hey guys,
    Thanks for taking the time to post up. This is what I have:
    http://cgi.ebay.com/RED-9-LED-FLEXI...sidZp1713.m153.l1262?_trksid=p1713.m153.l1262

    Will those burn out if hooked up as a brake light? is that too much current?

    What I have figured out thus far, is that I took 2 of them (each with 2 wire red & black). And I tied the blacks together and grounded them.... I then hooked one red from one light to the brake wire. I then hooked the other red from the other light to the tail-light constant. The results:

    1 strand stayed lit for as the tail light
    the other operated as the brake light. I guess that this would work.... but I would really like them both to be constant, and then both get brighter when the brake is applied.

    I really appreciate all of your help, as I know nothing about this.
     
  9. Bernard

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    Aug 7, 2008
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    Still no op current figures, so can-not give realistic resistor values. My LED strings are rated @ 70mA ea. Brightness adjusted for Brk. 3X Run.
    For the other 9, use another complete set in parallel.
     
  10. thatoneguy

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    Feb 19, 2009
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    The LED Strip you linked has a current draw of 23mA.

    The only way I can think to have the same lights get brighter would be a rather advanced circuit with PWM, using either 555 timers or a microcontroller and driver transistors.

    That same seller MIGHT have a "3 wire to LED" Taillight driver, they are quite common for people converting their cars to LED Taillights. I'm unsure of the cost though.
     
  11. stover954rr

    Thread Starter New Member

    Mar 26, 2009
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    Thatoneguy,
    So with 23mA, does that mean that it hand handle being hooked up as a tail light, and that it wont blow?
    If the seller does have a 3 to 2 driver, will that allow me to run them both as tail-lights and brake lights?
    Thanks
    Russell
     
  12. stover954rr

    Thread Starter New Member

    Mar 26, 2009
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    These are the only 3 to 2 converters I can find:

    http://www.amazon.com/gp/product/B001EP0GI6

    But they just split the brake light & include the turn signals.

    I just need something that will basically bring the brake and tail light "together" and then split them so that I have one wire (with brake and run) going to each of the 2 led strands.

    Does that make sense or is my nievity dreaming up something that isn't possible?
     
  13. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Do you have the strings? If the seller sais they operate on 12V go for it, but verify. Connect to 12V with some series resistance, start around 470Ω and work down to 0. Measure current, 23mA does'nt sound right to me, maybe X 3 for 69 mA for whole string.[ 3 sub strings @ 23mA ea ??]. LED's are easy to dim, just add a little resistance, go from off to full brilliance.
     
    Last edited by a moderator: Dec 27, 2013
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