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Thread: L.E.D. Resistor Help

  1. #1
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    L.E.D. Resistor Help

    I have 2017 R1200R

    Recently installed a Puig fender eliminator kit that also has a L.E.D. license plate light replacement.
    Everything works and looks great. However, the new L.E.D. light is tripping my dash warning light for bulb malfunction.

    Since the L.E.D. is not canbus I believe I need a resistor to match the previous bulbs load, voltage, etc.

    Does anyone have any experience and/or fixed this issue? I do not know how to determine wich resistor I need to install. Puig has been no help.

    Thanks in advance!

  2. #2
    Liaison 20774's Avatar
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    Welcome to the forum! There are a couple of threads in the Similar Threads pane at the bottom of the screen that seem to touch on the issue. Good reading while you wait for more current answers.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
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  3. #3
    Registered User gloucesterman's Avatar
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    It's All Math

    Hi,
    Using Ohm's law where current (amps) = voltage divided by resistance, you only need two of the values to figure out the 3rd. Once you have all three values multiply current (amps) times volts to get watts. Again if you know two of the values you can calculate the third. Calculate your original load, using the formula's figure out how much resistance is needed to equal the original load than calculate the wattage of the resistor needed.
    Later,
    Norm
    You'll never see America from 30,000 feet or an interstate.

  4. #4
    Fortis Fortuna Adiuvat Omega Man's Avatar
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    Welcome to the forum!
    I did some looking around and any cures past purchasing a whole aftermarket specific LP light ended up either not working or only working a short time.
    I guess to really attempt to get this to work, you would have to get a few LEDís and some lab grade resistors and make up a perfect match.
    OM
    "You can do good or you can do well. Sooner or later they make you choose." MI5
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  5. #5
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    Quote Originally Posted by gloucesterman View Post
    Hi,
    Using Ohm's law where current (amps) = voltage divided by resistance, you only need two of the values to figure out the 3rd. Once you have all three values multiply current (amps) times volts to get watts. Again if you know two of the values you can calculate the third. Calculate your original load, using the formula's figure out how much resistance is needed to equal the original load than calculate the wattage of the resistor needed.
    Later,
    Norm
    Thank you for your the info!
    The original bulb and wire, I'm unable to locate and test for the above values.
    Far as I can tell from the bulb itself from online, is 5watts-12 Volts.
    Is this enough to go on?

  6. #6
    Registered User gloucesterman's Avatar
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    Yes

    Hi,
    Yes, 5 watts at 12 volts using Watt's law and basic algebra will give you .42 amps draw per bulb which you can now plug into Ohm's law to get the resistance of each bulb, 5.04 ohms.
    Later,
    Norm
    PS
    Watt’s law - 5 watts = amps X 12
    Algebra – amps = 5 / 12 or .42 amps per bulb
    Ohm’s law .42 amp = 12/resistance
    Algebra – resistance = 12 x .42 or 5.04 ohms per bulb
    Last edited by gloucesterman; 01-11-2019 at 10:25 PM.
    You'll never see America from 30,000 feet or an interstate.

  7. #7
    Addicted to curves azgman's Avatar
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    Correction: R=V/I so 28.8 Ohms for the resistor. Or, P=V2/R so R=V2/P 144/5=28.8 ohms
    MOA #107139
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  8. #8
    Fortis Fortuna Adiuvat Omega Man's Avatar
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    From the Department of Keeping it Simple-

    https://www.electricalsafetyfirst.or...ps-calculator/

    OM
    "You can do good or you can do well. Sooner or later they make you choose." MI5
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  9. #9
    Close however keep in mind the resistor must be placed in Parallel. so this changes some values.
    Gator

  10. #10
    Addicted to curves azgman's Avatar
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    Quote Originally Posted by Omega Man View Post
    From the Department of Keeping it Simple-

    https://www.electricalsafetyfirst.or...ps-calculator/

    OM
    What, we can't do simple math anymore?!

    Now if you want to get picky, there may be a more complex impedance at play here so you would need to look at inductance and capacitance too. Then there is the fact that the voltage varies from about 12.6 to 14 as load changes on the bikes electrical system, and then of course, the phase of the moon has to be considered...
    MOA #107139
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  11. #11
    Quote Originally Posted by sharsman View Post
    I have 2017 R1200R

    Recently installed a Puig fender eliminator kit that also has a L.E.D. license plate light replacement.
    Everything works and looks great. However, the new L.E.D. light is tripping my dash warning light for bulb malfunction.

    Since the L.E.D. is not canbus I believe I need a resistor to match the previous bulbs load, voltage, etc.

    Does anyone have any experience and/or fixed this issue? I do not know how to determine wich resistor I need to install. Puig has been no help.

    Thanks in advance!
    If Puig can't supply a light that works and is compatible with your bike I would send their junk back to them. We shouldn't need to buy stuff and then find work-arounds for their crap not working.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
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  12. #12
    Registered User gloucesterman's Avatar
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    ????

    Hi,
    azgman your confusing me, ohm law is I = V/R, that’s a formula, so when you move a value from one side of the equal sign to the other the function that took place on the original side is reversed, ie was multiplication, now division, was addition now subtraction???? The same with Watt's law W = I x V. So when I plug in his values to Omega Man’s link it comes up .42 amps draw per bulb. And resistance per bulb is 5.04 ohms. His resistor will be based on the difference between the stock bulb and the new LED's. Also Gator using these formula's the fact that it is being wired in parallel which is needed will not change the values??? The bike is spec'ed at 12 volts so that is what all of the electrical spec's are based on. Inductance and capacitance, yeah let's keep it simple!!!
    Later,
    Norm
    You'll never see America from 30,000 feet or an interstate.

  13. #13
    Addicted to curves azgman's Avatar
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    Quote Originally Posted by gloucesterman View Post
    Hi,
    azgman your confusing me, ohm law is I = V/R, that’s a formula, so when you move a value from one side of the equal sign to the other the function that took place on the original side is reversed, ie was multiplication, now division, was addition now subtraction???? The same with Watt's law W = I x V. So when I plug in his values to Omega Man’s link it comes up .42 amps draw per bulb. And resistance per bulb is 5.04 ohms. His resistor will be based on the difference between the stock bulb and the new LED's. Also Gator using these formula's the fact that it is being wired in parallel which is needed will not change the values??? The bike is spec'ed at 12 volts so that is what all of the electrical spec's are based on. Inductance and capacitance, yeah let's keep it simple!!!
    Later,
    Norm
    I = V/R, to find R, multiply both side by R this gives I * R = V * R / R. R/R = 1 so I * R = V. Next divide both sides by I, so I/I = 1 and gives R = V/I. To prove this, take the equation I = V/R If V=12 and R=5.04 Ohms then I = 12/5.04 = 2.38 Amps, not .42 Amps. 12/28.8 = .416 Amps
    MOA #107139
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  14. #14
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    Quote Originally Posted by PGlaves View Post
    If Puig can't supply a light that works and is compatible with your bike I would send their junk back to them. We shouldn't need to buy stuff and then find work-arounds for their crap not working.
    ^^^this^^^
    Unless, of course, the description (not the fine print) indicated something else was needed...AND they told you what it was. I'm becoming a "find a good dealer and build a good relationship with them" kinda guy; to the point where they might even advise me on aftermarket ideas that they may not sell (in exchange for your ((my)) willingness to pay the briksandmortar premium.

    ok back to the thread...

  15. #15
    MOA #24991 Pauls1150's Avatar
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    The warning light is tripped by the current draw in that branch not being within the computer's "spec window"; it can be either too high or too low to cause the warning light to come on.
    So the first step is to determine if the replacement light is drawing more or less current than the stock setup.
    If it draws less current, then a resistor in parallel would fix that; you need to know what the difference in current is - the stock vs. the Puig - to figure the resistor's value.
    If the Puig lighting draws more current, put a piece of black tape over the warning bulb.
    Ohms Law Pie Chart Formulas.jpg

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