1. ## 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.  Reply With Quote

2. 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.  Reply With Quote

3. ## 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  Reply With Quote

4. 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 LEDs and some lab grade resistors and make up a perfect match.
OM  Reply With Quote

5. Originally Posted by gloucesterman 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?  Reply With Quote

6. ## 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  Reply With Quote

7. Correction: R=V/I so 28.8 Ohms for the resistor. Or, P=V2/R so R=V2/P 144/5=28.8 ohms  Reply With Quote

8. Originally Posted by sharsman 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.

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.  Reply With Quote

9. ## ????

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  Reply With Quote

10. Originally Posted by gloucesterman 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  Reply With Quote

11. 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  Reply With Quote

12. Originally Posted by Pauls1150 T
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
Send it back!  Reply With Quote

13. Hi,
You're right. My bad. That is a per bulb value. His resistor for each bulb will be the difference between his original load and the new led load. Once he has that difference he can figure out what wattage he needs for each resistor. I would up the wattage rating on the resistor to take into consideration overall voltage fluctuation.

https://www.rapidtables.com/calc/ele...alculator.html

5 Watts
12 Volts
.42 Amps
29 Ohms

Later,
Norm  Reply With Quote

14. Well, it seems a lot of anger directed at Puig. While I don't know anything about Puig or their products....I thought I would take a look.

I can't find Puig supplying lights- https://puig.tv/en/tuning-motos/lice...ort?bike=12860

It seems RevZilla has a kit- with a light- https://www.revzilla.com/motorcycle/...r-rs-2015-2019

There is a caution that-
This product FITS your 2017 BMW R1200R
Fitment Notes & Exceptions
Not compatible with OEM turn signals
Requires splicing of OEM license plate light harness
It would be nice if the OP could return and give us an idea how the kit was supplied.

OM  Reply With Quote

15. Originally Posted by gloucesterman Hi,
Also Gator using these formula's the fact that it is being wired in parallel which is needed will not change the values???
Norm
The value of the LED and the resistor in parallel will be different. When you have two devices in parallel the combined resistance is measured at the point where the two devices connect. Since you will now have two paths of current flow the resistance will be lower. Also, this means that it will always be lower than either device by itself.  Reply With Quote

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