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Up until yesterday, I had Rizoma signals on the front and factory signals on the rear...and everything worked perfectly.
 

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Through further research both here and abroad, it appears that the problem is caused by the LEDs. They do not have enough draw and are causing the bike to react as if a bulb is blown. Has anyone else experienced these symptoms after doing a full LED swap. Like I stated before, there was NO problem w/ 2 LEDs and 2 factory...it began once I went to all 4 LEDs.
Also, does anyone have a fix for this. I saw that wiring a resistor between the 2 signal wires is the typical fix, but at what ohm? One site claims that you can use four, 6 Ohm resistors (1 at each light) or two, 3 Ohm restitors (1 left, 1 right)...not being an electrical engineer and it being about 10yrs since I last had physics, could someone help me out?
Thanks,
Eric
 

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If it worked with the incandescent bulbs in there, I'd think that you could just ohm out one of the bulbs and add that much resistance to each circuit.

Using the theory that the you've provided, you've just proven that each light in the left and right circuits are the same place electrically speaking, so I wouldn't bother adding resistors at the front and back. Just do it in the rear where it's easy to get to.

--Fillmore
 

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I'm not an EE, but I'm pretty sure that the resistance of a light bulb changes a lot due to the extreme temperature change of the filament. Perhaps someone more sparky will weigh in...
 

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I'm not an EE, but I'm pretty sure that the resistance of a light bulb changes a lot due to the extreme temperature change of the filament. Perhaps someone more sparky will weigh in...
I am not a real Sparky, but you are right, resistance goes up as temperature goes up.
 

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I did a quick search on Google, and found this site that speaks a little to your problem:

http://www.superbrightleds.com/1157.htm

See the paragraph:
LED bulbs may cause some newer vehicles to indicate a bulb is burnt out (because of their low power consumption). Some cars indicate this by increasing the flash rate of the turn signals, some do not flash at all. This can be remedied with load resistors wired across the turn signal bulbs to simulate a filament bulb load. We have these available by our LED turn signal bulbs in our online shopping cart.

I think what they mean by a load resistor across the terminals is a parallel connection.
 

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Discussion Starter #7
Thanks for your help, Mitt!

Thus, accounting for the inverse proportionality, if 6 ohms is for 1 bulb, then they are correct that 3 ohms would suffice for 2 bulbs (ie 1 side)?

Eric
 

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I don't remember the wiring diagram, but it would depend on if the front and rear bulbs were in series or in parallel. I think that they might be in series.

You use the reciprocal rule if they are in parallel, but the sum of the resistance if they are in series.

If the signals are in series, you could just use something like a 12 ohm resistor on just one signal. If they are in parallel, then you're right and you'd drop down to a 3 ohm.

--Fillmore
 

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Bulbs are in parallel. Also, note that the ground for the dashboard indicator comes through the OTHER side's lamps. The reason this works is that the current draw through the opposite side's lamps is not enough to illuminate the "off side's" bulbs but is enough to illuminate the indicator.

SO, the point is that when you engage either left or right, there is current flowing through BOTH sets of indicators. But, only the chosen side gets enough draw to light up the bulbs.

:) Chris
 

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I assumed the bulbs were parallel, so that if one burned out, the other would still work. I think the 3 ohm thing would work. Maybe someone with more hands on can verify this.

Assuming parallel front and back 6ohm original bulbs, the equivalent circuit is like this;



Then, when you had just the leds front and rear, it is like this, and is equivalent to a blown bulb;



Adding a 3ohm resister in parallel to the front and rear bulbs should give an equivalent resistance similar to the original (assuming the original had 6 ohm bulbs);



mitt
 

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Discussion Starter #12
I sent an email to a fellow board member who made the LED taillight...here's his reply:

after a quick glance at the post, it looks like the guys have the right idea. a parallel resistor with the LED's to bring the total current draw approximately equal to that of the regular bulb. the formula's on there are correct. you could easily approximate the desired load by just measuring the resistance of the bulb your replacing. i intend to convert my turn signals to LED's in the same way I did the tail light. i will certainly run into this issue as well, so i can offer you more feedback based on experience if you havent resolved this soon....

sandin


Looks like I'm off to Radio Shack (or is it Shaq?) this afternoon.
Thanks again for all your help...I'll post w/ the final outcome whence complete.

Eric
 

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12V / 3Ohms = 4A
P = V*A = 48W
That's one big a$s resistor burned out spot.
So what are you suggesting? 4A will burn something up? I thought that was what fuses were for. What size resistor do you suggest?

What is the resistance of the orignal bulbs? That was something I still don't know. I was just doing the math to show how to make a circuit equivalent to what was there originally. I have not seen anyone else post something that might help Eric fix this problem yet. [smiley=idea.gif]

mitt
 

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Discussion Starter #15
Resistance of the bulb = .003 Ohms on the "standard" scale and = 1.2 ohms on the 200 scale?
 

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Bulbs are a continuous wire, thus technically have no resistance. BUT, they have a Wattage rating which means the current through them will be a set value assuming 12VDC feeding them.

P=power (watts), I=current (Amps), E or V = Volts
P=I*V
I = P/V

R=resistance in ohms.
Now, use P=I*I * R to find "resistance"... (Note that I*I is I squared)

R = P / I*I

But, yes, a 48W 3Ohm "resistor" would more commonly called a resistive load, as it would be bigger than a Coke can. Most of the resistors you see used in electrical devces and on circuit boards are 1/4 Watt. We tested them and they'll turn black between 1/2 and 1/3 W and if done right, will actually explode and leave burn marks if you quickly approach 1W. This is called "letting the smoke out". Black devices with multiple pins on them hold a LOT of smoke. ;D

The gizmos you see for sale are likely a wound coil of some sort, properly called an inductor. The more common name is "ballast", which implies resistor or load.

:) Chris
 

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If this 50watt 6 ohm resistor is as big as a coke can, those must be some 1 inch diameter cables running out of it.

And I think that bulbs have resistance, otherwise they would draw infinite amps. They have a tungsten wire that has a high resistance per unit length property that causes them to heat up (ohmic heating i^2*R) and emite light. They are less efficient than LEDS because the majority of energy is wasted as heat.

I still have yet to see a definite answer for Eric from anyone on how to fix this problem.

mitt
 

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If this 50watt 6 ohm resistor is as big as a coke can, those must be some 1 inch diameter cables running out of it.
::) Well, obviously, if that's purely a resistor, it's something new-ish. Certainly isn't 100% ceramic, huh? And keep in mind that this thing is like a 50W bulb. (well, 60W since you don't see 50W ones...) and will get equally warm. BUT, since sarcasm is directed at me indicating that my presence is unwanted, I'll bow out of this thread.
 

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But, yes, a 48W 3Ohm "resistor" would more commonly called a resistive load, as it would be bigger than a Coke can.
:) Chris
Chris,

I was just giving back some of the sarcasm you started with :)

I am not an expert on resistive materials, or how this 50W device is constructed, but I do know that everything has a resistance. Even wire is a resistor (just a really slight one). I deal with it daily in the form of silver, copper, and tungsten contacts in the electrical industry. And our contacts can handle 100KA at 600V, so we are talking MW of power.

I am just trying to keep this topic simple, talking about resistors as generalities, what you can buy at a Radio shack or an auto store.

No offense intended. I think it was a good discussion, and hopefully we can see the results when finished.

mitt
 
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The resistor you have identified should work. Yes high wattage resistors are available and do not need to be huge. The watt is a unit of heat and the more heat you can remove (hence the aluminum heat shroud) the higher the wattage.
Here is a link to a similar resistor spec sheet.
http://www.heiresistors.com/aluminum.htm


Digi-Key Part Number TMC50-6.0-ND Price Break
5.21

Here is the part number and price from digikey. They are a component catalog with more spark chaser parts than you can throw a stick at.

Manufacturer Part Number TMC-50-6.0-1%
Description RES ALUM HOUSED 6.0 OHM 50W 1%
Quantity Available 489

This (and the kits others found) will work if you install across the + and - leads.

Multimeter tip for hinkle_e the scales you are looking at are multipliers. Is you have the mater switch in the 1 OHM range setting then you need to use the "standard" scale. The 200 scale corresponds to a different switch setting labeled as such. If you are new to spark chasing I would but a decent digital meter, they are much easier to use and remove some of the confusion the bk precision from digikey are good, and radio shaK versions are OK too, should run about $30-$50. Hope this helps I chased sparks for a long time to earn a living.
 
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