Just did this mod (see earlier thread). I jumped in the car on Saturday and as I was driving off, I got a warning on my dash to check the parking lights. This is probably due to the lower resistance of the LED bulb. I will have to find the right resistor and put it in series with the bulb.
I thought the parking lights and the sidemarkers were 2 diff things. Parking lights are in your fog assembly, its what turns on with your
headlights
...."daytime running lights" if you will.
Confused.
I think that is the message which came up although I may not have read it correctly. The point is that the LEDs will throw an error code. Need to add a resistor to it. Simple enough.
I think there was some discussion on this before - this is not an easy problem to solve. If the LED his higher R value ( which most likely is the case ), in order to make the overall R match the original you would need a parallel resistor - in series would only make it higher. As well the bulb resistance when off is higher compared to the on value.
Here are some equations for those not familiar with electronics:
- assume the bulb is 8 W ( if I recall correctly )
P=I*V => I = P/V => I = 8/12.6 = 0.63A
- assume the LED lights need 0.2A
Itot = I1 + I2 ( where Itot = 0.63, I1 = 0.2A )
I2 = Itot - I1 => R = V/I => R = V/(Itot-I1) = 12.6/(0.63-0.2) = 29.30 ohms
and the important factor will be the power rating for the resistor:
P=V*I2 = 12.6*(0.63-0.2) = 5.41Watt
The above Wattage is the minimum - one would need higher value in order not to have problems with heat.
Oh man this resistor talk gets so confusing. I know I gave up on it... - Suneet
euroboy, your analysis makes sense.
I took a different approach which worked for my CBR 1000:
When current flows through LEDs, they illuminate. LEDs have very little
resistance compared to regular light bulbs. That means that you
have to place a resistor in series with the LED. As current flows
through the resistor, the LED will light up. The smaller the resistor,
the more current flows and the brighter the LED gets.
Most LEDs are designed to have 20 mA (milliamps or 0.020 amps) through
them. Some are 50 mA.
To figure the size of the resistor that you need:
V=IR
V is voltage (12 V)
I is current in amps (0.020 or 0.050)
R is resistance in ohms
For example:
12 volt battery, 20 mA rated LED
12=0.020xR
12/.020=R
600=R
So you would need at least a 600 ohm resistor in series with the LED.
Crocrr,
Close, but slightly incorrect. You forgot to include the fact that an LED is in fact a Diode and as such has a forward and reverse bias voltage. We are concerned with it's forward bias voltage, the voltage that will be displaced across the diode. In most cases, LEDs have a forward bias voltage of ~2 volts. That means that your resistor needs to displace 10 volts (12 -2). With 20 milliamps of current flow, that resistor would need to be = 10 volts / 0.02 Amps = 500 Ohms.
The problem with the errors comes from the LCM (light control module) which checks the resistance of the bulbs at rest (when they are not on). If you grab an Ohm meter and do this, you will find that a cold bulb will have a resistance that is very low. Probably <5 Ohms. When the LCM looks at the LED at rest, with a 500 Ohm resistor in line, it sees 500+ Ohms which it believes to be a bad bulb, so it kicks an error.
To duplicate the cold resistance of a filament, you would need to add a resistor parallel to the whole LED circuit that is very low in resistance, which as Euroboy pointed out, would result in a lot of heat and current.
AAAAARRRRGHHHH!! Yup. You are right. It will still throw the error codes. On the bike, the ECU does not send a pulse to check the electrical levels. Back to the amber bulbs for now.
It still can be done - just follow my equations to figure out what value of parallel resistor you need.
I made an assumption that the bulb you purchased was internally limited with a resistor - I know of many 5V LEDs that include a resistor, and assumed that would be the same for a bulb designed for use with 12.6V.
The parallel resistor is not very expensive, and even if it does heat up a bit it should not be a problem - one just needs to get something with 50% more Wattage rating - for a large selection of parts check out
http://www.digikey.com
. The resistor will be warm, but compared to how hot the engine gets, not even close.
In addition, as other have pointed out there are special silver bulbs that remove the egg yoke effect ;-)
And because the side marker bulbs only blink intermittently when using the turn signals, the duty cycle alone will keep the resistors cool enough.
But like Euroboy said, I would opt for the clear bulbs that light up orange.
