GEN Light Auxiliary Circuit

[MrRiden]

Made up a resistor following Monte's great instruction. Now too chicken to connect it without some confirmation. Have a look at my curving red line on the schematic and my cheap cell phone photo. Will I burn anything down? Do I have this right?

[Bob_Roller]

Rich, that's the way I've understood how the resistor is placed between the 12vdc power wire to the coil and the light blue wire from the regulator .

I don't know if you can do this on an LS without removing the fairing, but can you remove the connector from the tachometer to simulate the GEN light bulb failing and with the resistor installed, check your charging voltage with the engine running to see if it works or not .

[montmil]

Looks right.

At the coil connection, it's the terminal with the green/blue wire. The other end connects to the light blue wire coming out of the voltage regulator; the D+.

Note the Ohm rating stripes on the resistor. The wire from end of the resistor with the stripes goes to the voltage regulator.

Btw, Snowbum has a section on Alternator GEN Lamp Circuit Mods. http://bmwmotorcycletech.info/genlampresistor.htm

Be sure to support/secure the resistor and the hard wire leads to prevent flex and possible breakage.

[georgesgiralt]

Hello !
You can put a 25 W or more resistor (way overkill) because these are packaged in an aluminium mount with two holes for fixing screws. They are neat and with a bit of shrinking tubing are perfect for the job...

[Barry]

Your suggested connection points are correct.  Switched positive feed to the rear coil and D+ on the regulator.

Monte, You've got me worried, what have you been smoking  

Resistors have no polarity and it doesn't matter a damn which way around they are connected.

[Bob_W]

Hey Barry,
It's early in the morning here in the states and I haven't had much coffee yet and I had to think about the resistor.
First digit is on one end and the temp coefficient on the other so the end with the band must be connected to the voltage regulator, but only if a temp coefficient is indicated.
How is that for a wise ass answer early on Sunday morning.
Bob

[montmil]

And that's quite the PO's dual coil installation on your LS. Definitely not stock as the bike came with the single Bosch "Crack-O-Matic" coil. Should you ever wish to clean up the mess under the tank and lose some weight at the same time, fit a nice Dyna "brown" coil to the OEM coil bracket.

Barry, I asked Rick Jones about his own GEN lamp aux circuit when we chatted at Barber Motorsports Park and followed his install comments to me. For my install, his word is gospel. So if it, "doesn't matter a damn" what's your squawk?

[Barry]

Point taken Monte. I have no problem which way around anyone installs a resistor.  What I was concerned about is that other folk reading the thread will start to think the rings on a resistor have some significance about polarity. For standard 4 band resistors, 3 bands denote the resistor value and the band on it's own denotes the tolerance.

Can't think what Rick can have had in mind. Just trying to point out a bit of miss information in a humorous way.  

nhmaf,  your a proper electronics man. Come to my aid and tell em ordinary resistors don't have polarity.

[Bob_Roller]

Resistors don't have a polarity, as Barry has said, the color rings are for resistance value and one is a % tolerance of the resistor value .

[Luca]

Not to be a pain in the arse, Monte, but to help clarify for others who stumble across this; the dyna coil alone does not bolt to the frame.  Rick Jones sells them with a bracket that goes between coil and frame.  Shop elsewhere and that bracket might not be included.

[montmil]

Not to be a pain in the arse, Monte, but to help clarify for others who stumble across this; the dyna coil alone does not bolt to the frame.  Rick Jones sells them with a bracket that goes between coil and frame.  Shop elsewhere and that bracket might not be included.

That's quite possibly true but I wouldn't know for sure. The two Dyna coils I've purchased both came from Rick -as did a buncha other Airhead stuff. I'm spoiled with his service and attention to details. I had the good fortune of visiting with Rick at the ABC tent during one of my Barber trips to Alabama. Big beard on a big guy.

I hope folks understand that Rick Jones and MotoraddElektrik are a one-man band. I hear the occasional complaint that he sometimes doesn't answer the phone. Patience. He's probably in the privy or talking to me at Barber.  

[MrRiden]

Ok, got it installed with no further issues, Charging at 13.4dcv @ 3krpm so i assume I did no harm. I haven't tested it with the bulb removed but I plan on doing that next weekend. As for my coil setup, yeah it has all the earmarks of a "custom" installation and at some point I do want to pit in the brown Dyna but I'm seeing it going for anywhere from $95-$150. I'll wait for a sale. As for resistors having polarity I always thought it didn't matter but I did some research. You can put them in facing any old way but the consensus among electronics hobbyists is to face them all the same way for neatness. The only other item I found was that when measuring voltage drop in a circuit across a resistor there is a polarity concern but this only applies to taking readings in a live circuit. Maybe this is what lead to some speculation. Anywho, thanks for the excellent advice and if my pics help any add them to the how-to. Football is almost on, gotta go. Thanks again all!

[Semper Gumby]

Hi Barry,

That looks right to me.  Instead of a resistor I used a GE90 light bulb.  So I have two gen light bulbs!   8-)