Charging system help

[posplayr]

I got an Ebay Caltric, about 35 bucks. Works fine. I cannot remember ever personally seeing an alternator feed wire back to the battery that was fused. Mine are not. Unless you are running a very small wire, I can't see a problem. Somebody I know who is an electrical engineer by trade backs me up on that.

Every GS has a fuse coming directly off the battery even if it is contained in a multi fuse box. Even the R/R is fused (with the same fuse) as they can short. The only thing that is not used is the starter solenoid but then I mentioned this already.

If you want the possibility of your bike to burnup, then connect things to the battery without fusing.

[wymple]

Let me correct myself. I have never used a fuse in the feed wire from the R/R to the battery. I've also never had any problem with that. A lot of stuff I have done over the years was chopperesque & custom. The wiring from GM alternators has no fuse back to the battery, I've used a lot of those on car, truck, tractor conversions. Say what you will, I damn sure won't worry about something that's never happened. I'm 71, and I have never seen a fried motorcycle from anything but a fuel leak.

[posplayr]

Let me correct myself. I have never used a fuse in the feed wire from the R/R to the battery. I've also never had any problem with that. A lot of stuff I have done over the years was chopperesque & custom. The wiring from GM alternators has no fuse back to the battery, I've used a lot of those on car, truck, tractor conversions. Say what you will, I damn sure won't worry about something that's never happened. I'm 71, and I have never seen a fried motorcycle from anything but a fuel leak.

Well anybody familiar with GS systems know that shorted R/Rs are a fairly common (certainly not uncommon) occurrence. That means that the R/R's internally short between the RED and Black wires.
If the main GS fuse was not there, then you would have a direct short between the battery, R/R through the R/R ground wire. The result would be a glowing orange wire from battery to ground through your harmness till your R/R ground wire fried. If you have improved grounding then you might have to burn through 14 or 16 awg wire which would take even longer.

Anybody familiar with electricity knows that fuses are intended to protect wiring by limiting the current through the wire to design levels. When any battery is shorted to ground it will deliver very high amounts of currents (100+ amps) and will turn any battery into a welder. This is why it is especially important to not draw current from a battery without having an inline fuse.

I will clarify that you do not need to fuse the power coming from the R/R (that is only about 15 amps), but you do need to protect against the R/R shorting and pulling massive power from the battery. That is what the main fuse is for.

Apparently Wymple has magic powers or little guardian angels looking over him ; for the rest of us we should always make sure there is an inline fuse somewhere in any lead coming from a battery in case that wire somehow gets shorted .

[Steve]

There is also a big difference in automotive alternators, but there is still a BIG fuse in the fusebox. At least there is in mine. I have a 150 amp "fusible link" as the first item in the box from which everything else branches off.

An alternator regulates its output by varying the strength of the magnetic field. A stock GS R/R momentarily shorts the output of the stator to ground to reduce any excess. If it stays stuck in "short" mode, you have uncontrolled current straight from the battery to ground. In the stock wiring, that is protected by the MAIN fuse.

.

[wymple]

"That is what the main fuse is for." I am not unfused in the end, then, am I? Is my 12 gauge wire going to get that hot and the main fuse doesn't blow with all that?

[posplayr]

There is also a big difference in automotive alternators, but there is still a BIG fuse in the fusebox. At least there is in mine. I have a 150 amp "fusible link" as the first item in the box from which everything else branches off.

An alternator regulates its output by varying the strength of the magnetic field. A stock GS R/R momentarily shorts the output of the stator to ground to reduce any excess. If it stays stuck in "short" mode, you have uncontrolled current straight from the battery to ground. In the stock wiring, that is protected by the MAIN fuse.

.

Steve,
I think the R/R can short when a pair of the blocking diodes fail (in a short mode) in the rectifier. If it is a MOSFET device then it would be a pair of MOSFETS. I have seen on the Series devices they only switch one leg with a MOSFET and use a diode for the other side. MOSFETS tend to fail shorted and bipolar devices fail open.
Jim

[hannibal]

"That is what the main fuse is for." I am not unfused in the end, then, am I? Is my 12 gauge wire going to get that hot and the main fuse doesn't blow with all that?

You are unfused because instead of connecting the R/R positive through the stock harness and fuse, you wired it straight to the battery.

As I said earlier, I had electrical problems when I bought my bike and little experience. These guys got me up and running. I suggest you at least consider and even listen to their advice.

[Qumodo]

Help! I am now on my third Stator chasing this issue, With the most recent stator I am only getting 30V AC @ 6K RPM from each of the three phases. At this point it has to be the magneto...right? I dont see anything else that it could be. The magneto looks fine to be but see pic attached. Thanks again for all the help!

also, all three stators are measuring less than 1 ohm across all three phases.

IMG_3601.jpg

[posplayr]

Help! I am now on my third Stator chasing this issue, With the most recent stator I am only getting 30V AC @ 6K RPM from each of the three phases. At this point it has to be the magneto...right? I dont see anything else that it could be. The magneto looks fine to be but see pic attached. Thanks again for all the help!

also, all three stators are measuring less than 1 ohm across all three phases.

[ATTACH=CONFIG]59594[/ATTACH]

Go back to basics:
1.) confirm that your meter reads 120VAC from a standard household outlet. (if not then replace and re-perform the leg-to-leg test)
2.) measure leg to ground voltages at 5K RPM (This is the most important stator test) You should get zero volts AC. If you have voltage then there is a short somewhere.

I don't think i have ever heard of a confirmed rotor failure where the magnets were damaged or too weak to charge. I have heard of magnets losing the bond and falling out.

A mismatch between rotor and stator poles is the most likely reason for low voltage on new stators. i don't know what bike you are working on but IIRC it is the 550's that have the confusion.

[hannibal]

You confirmed an 18 pole stator. Are you sure the rotor matches?

[Qumodo]

posplayr, I am measuring from each of the three phase wires to the negative battery post and reading 30V AC. the stator is not connected to the R/R. does this seem like a short and if so where is it likely to be?

just double checked my meter, it is reading 120V AC from the wall outlet

[Qumodo]

hannibal, yes it is an 18 pole stator, but i am less sure about the rotor. it is the rotor that was installed when i got the bike. how do i confirm compatibility?

[Qumodo]

Picture of 18 pole stators

IMG_3604.jpg

[Qumodo]

Picture of rotor, please let me know if this is the correct rotor, it is the original as far as i can tell.

IMG_3601.jpg

[posplayr]

posplayr, I am measuring from each of the three phase wires to the negative battery post and reading 30V AC. the stator is not connected to the R/R. does this seem like a short and if so where is it likely to be?

just double checked my meter, it is reading 120V AC from the wall outlet

Yes you have a short; This should be open of no more than 1 volt of extraneous voltage.

probably somewhere under the cover. You have to be careful with that retaining bracket that guides the wires under the cover.

You can chase down the length of wire outside the cover and confirm you didn't pinch them anywhere.