RRR R/Rs

[Dogma]

Those of you who weren't lucky enough to attend the RRR may have surmised from the stories and pictures that a few rectifier/regulators were destroyed over the weekend. Everyone else already knows. My 1000G destroyed 3. But I'm getting ahead of the story.

First, big thanks to John, Matt, George, Steve, Mike and Mark who contributed time to help me instead of riding, eating breakfast, or visiting with other attendees. Also, thanks to Tim and Joe for having R/Rs available as spares for me to use. Joe even loaned me a stator, just in case. Thanks again to Steve for hauling the bike back to Ohio for me.

Here's the story, as concise as I can make it. The stator tests OK if marginal: just under 60 Vac at 3500 rpm, and 0.8 Ohms on all 3 legs. All the wiring associated with the charging system seems to be in order (visual inspection). The R/Rs were all grounded directly to the battery, and the the outputs connected directly to the positive post on the starter relay. My R/R simply didn't charge. We didn't examine it. Tim's R/R was never observed to charge, but it passed all the diode tests. Joe's R/R seemed to be working, with good charging voltage. Within 30 seconds (by my memory), as we checked higher rpm, the voltage on the battery climbed to 15 V, then fell to 12.6 V. The R/R was blistering hot, and so were the stator wires.

Other symptoms that appeared on Friday, but may be red herrings: the start button intermittently failed to work. The engine stumbled hard at 7k, before continuing strongly to redline under load. Saturday morning had a weak spark and had to be bump started.

In retrospect, I had quite a few clues that something was wrong. Procedurally, we probably should not have assumed that a solid state device (even a GS R/R) "just blew", without investigating causes. My question is this: What are possible causes of destroying R/Rs like this? Some of the brightest GSR minds were in attendance, and we had no immediate idea where to look. We were out of R/Rs anyway.

My own best theory so far is some kind of unfused short to ground of the charging wire. The battery is charging tonight, I can start testing tomorrow evening, I hope. What do you all think?

 

[posplayr]

Within 30 seconds (by my memory), as we checked higher rpm, the voltage on the battery climbed to 15 V, then fell to 12.6 V. The R/R was blistering hot, and so were the stator wires.

?

Classic Voltage Foldback associated with bad connections(most likely + side) ; check the voltage drops across the r/r to battery connections

see the revised stator pages Phase A tests #2 and #3

Finally STEP #3.) Perform Stator Paper Checks. The stator pages checks are not perfect, but they are designed to help you through a process of elimination in determining what is wrong with your charging system. The good news about doing steps #1 and #2 above first, is that when the stator pages say to check your connections you know you already have done it. Here is the update.


http://www.thegsresources.com/statorpapers4.php

Link to Revised PHASE A of Stator Pages:

ORIGINAL_STATOR_PAGES

The most important thing to do checks at 5000 RPM which is typical cruising speed. You might find that you will need to clean your fuse box to get the positive side voltage drops below 0.2V at 5000 RPM. In steps #1 above you should of gotten most of the connections between the R/R(+) to battery (+) in good shape except the fuse box.

 

[Dogma]

Voltage foldback? Is that anything like blinker light fluid? OK, seriously, I've never heard of that, and Wikipedia describes is as a function of a device, not a symptom. Can you explain this phenomena while I consult the revised Stator Papers? (Thanks for posting the link. It saved me the effort of looking it up, as it was on my list of troubleshooting tools to try.) Also, any speculation as to why the R/R isn't protected by a fuse? Or am I just showing my electrical ignorance again?

 

[posplayr]

Voltage foldback? Is that anything like blinker light fluid? OK, seriously, I've never heard of that, and Wikipedia describes is as a function of a device, not a symptom. Can you explain this phenomena while I consult the revised Stator Papers? (Thanks for posting the link. It saved me the effort of looking it up, as it was on my list of troubleshooting tools to try.) Also, any speculation as to why the R/R isn't protected by a fuse? Or am I just showing my electrical ignorance again?

Do a GSR search for voltage foldback: e.g.

http://www.thegsresources.com/_forum/showpost.php?p=1212405&postcount=9


There is no stator fuse required because by design it operates shorted.
There is a fuse between the R/R (+) and the battery

 

[Steve]

Thanks again to Steve for hauling the bike back to Ohio for me.

Shucks, it was Mrs. Steve that hauled the bike, Josh and I just rode escort.

.

 

[TheCafeKid]

One fact you neglected to mention that I heard only second hand was that your battery is FIVE years old. AGM or not, this is pretty old in my assesment. Your bat may be refusing the voltage, and therefore the regulator simply fries because it can't dump it to ground fast enough. I'm no electrical genius but that seems like the first thing I would check before frying another RR hunting for a different problem. The other symptoms you described sound like a battery that's either not charging, or is having difficulting producing the required amps. If you've proved the stator is putting out, the RRs were working, or should have been, (a d I find it hard to believe 3 different RRs were faulty prior to being slaughtered) the next logical device to check in my lay opinion, is the bat. Put it in a trickle and see if it will pull a charge. If not you have at least part of your problem.

And, BTW just in case what I heard wasn't true, you can ask Jimmy how many brand NEW AGM batteries he went through before finding a functional one. They're better tech, but not always handled properly, and far from flawless.

 

[koolaid_kid]

Is there a fuse between the RR and the battery? I do not recall seeing one, but perhaps I was not looking in the correct location. It would be an easy check with a multimeter to see if there is a short.
Personally, I would go through your wiring harness to make sure you do not have something drawing too much current. You told me that you had gone through the headlight shell and the tail, what about under the tank?
Just a thought, since we never pulled your tank to check any wiring.

 

[Steve]

One fact you neglected to mention that I heard only second hand was that your battery is FIVE years old. AGM or not, this is pretty old in my assesment. Your bat may be refusing the voltage, and therefore the regulator simply fries because it can't dump it to ground fast enough.

Well, I can verify that the third R/R, the one that went to 15 volts, was pumping that into Mrs. Steve's battery. :-k

Since Dogma's battery was ... shall we say "less than fully-charged", we stuck her battery in there to fire up his bike.

Her battery is only one year old.

.

 

[Dogma]

Do a GSR search for voltage foldback: e.g.

http://www.thegsresources.com/_forum/showpost.php?p=1212405&postcount=9


There is no stator fuse required because by design it operates shorted.
There is a fuse between the R/R (+) and the battery

I'll do that search. I thought I remembered reading of new R/Rs getting fried, but I couldn't find those discussions.

Thanks.

 

[Dogma]

Is there a fuse between the RR and the battery? I do not recall seeing one, but perhaps I was not looking in the correct location. It would be an easy check with a multimeter to see if there is a short.
Personally, I would go through your wiring harness to make sure you do not have something drawing too much current. You told me that you had gone through the headlight shell and the tail, what about under the tank?
Just a thought, since we never pulled your tank to check any wiring.

George, I did a lot of work under the tank too. Not saying I didn't miss something... for example, I was dinged a few points for not having everything stuffed with dielectric grease after cleaning.

 

[posplayr]

I'll do that search. I thought I remembered reading of new R/Rs getting fried, but I couldn't find those discussions.

Thanks.

This thread is a little amusing.

The symptoms that you have sound exactly like voltage foldback. Voltage foldback occurs when there is too much resistance (e.g. 0.25 ohms) between the R/R and battery. I have seen it most often when the resistance is in the positive path between R/R(+) and the battery (+).

The R/R voltage will typically peak around 2-3K at 14V and then drop to 13.0 perhaps at 5K. If the resistance is even higher the voltage at the battery can drop to as low as 12V. It is this kind of situation where the R/R and stator get very hot because there is no charging currrent going to the battery which forces the R/R to shunt even more current getting it and the stator even hotter.

If you simply go through the checks of the revised stator pages, it will become clear if connection resistance is the problem. If you have voltage fold back you will NOT pass.

No need to stick anymore pins in the "sparks and magic" voodo doll.

 

[rustybronco]

Jim, I think you found your new avatar!!!!

 

[posplayr]

Jim, I think you found your new avatar!!!!

Good Idea

 

[bwringer]

I'm fairly certain that the "new" R/Rs were connected directly to the battery, but I could be mistaken about that.

Of course, a bad ground connection between the battery and engine could do much the same thing. Just throwin' that out there.

 

[mriddle]

Of course, a bad ground connection between the battery and engine could do much the same thing. Just throwin' that out there.

That is what I was sayin' too.

 

[posplayr]

I'm fairly certain that the "new" R/Rs were connected directly to the battery, but I could be mistaken about that.

Of course, a bad ground connection between the battery and engine could do much the same thing. Just throwin' that out there.

I'm not sure that a direct connection to the battery is the best thing on the positive side although it could be sufficent . The source of the current to the GS system (coils, lights etc) alternates rapidly at 1/10 of the RPM (18 pole stator) between the R/R and the battery. So the battery (+) and R/R(+) need to come together into a T which feeds the GS electrical. The OE schematic shows this clearly.

I always run the R/R(+) output to this same place in the harness and make sure that all the drops from there to the battery are low resistance by measuring voltage drop at 5k RPM which is about maximum charging current load.

If you have low impedance conenctions between teh R/R and the battery such that you pass the stator pages 0.2V drops at 5k RPM I don't think it is probable to have too much resistance say in the ignition switch and cause charging problems. If there was 0.1 ohms in the ignition switch it would drop the voltage to the coils by about 1.4 V but the current would almost be uneffected and so the R/R would hardly notice any drop in the load. Bottom like the SHUNT R/R is much more susceptable to the battery connections but others after the T will have some effect.

 

[TheCafeKid]

I've always run my new RRs direct to the battery with an inline fuse. Has worked well so far, and bypasses all that BS crimped and long strands of wire running all over the bike to cause exactly such a problem. Worked well so far, though I did lose an FET RR this weekend, but I'm suspecting both a beat up when I got it unit, plus the ground connector I installed coming apart at the RR to be the culprit there. It's a bitch to squeeze one of those into the footprint of the old one.

 

[rustybronco]

On the positive side of the equation, the wiring diagram shows the R/R (+) going through a single butt connector and onto the fuse panel's main 15 amp fuse. from the fuse panel it goes directly to the battery positive terminal. the fuse holder(s) and where the wires connect to them can be a source of excessive resistance along with the butt connector. on my '80 I soldered the wires to the fuse terminals, then tightened and brightened the fuse holder contacts.

 

[TheCafeKid]

On the positive side of the equation, the wiring diagram shows the R/R (+) going through a single butt connector and onto the fuse panel's main 15 amp fuse. from the fuse panel it goes directly to the battery positive terminal. the fuse holder(s) and where the wires connect to them can be a source of excessive resistance along with the butt connector. on my '80 I soldered the wires to the fuse terminals, then tightened and brightened the fuse holder contacts.

Dunno if it was the same on all the GSs but the diagram doesn't show the crimped connection for that red wire that splits three ways. This could also be a source of corrosion and obviously resistance which is why I chose to bypass the harness entirely with the RR

 

[Dogma]

Quite the educational discussion folks. Thanks. I have several things to look into now, even before I read the thread on ground loops and checking them. I still haven't finished reading about foldback, and some of the discussion via PM, on account of I'm supposed to be working today.

Keep it coming please. I'd like all the wisdom and knowledge possible going into this. Being stranded or an inconvenience to others sucks.