Ground Loops

[posplayr]

This first post was edited to bring the primary analysis , summary and test method to the top. Everything following that has been discussed that is relevant to the analysis has be added here.

GS Power and Grounding Scheme

Here is an analysis of a preferred GS power and grounding scheme. This probably will diverge from your original GS wiring as well the conventionally wisdom.

The first step is to re-look at what the shunt R/R is really doing. Initially my original thought was that the R/R is shunting current to ground. We it is sort of but not how I originally thought. I was struck by this when I was reading the manual charging system description. Then it because obvious that because of the combo Rectifier and Regulator the R/R does shunt current, but there is a continual load current that it has to sink through its’s negative (black lead). Sinking current means the R/R has to absorb this current direct it back to the stator through the lower legs of the diode bridge. Well big surprise this changes the ball game as far as establishing a proper single point ground.

Analysis:

Here is a summary of the elements of the physically schematic:

a.) I used the current measurements I previously measured along with a simplified version of a typical GS charging system to illustrate where the proper power and grounding connections should be.
b.) Generally at 3k RPM the GS charging system puts out about 12 amps with about 2 of those amps going to charge the battery. The various loads receive the remaining 10 amps.
c.) In the physical schematic, the stator produces A/C power, that is rectified in the R/R producing DC (12 amps) out of the red R/R wire. That power is split between the battery and the various loads (10 amps for load; 2 amps for battery) in the fuse box (I ignored the ignition switch which provides a detour to switch the various loads prior to the fuse box.).
d.) Another interesting feature is that most of the load current return paths are through the frame. In fact some GS schematics I looked at did not even have anything other than the large starter ground strap connected to the negative side of the battery.
e.) I also showed conventional direct connections between:
i.) the R/R + (through the fuse box) to the plus side of the R/R as well as
ii.) a direct connection between negative leg and the battery.
iii.) R/R (-) tied to its’ own case at the mounting bolt.

f.) I also added a R/R ground to the frame. As it turns out this is very important to reducing sensitivity to connector corrosion and high connector resistance. Since the load return current has to come back into the negative side of the R/R to return to the stator, the primary return path should be back through the frame to the frame grounded R/R !!!!

To be clear, the R/R is not shunting current to ground (i.e. to the frame or the battery), it is absorbing load return current from the path of least resistance. That should be the frame ground attached to the R/R. If that R/R negative leg is not grounded, then the only return path for the load current is either
a.) a direct connection of a ground wire from the harness to the negative side of the battery and then back to the R/R or
b.) a frame ground path back through the motor mounts to the battery via the starter ground strap and then finally top the R/R on the R/R ground to the battery.


It is important to note that the R/R attempts to regulate based on voltage it measures internally which the best we can tell is the voltage between the red and black leads on the R/R. Any current flow between the battery and the R/R tends to reduce the voltage that the battery sees because of voltage drops coming from the positive side or from the negative side. Minimizing the current flow from R/R (+) to the battery or from the battery back to the R/R (-) helps keep the sensed voltage more accurate.

You can reduce the return current from the battery by providing a good frame ground so that the bulk if not all of the load return current come through the frame to the negative side of the R/R.

On the positive side of the R/R , the full 12 amps goes to the fuse box. Any resistance there will cause a voltage drop (from 12A) and erroneous regulation. If you can not keep that resistance low, then put in a separate fused wire directly from the battery to the + R/R. It is this resistance on the positive side that can cause the fold back where your full R/R current is going through a relatively small resistance and causing voltage drop off at the battery at higher RPM.






Summary:

So what this analysis suggests is that:

1.) The R/R (-) should be SOLIDLY connected to frame ground.
This avoids current sharing between the 2A charging current returning from teh battery and the 10A load returns. By having the R/R grounded the voltage sensetivity to resistance between the R/R (-) and the Battery (-) is 1/6 (i.e. 2A v.s. 12A)

2.) The battery should NOT be connected to frame ground.
This causes current sharing as described above in 1.)

3.) Other than the starter/solenoid connections (pos and neg), the battery + should only connect to the positive side of the R/R and the battery negative should ONLY connect to the negative side of the R/R.
minimizing the current between the battery and the R/R on both (+) and (-) side reduces teh errors described in 1.)


4.) If the resistance is low enough the R/R (+) leg can go through the fuse box (to teh battery +) but be careful of getting voltage drops from the full 12 amp supply current.
If you share the 12A coming right from teh R/R (+) to the Fuse box keep any resistance to a minimum becuase it will cause more drop than just 2A of charge current alone.

5.) If there are spare load ground lines they should be tied to the R/R ground or to a frame ground. This follows from a single point ground philosoph where all currents shoudl return directly to the R/R (-). The frame is god enough or go direct to teh R/R (-) if it is closer than a frame ground.

Comments welcome.
Pos

Edited Verification Tests:

A simple point to point list for you:

1.) Three wires tied together at a mounting bolt for the R/R at the side plate. Note this is not a frame ground point because the R/R is mounted on a plate mounted in rubber. connection 1C performes the frame ground.
a.) R/R (-) from the black regulator wire to ring lug on a mounting bolt
b.) Battery (-) to a ring lug on the same mounting bolt
c.) Frame ground strap from mounting bolt to frame (not the rubber mounted side plate)

2.) R/R (+) goes to the fuse box as normal

3.) Only connection other than 1b above to battery (-) is the 8 guage wire ground strap to the engine.

4.) For a Honda Regulator connect your sense wire as suggested by Duanage

For the following discussion:

V_negative is measured from battery (-) to R/R (-)

V_battery is measured directly across the battery terminals

What you should notice if you omitt 1c above is the following:

The wire from the battery (-) to the R/R common ring lugs should carry 10 amps at idle and 12 amps at 3K RPM.

V_negative should drop and will likely be between 0.25-0.5V.

V_battery measured across the battery terminals should be something like 13.0V at idle and rise to 14.0V at 3K RPM.

After reconnecting 1c above you should notice the following:

The wire from the battery (-) to the R/R common ring lugs should carry 0 amps at idle and 2 amps at 3K RPM.


V_negative should drop by at least about 1/5 of what ever it was. If it was 0.5V it should be 0.1V.

V_battery should rise by what ever the change in V_negative is. So 13.0V will turn into 13.4V.

[BassCliff]

Thanks Mr. posplayer,

(That's positional player, NOT P.O.S. player, for those of you who are wondering.)

I guess I should get a longer bolt for my battery's negative terminal. I grounded my turn signal flasher and my coil relay to the frame because the bolt wasn't long enough to pick up the nut. I have scrubbed and cleaned the ground wire from the battery to the engine. So I'm probably OK. But I'll find a longer bolt anyway.


Thank you for your indulgence,

BassCliff

[chef1366]

Jim, I knew you couldn't leave that one alone.

[posplayr]

ON Hold

Put this on hold i schematic to draw a schematic and now I'm a little more confused.

Schematic coming

[chef1366]

How about a nice Power Point presentation.

[posplayr]

How about a nice Power Point presentation.

Working on it but I'm getting a widdle sweepy

Pos

[duaneage]

Ground everything to the frame and leave it at that. It's real simple.

[reddirtrider]

Ground everything to the frame and leave it at that. It's real simple.

That's how it's done. The frame is the lowest impedance path you'll find on the motorcycle.

The battery to frame connection is typically a heavier guage wire that any others. The voltage difference between the negative battery terminal and the frame is the current squared x's the resistance of the battery cable (which should be very small.)

The largest contributor to voltage irregularities will be the connectors. Make sure they are clean and well seated.

[posplayr]

GS Power and Grounding Scheme

GS Power and Grounding Scheme

Here is an analysis of a preferred GS power and grounding scheme. This probably will diverge from your original GS wiring as well the conventionally wisdom.

The content in this post was moved to Post #1.

http://www.thegsresources.com/_forum/showthread.php?t=139115

top of this page.

pos

[duaneage]

So what this analysis suggests is that:

1.) The R/R (-) should be well connected to frame ground.
2.) The battery should not be connected to frame ground.
3.) Other than the starter/solenoid connections (pos and neg), the battery + should only connect to the positive side of the R/R and the battery negative should connect to the negative side of the R/R.
4.) If the resistance is low enough the positive leg can go through the fuse box but be careful of getting voltage drops from the full 12 amp supply current.
5.) If there are spare load ground lines they should be tied to the R/R ground or to a frame ground.

Comments welcome.
Pos

1. True that.
2. Why not? How is the battery supposed to be grounded to the frame then?
3. if we are connecting the battery to the negative side of the RR, and the negative side is connected to frame ground, then what? And you are proposing to only connect the battery to the starter solenoid and not the fuse box link?
4. So how does the fuse box get power and why not connect the RR output to it? What is meant by "positive leg"
5. Spare grounds bonded to the RR ground? What is wrong with the frame at any point?

I'm sure you mean well but these recommendations can be confusing and contradictory. All someone has to do is clean the connections they see, and connect the ground leads from devices like the ignitor, RR and turn signal controllers to the frame at some point.

You should post a contact number for support for when someone shorts out a lead or can't get the bike powered up.

[posplayr]

duaneage

See comments below:

1. True that.

I have tried to provide the technical reason for providing teh strong tie between the R/R negative and frame ground.

2. Why not? How is the battery supposed to be grounded to the frame then?

The battery is grounded to the frame indirectly through the daisy chain to the R/R mounting bolt. The purpose is so that this ground connection between R/R and battery doesn't not share any load return current but only carries charging current return.

if we are connecting the battery to the negative side of the RR, and the negative side is connected to frame ground, then what? And you are proposing to only connect the battery to the starter solenoid and not the fuse box link?

This indirect link via frame ground should not leave anything ungrounded when under battery power only. The solenoid control should be grounded to frame or the R/R negative as suggested in 5.)

4. So how does the fuse box get power and why not connect the RR output to it? What is meant by "positive leg"

Look at the schematic ; it should be clear that a fused connection between R/R (+) and battery + needs to exist to support charging alone. Care must be taken when that path also shares load current (other than charging) excessive voltage drop can occur (i.e. voltage fold back).

5. Spare grounds bonded to the RR ground? What is wrong with the frame at any point?

Either or, it might be just as convenient to go direct to the single point ground which is the R/R (-). In this proposed design, the frame is in fact just an extension of the R/R (-) single point ground.

I'm sure you mean well but these recommendations can be confusing and contradictory.

Well I appreciate your comments and I can understand how this might be confusing if some one doesn't take the time to understand or does not understand electrical theory that well.

All someone has to do is clean the connections they see, and connect the ground leads from devices like the ignitor, RR and turn signal controllers to the frame at some point.

Are there any technical reasons for why you have to add frame grounds all over where they dont already exist?

You should post a contact number for support for when someone shorts out a lead or can't get the bike powered up.

This is a technical forum with a technical post on electrical matters. It is not a "how to wire my headlamps" post.

There are a few of reasons for pursuing this topic.

a.) Almost every GS model seems to have a variation on how the battery, headlamps, stator, regulator and various grounds are connected. The OEM wiring is hardly anything that is beyond suspicion or beyond design defect.


b.) There are clearly grounding changes that have been learned the hard way that need to be performed to make GS charging more reliable. Simply restoring factory connections is not a viable solution.

c.) Since there are specific needs to modify the GS power and grounding, a though study of the theory of operation is required to develop what objectively is best to do. While practical considerations may dictate that the full objective solution is not warranted, that must be evaluated following the development of an objective solution.

d.) The changes I'm suggesting are by objective and design intended to reduce the sensitivity of the GS charging system to changes in connector resistance. What I have outlined I believe provides a strong theoretical foundation for making those changes.

Thank you for your comments; I'll try and answer your questions and feel free to add any technical content or concerns.

Pos

[duaneage]

See comments below:



I have tried to provide the technical reason for providing teh strong tie between the R/R negative and frame ground.



The battery is grounded to the frame indirectly through the daisy chain to the R/R mounting bolt. The purpose is so that this ground connection between R/R and battery doesn't not share any load return current but only carries charging current return.



This indirect link via frame ground should not leave anything ungrounded when under battery power only. The solenoid control should be grounded to frame or the R/R negative as suggested in 5.)


Look at the schematic ; it should be clear that a fused connection between R/R (+) and battery + needs to exist to support charging alone. Care must be taken when that path also shares load current (other than charging) excessive voltage drop can occur (i.e. voltage fold back).



Either or, it might be just as convenient to go direct to the single point ground which is the R/R (-). In this proposed design, the frame is in fact just an extension of the R/R (-) single point ground.



Well I appreciate your comments and I can understand how this might be confusing if some one doesn't take the time to understand or does not understand electrical theory that well.



Are there any technical reasons for why you have to add frame grounds all over where they dont already exist?




This is a technical forum with a technical post on electrical matters. It is not a "how to wire my headlamps" post.

There are a few of reasons for pursuing this topic.

a.) Almost every GS model seems to have a variation on how the battery, headlamps, stator, regulator and various grounds are connected. The OEM wiring is hardly anything that is beyond suspicion or beyond design defect.


b.) There are clearly grounding changes that have been learned the hard way that need to be performed to make GS charging more reliable. Simply restoring factory connections is not a viable solution.

c.) Since there are specific needs to modify the GS power and grounding, a though study of the theory of operation is required to develop what objectively is best to do. While practical considerations may dictate that the full objective solution is not warranted, that must be evaluated following the development of an objective solution.

d.) The changes I'm suggesting are by objective and design intended to reduce the sensitivity of the GS charging system to changes in connector resistance. What I have outlined I believe provides a strong theoretical foundation for making those changes.

Thank you for your comments; I'll try and answer your questions and feel free to add any technical content or concerns.

Pos

Jim,
IF an RR is solidly grounded to the frame, the battery "charging current" is returned to the RR through the 8 ga wire and the chassis. Unless the RR is disconnected, there is not a case where the engine runs under battery power alone. The RR powers the machine, not the battery.

The output from the RR goes through a fuse (for safety) and connects to the lead that feeds both the battery and the fusebox. There is nothing inherently wrong with powering both at this point. The fuse box takes the 12 volts and sends it through the ignition switch then back to the fuse box for distribution. All that needs to be done is make sure every connector along the way is in good shape. Clean the spiders out of the fuse box and solder those crimped connections underneath and all is well.

I disagree that the Suzuki wiring system needs to be analyzed at a theoretical level. After 30 years the problems are not design related, they are moisture caused. Just reclean the grounds, replace a few brass connectors with alloy, and leave well enough alone. Grounding the ignitor right to the frame might even give you a little better spark, maybe?

For what it's worth I have all the original grounds on my battery box. I put new connectors on them and they all work fine. They have all these ground wires because the battery box floats on rubber insulators to protect the electronics and battery from vibration.

The only change I made to the ground scheme was to ground the RR to a frame bolt. When I test RRs on the bike I connect to a different frame bolt on top next to the seat. It all works for me. I don't concern myself with micro amps of current flow or millivolts of potential differences. It's a motorcycle for cripes sake.

I'm not trying to break stones, just keep in mind the audience and remember not everyone has years of electronics experience like we do.

[posplayr]

duaneage

IF an RR is solidly grounded to the frame, the battery "charging current" is returned to the RR through the 8 ga wire and the chassis. Unless the RR is disconnected, there is not a case where the engine runs under battery power alone. The RR powers the machine, not the battery.

The point of selecting the R/R negative as a single point ground. ALL Load or charging currents are returned only through the R/R (-) back to the stator. You can have more loops but the only circuit that completes the circuit with the stator windings is back through the R/R (-).

The output from the RR goes through a fuse (for safety) and connects to the lead that feeds both the battery and the fusebox. There is nothing inherently wrong with powering both at this point. The fuse box takes the 12 volts and sends it through the ignition switch then back to the fuse box for distribution. All that needs to be done is make sure every connector along the way is in good shape. Clean the spiders out of the fuse box and solder those crimped connections underneath and all is well.

If the connection between the R/R (+) to the battery (+) carries more current than just the charge current then there will be a larger voltage drop to the battery. Your Honda regulators with a sense wire does not suffer this problem, but any 5 wire R/R will have the issue.

As an example , say there is a 0.1 ohm of resistance in the fuse box. If the R/R output supplies both the Load current(10A) and the charge current (2A) then there will be a 1.2V drop below the regulation voltage at the battery. If regulation were at 14.5V then the max the battery would see is 14.5V-1.2V = 13.3V. If the two currents were separated then the drop would be 2x0.1=0.2V which results in 14.5-.2=14.3V at the battery. While the Honda 6 wire doesn't have this issue, the FH012AA FET regulator is a 5 wire device and so this current sharing is an issue as it will increase the voltage drop due to resistance in the fuse box by 6 fold. That is not a minor issue if you can not control the resistance.

This is primary reason why the imfamous "voltage foldback" occurs due to resistance in the connection between batt (+) and R/R (+) for 5 wire regulators. This current sharing makes the + side much more sensitive than even the negative side corrocion issues.

I disagree that the Suzuki wiring system needs to be analyzed at a theoretical level. After 30 years the problems are not design related, they are moisture caused. Just reclean the grounds, replace a few brass connectors with alloy, and leave well enough alone. Grounding the ignitor right to the frame might even give you a little better spark, maybe?

Sensitivity to corrosion is a design issue as well as a practical issue. I'm not sure why understanding how the power and grounds should be constructed to minimize corrosion issues should cause you consternation.

The maybe you refer to is explained in my analysis all grounds currents flow into the R/R (-) leg.

The only change I made to the ground scheme was to ground the RR to a frame bolt. When I test RRs on the bike I connect to a different frame bolt on top next to the seat. It all works for me. I don't concern myself with micro amps of current flow or millivolts of potential differences. It's a motorcycle for cripes sake.

Well in doing this analysis I discovered how important it was to have the R/R (-) tied direct to ground.

I don't think I referred in any way to mico amps or mili volts. I'm talking about 12A total, 2A charging and 10A load. 0.1 ohms causes 1.2 V drop on 12A and 0.2V at 2amps.

I'm not trying to break stones, just keep in mind the audience and remember not everyone has years of electronics experience like we do.

Anybody that doesn't, doesn't know and so there is no harm in having a technical discussion in a technical forum. On the other hand there are plenty of EE's lurking that have GS experience that I'm looking for input from.

Jim

[lucabond]

In your post you say the battery uses 2 amps for charging and 10 amps for running the rest of the bike. So why is the main fuse a 20 amp? Can we get 20 amps out of the GS RR? Does that leave us with 8 amps for other electrical items ?

[posplayr]

lucabond

http://www.thegsresources.com/_forum/showthread.php?t=134690&page=9

In post #82 I posted my measurements with a GS1100ED aftermarket Stator and the FH012AA. 12.5 Amp at about 4K and I could vary the charge current based on RPM but it was about 2 amps at 3K (roughly).

My main fuse is only 15amps and I think that matches the fuse cover. If you have 20 amp fuses someone likely changes it out.

The stator rotor likely limitss the current output you can get.

Pos