My voltage readings are opposite of what I'd expect!!

[Guest]

I'm encouraged by your optimism and will try to trace the wire between the battery to the fuse box to the R/R. Thanks for your help. I'm sure you and Jim (posplayr) have a great deal of information that will be helpful for many of us.\\/

i'm only a learner here but nonetheless heres my 2c :-D

from my RR 1 wire goes directly to the bat pos
the 2nd wire goes to the fuse box
the neg goes directly to the bat neg

my rr is not stock, i suspect, but having read a lot of stuff about the subject lately, my setup indeed makes good sense :-D (not that i could reproduce the reasons why )

 

[chuckycheese]

Yeah!

Yeah!

Wow, the stuff written above still has my brain sizzling. Suzuki should give out awards to you guys.

Ain't that the truth!!!\\/

 

[chuckycheese]

Clean

Clean

i'm only a learner here but nonetheless heres my 2c :-D

from my RR 1 wire goes directly to the bat pos
the 2nd wire goes to the fuse box
the neg goes directly to the bat neg

my rr is not stock, i suspect, but having read a lot of stuff about the subject lately, my setup indeed makes good sense :-D (not that i could reproduce the reasons why )

That sounds like a really 'clean' set-up! (But I don't understand why you have wires going to both the fuse box and the positive terminal? I would think that the one going to the positive terminal would be the one that's fused.:-s)

 

[north49]

12.7 is probably normal

12.7 is probably normal

Re. Chucycheese voltage readings...... could be that everything is pretty normal. I have a digital voltmeter installed on my GS 1000 and 12.7 V is normal at 4000 RPM with all the lights on.
My theory is that as the RPM' s increase, the ignition system is loaded more so that the voltage starts to drop.

Also..... at 4000 RPM with a fully charged battery, the charging system is suppling the required load. If the battery was continually being charged at more than 12.7 then I think it would be boiled dry.

I don?t know if any of this is acurate electrical theory...I just know from 1000's of miles of riding that it all just works.

cheers

 

[posplayr]

GS750 Charging specs

GS750 Charging specs

I extracted this from a GS750 reprint Suzuki manual (printed 1990). The specs on charging system at 5000 RPM. It is intended that at 5000 RPM, the charging output with lights on high beam should be between 14.0-15.5 volts (but not over). Assuming that there is low resistance, then that is basically what you should have directly across the battery. The test is suspect as it could be right but with resistance the battery would actually be much lower.

On my own bike when I checked last nite.

Key off 12.8V
Key on 12.3V and dropping to 12.0 within 1 minute
Start approx 10v during cranks
idle 12.6
rev 2000 13.0
rev steady climb
rev 5000 14.25 max battery voltage
idle 13.2 with a slow drop to about 13.0

Conclusion is that when operating properly there is a slight discharge of the battery when light are on at idle

The battery voltage should climb monotonically (linearly???) as RPM's increase to something over 14.0 v

The max voltage should not exceed +15.5 v

My bike checks out against the spec and I have a 0.2v drop from R/R out to +bat at idle that increases to about 0.35v at 5000 RPM. The R/R-Bat grounds are tied together so it is always less than 0.015 volts.


PS2: It is clear from this test that the designers did not even consider poor connections in their design as they obviously conclude if the output voltage is not within their spec then a part is broken. Reality is the design is faulty as it is sensitive to poor connections which cause over/under charging)

YMMV

Posplayr

P.S. I have measured this same basic characteristic after cleaning all terminals, fuse box, swap out bullets with spade connectors and adding the additional R/R ground straps with different combinations of:
an OEM stator,
New Electrosport Stator
two different OEM R/R's (1980 and 1981 GS750E's).

Before that I had a burnt ground strap, bullet connectors that had gotten very hot, boiling over (low acid) and dead battery. Everything got fixed with cleaning and did not change after adding the electrosport stator.

 

[chuckycheese]

Interesting

Interesting

Well, Jim, I find that information interesting and, after all of your advice, I have some information to have you take a look. I was getting a reading of about 0.9V when placing the negative probe on the positive battery terminal and the positive probe on the R/R output...at idle.

I put a new wire between the battery and the fuse box and grounded the R/R to the battery. I have done nothing with the wire that goes from the R/R to the ignition and am still using that connector. Here are the number I'm getting now:
When doing the previous test that showed 0.9V, I'm now showing .28V-.30V and the rest of it looks is as follows:

1100RPM.....12.8V
3000RPM.....13.6V
4000RPM.....13.52V
5000RPM.....13.53V

I suppose I could 'clean up' the numbers by running the R/R straight to the fuse box, but would it be worthwhile? Or, should I leave well enough alone, for now? THANKS!!

 

[chuckycheese]

Thanks to all!

Thanks to all!

Thanks to everyone for your thoughts and suggestions about my voltage readings.\\/ I think the numbers I mentioned should be acceptable but would be interested to know if any of you think I should keep trying to improve upon them.

 

[Guest]

That sounds like a really 'clean' set-up! (But I don't understand why you have wires going to both the fuse box and the positive terminal? I would think that the one going to the positive terminal would be the one that's fused.:-s)

the original setup has a pos wire from the rr go (1) through the fuse box to the batt pos, however this wire also feeds a wire (2) to the ignition switch and then back to the fuses and onto other circuits

using two separate wires (one direct to the batt), i assume:
A - avoids poor connections at the fuse box (as it goes directly to the batt)
B - doubles the "size" of the pos wire from the rr to the two circuits

 

[posplayr]

psyguy and Chucky

psyguy and Chucky

Psyguy,
Sounds like you are on the right track with trying to minimize the resistance from R/R to Batt.

Chucky,
Those voltages don't sound that bad (0.5V out of spec) but a couple of questions:

1.) 13.4 volts is with headlamp high beam on or off?

Make sure you performance is adequate with the lights on.

2.) You are measuring a voltage drop going to the Battery (the + side of the battery has a lower potential that the + side of the R/R.

As best I can tell that is a drop due to the current being supplied to the battery/system. Getting one of the $40 Honda regulators would solve the problem I suspect. The sense wire is high impedance and so it has no current flow and so it accuracly measures the voltage at the sens point. That is going to be my next change (I already have it).

I would look at the voltage drop at 5000 RPM and see if you feel happy. If you are getting 0.3v at idle then it will probably climb at least to 0.75 v. At least you got rid of the inversion (almost).

Posplayr

 

[chuckycheese]

Lights! Action!

Lights! Action!

Psyguy....I understand exactly what you did (I wouldn't have 3 days ago). I was just wondering if it came that way. (By the way, I watched "The World's Fastest Indian" last night....what a cool guy and a cool movie!\\/

Posplayr (Jim)....No! I forgot to do the test with the high beam on (although the low beam was). If your second point was a question, I didn't understand it!:-s By the way, I have a really nice Honda Shendegen R/R which I'll put on one bike or the other at some point.:-D

 

[posplayr]

Chucky

Chucky

I was just trying to confirm that your voltage drop from R/R to battery was positive. In other words the Battery is lower than the R/R. If you have the black lead on the batt + and the red lead on the R/R + out and you read a positive voltage then the answer is yes.

Just to make sure reverse the leads and your VOM should read a negative voltage of same magnitude.

This is simply a confirming measurement that you are seeing a voltage difference that is a drop going to the batt. By most conventional electrical theory that means there is resistance in the line that is dropping voltage due to the positive R/R output current.

This is the point I have been trying to expose and that seems to be overlooked in the Stator Pages is that:

excessive voltage inversion and low (12.5-13.0)Battey voltage (at 5000 rpm) are symptoms of high resistance on the positive lead to the battery. It does not automatically point to stator or R/R problems.​

This has been the premise for all of my recommendations.

I would give a Thevenin equivalent model, but I would probably need to draw a schematic for this audience which I will do later after I confer with my other electronics engineering buddies on some open R/R function issues .

More later

Posplayr

 

[chuckycheese]

Thanks!

Thanks!

I look forward to ANY and ALL of your information and I'm sure others do, as well. \\/

EDIT: The answer is "Yes"..it's positive. Also, I cleaned up some more connections and applied dielectric grease and got the number down to 0.16V

 

[Guest]

Psyguy....I understand exactly what you did (I wouldn't have 3 days ago). I was just wondering if it came that way.

yup, done by po

(By the way, I watched "The World's Fastest Indian" last night....what a cool guy and a cool movie!\\/

a true story too :-D

cheers .

 

[Guest]

This is the point I have been trying to expose and that seems to be overlooked in the Stator Pages is that:

excessive voltage inversion and low (12.5-13.0)Battey voltage (at 5000 rpm) are symptoms of high resistance on the positive lead to the battery. It does not automatically point to stator or R/R problems.​

This has been the premise for all of my recommendations.

this is very good point imho

i have come to the same conclusion not by knowing a lot about the elctrics but by reading some posts where people solved charging problems (that first appeared like shot el parts) just by cleaning the connections

i think it might save some people some money (and head-scratching) if this info could be included in the original stator papers
(it is actually mentioned there but more implicitly)

 

[earlfor]

I dont see how this can be since normally, the positive and negative DC output wires from the R/R are new, less than 12" long and are connected directly to the battery terminals.

?????

Earl

excessive voltage inversion and low (12.5-13.0)Battey voltage (at 5000 rpm) are symptoms of high resistance on the positive lead to the battery. It does not automatically point to stator or R/R problems.[/INDENT]

 

[Guest]

I dont see how this can be since normally, the positive and negative DC output wires from the R/R are new, less than 12" long and are connected directly to the battery terminals.

?????

Earl

not too sure what you might be referring to... but:
the above is true for an upgraded system, but not for the factory setup

 

[earlfor]

I'm not sure what you consider an upgraded system. If installing a higher capacity Honda RR is considered an upgrade and it has new, short wires connected directly to the battery terminals. I dont see where increased
wire resistance is going to come from. To me, "the positive lead to the battery" is a wire. Maybe it isnt to some folks. ??

Earl

not too sure what you might be referring to... but:
the above is true for an upgraded system, but not for the factory setup

 

[Guest]

I'm not sure what you consider an upgraded system. If installing a higher capacity Honda RR is considered an upgrade and it has new, short wires connected directly to the battery terminals. I dont see where increased
wire resistance is going to come from. To me, "the positive lead to the battery" is a wire. Maybe it isnt to some folks. ??

Earl

huh, are we on the same wave length here, earl ?
maybe i should shut up it's not like i know much anyway 8-[
but...
chuckycheese in his first post suggests he's got the factory setup
(no direct lead to the batt in the factory setup)
in that case cleaning all the connections involved and making sure the ground system is ok can indeed sometimes rectify the charging problem

 

[posplayr]

Earlfor

Earlfor

The comments about voltage drop applies only to the GS Suzuki OEM R/R or or separated R and R. As best I can tell the issues of voltage drop is one of the "design defects " referred to but not explicitly identified. The Honda unit at least fixed the problem to be described below.

From an electrical engineering perspective (but with some uncertainty as I have never actually seen a Honda schematic) it is clear why the Honda regulator has the 6th sense wire. It is to provide a design feature that makes the voltage regulation independent of the positive voltage drop on the Regulator + supply out.

From an electrical circuit and harness design perspective, not having at least a sense wire, represents "amateur and inexperienced" charging system design. At least I would bet that is the considered opinion of most any experienced design engineer. In fact a well thought out and robust design would probably have a full differential battery voltage measurement (i.e. sense wire for ground and sense wire for battery).

As I have discussed , the R/R operation further with another engineer, it seems pretty clear that while voltage fold back is possible from some mysterious form of Stator shorting, except for this condition any other fold back is due purely to the in line resistance. I should note that any shorted condition is not likely to be stable and wont last long. The resistance build up is due primarily to corrosion which takes longer and is not as subject to heating or current flow.

The R/R regulation (control) performance is loose and it can't cause fold back. This is for several reasons.

a.) The Regulator does not control the output voltage at the battery or even the output of the regulator. It controls the voltage at the center of one of the legs of the rectifier. So there is always an uncontrolled forward drop of the rectifier bridge diodes. This probably goes from +0.5 volts at low RPM charging to over +1.0 volt at max current demand (diode is at max forward bias voltage).

b.) The regulator does not operate on average voltage, it operates on instantaneous voltage. When the stator output approaches the zenor limit (on a rectified cycle by cycle basis), it only clips the tops of the cycles. As the current and voltage increases(due to RPM), more of the top is clipped but the average current/voltage is actually still increasing asymptotically toward the zenor voltage limit. In other words, the average output voltage "sneaks" up on the upper limit as more and more of the full cycle clips into the limit. If anything but full clipping exists, then the average voltage will be less than the clip voltage. This is effect is outside of any closed loop control and is there for a form of soft indirect control of the output voltage.

c.) In addition to the instantaneous control, there is also no filtering on the sense voltage to derive an estimate of average output voltage.

d.) There is no filtering or integral control on the zenor reference. This would at least tighten the control up. ADVANCED ONLY: Even if for perfect Type 1 integral control, the control would not over control but hold to a fixed voltage even for increasing RPM/stator voltage.

Bottom line for the R/R is that it is an effective means of voltage control , but it is weak and indirect control that exhibits a positive error as RPM is increased. Look at the Dealer Manual sepc for a 5000 RPM test. The output voltage should be 14.0-15.5 volts which is well above the no load batter of 12.8V or so.

So there is really no obvious way the OEM regulator can cause voltage fold back. So we are left with the inescapable, low output voltage or voltage fold back can be directly attributable to inline resistance and getting the battery to R/R terminal voltages to match as best as possible at 5000 RPM is the first order of business in trouble shooting.

As to the Honda R/R, it is in fact a significant upgrade relative to the GS OEM. It at least controls the regulation based on sensed voltage (i.e. the sense wire) that is not sensitive to the current supplied or the resistance connection to the + side of the battery. It still needs a good ground.

If any one has a Honda schematic of not only the R/R but also the harness it would be interesting to see.

Posplayr

 

[posplayr]

Earlyfor

Earlyfor

I dont see how this can be since normally, the positive and negative DC output wires from the R/R are new, less than 12" long and are connected directly to the battery terminals.

?????

​

If the above is true then you are likely correct there will be no voltage drop . However, my preliminary calculations are that you only need about 0.1 ohms of resistance to make your charging system flat line at not much above your no load battery voltage. Anymore and you will get a reversal due to the charging system output dropping voltage through the plus lead.

It doesn't take much corrosion to create 0.1 ohms nor does it takes much cleaning to make it go away. That is why this seems to be so elusive about "under charging" symptoms. Most cheap ohms meters only read to 0.1 accuracy so unless you confirm by measuring voltage and 5000 RPM you really wont know.

I'm still trying to figure out an overcharging mechanism so more on that later.

Posplayr