Reg/Rec ground question

[Grimly]

In my bike there are many accessories, and lo I didst taketh the SPG very seriously indeed.
Each one lovingly crafted with the finest of crimps, all coming together in the SPG to beat all.

[Rich82GS750TZ]

Aw, my SPG only has 5 lugs.

[Gorminrider]

My "spg" is the frame...so any bolt attached to the frame is a place to connect a ground....but, if people want to stack ring-lugs in awkward star shapes, sure, but it must be a bit of a nuisance disconnecting just one thing, let alone running extra wire to the "special golden bolt" and accounting for the rotation each lug needs to sit flat too....

[posplayr]

My "spg" is the frame...so any bolt attached to the frame is a place to connect a ground....but, if people want to stack ring-lugs in awkward star shapes, sure, but it must be a bit of a nuisance disconnecting just one thing, let alone running extra wire to the "special golden bolt" and accounting for the rotation each lug needs to sit flat too....

The primary idea of the SPG for the GS is to steal current away from the direct battery(-) to R/R(-) connection ( a standard upgrade recommendation) . That means providing lower impedance path than say the dirty starter ground strap.
The frame is not a SPG other than at one point.

For example If you have a Dyn-S, it returns current through the engine case. So how does this engine case current get back to the R/R(-)? The most obvious way is that the current flows from the engine case to the 6 AWG started ground cable then to the battery(-) and then on to your R/R(-). This is exactly what (if possible) you want to minimize. It may not be possible, but oif your 6 AWG groudn streap gets dirty enough, you can provide a frame ground pickup to (where engine case current grounds through the multiple mounting bolts) and you can divert that current from going past the battery.

In the case of having a large accessory (like heated vest/gloves), if you run this right back to the battery then that current travels between battery(-) and R/R(-) increasing the drop. On the other hand if you "ground" the negative side of the acc to teh SPGF then the current will bypass the battery and go direct from SPG to R/R(-).

Additionally I don't know what you mean if the entire frame is SPG with respect to the harness B/W wire? How doe the harness get to the R/R(-)?

[Gorminrider]

The primary idea of the SPG for the GS is to steal current away from the direct battery(-) to R/R(-) connection ( a standard upgrade recommendation) . That means providing lower impedance path than say the dirty starter ground strap.

For example If you have a Dyn-S, it returns current through the engine case. So how does this engine case current get back to the R/R(-)? The most obvious way is that the current flows from the engine case to the 6 AWG started ground cable then to the battery(-) and then on to your R/R(-). This is exactly what (if possible) you want to minimize.

see, that's the kind of stuff I don't get. Any suspect path can be tested as a voltage drop...firstly, if the assumption is that the device will work noticeably better "correcting" a tiny voltage drop and that secondly, running a parallel path is the solution, go at it. Myself, I'm not convinced that these extras improve function. I'm comforted that manufacturers agree with me:I don't see ground wires running very far in any car or bike I've seen.

If someone wants an electric vest or gloves plugged into the dash, sure-run an extra ground wire to the frame(not merely to the existing B/W) I'd agree that suzuki's B/W wires were a little light.

but What "dirty ...ground strap"? I say, Clean it up! What impedance? ...it's amply sized to weld...and even if a dyna-S grounded to engine "wants" to get to the R/R (-), (assuming its got the higher potential), it can go there direct via the multiple engine mounting bolts to the frame, thence to the R/R (-) also attached to the frame. The frame may not be copper but its mass determines that it's resistance is effectvely 0. Likewise multiple steel bolts*

But,
*threadlock or antiseize notwithstanding...graphite or copper-based antiseize is going to be pretty low on the worry list especially as the threads themselves are not the only contact point.

[posplayr]

see, that's the kind of stuff I don't get. Any suspect path can be tested as a voltage drop...firstly, if the assumption is that the device will work noticeably better "correcting" a tiny voltage drop and that secondly, running a parallel path is the solution, go at it. Myself, I'm not convinced that these extras improve function. I'm comforted that manufacturers agree with me:I don't see ground wires running very far in any car or bike I've seen.

If someone wants an electric vest or gloves plugged into the dash, sure-run an extra ground wire to the frame(not merely to the existing B/W) I'd agree that suzuki's B/W wires were a little light.

but What "dirty ...ground strap"? I say, Clean it up! What impedance? ...it's amply sized to weld...and even if a dyna-S grounded to engine "wants" to get to the R/R (-), (assuming its got the higher potential), it can go there direct via the multiple engine mounting bolts to the frame, thence to the R/R (-) also attached to the frame. The frame may not be copper but its mass determines that it's resistance is effectvely 0. Likewise multiple steel bolts*

But,
*threadlock or antiseize notwithstanding...graphite or copper-based antiseize is going to be pretty low on the worry list especially as the threads themselves are not the only contact point.

You would be best to run that accessory ground to the SPG rather than the frame. The difference is if you go to teh SPG then none of the accessory return current will pass by the battery. Depending on how dirty the starter groudn strap is some of the frame return current will pass past the battery (-) lugs on way to R/R(-).

These PM alternators on the GS are just sensitive to voltage drops and only have limited output. As i have stated multiple times, it is not the end of the world is you don't use a SPG, but with degradations in contacts, the SPG minimizes the loss of charging voltage to the battery.

Again do your own calculations on how low that resistance how has be to avoid dropping less than 0.25V between battery(-) and R/R(-) when you have 10 amps flowing between them.




ANSWER: R=0.25/10=0.025 ohms This is a very low resistance and it drops charging from 14.5V to 14.25V

[Gorminrider]

none of the accessory return current will pass by the battery.

first, so what. The bike and accessories in essence run off the stator and R/R , the battery being just another accessory albeit acting as a kind of capacitor per any ripple? but whichever,

depending on how dirty the starter ground strap is

is pretty much a non-issue in my experience,whatever it looks like.*

* But it doesn't of course, hurt to
A) check the voltage drop across it
B) given a noticeable voltage drop in the "High-charging condition"** try to "clean it up" a..battery post and motor connection point and even engine-mounting bolts...

**"High-charging condition" =Hibeam,brakelight,turn signal, accesories all on at 4-5 thousand rpm

[posplayr]

first, so what. The bike and accessories in essence run off the stator and R/R , the battery being just another accessory albeit acting as a kind of capacitor per any ripple? but whichever, is pretty much a non-issue in my experience,whatever it looks like.*

* But it doesn't of course, hurt to
A) check the voltage drop across it
B) given a noticeable voltage drop in the "High-charging condition"** try to "clean it up" a..battery post and motor connection point and even engine-mounting bolts...

**"High-charging condition" =Hibeam,brakelight,turn signal, accesories all on at 4-5 thousand rpm

You seem to have missed the who point of the SPG. The so what is to obtain the best charging voltages for the battery. The bike can happily run for few hours running the lights and ignition and not charge the battery adequately. It depends on charging voltage at the battery terminals. Just because you have maxed out the charging output, does not mean that the battery is being fully charged.

We have seen this plenty of times where people have been on long ride, stop their bike and go to restart and the battery is dead. Just becuase it has never happened to you does not mean it does not happen.

If anybody actually tries to follow the stator Pages Phase A which is to measure the voltage drops at 5k RPM (positive and negative drops), these are the factors that will most effect those results.

[Gorminrider]

Hmm well if by "SPG" you think

So for the SPG configuration, the only additional wire is an R/R(-) to somewhere on the frame. If this overcomplicates everything such that the walls come caving in

well,I can't see it does any harm or good versus where the original was. But if you mean this



that'd be something I will avoid except in some kind of emergency.
And still, I think neither to be the elegant or correct fix for:

The bike can happily run for few hours running the lights and ignition and not charge the battery adequately

or

where people have been on long ride, stop their bike and go to restart and the battery is dead

[posplayr]

Hmm well if by "SPG" you think well,I can't see it does any harm or good versus where the original was. But if you mean this



that'd be something I will avoid except in some kind of emergency.
And still, I think neither to be the elegant or correct fix for:
or

For an SPG there are only three wires:

Battery(-) to SPG
Harness Ground B/W ring lug to SPG
Frame to SPG

of course all these collected returns have to go to teh R/R(-) so they should be one final
SPG to R/R(-)

The additional wires you see in the picture above are ground wires that would usually go to the battery (-). All those accessory wires should "correctly go to the SPG as shown.

Basically a Single Point Ground means to have all loads connect to a "home run" all the way back to the power source that powers that load.

The R/R is the source of the power not the battery so return to the R/R()-). It is that simple.

It works connecting to battery ground as well but now more current has to flow between battery(-) to R/R(-) to complete the circuit raising your voltage drops between battery and R/R.

All teh other

[Grimly]

The neg lead of the SH-775 is one of the lowest (first) ones in that stack. There's a common lead running back to the battery neg, so only the main starter return from the engine casing and the SPG return lead are paired up on the neg terminal.
I have had no trouble since instigating this system, and frankly it's one I would probably not have done if not for reading about it here by your good self, so it's all your fault.

It's far more likely I would just have carried on the way it was always done, with individual items being grounded at their installation points and have the inevitable headaches resulting from multiple corrosion points as time took its toll.

There's never a time when all the accessories are on, but I think it might be a good idea to upgrade the SPG-batt return wire, as it was chosen to handle a relatively modest current. It's not skinny by any means, but a size up might be better.

The other point is, I don't give a fiddler's fig about others' opinions of it - it works, it's saved me trouble and while it's dirty it's on a bike that's always worked for its keep.

[posplayr]

The neg lead of the SH-775 is one of the lowest (first) ones in that stack. There's a common lead running back to the battery neg, so only the main starter return from the engine casing and the SPG return lead are paired up on the neg terminal.
I have had no trouble since instigating this system, and frankly it's one I would probably not have done if not for reading about it here by your good self, so it's all your fault.

It's far more likely I would just have carried on the way it was always done, with individual items being grounded at their installation points and have the inevitable headaches resulting from multiple corrosion points as time took its toll.

There's never a time when all the accessories are on, but I think it might be a good idea to upgrade the SPG-batt return wire, as it was chosen to handle a relatively modest current. It's not skinny by any means, but a size up might be better.

The other point is, I don't give a fiddler's fig about others' opinions of it - it works, it's saved me trouble and while it's dirty it's on a bike that's always worked for its keep.

Thanks. As I have mentioned before, the SPG is not mandatory, but as you have noted you have collected all the grounds into one place and they are much easier to check and maintain and you can basically forget about it.

but one thing I'm still confused about, which is the negative and positive posts on that battery? The right has red on it, but the big wrap on the wires with fuses is on the left.

i assume the left is the positive, but where is the ground strap for the starter/engine case?


BTW I'm assuming the two inline fuses are + side for your accessories.

[Grimly]

The Motobatt has two pos and two neg terminals, making it a universal fit.
I've resisted utilising the extra terminals because if I have to replace that with a conventional LA battery I'd have to re-route some wires and/or try to squeeze them all on to the normal terminals.