Why does Suzuki split R/R + output between ignition and battery?

[OldVet66]

I would imagine the main reason for wiring it that way would be so the headlight does not go out if the main blows. I am considering wiring mine direct and using circuit breakers.

[koolaid_kid]

Thanks for the replies. Allow me to respond in order received:
bakalorz - If I do this, I will place a 20A fuse between the R/R and the battery. I also have an LED voltmeter which glows in different colours, according to the voltage:
Voltage
Output
>15.20
Green/Red alternating (over-voltage)
>13.20
Green (charging)
>12.45
Amber (75% plus)
>12.25
Red slow flash (50% approx)
>12.00
Red 2 flashes, repeat
>11.80
Red 3 flashes, repeat
<11.80
Red 4 flashes, repeat

I believe that the combination of these two safeguards will be sufficient safeguards to warn me if an overcharging occurs.
However, I believe you might be a bit confused. I am looking at a wiring diagram right now. If I go straight to the battery and the main fuse blows, the Battery no longer has power to supply to Ignition Switch, which cannot supply power to the other 3 fuses, and the engine dies, the bike shuts down, including the lights.
OTOH, if I keep it in the loop and the main fuse blows, the R/R is still supplying voltage to the Ignition Switch, which in turn supplies the other 3 fuses, so the bike keeps running. However, the R/R now believes the battery is severely undercharged and goes through the roof. And there is no fuse to protect the system any more. Please correct me if I am reading the diagram wrong.

Matchless, you are correct. In OEM configuration the supply from the R/R to the ignition switch is not fused. Please see previous reply.

OldVet66, you are correct. If the main fuse dies you are done.

Let me theorize a bit further if I may: In my TransAm I place relays everywhere it is very important to keep maximum power available. Each relay is fused in case things get out of hand. Where I really, really care, I also place a bimetal breaker in series with the fuse. If it overheats, the metals expand away from each other and the circuit broken. If I do this, there will be a bimetal breaker in place also.

I am really attempting to understand and grasp this circuit, so please LMK if I am mistaken in some area.
Thank you.

[koolaid_kid]

I would really appreciate responses to this. If I have read/interpreted the schematic incorrectly, please tell me and explain how. I do not mind being wrong; it won't be the first time. Just show me the way and I will follow. I traced this using 650, 850, VX800, and 1100E wiring diagrams. If you have a different model, as long as our good friend BassCliff has the Service Manual on his website, I will download it and trace the wiring diagram for that particular bike.
I would like to understand all the ramifications of removing the link from the R/R to the Ignition Switch. If I do this, there will be both a 20A fuse and a 20A bimetal breaker between the R/R and the battery. The Main Fuse will also be upgraded to 20A, since it could now carry the entire output of the R/R. (More on this later.)
All I have really done is take a wiring diagram and trace everything out, with the unfused Ignition Switch link included (OEM) and with it removed.
If I am incorrect, LMK, and explain why/how. I will gladly accept your response(s) and investigate. If I am correct (it does happen on the rare occasion) LMK also.
Thank you in advance.

[Nessism]

I am looking at a wiring diagram right now. If I go straight to the battery and the main fuse blows, the Battery no longer has power to supply to Ignition Switch, which cannot supply power to the other 3 fuses, and the engine dies, the bike shuts down, including the lights.
OTOH, if I keep it in the loop and the main fuse blows, the R/R is still supplying voltage to the Ignition Switch, which in turn supplies the other 3 fuses, so the bike keeps running. However, the R/R now believes the battery is severely undercharged and goes through the roof. And there is no fuse to protect the system any more.

I believe this is correct. Suzuki's wiring method has a safeguard to avoid a complete electrical shut down in case the main fuse blows. I also believe you are correct in noting the R/R will start pumping out max voltage, but I'm unclear if that would hurt the system in any way.

[bwringer]

I also believe you are correct in noting the R/R will start pumping out max voltage, but I'm unclear if that would hurt the system in any way.

When R/Rs run amok, the max they will put out is around 17V. This will start blowing light bulbs more quickly than normal and boiling the battery dry eventually, but the bike will continue to run normally for many, many miles. So it's not enough of an overvoltage to destroy anything right away.


On my VX800 (same basic electrics as a GS), the regulator would stop regulating only when it was above a certain temperature. It took me several months and about five burned-out headlight bulbs to finally catch the bike overcharging and understand what was happening. Fortunately, the sealed Wally World battery wasn't damaged because the failure was so intermittent. I replaced the R/R with a Honda unit relocated from the idiotic stock location (right next to a hot exhaust pipe). Then a few months later, the overstressed stator finally gave up, but this was expected...

[posplayr]

Thanks for the replies. Allow me to respond in order received:
bakalorz - If I do this, I will place a 20A fuse between the R/R and the battery. I also have an LED voltmeter which glows in different colours, according to the voltage:
Voltage
Output
>15.20
Green/Red alternating (over-voltage)
>13.20
Green (charging)
>12.45
Amber (75% plus)
>12.25
Red slow flash (50% approx)
>12.00
Red 2 flashes, repeat
>11.80
Red 3 flashes, repeat
<11.80
Red 4 flashes, repeat

I believe that the combination of these two safeguards will be sufficient safeguards to warn me if an overcharging occurs.
However, I believe you might be a bit confused. I am looking at a wiring diagram right now. If I go straight to the battery and the main fuse blows, the Battery no longer has power to supply to Ignition Switch, which cannot supply power to the other 3 fuses, and the engine dies, the bike shuts down, including the lights.
OTOH, if I keep it in the loop and the main fuse blows, the R/R is still supplying voltage to the Ignition Switch, which in turn supplies the other 3 fuses, so the bike keeps running. However, the R/R now believes the battery is severely undercharged and goes through the roof. And there is no fuse to protect the system any more. Please correct me if I am reading the diagram wrong.

Matchless, you are correct. In OEM configuration the supply from the R/R to the ignition switch is not fused. Please see previous reply.

OldVet66, you are correct. If the main fuse dies you are done.

Let me theorize a bit further if I may: In my TransAm I place relays everywhere it is very important to keep maximum power available. Each relay is fused in case things get out of hand. Where I really, really care, I also place a bimetal breaker in series with the fuse. If it overheats, the metals expand away from each other and the circuit broken. If I do this, there will be a bimetal breaker in place also.

I am really attempting to understand and grasp this circuit, so please LMK if I am mistaken in some area.
Thank you.

You have gotten deep enough into this that you should be using a schematic and askng questions about a schematic. Doing a failure modes analysis is the correct way to approach it (ask you self what happens if this shorts or that).

Right now you seem to have conviced yourself to put a 20 amp fuse between battery and R/R but it is not clear whether that is in the original OEM "T" configuration (which only requires 15 amp fuse) or the modified version that requires 20 amp and (tries) to goes around the stock fuze box?

[koolaid_kid]

You have gotten deep enough into this that you should be using a schematic and askng questions about a schematic. Doing a failure modes analysis is the correct way to approach it (ask you self what happens if this shorts or that).

Right now you seem to have conviced yourself to put a 20 amp fuse between battery and R/R but it is not clear whether that is in the original OEM "T" configuration (which only requires 15 amp fuse) or the modified version that requires 20 amp and (tries) to goes around the stock fuze box?

You are correct. Currently I am using schematics from a GS650, GS850 & VX800. All are slightly different, but all show:
a) A similar loop
b) Similar responses if the Ignition Switch is removed from the unfused loop.
I have drawn out each circuit by hand, and observed similar responses if that part of the loop is removed (theoretical only, of course). I use a 20A fuse because the output of the stator was rated a 230W back in 1981 http://www.cbxclub.com/davespage/mcy80-11.html, and I have seen no changes that would indicate a larger power output. The modified version does not actually go around the stock fuse box, rather it uses only the stock fuse box. The OEM design goes around the stock fuse box by also wiring in directly to the Ignition Switch, unfused. I have not yet examined the 1100E wiriing diagram, because it will be my final analysis machine, but I expect it to be similar.
I have also done a theoretical failure modes analysis (on paper, of course). All show the main fuse blowing and the bike stopping. The unfortunate part is that if you are on HWY 1 and the fuse blows, you stop. Which could really suck.
What I have not done (yet) is the analysis of running this much power along one tiny 18-gauge wire instead of two.
Another theory could be history. Observe the stator headlight loop. Is this Ignition Switch loop another history lesson, we always did it that way and it would cost money to change it? IDK, perhaps an examination of a T200, T250 or T500 is in order. At some point in time an engineer convinced a manager, who convinced a committee, who convinced a bean counter that this is the correct way to do it. We both know how the system works. Once in place, it is another difficult task to convince them to change.
IDK, which is why I am asking questions. The thirst for knowledge runs deep in an engineer, as you know. I am just delving into the "Yes, but WHY" part.

[Nessism]

I have also done a theoretical failure modes analysis (on paper, of course). All show the main fuse blowing and the bike stopping.

It seems to me the bike WILL keep running even if the main fuse blows with the T-loop in place, but it won't if the R/R output runs straight to the battery. This thread has convinced me to keep the T-loop in place.

As an aside, my bike is setup with the factory "accessory" fuse feeding power to the coil relay mod. The stator wires feed directly into the R/R (bypassing the headlamp loop) and one of those flashing LED voltage meters are hooked up to the output side of the coil relay so the charging system can be monitored.

The output of the R/R is 14.5 volts, but the voltage at the main and accessory fuses was only 13.8 - 14.0 volts or so and the flashing LED was showing a lot of RED (not charging properly). Measured resistance though the fuse block and there isn't any so I conclude the system draw is using up some of the available power. I wound up installing a new battery and a series R/R and now the LED is showing GREEN like it should, but I'm wondering how long it will last.


.

[koolaid_kid]

It almost seems like a Catch 22. If the loop is in place it should stay running. However, now the R/R is trying like crazy to charge a non-existent battery. If the loop is removed, you run the risk of stopping on a 70 mph freeway, unless you designed in a "go-back" circuit, but I doubt you would be able to trigger it without stopping first.
I have an LED voltmeter ready to install; I believe it was you that recommended it. The voltage levels it triggers at seem a bit questionable, but it is better than nothing at all.

[bakalorz]

You are correct. Currently I am using schematics from a GS650, GS850 & VX800. All are slightly different, but all show:
a) A similar loop
b) Similar responses if the Ignition Switch is removed from the unfused loop.
I have drawn out each circuit by hand, and observed similar responses if that part of the loop is removed (theoretical only, of course). I use a 20A fuse because the output of the stator was rated a 230W back in 1981 http://www.cbxclub.com/davespage/mcy80-11.html, and I have seen no changes that would indicate a larger power output. The modified version does not actually go around the stock fuse box, rather it uses only the stock fuse box. The OEM design goes around the stock fuse box by also wiring in directly to the Ignition Switch, unfused. I have not yet examined the 1100E wiriing diagram, because it will be my final analysis machine, but I expect it to be similar.
I have also done a theoretical failure modes analysis (on paper, of course). All show the main fuse blowing and the bike stopping. The unfortunate part is that if you are on HWY 1 and the fuse blows, you stop. Which could really suck.
What I have not done (yet) is the analysis of running this much power along one tiny 18-gauge wire instead of two.
Another theory could be history. Observe the stator headlight loop. Is this Ignition Switch loop another history lesson, we always did it that way and it would cost money to change it? IDK, perhaps an examination of a T200, T250 or T500 is in order. At some point in time an engineer convinced a manager, who convinced a committee, who convinced a bean counter that this is the correct way to do it. We both know how the system works. Once in place, it is another difficult task to convince them to change.
IDK, which is why I am asking questions. The thirst for knowledge runs deep in an engineer, as you know. I am just delving into the "Yes, but WHY" part.

The way the wiring system is designed is not a bean counter or commitee thing. It is the right way to do it !

The reason is that this in not simply a continuous DC circuit; it is a DC circuit with significant alternating currents superimposed on it as the R/R provides current to the circuit from the stator, and then shunts the stator. This goes on in a continous cycle, and the OEM Suzuki wiring minimizes the amount of wiring the overall currents have to traverse.

To get a better idea of what the actual currents are you can look at what I wrote in post #24 of posplayrs charging contest (and for more detail than you could possibly want look towards the end of that thread)

[koolaid_kid]

Thanks for the link. Post #24 looks interesting; I'll have to start at the beginning. I appreciate it.

[posplayr]

It seems to me the bike WILL keep running even if the main fuse blows with the T-loop in place, but it won't if the R/R output runs straight to the battery. This thread has convinced me to keep the T-loop in place.

As an aside, my bike is setup with the factory "accessory" fuse feeding power to the coil relay mod. The stator wires feed directly into the R/R (bypassing the headlamp loop) and one of those flashing LED voltage meters are hooked up to the output side of the coil relay so the charging system can be monitored.

The output of the R/R is 14.5 volts, but the voltage at the main and accessory fuses was only 13.8 - 14.0 volts or so and the flashing LED was showing a lot of RED (not charging properly). Measured resistance though the fuse block and there isn't any so I conclude the system draw is using up some of the available power. I wound up installing a new battery and a series R/R and now the LED is showing GREEN like it should, but I'm wondering how long it will last.


.

Ed,
I just happened on to the thread again while looking for 4:1 dyno results thread. Any updates from when you posted the above?


I also had my ED electrical coil relay mod wired as you described and powered using the fused accessory. Later when I opened up my harness, I moved the relay power to the "T" location and put a 10 amp in line fuse.

I also wired in a accessory plug with additional inline fuse mounted on the handlebar for IPhone and battery charger. It is also wired into the "T:.

Jim

[posplayr]

I did a side by side compare of the OEM R/R to battery wiring and a comparison to the "popular" way people hook up new R/R and go "direct to the battery". I'm making some assumptions here as I think people normally only add one additional inline fuse. So with that here is a side by side compare.

Bakalorz has also brought up the issue of the high speed current switching that goes on depending upon whether the R/R is sourcing current or not. What that means is when the R/R is not sourcing current it is identical to the condition that I show with engine off so that point is considered in this analysis. The average currents (as measured) remain unchanged as they take the current switching into account.

Bottom line is to stick to the way Suzuki designed it in the first place. This is something they did get right.

[GSJim]

I did a side by side compare of the OEM R/R to battery wiring and a comparison to the "popular" way people hook up new R/R and go "direct to the battery". I'm making some assumptions here as I think people normally only add one additional inline fuse. So with that here is a side by side compare.

Bakalorz has also brought up the issue of the high speed current switching that goes on depending upon whether the R/R is sourcing current or not. What that means is when the R/R is not sourcing current it is identical to the condition that I show with engine off so that point is considered in this analysis. The average currents (as measured) remain unchanged as they take the current switching into account.

Bottom line is to stick to the way Suzuki designed it in the first place. This is something they did get right.

Interesting. I was just about to order some stuff from Eastern Beaver to install my SH775 regulator. (Why are Furukawa connectors so hard to find and/or out of stock everywhere? Grumble, snarl...). My stator to regulator wiring was cooked, including a melted connector, but the positive wire into the harness looks OK. The regulator on the bike now is an almost new Electrosport which is connected directly to the stator with bullet connectors (shiny new and clean). Because the bike is in pieces for other reasons I bought the SH775 from my local Polaris dealer to upgrade my electrics.

So your recommendation for installation is to keep the T. Searching shows this this has been debated before.

Regulator +ive to the harness (solder or shiny new connector).
Regulator negative to the battery or good frame ground (shiny new ring connector).
Stator connected directly to the regulator (solder or shiny new connectors). I might use new bullets to match what is already on the stator.

Thanks.

Jim

[Nessism]

Ed,
I just happened on to the thread again while looking for 4:1 dyno results thread. Any updates from when you posted the above?


I also had my ED electrical coil relay mod wired as you described and powered using the fused accessory. Later when I opened up my harness, I moved the relay power to the "T" location and put a 10 amp in line fuse.

I also wired in a accessory plug with additional inline fuse mounted on the handlebar for IPhone and battery charger. It is also wired into the "T:.

Jim

Jim,

Using your updated Stator Paper's guide figured out there was voltage loss between the R/R positive output wire and the battery. Cleaned the brass terminals in the circuit by extracting them from the connector shell and dunking them in acid. Pinched down the female prongs on the terminals and reassembled everything back together. Voltage loss went from more than 1/2 volt down to about 1/8 volt (can't remember exactly). Stupid flashing LED volt meter still doesn't work properly, but the charging system seems to be.