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

[Nessism]

For some reason Suzuki splits the R/R positive output and sends juice into both the ignition switch and the fuse box...which then goes over to the battery.

Why does Suzuki send unfused power over to the ignition switch? Checking what other manufacturers do shows Honda sends all the R/R + output over to the battery (via the fuse box), none of this splitting business like Suzuki.

On my 1000S I wired the R/R output to split and feed both the fuse box and the ignition switch. Wiring the system this way results in 14 volts at the battery even though the R/R output is 14.5 volts. I've got one of Posplayer's (recommended) Compufire R/R's on the way so now I'm contemplating how to wire it.

What are the pros and cons of Suzuki's wiring method. I' leaning toward the direct to battery method but electrical is not my strength so thought I'd ask the question now.

[Billy Ricks]

I've wondered about that myself.

[posplayr]

For some reason Suzuki splits the R/R positive output and sends juice into both the ignition switch and the fuse box...which then goes over to the battery.

Why does Suzuki send unfused power over to the ignition switch? Checking what other manufacturers do shows Honda sends all the R/R + output over to the battery (via the fuse box), none of this splitting business like Suzuki.

On my 1000S I wired the R/R output to split and feed both the fuse box and the ignition switch. Wiring the system this way results in 14 volts at the battery even though the R/R output is 14.5 volts. I've got one of Posplayer's (recommended) Compufire R/R's on the way so now I'm contemplating how to wire it.

What are the pros and cons of Suzuki's wiring method. I' leaning toward the direct to battery method but electrical is not my strength so thought I'd ask the question now.

EDIT: See this link for gory details.

http://www.thegsresources.com/_forum/showpost.php?p=1913839&postcount=28

I thought this had been covered already ????

First if all you are going is changing the R/R, then I would prefer retaining the stock configuration which is to retain the split. I know some people go direct from R/R output to the battery but this pushes more current through the fusebox's main fuse.

The Reason the Suzuki design makes sense is:

a.) about 14 amps of current is supplied to the electrical system from the R/R when the R/R is not shorting the stator. About 3 amps of this is charging current that goes to the battery.

b.) current is supplied to the electrical system from the battery alone when the R/R is shorted (about 11 amps) or the engine is off and the stator is not producing enough to generate the required 11 amps.

c.) The battery and R/R are tied together to feed the ignition switch because they are both sources depending on how much the R/R can provide.

The main fuse is there to stop the battery from shorting out, for example into the R/R if the R/R were to develop a short to ground at the (+) output leg.

All other currents are protected by one of the down stream fuse legs (after power goes to the ignition switch and returns to the fuse box).

If you choose the direct method, experience has it you need to boost the series fuse from 15amps to 20 amps else it will blow occasionally.

Good luck with the Compufire, if you have a temp gauge, monitor before after temps.

[Steve]

The only advantage that I can see in that scenario is that if, for some reason, the MAIN fuse blows after the bike is running, the bike still gets full power from the R/R. The battery won't charge, but the bike will run.

By re-routing the R/R output directly to the battery, ALL electrical power that the bike uses (except for the starter) will have to go through the MAIN fuse all the time. If you add up all the loads: headlight, 5A, ignition, 8A, brake light 2.5A (if you have a single bulb, 5A if double), then hit the horn, you might blow the main fuse (we're not even considering the turn signals here). Might want to install a 20A fuse, just to be sure.

.

[posplayr]

The only advantage that I can see in that scenario is that if, for some reason, the MAIN fuse blows after the bike is running, the bike still gets full power from the R/R. The battery won't charge, but the bike will run.

By re-routing the R/R output directly to the battery, ALL electrical power that the bike uses (except for the starter) will have to go through the MAIN fuse all the time. If you add up all the loads: headlight, 5A, ignition, 8A, brake light 2.5A (if you have a single bulb, 5A if double), then hit the horn, you might blow the main fuse (we're not even considering the turn signals here). Might want to install a 20A fuse, jsut to be sure.

.

That is an advantage if you happen to have a blow main fuse at the top of a big hill

[Nessism]

So if Suzuki's system is better how come Honda routes the power like this?

[posplayr]

So if Suzuki's system is better how come Honda routes the power like this?

non enough info there Ed. Where is the load?

[Steve]

non enough info there Ed. Where is the load?

Agreed. If you ignore the load, that is exactly the same as Suzuki's wiring.

The difference would be whether the load is on the R/R side or the battery side of the main fuse.

.

[duaneage]

I saw a bad suzuki regulator pop the main fuse as soon as the bike started. The regulator shorted to ground as soon as the ac voltage hit the RR.

[Guest]

Nessism, you won't regret the switch to the Compufire system. I've got a set of the Weatherpack crimping tools on the way. I'll post up some links to pictures when I install the sealed weatherproof connectors.

[koolaid_kid]

I just found this thread, and I would like to continue the discussion, please. If this has been gone over before, could someone please point me to the previous thread. I would like a thorough understanding of the ramifications of removing the loop through the ignition switch.
Thanks.

[Matchless]

I would like a thorough understanding of the ramifications of removing the loop through the ignition switch.
Thanks.

Just some background info. If look at the service manuals from the early 80's they show different schematics for the R/R internals. In many cases some R/R's of the era only regulated one phase sometimes two, nowadays all three phases are regulated.

Suzuki was also the only manufacturer that used specific coloured wires for each phase instead of 3 yellows or 3 whites. The reason for this was that they did not want the regulated phase to be switched in and out on the light switch, but specifically the unregulated phase.
A few years on, regulation on all three phases became the norm and such provision was not important anymore. Unfortunately the fact that parts such as regulators were in some way interchangeable and newer ones superceded the old type and they may have had a huge amount of spares out in the stores they retained the distinctive wiring.

At that time electronic components were quite bulky, especially if they had to handle a lot of heat and also expensive. It was thus easier and cheaper, or seemed so to them, at the time to not regulate all 3 phases.
They used the approach that if you "disconnect" one phase of the AC to the R/R, you in fact reduce the output capacity of the alternator by one third and if you are not using the headlight, two thirds of the output capacity should be more than enough to provide all the current the bike needs and have enough left over to charge the battery. The one or two phases then regulated would ensure that the alternator output is regulated as needed. With the lights on, the headlamp and other lights (55W + 10W + 3W+ 3W+ 3W = 74W) would immediately use the additional 6A and the regulation will still happen as when the lights were off.

Legislation changed in some countries and required lights on at all times and in other countries it was not required. In the USA they did away with the light switch to comply and retained the light switch on exports to other countries. The harnass was kept the same so they just bridged the USA bike wires that would have gone to the light switch at the plug.

The rest you should know...
This may not be 100% what they thought and why they did it at the time, but gives you the picture.

[koolaid_kid]

Umm, thanks for the reply. That was an excellent explanation as to why one of the three phases of the stator went through the headlight shell. Unfortunately, that is a different question.
I am asking about the output of the R/R: "For some reason Suzuki splits the R/R positive output and sends juice into both the ignition switch and the fuse box...which then goes over to the battery."
Thank you.

[bakalorz]

The only advantage that I can see in that scenario is that if, for some reason, the MAIN fuse blows after the bike is running, the bike still gets full power from the R/R. The battery won't charge, but the bike will run.

<snipped rest>

.

I would STRONGLY advise NEVER letting the bike continue to run on the R/R output if the main fuse blows.

The R/R regulates by alternating between letting the full current/voltage of the stator through in pulses and comletely shunting it.
The battery acts as a giant smoothing filter or capacitor to keep the voltage near an average.
(even a completely shot battery that is no where near capable of starting the bike will still provide this smoothing)

When the main fuse blows, the battery is no longer in the circuit ... and no longer smoothing out the pulses.
So the voltage to the rest of the system is bouncing between 0 volts and significantly more than 14 volts ...

This doesn't seem to harm the lights, but it apparently is potentially BAD news for the ignitor.

If you search previous threads, you will find 3 or 4 threads where people blew the main fuse (or uninstalled the battery), push started the bike to get home, and ended up with a ruined ignitor.

[Matchless]

Oops, did not read it properly, thought it was loop through light switch!!
Old age does that they say!

On your original question, there are some theories around, but the fact remains that the supply to the ignition switch from the R/R is not fused while the other leg to the battery is protected by the main fuse.

Edit: Martin beat me to it. It is as he says!