Another GS Charging system question

[fatnfast]

I have upgraded my GS750 to work with a Honda Reg/Rec unit. All is well, charging is good etc. However, as Im sure you are all aware, one phase goes through the lighting switch. I know most USA bikes have their lights permantly wired on, but my with my GS I have a choice.

From what I understand having read the stator papers, with the original set up this phase was unregulated, but with the honda RR this is no longer the case. Am I likely to do any damage with the lights switched off and therefore one phase of the stator disconnected?

If this phase of stator has no circuit (as the light switch has disconnected it), can I assume no heat will be generated within that phase, and therefore the stator will run cooler and last longer?

Then when I switch the lights on, that phase now comes back into play and assists the charging to overcome the load now created by the lights (and is of course now regulated by the honda RR)?

I ask this, because, as pointed out on this forum, I can eliminated the 'switch' wiring by connecting the phase directly to the RR. However, I am concerned that this will put all 3 phases into play at all time, thus generating more heat in both the regulator and stator.

So, can I connect all 3 phases, run with my lights off (I know, we should always ride with them on, but there are times when I would like to be more stealthy) and not burn anything out?

[chef1366]

Wire the R/R directly to the Stator and ignore that wire.

[tom203]

If you get adequate charging output at low rpm's , sure leave it like this if you run often with headlight off. I doubt the regulator will care and , yes, the stator will have less internal heat generated with one phase blocked.

[bonanzadave]

ignore that wire.

Wires. One going up and one coming back.

[sschering]

If you really wanted to keep the 3rd winding off when the lights are off you could always wire in a relay back by the regulator to connect the 3rd leg when the headlight was turned on.. I'd use one of the existing stator wires that goes to the headlight to pick up power off the headlight switch harness and feed it back to the regulator..

When I did my R/R mod I just wired all 3 legs right to the R/R.. In this state the law requires the headlight to be on so I rarely turn it off..

[fatnfast]

Thanks for the replys. I ran a few simple voltage checks with the lights off (and therefore a phase taken out) and on, then repeated with the lighting switch 'loop' taken out and the Honda RR connected direct to each phase.
The only noticable difference in voltage across the battery occured at tickover, from 2k revs onwards the voltage increased from 13.5 to 14.6 (@5k revs) and stayed put from 5 k onwards, regardless if the lights were on or off.
RR got a little warm to touch, so its doing its job and not cooking itself.
Conclusion - get rid of the switch loop, with a Honda RR it doesnt need it.

[earlfor]

Thanks for the replys. I ran a few simple voltage checks with the lights off (and therefore a phase taken out) and on, then repeated with the lighting switch 'loop' taken out and the Honda RR connected direct to each phase.
The only noticable difference in voltage across the battery occured at tickover, from 2k revs onwards the voltage increased from 13.5 to 14.6 (@5k revs) and stayed put from 5 k onwards, regardless if the lights were on or off.
RR got a little warm to touch, so its doing its job and not cooking itself.
Conclusion - get rid of the switch loop, with a Honda RR it doesnt need it.

You only need the switch loop if you ride with the headlight off. With the headlight off and if you were to have all three stator phases charging the battery, the R/R is forced to shunt too much excess to ground and will cook itself in short order.

Earl

[posplayr]

You only need the switch loop if you ride with the headlight off. With the headlight off and if you were to have all three stator phases charging the battery, the R/R is forced to shunt too much excess to ground and will cook itself in short order.

Earl

sorry to be a nit picker but it is:

....the R/R is forced to short the excess "current" in the stator windings and will cook the R/R and the stator.

[earlfor]

sorry to be a nit picker but it is:

....the R/R is forced to short the excess "current" in the stator windings and will cook the R/R and the stator.

Wellllll, yeah. I will have to agree that the R/R gets it food from the stator.
Usually, the R/R is the first to go south. Aww go ahead and pick, I feel cavalier tonight.

Earl

[fatnfast]

Ahh, you see this was also a well documented problem here in the UK. With the standard SUZI RR the advice was to run with the lights on at all time to prevent cooking the RR/stator, which implies that when a phase is switched out by the headlight switch (ie lights off), the RR and/or the stator would eventually get fried?

But with the 'modern' combined Honda RR, this should no longer be a problem, and all three phases can be wired direct to the RR regardless of headlight status.

[tom203]

But with the 'modern' combined Honda RR, this should no longer be a problem, and all three phases can be wired direct to the RR regardless of headlight status.

Well, this is a nice thought, and while I agree the r/r is unaffected, you still have the stator to worry about! search for "compufire" discussions.

[mrbill5491]

just update the whole system

Regardless what the stator/RR tested, install a new one with the compu fire RR and save yourself some headaches later on. I did that to the my GS750E , I've rebuilt the system 7 times now and I do hope this is the end of it. I did the direct wiring to the RR and the one wire from the RR to the red wire in the harness, and my head light switch still works.

[posplayr]

Ahh, you see this was also a well documented problem here in the UK. With the standard SUZI RR the advice was to run with the lights on at all time to prevent cooking the RR/stator, which implies that when a phase is switched out by the headlight switch (ie lights off), the RR and/or the stator would eventually get fried?

Not if you have a ganged left hand switch.

I think here is the confusion.

a.) lf all three phases are being used in the R/R, then the headlamp load needs to be there. If not the R/R and stator will get hot as they now have to absorb the extra 55W the headlamp is not there to absorb.

Corollary
b.) with the headlight off, you better switch one of the stator legs out else it will over heat the R/R or stator. Loosing one stator leg, is probably about 1/3 of the 200 Watts or about 66W loss (comparable to a headlamp).

The left hand ganged light switch tries to implement a.) and b.) above.

[fatnfast]

Thanks posplayr, mrbill and tom.
I can see from the Suzi diagram exactly what your saying, and it makes sense, (although it really seems to suggest a poor initial design). It was widely reported in the bike press here about the need to run with the lights on (this is with the standard Suzi RR, which on my 750 used to be seperate items). From this I am assuming that even with a 'leg' switched out there was still to much power to be dispersed by the RR?
I have a Honda CB250N RR fitted now, and it seems to do the job just fine, capping the voltage to 14.6 and not getting overly hot. When I fitted it, I retained the standard wiring including the ability of the headlight switch to take a phase out when off. However, info from here suggests that this switched loop can be dispensed with, but I guess that because many of the US spec machines had the lights wired on all the time.

At the end of the day, I should just get on with riding it, and when it finally goes pop fit a decent stator/compufire combo!