Help with Wiring charging circuit gs650 1981

[Guest]

HI All,

I have an imported 650E that i am rebuilding from scratch with updated electrics, M-unit, Lithium battery etc, i had a question around the charging circuit. in the original diagram it shows that 2 of the Reg/Rec cables go direct to the AC Generator, and the third also goes to the AC Generator via the lighting switch.

My question is can i skip the lighting switch as I'm using an M-unit to control all that and wire the third cable directly to the AC Generator.

The second question is that the the 12v+ that leaves the Reg/Rec goes via the Ignition through the fuse board to the starter solenoid, can the ignition switch be skipped as per the universal M-unit wiring diagram?

Apologies for the hand drawn diagram its how my brain works best!

20210129_162726.jpg
Any help on the would be great

Thanks

Mat

[Brendan W]

Had to look up what an M unit is
Many of us have long ago skipped the long loop to the light switch for the generator and wired all three phases directly to the rectifier.
I don't see how the M unit would affect this in any way.
The dashed red supply to the M unit in the diagram looks to be closer to the stock wiring where the r/r output injects directly into the main harness.
The option to take the M unit supply from a common point on the starter relay seems a curious choice and my gut reaction is that it introduces more connections.

[Guest]

Haha yeah trying to modernise doesn't always help, i'm choosing to ignore that dotted line in the universal diagram and running a live through the fuse direct to the M-unit.

Am i right in thinking i can skip the ignition connection on the 12v+ out of the reg/rec and plumb it straight back into the starter solonoid?

[Brendan W]

Haha yeah trying to modernise doesn't always help, i'm choosing to ignore that dotted line in the universal diagram and running a live through the fuse direct to the M-unit.

Am i right in thinking i can skip the ignition connection on the 12v+ out of the reg/rec and plumb it straight back into the starter solonoid?

Well it looks to me like the M unit is the actual ignition switch slaved off the low current switch on the left of the diagram so, yes I would think so.
Are 6 & 5 common on that starter relay?
It seems a curious arrangement and one that would act as a barrier to the M unit seeing the full output of the r/r?
My money is on the dashes

[Nessism]

SH775 Install by nessism, on Flickr

[Guest]

Perfect that covers both of my questions, one final question. i need to supply power to the Rebelmoto led switches i have, my plan is the wire the 3x+ connections together on one side and the 3x+ connections together on the other side join them each to a single cable which joins into a single back to the M-unit for power, how thick should the cable be from the m-unit? and can i reduce the cable size for each split. Rebel moto suggests a 24awg cable for each switch+.

the pinky/purple lines in my diagram,

20210129_2005132.jpg

[Brendan W]

Don't know right now and my head is hurting from all the work I had today.
A word of caution. What regulator/rectifier have you got?
If a shunt type you have a lot of current all the time which gets dumped back to the generator windings if not used up. Using led lighting will make this worse as the excess current will be higher and you can fry the stator. Even without leds you can still fry it with a shunt r/r.
If you have a series r/r like the SH775 as in Ed's diagram then you don't have to worry about reducing the lighting current demand.

[Guest]

i have the Ricks motorsport electrics hotshot rec/Reg 14_202H as recommended by the guys at antigravity batteries.

https://ricksmotorsportelectrics.com/Hot-Shot-Series-Rectifier-Regulator-Lithium-Compatible-14_202H

[Brendan W]

That looks good. At least it says series on the tin

[Guest]

So i should be ok hopefully then!

[Grimly]

Yeehah, at last the mainstream aftermarket is catching up, instead of dumping their obsolete technology on unsuspecting punters.

[Guest]

Yeehah, at last the mainstream aftermarket is catching up, instead of dumping their obsolete technology on unsuspecting punters.

??????????

[Grimly]

??????????

For several years after it was known of the existence of series reg-recs, the major aftermarket suppliers continued to push the obsolete shunt reg-recs, unti they had cleared out their stocks.

[Guest]

Ah makes sense, it was a pricey piece but the only one that was recommended as safe to run with my lithium battery!

[Brendan W]

I recall Jim remarking that the SH775 units were limited in the frequency they could switch at and that was fine for slow revving GSs but newer sports machines would have to move up the food chain for a series r/r.