R/R wiring question

[Joe Nardy]

I've searched through a lot of posts regarding regulator/rectifier wiring. I get different opinions about whether to wire the +12 volts directly to the battery or to a switched source. My question is if wiring it directly to the battery causes the battery to drain when the ignition is turned off. I'm guessing since current flows OUT of the R/R, the 12 volt line comes from a diode(s) allowing flow TO the battery. This would be basically an open circuit to current flowing FROM the battery. This would explain why the R/R could be wired directly to the battery without draining the battery but I'm not sure this is correct.

How about all you electrical geniuses pitching in with theory, explanations, or just a quick answer.

Thanks,
Joe

 

[Doctor Shifty]

The Suzuki manual wiring diagram for my 1981 GS1000G shows the wire running unswitched through fuse #4 and then to the battery. I imagine this is the norm for all the GS bikes.

If you have a switched circuit it will enable you to wire in some theft protection (depending on what side of the fuse you switch it), but it won't have any electrical effect according to this diagram.

However, that red wire also feeds the ignition switch, which means that the switch foils are carrying the full electrical load - and sometimes they burn out. It might be that the discussions you are referring to are actually about fitting a relay so the ignition switch only takes the switching load and the relay takes the operating load.

Kim

 

[Keith Winter]

If the reg/rec unit is a "stock" type it could be hooked direct to the battery and as long as the diodes are ok and the unit is working properly, it will not drain the battery. Diodes are one way switches and in a functioning full wave rectifier the current can only flow FROM the B+ to the charging system once the positive voltage from the stator windings is higher than the battery + voltage, then, back to the negative side of the battery through the diodes that switch the "negative" voltage and the frame. Once the stator has no output, the engine is turned off, electron flow is TOWARD the B+ and is opposite to the direction of current for the diodes and should not drain the battery.

 

[Boondocks]

As Doctor Shifty has indicated, the charging circuit is not switched but it is fused through the main fuse. I would leave it as is and make sure that the connections are clean and tight with a little antioxidant grease applied.

There is no need for a direct connection to the battery, but if it is done there should be an inline fuse in the wire near the battery to protect against short circuits.

 

[earlfor]

I alway run a direct wire from the red DC output of the R/R to battery and another from the black - DC R/R ground to battery. Never had any problems.
There is no reverse flow through the diodes of the R/R.

Earl

 

[jonr]

Joe,

I run my +wire straight to the battery terminal and the -black wire straight to the frame. Then again, my 78 750E does not have a switched fuse block, but one fuse in between the +side of the starter relay and the ignition switch.

I could have sworn in the stator papers it mentions to run the +red wire straight to the battery, but it's been a while since I looked at them.

Everyone is right about the diodes - so no reverse flow.

-J