CB360 Charging System Wiring

[fiedler.casey]

Hey all, I'm wiring my CB360 back together right now and have decided to wire in the old regulator/rectifier (I know you're all going to want to tell me to buy a new one). It would be extremely helpful if someone could clarify a question I've got going on right now. Attached is a wiring diagram of how I've got the charging system put together right now.

The white and yellow from the alternator combine and split to the regulator and rectifier at the same time. I don't understand why this works (it's wired this way stock, too). Doesn't the AC current from the alternator first need to be rectified and then regulated back to 12V before going to charge the battery? Or does the current to the battery not get regulated and is, instead, dumped straight into the batter after simply being rectified. If that be the case, then I need not regulate the current.

All of my wiring is coming from the battery, through the fuses, and then out to load devices. If I'm only sending current from the charging circuit straight back to the battery (as opposed to stock where it appears they regulated the voltage and ran load devices off of that) then do I still need to keep the regulator in the system? I assume the black wire from the regulator goes to load devices, since yellow comes from the alternator/rectifier, and green goes to ground.

One thing I don't understand is how the current passing through the regulator gets rectified, since it's split to the regulator before the AC current from the alternator reaches the rectifier. Then wouldn't the current running out of the regulator (and subsequently to the load devices) be 12V AC? Seems that the only rectified current passes out of the rectified via the R/W wire straight to the battery (though it would be unregulated).

If someone could clear up the function of these two devices as it pertains to the wiring schematic (both stock and my modified wiring), I would be infinitely grateful.

 

[crazypj]

put a bridge on the w/y wires
I don't use stock, I fit late model reg/rect and wire 3 ac outputs to it
Regulator is needed because AC voltage can rise to about 90v or more at red line, about 47% when rectified so you would still get over 40V DC

 

[tweakedlogic]

White and yellow are just connected together stock. Why they do this at the end of the wire harness instead of the alternator, I have no idea. But you can just wire them together and then hook up the rectifier.

The rectifier takes the a/ signal from the alternator and turns it into dc with diodes. The regulator "senses" the voltage at the battery and dumps the excess to ground. The old regulator are not that great and can quickly cook the battery. Modern is better.

 

[crazypj]

The original wiring was in place because there was freedom of choice in the early 70's.
You could decide if your lights needed to be on or off
Instead of prosecuting car drivers and forcing higher driving standards it was easier to make motorcyclists have lights on permanently then 'blame' them for riding bikes in the first place

 

[mydlyfkryzis]

Also, the regulator (Stock) has 3 wires. One is "Ground" (Green) , One is switched Battery Voltage (Black) and the other is A/C from the alternator. The regulator regulates voltage by shunting the A/C to ground using the Black wire to see what the battery is actually receiving.

The alternator is a Current Generator, not a voltage generator. At a constant RPM, the current is constant. More RPM = More Current (Amps). The way the system actually works is the battery, lights and ignition all have a resistance. Ohm's law is quite handy here. So if the alternator is generating 7 amps of current, the voltage = Amps * Resistance. So, for 15.0 V (Honda spec), the resistance of the whole electrical system together needs to be 2.14 ohms. 7 AMps * 2.14 = 15V. If the battery is discharged, it's resistance goes down and your voltage goes down. 7 amps times 1.75 = 12.25 Volts. However, as the battery becomes fully charged, or you turn lights on or off, the resistance gets higher, 7 amps * 2.5 Ohms = 17.5 volts. Since 17.5 volts is going to burn out bulbs, the regulator reduces the resistance of the system back to 2.14 ohms, maintaining the voltage at the correct level. Obviously, if you speed up the engine you produce more current, slow the RPM down, you get less current.

Think of this way. If the alternator is generating 7 amps, and your bike is only using 5 amps, 2 amps have to get shorted to ground. The regulator is carrying 2 amps of current at that point.

That is why Honda used split coils, a low output and high output. If the lights are off, the system is about 3.5 amps. That's enough for the ignition and brake light and signals. AT night, it has high output, for the headlight addition. The reason to do this is to limit the amps through the regulator. If you permanently wire the alternator for high output, and turn your lights off, you could be putting as much as 7 amps through the regulator. That's what burns them up. That's also why they need to be mounted where they have air circulation (Not under a closed seat hump). At 7 amps, the heat is about the same as a 100 watt bulb makes. Heat kills electronics.

But everyone hides the regulator in closed spaces. If they are not mounted to metal that can absorb heat, they do overheat. That's another reason so many issues with charging systems.

 

[fiedler.casey]

Is there anything I should keep in mind when looking for a combination regulator rectifier?

 

[crazypj]

Not really, Rich Ard posted a list of Mosfet R/R which are more efficient
I like to wire 360 as a 3 phase system using the white, pink, yellow wires as 3 separate AC inputs to R/R instead of twisting white and yellow together
You'll usually get 5 or 6 wires total, unless it's a dedicated device that plugs into original harness (3 AC in, one DC out to battery, one 'control' from 12v switched)
sixth wire would be a ground lead but many ground through heat sink or have a ring terminal on bolt hole so you only see 5 pigtails
You will need to know what manufacturer made it if you use anything other than Honda as the battery/ground connection colours vary

 

[mydlyfkryzis]

A more efficient rectifier is needed, I can vouch for that. But since the regulator is a limiter, rather than a field controller, what efficiency does a mosfet offer. Since the regualtor is shunting AC to ground through a resistor, whether an SCR or Mosfet device, there is going to be heat.

am I missing something? Is the MOSFET not shunting to ground? I have never seen a mosfet regulator schematic that showed schematically how it worked....

If you are shunting to ground anyway, efficiency is irrelevant.

I am going to look around to see if I find any information on exactly how it works....

The alternator is a current generating device, not voltage. The current delivered at a given RPM is the same regardless of the voltage. The only true regulation of the alternator is RPM. Since we need the RPM to drive, the only other convenient way is to shunt send the excess current home.