Various Alternate Charging-Systems for W-C Alternators

[DewCatTea-Bob]

" The convention I'm used to regarding the rectification schemes is (referring to your drawing):
Single diode ('25%'): Half wave rectifier
2 diode ('50%'): Full wave rectifier
4 diode ('100%'): Full wave bridge rectifier "

____ Mostly correct but,
first, I haven't yet posted a drawing, so you must mean Mike's drawing of my suggested wire-scheme. (?)
Second, THIS is actually the correct step-way...
_LOW - 'single-diode' for half-wave rectification of one half of the alternator, to get 25% output;
_MEDIUM - 'dual diodes' for dual half-wave rectification so as to half-wave rectify each half of the alternator, to get 50% output;
_HIGH - 'full-wave/bridge-rectifier' for full-wave rectification of both halves of the alternator, to get 100% output.


" but it may be difficult to deal with depending upon what sort of riding you do. for example...remembering to turn on the switch for a night ride, "

____ Whenever I've done my very-own rewire-jobs, I've always chosen to include an ammeter so as to be able to decide if extra alt.power is needed, and flip the switch if I so chose.
The Jap-bike makers realized that if they were to expect more buyers of their bikes to enter the market, that something that's needed, is to not make it any more complicated to ride their products,, so for one thing, they built an extra circuit-switch right in-with the light-switch itself, so that both circuit-switches would always get done at the same time, (but I myself prefer the added choice of doing the power-switching as I see fit !).
__ I had planned to make this point within the post I've already started for this thread, and that the individual can choose the type of switch they prefer.


" One solution would be to use a series type regulator. When the battery is fully charged, the regulator switches off instead of shunting all of that current to ground, heating up both the stator and regulator. "

____ It seems that you have a pretty-good understanding of the situation that I've been trying to get others to realize, Scott !
The type of regulator you've brought up seems to be what could be fairly called a 'Green Thinking' type of equipment, and the type of voltage-regulator that I would recommend.


" Two companies I know of making the series type are Compu-fire and CycleElectric,"

____ I'd really very much like to look-over the schematic-plans for those units, to see how they might be workable with any of the various modification-plans that I've come-up with. . (Not that I know of any real need for one of them on any DUKE which employs a full-sized battery.)
__ Thanks very much for the cool info Scott !


Happy-Cheers,
-Bob

[MotoMike]

Bob

I dont' know if it is that important that we agree on which way current flows because you can explain the circuit so long as you are consistent. I was taught neg>Pos. Of course I prefer this method, believe it is technically correct and I think the generally accepted method now as when they came up with pos>neg, they didn't really understand or know about electrons and their negative charge. But you can figure the circuit out either way.

I don't know how the rotors are designed but now that I am sure of diode arrangement, I am pretty sure your design is sound. Here is how I think it is working. I've closed S1 so both halves are working. I find it easier to understand these circuits if i take a snap shot of them. in the first instance consider the action frozen some time while the induced voltage across the coil is positive going.

wide case full wave 4.JPG

Here I have erased the neg excursion. I'll call the top coil Y1 for yellow wire 1 and the bottom y2 for yellow wire 2. Even though that input is causing the voltage across the two coils to change, their polarity will remain the same as shown throughout the positive excursion. So I've marked the top (Y1) positive and the bottom (y2) negative. the next markings at the center where the red wire leaves is the polarity of each coil realative to the potential at the other end. In other words the bottom of the y1 coil is more negative than the top of the y1 coil. the top of y2 coil is more positive than the bottom. So during this excursion, the diode connected to the y1 coil is reverse biased and will act as an open, not conduction through that half of the circuit. The diode connected to the y2 coil is forward biased and becomes a closed switch essentially allowing current to flow in that half of the circuit. since the bottom of that diode is connected to ground, and the battery negative is also ground potential, the positive end of coil y2 is going to be positive in relation. A simple way to look at it is that coil y2 becomes a source in paralell to the battery. so long as the voltage induced into y2 coil is greater than that of the battery, the battery will charge. just as if you were using jumper cables on a battery, pos to pos neg to neg.

wide case full wave 4.JPG

here I have drawn only the negative excursion. it will induce the opposite voltage across the coil, so I have switched polarities at each end of the coils. again the polarity marks near the center are realative to the other end of each coil being examined at that snap shot of time. again the voltage will be changing but the polarities will remain the same thoughout the negative excursion. In this case the diode connected to y2 is reverse biased so acts as an open. diode connected to y1 is forward biased and acts as a closed switch allowing current to flow and the voltage on coil y1 to be felt at the battery. again the bottom of the diode connected to y1 is at ground potential, so the other end will be positive relative to it and again consider coil y1 as a source in paralell to the battery and while it is greater than battery voltage the battery will charge. The output wave form on the red wire will be positive pulsing act will approximate DC. I tried to show on the red wire. commercial systems would typically put a filter in there to make it more pure dc. through taking advantage of the way Ducati phased the coils, bob had created a full wave rectifier.

you mentioned that the red wire be connected to the battery indirectly and I expect you will get to what you mean. (switch and a fuse?)

let me know If' I am off track and I look forward to your next installment

[frankfast]

I'm having a bit of trouble with this discussion because I'm not electrically inclined but I'm trying. The rectifier I'm employing is the small cube with two positive terminals and two negative terminals. Am I correct in stating that the two yellow altenator wires are connected to the positive terminals of the rectifier while the red wire connects to the positive side of the battery via a switch. The positive side of the battery would also connect to the ignition coil and also to the lights via a fuse box. Where would the two negative terminals on the rectifier connect. I think that you wish to have the one yellow lead that's in phase with the ignition system to go directly to the coil via the negative terminal of the rectifier and independent of the battery. Where would the other negative terminal connect or would it go directly to ground? Sorry for my being so confused regarding this discussion.

[MotoMike]

Frank

You probably have a bridge rectifier that has 4 diodes in it. usually they are marked +,-, ac, ac. I suspect that Bob will get to it in due course.

the nice thing about the detailed instructions is that you can install the diodes as Bob suggests and it will just work without worrying about the theory.

[DewCatTea-Bob]

" I'm having a bit of trouble with this discussion because I'm not electrically inclined but I'm trying."

____ If someone besides myself were to help you with this, I'd figure that the first thing they would point-out to you is that my plan for your 6-volt system set-up requires two separate (half-wave) diodes, and yet you're still trying to figure-out how to wire-up your full-wave bridge-block. _ However, a bridge-block does contain four diodes (arranged in a 'bridge' layout), and fortunately two of them happen to be arranged just the way you need them to be. _ (The other two will be ignored.)


" The rectifier I'm employing is the small cube with two positive terminals and two negative terminals. "

____ If we're correct that you actually do indeed have a bridge-block, then it should have two AC-inputs (where your Yellow alt.wire-leads were connected) at opposite corners, one negative-output, and one positive-output at a corner that's indicated either by it's terminal being cocked at 45-degress (unlike the other 3, which will be parallel aligned), or it's corner will have it's right-angle point flattened by a 45-degree-cut,, otherwise the four terminal corners will be marked as Mike has pointed-out, (although some blocks will only have the positive-corner marked with '+'), and the negative-terminal is always at the opposite corner from the positive-corner.
__ If this info doesn't seem to match the black "cube" that you have, then please post a picture of it.


" Am I correct in stating that the two yellow altenator wires are connected to the positive terminals of the rectifier while the red wire connects to the positive side of the battery via a switch. "

____ Sorry, no ! ... The two Yellow wire-leads are to be connected to the pair of AC-input terminals ! _ And the Red wire-lead is connected (indirectly) to the Pos.terminal of the battery,, this means that you can either attach it (as Ducati did), directly to ANOTHER wire that's directly-connected to the battery, or, to a 3-pole ignition-switch -(like the stock key-switch), which is the preferred way (so as to prevent battery-discharge when key is turned-off).


" The positive side of the battery would also connect to the ignition coil and also to the lights via a fuse box."

____ Yes, after first going through a key-switch (to the ign.coil) and then a light-switch (to the lights). _ You can simply follow the large schematic that I posted (for w-c/450), for all of that other stuff -(other than the charging-circuits).


" Where would the two negative terminals on the rectifier connect. "

____ There should not be "two" ! ... If you're sure that there are indeed two/2, then please post a pic of just what it is that you have there ! - (I'm sure that whatever, we can still make use of it.)


" I think that you wish to have the one yellow lead that's in phase with the ignition system to go directly to the coil via the negative terminal of the rectifier and independent of the battery. "

____ I believe I understand the sensible-logic behind your thinking with that connection but, as you've worded your (enhancing)- circuit, it can't be wired that particular way ! - (And if it could, you'd not be able to turn-off your ignition, once started.) ...
The alt.circuit that's in-phase with the ignition should go through a rectifier and then to ground, (just as Ducati has done it) ! _ However, (in the spirit of your own thinking concerning the strength of the ignition empowerment circuit), it would better be grounded at the ign.coil-mount, (or the points-plate, which is not so easy to do!).


" Where would the other negative terminal connect or would it go directly to ground? "

____ The other negative-output from the rectifier would not then go to ground (as Ducati had it doing), rather, it should go to an added switch, (as I've previously mentioned), and then to ground within the headlight-shell.


" Sorry for my being so confused regarding this discussion. "

____ And I'm sorry that I've posted my opening-post for this thread without first getting it all completed & done, before-hand.


Fun-Cheers,
-Bob

[frankfast]

" You probably have a bridge rectifier that has 4 diodes in it. usually they are marked +,-, ac, ac. I suspect that Bob will get to it in due course. "
MotoMike


You are correct. I was wrong. There are two AC terminals, one plus and one minus. Bob, are you saying that there are no connections to the plus and minus terminals on the rectifier?

[DewCatTea-Bob]

" Bob, are you saying that there are no connections to the plus and minus terminals on the rectifier? "

____ Okay, good question ! _ And it's good that you've brought it to my attention now.
You see this situation of having started into YOUR particular project (with YOUR available parts), before finishing my original-post for a 6-volt system, has now lead to confusion ! ... As I've now been writing both about using two separate diodes (like Ducati has), and also (over the same time within this thread), telling of making use of your existing bridge-block, so as to do the same job, (electrically but not physically).
So in my posts which were directed to yours, (since you've now brought this confusion-issue to my attention), I'll have to go back & do some clearing-up of what I've been telling, (later!).
Due to the (unavoidable) fact that the outputs of both Yellow wire-leads are combined (after rectification) within your bridge-block, that means that YOUR project will therefore have only the ONE (combined) negative-output to then run to ground ! _ And also that the "added switch" will therefore need to be connected between the extra/2nd Yellow alt.wire-lead & your bridge-block. - (Which is just as some Jap-bikes have it set up.)
While Ducati has that ground-connection made where the rect/reg.box bolts to the frame, you should prefer to make your (single) ground-connection (from your bridge-block's neg.terminal) to the ign.coil-mount.
__ Now as to the part of your question concerning the Pos.output of your bridge-block, THAT terminal shall be left unused (because it's connected to the EXTRA/unneeded pair of diodes within).

____ I have lots to get done now that's currently not all making concerting-sense within this thread, so it's going to take another day or so to get everything all ironed-out.
Hope ya understand till then.


Hopeful-Cheers,
-Bob

[frankfast]

So one yellow lead is to be switched - possibly to be switched on when lights are in use?

[DewCatTea-Bob]

" So one yellow lead is to be switched - possibly to be switched on when lights are in use? "

____ That's right (in your case),, since you wish to continue making use of your bridge-block, the secondary Yellow alt.output needs to be switched before the connection to your bridge-block/rectifier ! _ And the switch is needed because if the lights are not turned-on, your battery would otherwise get over-charged (during extended running-periods).
__ I myself prefer a separate switch for doing the job independently but, ya can find switches that will do the job at the same time as when the lights are turned-on (just for convenience).
However with that type of (Jap-bike convenience) switching, then for such times as when your DUKE has been setting for a long enough time for the battery to run-down, then there'll be no way to supply it with a fast charge-up (with lights off) during the first hour of a slow-speed ride, (for just one somewhat note-worthy instance).
__ The one Yellow alt.wire-lead that's always left connected to the charging-system at all times, will put-out enough power to not only run the ignition and keep the battery charged, but will also power the lights so long as the (normal-range) RPMs of the alternator-rotor are kept high enough (to avoid running-down the battery). _ So you see, the secondary/extra Yellow alt.output is really not needed unless city-riding with lights on. _ That's why being able to shut-off the extra-power is good to be able to do, (when there's no voltage-regulator in the system).
__ This suggested straight-forward dual-diode charging-system set-up should supply the battery & electrical-system with a somewhat stronger charge than the stock set-up does, (so there's no loss compared to stock, other than the convenience which a regulator affords ya).

____ BTW, I've now edited my previous-post, so ya ought to go-over that for the added details.)


DUKE-Cheers,
-Bob

[frankfast]

I have one more question and then I'm done. Why is it better to ground the negative terminal of the rectifier to the coil mount rather than any other place that's more convenient?

I can't tell you how much I appreciate the time you've spent on my particular wiring scheme. I doubt very much that anyone will wire their single as I have, however I believe that your explanation will be useful for everyone. Thanks again Bob.