Various Alternate Charging-Systems for W-C Alternators

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DewCatTea-Bob
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Various Alternate Charging-Systems for W-C Alternators

Postby DewCatTea-Bob » Thu Oct 14, 2010 10:53 pm

______ This first post is divided into two sections, the top-half is a review of the stock charging-system, while the bottom-half is to be solely about the simplest alternate system for replacing the stock 6-volt charging-system.
Until completely finished however, the two slightly different subjects will be somewhat mixed-together within this single post.

____ Ducati has used about 7 different alternator set-ups for their OHC-Singles, and the one used on most of the wide-case models is naturally the best of all ! _ But like all the earlier examples, it's just a simple alternator which produces electrical-power in greater & greater amounts as it's rotor's rev-speed increases ! _ It doesn't produce any certain preset amount of voltage or current, or even wattage, despite any such figures stated for them, (which are just merely 'ratings') ! _ It's only able to create more & more wattage as it's revs increase, and the amperage & voltage that can be measured on it's various loads, are determined by the (resistance of the) loads themselves ! _ So as the power-output -(wattage) of the alternator increases, then so does the voltage & amperage (which the load is exposed to), also increase ! _ It's only the battery & voltage regulator which tend to cause electrical-systems to become 6 or 12 volts, and even that is not kept steady and can vary by a volt or two !! - (Of course even more-so without either of those two voltage anchors.)
__ The "70-watt" rating is just that, as that alternator only makes a fraction of that power at idle, and yet can also make more watts than it's rated for but it would then also get hotter than it was intended to be able to reliably stand.
Ducati came to that "70-watt" rating using their own (unknown to me) methods or formulas to reach or calculate that figure, and therefore it's somewhat suspect. _ As there's fair reason to believe that Ducati's stated-figures (for their alternators) are not actually that of just merely the alternator-output itself, but rather, fairly-likely a somewhat intra-balanced out-come when used in combo with the particular charging & load-systems which were chosen to be stock on the Ducati-models it's matched-up with. _ (In other words, if the same alternator were matched-up with a completely different charging/load-system, then Ducati's resulting rating for their alternator may have instead been 65 or 85 watts, for examples.)
This being the (likely) case, then since Ducati only allows 1/2 of the alternator's available power to possibly be utilized in their own stock electrical/charging-system, then it certainly may be quite fair to say that if 100% of it were to be made available (for the very-same load-system), that it could then be rated at 140-watts, instead.
Whatever, one thing is for sure, and that's that the alternator's available power can pretty-much be doubled from that of whatever's actually stock ! _ But with the stock 6-volt electrical load-system, it's just not needed ! _ (Unless perhaps you intend to let your w-c DUKE idle 24/7 with lights left on.)
Anyhow, whatever exact method Ducati used to figure their '70watt' figure, some particular/average-RPM had to be chosen in order to pin-down an exact figure (such as the 70-watts).
__ Now as to how it's determined that Ducati only makes use of (up to) just one-half of the alternator's available power, that's been determined due to the fact that Ducati's w-c regulator-box contains only two rectifiers, (one for each of the alternator's two power-windings).
The stock rect/reg-box also contains a batch of controlling electronics (sealed within a block) of which I was never able to open & determine it's circuits so I could understand how it controls the amount of juice that it's pair of rectifiers pass into the system.
Besides having the pair of electrically-functional terminal-connections for the two Yellow alt.wire-leads, the stock rect/reg.box also has a pair of non-functional (for itself) terminals for the alt.center-tap's Red wire-lead as well as the wire connection to the battery's Pos.terminal. - (That pair of terminal-connections is merely for a convenient-location for otherwise directly connecting that alt.output to the battery.
The last terminal connection on the stock rect/reg.box is for the brown-wire which connects to the key-switch, so as to turn-on the internal-circuit which allows the rectification... Without that terminal being able to feel the potential of a battery (that's not dead), the rectifier/regulator-unit will not work. _ (Thus protecting itself from having to power the load-system without a battery.)
As noted by other sources, it will render the rect/reg.circuits permanently inoperable if ya allow the unit to first be turned-on and then still continue to run the electrical-system after then having disconnected the battery from the system. _ Which can also happen due to vibration busting either of the wire-connections to the battery while running. _ That's what often leads to the death of the otherwise quite well suited (for their intended job) stock-units.
So if ya ever happen to notice your lights get brighter & flicker, stop the engine asap and check your battery-leads ! _ (The internal electronics can withstand that situation for a short period, so long as they don't get overheated by working that way for too long).
That problem is about the only issue that keeps the stock-unit from being completely perfect for it's intended job.
And that the lights can get extra bright (without the battery to hold-down the actual system-voltage), thus indicates that it's not the type of regulator that dumps excess power-juice to ground, in order to keep the voltage held-down near 6-volts.
(That the lights get so bright when the battery is un-connected, leads me to think that the brains of the regulator-circuit think that the battery is way-down & in need of charge, so thus it then allows the full available [negative] power-juice [from both of the alternator's two power-windings] to pass-through itself, so as to get the battery-voltage back up to par.)
____ The WideCase '70-watt' alternator is much like that of the narrow-case's -(2-winding 6-pole '60-watt' version) alternator, except that all six of it's poles are with coils (instead of just 4 of 6), and it includes a 3rd wire-lead which is Red instead of Yellow like the other two wire-leads. _ Missing from the '60-watt' alt.version, the Red wire-lead externalizes the opposite ends of the two Yellow wire-leads, (instead of grounding them internally), thus making the w-c version much more versatile !
The two Yellow wire-leads each connect to one of the two power-windings, and the opposite ends of those two windings both connect to the Red wire-lead.
Since the two separate power-windings are connected to their Yellow wire-leads so as to be out-of-phase, and their opposite ends are connected together along with the Red wire-lead, the Red wire-lead is thus much like a center-tap (of a single continuous power-winding).
__ With the alternator-stator's two windings connected to it's three wire-leads as they are, and with those three wire-leads wired-up as they are to the stock charging-system with it's stock rect/reg.box being what it actually is,, the stock electrical-system's Ground thus receives three negative power-pulses from each of those two alt.windings, per revolution of the alt.rotor ! _
And because those two sets of three power-pulses are produced from alt.windings which are opposite in phase, that means that when one alt.winding/diode-combo is producing it's negative power-pulse, the other output is then dead (at that same instant),, and that also means that each set of three pulses (conveniently) fill-in the other's down-time/dead-spaces, so that the combined-output from the pair of outputs then APPEARS to be as a full-wave type output. _ (However, all six -[2 sets of 3] POSITIVE power-pulses -[of an AC-cycle], that are available from the pair of alt.windings [every full-rotation of the alt.rotor], are left ignored [by the stock rectifier] and thus unused by the electrical-system !)
__ Bottom-line... the stock (wide-case)- electrical-system as a whole is quite well balanced, and all the wide-case models I've ever had (with Ducati's battery-type system), were always quite sufficient at staying fully charged & powered !

_____ NEXT, (now that I'm done with explaining the stock-system), I begin explaining an alternate 6-volt system which I think works better than the stock charging-system.....

____ This center-tap like set-up, along with various types of rectifiers, allows for dividing the alternator's power into different output-levels (much like a 3-way light-bulb !) _ Thus ya could choose to use 100%, or 50%, or even just 25%,, depending on the chosen wiring and your choice of how it's switched.
__ With the w-c alt's 3-wire set-up, there's a fair number of wiring-methods that could be chosen for various load-duties ! ...
But for the first case requested for this thread, we have need for only one of the simplest (of all the many ways that could be wired-up & used) !
__ To keep this proposed wiring-plan reasonably close to the stock-wiring lay-out, the Red alt.wire-lead should be connected (indirectly) to the 6-volt battery's pos.terminal. _ While the two Yellow wire-leads each need to be connected to one (of two) dedicated rect.diode, with one diode's neg.output going to Ground (preferably with a direct-connection to the motor), and the other diode's output going to a On/Off-switch, before then going-onward to Ground (preferably within the head-lamp).
__ It's unfortunate that Ducati chose to attach the same color of wire to both of the alt.power-windings ! _ Cuz while their outputs are about equal in power, their 'phase' is not ! _ Therefore at the point when the ign.spark is needed, one alt.winding's power-output will keep the engine running, but the other will be dead at that point. _ So that issue should be sorted-out (before making any permanent wiring-connections). _ That's most easily done by running the engine with the battery & the output from just one of the diodes, then disconnect the battery, if the motor then dies, you then know you have the out-put that should be left just for running with lights on, (if both out-puts let the engine die [without battery], then your alt.rotor is out-of-time), and if you've chosen the out-put that still runs the motor, then you've found the correct Yellow wire-lead -(with the out-put which should be kept grounded whenever the ign.system is running).
__ The power output from either diode will supply 25% of the alternator's maximum available power -(which may very well be fair to say is about 35-watts), and that's much more than enough to keep the battery charged while also running the ign.system ! _ This is because the output (of either diode by itself) contains 6 negative-pulses of power-juice per 4-stroke cycle -(2-revs of the alt.rotor), and the ignition-system only consumes the juice of about 1 of all those pulses, which thus leaves the other 5 power-pulses for just charging the battery (when lights are off).
So thus furthermore, if a 6-volt battery is too small and/or the engine is kept running at top-revs (such as in racing), then a voltage-regulator may still be needed, to protect the battery (if lights are never used), even though only 25% of the alternator's power-juice is being tapped (with the use of ONE diode on HALF the alt.windings) !
With a fully-charged battery to begin with, the output of just the first diode can also even keep the lights powered, so long as the RPMs are kept near their upper range.
__ The output from the other/secondary diode should be left turned-off unless the lights are left turned-on. _ Indeed if the lights are turned-on for periods over 20-minutes of lower-RPM riding, the output of the secondary-diode is then really needed to prevent the battery from overly discharging. _ Conversely with the lights left on, the battery may still suffer also from overcharging as well, if the secondary-diode's output is left added to the system for over an hour of sustained higher-RPM riding. _ But for normal/varied RPM riding, the battery can handle things and will be the anchor for holding the system-voltage at 6-volts and averaging-out the charging-system's varied contribution to system-power.
It's just that you,yourself should be the battery's caretaker by taking the place of a voltage-regulator and make-use of the secondary-alt.power-switch for canceling the extreme effects on ether side of normal-RPM riding. _ But, not to be too concerned about that, cuz the system will be pretty-much balanced under normal riding conditions, by just making sure that the secondary-diode's output is being contributed whenever the lights are on.
And just as it's nice to have the freedom to decide when the lights are on, it's also nice to decide when the system is fed the extra alt.power ! _ But if you're the type who doesn't care for extra options, then you can just get a switch that does the light-switching at the same time.
____ There are many different wiring-systems (which most others have not conceived of), that can be chosen from, to work with the stock w-c alternator. _ The one I've (begun to) explain above is the system I most recommend for 6-volt systems. _ As it's somewhat better able to deal with the total available-power which can be produced by the (more than adequate) stock-alternator, than the stock charging set-up is capable of doing, and just needs a switch to take the place of the regulator - (who's job it is to try to control excess power whenever it's being otherwise forced into the system!).
With this suggested charging set-up, it's neat trick is to not allow excessive power to enter the charging-system (only to then become left unconsumed), in the first place.
As Jim has smartly proclaimed elsewhere recently, it's not very sensible to have more charging-power than your bike can make use of, (just to then waste it).

New-NOTE - I still have not finished this (dual-like) posting, however those who've been waiting have possibly noticed that I've since added quite a bit more info than this post originally had when I first posted it ! _ I think I've finally included all I've meant to, concerning the stock-system at least, but, now I still have yet to put everything into a more comprehensive order.
When I've done that added task, I'll then change this note to indicate so.


MoreFun-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

10531
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Location: Surrey, Canada/Atyrau, Kazakhstan

Re: Various Alternate Charging-Systems for W-C Alternators

Postby 10531 » Fri Oct 15, 2010 6:31 am

Hi Bob,

Many thanks for starting this thread. As a 1972 350 Scrambler owner, I will be watching this thread like a hawk!
My beastie has no wiring with it, except for the wires out of the alternator, so I will be making all new wiring looms. I plan on going to a 12V system, but still use points for igntion (at least for now). In Canada we need to have lights on whenever the engine is running basically, and I'd like the lights to be as bright as possible. While I am aware that 6V systems can run the lights quite brightly, they still can't match the light generated from a good 12V source, hence my wish to convert to 12V. I already have a 12V Voxbell horn from a 750GT, but will need a new Voltage Regulator and Rectifier. I seem to recall you saying that Honda parts are suitable (I'm thinking XL250 would do the trick).
I realise this thread is in its infancy, but if there are other widecase owners out there interested in running a 12V system using the stock alternator, then perhaps you could add that kind of system to this thread (in time, of course!).
Cheers from a cold and windy Kazakhstan!!
Cheers
Graham

MotoMike
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Re: Various Alternate Charging-Systems for W-C Alternators

Postby MotoMike » Fri Oct 15, 2010 1:30 pm

Bob is this the circuit you are describing? Image removed. revised below.



Mike
Last edited by MotoMike on Fri Oct 15, 2010 8:34 pm, edited 4 times in total.

DewCatTea-Bob
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Re: Various Alternate Charging-Systems for W-C Alternators

Postby DewCatTea-Bob » Fri Oct 15, 2010 2:46 pm

" Can somebody post the wiring diagram and schematic for this system in this thread? "

____ I'd have to draw-up one for each of the various wiring set-ups that's used, cuz each will be different, depending on the choice one makes.
Assuming that you certainly must realize that, I must assume that you're referring to a generic wide-case type schematic-diagram of a stock charging-system, which I don't have but, I'll post a complete electrical-system for a wide-case model.
__ Now note added pic below. _ (The file is too big to see well here, so download it & view on your PC.)


Happy-Cheers,
-Bob
Attachments
Electrical-layout of 1974 450-Mk3.jpg
Here's a child-ized w-c scheme-layout that unfortunately doesn't detail the charging-circuits.
Electrical-layout of 1974 450-Mk3.jpg (1.4 MiB) Viewed 1796 times
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

MotoMike
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Re: Various Alternate Charging-Systems for W-C Alternators

Postby MotoMike » Fri Oct 15, 2010 4:06 pm

Hi Bob
I knew you would have to do some drawing. And also I have not been able to find the genaric schematic in the pubs I have. wiring diagram I think I have that somewhere.

an intersting thought. Ducati makes it clear in my owners manual that you should not run the engine without the battery as damage to the voltage regulator will ensue. They could have easily taken care of this by timing the flywheel so that the output is passing through zero when the points open. then you couldn't run the bike without the battery if you tried.

Mike

DewCatTea-Bob
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Re: Various Alternate Charging-Systems for W-C Alternators

Postby DewCatTea-Bob » Fri Oct 15, 2010 5:25 pm

" I knew you would have to do some drawing. "

But of course, Mike. _ (My previous wording was a rush-job.)


" Ducati makes it clear in my owners manual that you should not run the engine without the battery as damage to the voltage regulator will ensue. "

____ That's another side-detail that I'm meaning to cover in my thread on the w-c charging-system.


" They could have easily taken care of this by timing the flywheel so that the output is passing through zero when the points open. "

____ Right but, of course you understand the reason they wanted the alt.power to actually be timed for max.output at that point.
__ It seems that the designing department for the regulator-unit was out-of-touch with what can happen, before committing to production.
Far too many of those reg.units have gotten burned-out by running without battery connected! _ The unit does have a way to protect itself from not working without a battery however.


Hopeful-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

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Re: Various Alternate Charging-Systems for W-C Alternators

Postby DewCatTea-Bob » Fri Oct 15, 2010 5:56 pm

" is this the circuit you are describing? "

____ Almost missed this out of chronological-order posted-question.
__ My answer is Yes & No ! ... Your diagram is done well enough except the diodes are faced in the wrong direction ! _ (So as it is, the battery is burning-up the diodes & alt.coils.)


Tillater,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

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Re: Various Alternate Charging-Systems for W-C Alternators

Postby DewCatTea-Bob » Fri Oct 15, 2010 6:33 pm

By: Graham...
" I seem to recall you saying that Honda parts are suitable (I'm thinking XL250 would do the trick). "

____ That recommendation was for the ignition-parts, intended for use on 250-DUKEs.


" I realise this thread is in its infancy, but if there are other widecase owners out there interested in running a 12V system using the stock alternator, then perhaps you could add that kind of system to this thread (in time, of course!). "

____ Actually, it's that particular modification posting that I've been putting-off for so long ! _ And I was already planning to add a post about a 12-volt conversion next. _ However, from what you're wanting for your situation, you may prefer to only do as another of us has already done, and just do the simplest connection set-up as possible. - (By connecting-up a full-wave rectifier to the two Yellow lead-wires, only.)
Didn't you see & read the thread titled "Ignition and Charging System Upgrades", about 2-months ago? _ It will soon be bumped-back to the top of page 4 (of this forum-section of topics). _ You may wish to start reading beginning with the 2nd-post on page-1 of that thread.
(It's too bad that that thread mixes-together topics on both charging-systems & ignition-systems, for OHC-models, (as only the non-OHC models use combined parts for such),
thus you'll have to read a little of each post to realize if you're interested, since many post-writers fail to rename their post-title.)


DUKE-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

MotoMike
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Re: Various Alternate Charging-Systems for W-C Alternators

Postby MotoMike » Fri Oct 15, 2010 7:17 pm

DewCatTea-Bob wrote:" is this the circuit you are describing? "

____ Almost missed this out of chronological-order posted-question.
__ My answer is Yes & No ! ... Your diagram is done well enough except the diodes are faced in the wrong direction ! _ (So as it is, the battery is burning-up the diodes & alt.coils.)


Tillater,
-Bob


Ok, I wanted to be sure as the phrase "diode's neg.out-put going to ground " led me to believe you had the cathode (-) hooked to ground, when it is the Annode (+) you want hooked to ground. I'll have another look. If I have it right now let me know
Attachments
wide case full wave3.jpg
wide case full wave3.jpg (31.01 KiB) Viewed 1785 times

DewCatTea-Bob
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Re: Various Alternate Charging-Systems for W-C Alternators

Postby DewCatTea-Bob » Fri Oct 15, 2010 8:38 pm

" I wanted to be sure as the phrase "diode's neg.out-put going to ground" "

____ Alright, this sort-of brings-up an old issue about current-flow direction... does it flow from Neg to Pos, or just the opposite. _ I myself use both ways of looking at it.
So therefore to me, any negative-terminal can have an OUT-put just as a positive-terminal can also have an output. _ I just don't bother to think about whether the electrons are going in or out of a DC-terminal.
__ I guess you would not have been confused if I had stated 'in-put' (instead of 'out-put'), or, instead wrote "diode's neg.terminal going to ground" .
Since we're not all electronic-techs here, I prefer to use wording & terms which cycle-mechanics are more apt to be able to understand, (although I'll slip once in a while). _ I realize that the auto-industry tends to reason that only the (positive) wiring has an 'out-put' and that everything goes into 'Ground', but for those of us who are not already aware of just what's really going-on, I wish for them to realize that there's a negative-output of a diode, which has a negative-charge (of electrons) flowing-out from it, (thus a positive-charge flowing-inward, as diodes correctly point the direction of), even though the point of a diode indicates it's direction of flow oppositely.
__ I'll try to keep myself more aware of this issue when I edit my posts, so that either camp -(Pos.flow vs. Neg.flow), will not have their trained-thought disturbed.


Hopeful-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob


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