Suzuki A50p (often known as Ap50) charging system.

[Fat bloke]

Hi, I wonder if anyone out there is an expert on the charging system used on this type of machine. I am looking to upgrade it but am really struggling to fully understand what I would need to do. It is fitted with a simple diode to rectify the AC output from the charging system, it also has an output to the headlight and tail light which seems to run on AC. My experience of this type of system is that the battery tends to go flat on short journeys and the battery tends to over charge on longer ones. The charging system has three coils and one of these is solely used to power the ignition system. One of the other two is for the headlights and the other one is for the charging system. Its a little more complicated than that because the charging coil has more than an earth one end three other wires connected at various points along the coil. According to the wiring diagram I have both coils connect to each other when the head lights are on and one of the wires doesn't connect to anything. What I would like to do is upgrade the system with a regulator /rectifier. I could convert to 12 volt or stick with 6volt but just don't know how to. Can anyone give me some idea
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[A100man]

Not sure about a 12v conversion but to get teh most out of what you have I'd try LED lamps if they are available in 6V and a more sophisticated regulator/rectifier. As I recall it's not even a full four diode bridge on those just one diode and no regulator..

Cheers
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Now: A100, GT250A, XJ598, FZ750, SL1000

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600, Skorpion

[redeem ouzzer]

I had an A100 (similar bike, same electrics). Granted the electrics were crap but I can't recall any issues with the battery under or over charging. If all components and the loom are in good fettle it should work ok, the battery doesn't really have much to do other than indicators and stop light.
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Be a REAL MAN!

[WD Forte]

I have a wiring diagram here and its pretty simple really.

Basically you have 3 circuits from three windings
1 AC for head and tail light plus speedo back light
2 Half wave rectifed DC for the neutral switch,indicators, horn and brake light
3 Ignition which is pretty much isolated from the other two.

Various upgrade options come to mind but for you,
leds are probably the easiest one as you don't seem to understand how your bike works and that's not a good basis to start modding from.
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[Fat bloke]

I have tried to add pictures but this platform just doesn't want to accept them.
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You're only supposed to blow the bloody doors off!

[Fat bloke]

Thanks for everyone trying to help. What I want to do is add a more sophisticated regulator / rectifier which I believe will monitor the battery rather than supply it with a very low unregulated trickle charge that doesn't really work well. It should be fairly straightforward but it is not clear how this could be wired. I would like to make a new loom with all the wires I need in place rather than adding wires and cutting others. The Haynes manual diagram shows only one induction coil for both the lights and the charging system and another for the ignition system making things difficult to work out.
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You're only supposed to blow the bloody doors off!

[WD Forte]

"I have tried to add pictures but this platform just doesn't want to accept them."

Dont blame the forum, adding pics is easy
is this what you have?

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fi.ebayimg.com%2Fimages%2Fg%2F6wEAAOSwbuFfjGUM%2Fs-l400.jpg&f=1&nofb=1
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[A100man]

[Fat bloke]

Thanks WD Forte that is exactly what I have. I am a bit of a dinosaur when it comes to computers but every time I try to add a photo I am told that the attachment is too big. Any tips on how to attach photos will be appreciated.

I will carry on trying though.


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You're only supposed to blow the bloody doors off!

[WD Forte]

Not sure how useful that regulator A100man points to would be
as its a solid state dynamo (DC) regulator
which replaces one of these old things
https://www.britishmcparts.com/images/cache/Electrical/Volt_Reg.500.png


What you need is a rectifier and regulator (RR) to rectify the AC to DC then regulate that voltage
to suit the system, 6v or 12V.
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bikers smell of wee

[Fat bloke]

Thanks A100man for your reply. I am not convinced that the regulator detail that you have given me is also a rectifier. I can however find a couple 4 wire 6v rectifier regulators on the interweb. My problem is that there are 3 charging wires that come out of the stator plate. A yellow with a white tracer that isn't used on the A50P model at least. A green wire that connects to the main switch and then onto the diode rectifier only when in day time (no headlights on) mode. A Yellow wire that connects to the main switch and then to the headlight, tail light and diode rectifier only when in night time (headlight on) mode. The wiring diagram I have from the Haynes manual (which seems to be a copy from the owners manual) only shows 1 induction coil but as you can see from the photo so kindly supplied by WD Forte the charging system has 2 induction coils. The third induction coil is purely for the ignition system which needs no modification. The two coils have different thickness windings so if incorrectly wired could overload the thin one.
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You're only supposed to blow the bloody doors off!

[Fat bloke]

Haynes wiring diagram.
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You're only supposed to blow the bloody doors off!

[Fat bloke]

Another go[/img]
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You're only supposed to blow the bloody doors off!

[Fat bloke]

Not sure if anyone can see the attachments I have made. Any tips on how can include them properly might help.
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You're only supposed to blow the bloody doors off!

[WD Forte]

https://www.bikechatforums.com/download.php?id=104426

https://www.bikechatforums.com/download.php?id=104425
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[Fat bloke]

Thanks WD Forte.
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You're only supposed to blow the bloody doors off!

[A100man]

[Fat bloke]

So looking at things it's a whole lot more complicated than I at first thought, but I don't like things to beat me. The flywheel / Magneto section of any wiring diagram I can find shows only one induction coil used for the lights and charging system but there are in fact two. The simple LED upgrade idea is probably going to be a non-starter because these are polarity conscious and the headlight, tail light and parking light run on AC when the headlights are on but the tail light and parking light switch to DC when in the parking light mode and the brake light is DC. This means that the stop and tail twin filament bulb runs one filament in DC and the other in DC or AC depending on main switch position. The indicators show as running in series with the warning lamp in the speedo which could also cause issues. The wires inside the magneto go into a sheath and come out the other end a different colour so its difficult to trace which is which. Apart from two extra dark blue wires the wire colours are at least the same as in the diagram. Using a multimeter on the wires doesn't really help much because the coil wires have very low resistance so pretty much all the wires seem to give low resistance to earth and each other. So my limited understanding of electrical engineering tells me that possibly running a bridge rectifier to each of the AC circuits will at least get rid of the AC complication. Then disconnect the green wire and use the yellow with the white tracer wire for the charging system through a regulator / rectifier. I would also need to alter the switching so that the headlight circuit has no connection to the charging system and the charging system continues to be connected when the headlights are on. An upgrade to the indicator flasher unit to allow for LED bulbs could also include a separate supply to the indicator warning lamp. It could be a year before I get to this stage because the bike is a back from the dead basket case and every step of the way has been hard so far.
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You're only supposed to blow the bloody doors off!

[WD Forte]

I wouldn't say its complicated.
It looks a pretty common system for that age and size of bike.
I reckon that it could be converted/modded in a number of ways
from a simple led upgrade up to a 3 phase 12v DC system using the points
to trigger a 12V CD CDI or TI ignition system.
Output Power will always be limited by the physical size of the magneto,
coils & windings, magnetic flux density and speed etc, so leds would be a good move in any case.

Parking lights could be dispensed with, who uses/needs parking lights?
The existing switch gear could be retained but the wiring modded to suit
the modifications done.

If you want simple get a Mobylette
https://www.bikechatforums.com/viewtopic.php?t=324407
1 coil 1 sodding coil was all I had to play with but got led lights to work on it
in 2018 and they were still working when he dropped in here with it a month or two ago.
I wanted to develop it more but he was keen to go off on it.
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[Fat bloke]

Thanks WD Forte, I started this by wanting to make a new loom where the old one was / is completely knackered. What I wanted to do is upgrade it but make it look like it came out of the factory like it. Simple things like indicators and brake lights that work even when the engine is only idling. Maybe a brake light that comes on which ever brake you operate. Even the possibility of a headlight that gives enough light to see more than 2 foot in front of you. It will mostly be used for shows and events but I will probably ride it a little more than that. I am going to have a hard think about what to do with it, I am sure that there is potential for improvement.
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You're only supposed to blow the bloody doors off!

[WD Forte]

clue
AC is rectified to DC by a diode
LED means Light Emitting XXXXX?

geddit?

Many leds will work on an AC supply but there's nothing stopping you
fitting a say 10A schottky diode on the yellow lead and going all
LED throughout the bike.

a 5W even 10W* LED bulb wil give out more light than
a 6V 25W bulb but use less than half the power and it really is the simplest option as most older bulbs
have direct one for one led replacements available.

(* I'm talking actual power used in the circuit not the nominal/equivalent values often stated by sellers so best check for this)


for instance check out
https://www.classiccarleds.co.uk/collections/6-volt-collection

and
https://classicandvintagebulbs.com/
for reference
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