AC / DC Combination

[Moonlight-Lover]

Hello all ,
I'm sure in the lifespan of Lambretta's existance , some of you hopefully have done what I'm intending to do.
And your advice will hopefully speed up my build.

My intention is to build up a 1970 UK Spec GP200 , 6v points model , but with a twist.
I'd like to get rid of using the battery altogether. And replace with a dummy battery box.
Can I use the following AC/DC components to make it all function ?
My wiring loom is the correct DC type.
Connected to the Original Large Ducati Rectifier Box on frame leg.
Ignition switch DC Original
Horn is an Original 6v AC
Stator plate Ducati 6v AC

Do I need to bridge any wires together to make a circuit etc
To make lights /brake light / horn work???

Thank you for reading
I look forward to your replies.

[Knowledge]

Here are a few thoughts on your plan.

First may I ask why would you want to settle for 6v lights when you can have 12v and actually see and be seen?

Now I’ve got that off my chest, let me point out that your “6v stator” does not give out 6v, but produces unregulated AC voltage which is then regulated by the ancillaries in the Wiring loom, in your case the large Ducati rectifier which delivers 6v DC. On an older DC system, it is usual to have a battery in the loom to soak up the surplus energy but as you have pointed out, you would prefer to live without a battery. If the stator has all four lighting coils wired is series, with a yellow wire at one (end of the series of coils) and earthed at the other, then it is an AC stator and probably suitable for 12v use. If the stator has the “power” coils grouped differently, with other wires like a brown coming out of the mag flange, then it is a bit more complex.

If you intend to live without a battery, perhaps what you need is a full AC system. You can still have your dummy battery (I have a 3D printed plastic one I bought a couple of years ago) but run your AC horn off the system quite comfortably (even at 12v if you wish). The DC loom and DC switch could be overcome with a bit of fettling and this might include joining a couple of wires together to correctly distribute your power to the horn, main lights, brake lights etc. Without seeing your DC Wiring loom, I can speculate on which wires will need to be bridged.

You would need an AC to AC regulator which you might be able to hide inside your existing rectifier box if you hollow it out. Anthony Tambs (Scootronics) should be able to supply something small enough.

The other way of doing this would be to keep things as they are but find a better battery. On my TV175 preservation project, I am using the 3D printed battery box to house a small 1.2Ah sealed battery. The battery won’t leak and it will give me a small reservoir of power for my lights and horn when the engine is off. Would that work for you?

Unlike you, I have gone for VAPE DC and I am hiding the regulator/rectifier unit in the four-pole original rectifier box on the rear footboard leg.

That’s enough for now. A grown up will be along shortly with the proper answers. Martin

[Moonlight-Lover]

Hi Martin,
Thank you for your thoughts and options. Much appreciated.

With this particular scooter. I would very much like to keep it as much to factory spec as possible. I'm not interested in 12v conversions , Full AC systems.
I wish this scooter too look fully UK Spec when looking under the panels. But without the hassle of battery use.
(With the option to convert back to Battery DC should I wish at a later date)
Having already sourced and fitted a new wiring loom ( Original Factory Spec ) GP200 6 Pole DC.
And sourced an Original Ducati 6 Pole AC Stator wire colours : Pink , Green , Brown , Purple.

As already mentioned Rectifer is the Large Ducati 6 Pole type.
AC Horn
DC Original Ignition switch

I look forward to any feedback , advice on the matter.

Best regards
Bruce

[lofty]

quick thoughts..

a- put a small modern 'gel' battery in the dummy battery box (as martin suggests).
b- put 'battery replacement' capacitor in the dummy battery box..

essentially everything else remains standard (including wiring) except the disguised battery..

[Moonlight-Lover]

But why would I need to be using a Battery or Capacitor ?
When I'm intending on using a AC ( non battery ) Stator plate.

[lofty]

ok, my misunderstanding..

in that case why not just duplicate a 'non battery' setup from a similar year (plenty of diagrams in 'stickys manual')
in a large part wiring diagrams/colours are similar, and if not, will show what needs to be reconnected and to where..

you will probably have to change regulator/rectifier if the existing one is for a DC system to one more suitable for a 'non-battery' model, or replace the guts of an original rectifier with something more modern.

other than that im out of ideas

[Captain Pugwash]

You can use the rectifier as a J/box, but it can't be left standard it would have to be modified.
If it was mine with the dc loom and switch gear from the ac stator
Green to green, brown to brown, purple to purple, and grey to pink.
The pink and grey would have to make a connection without running through any internal wiring of the rectifier. Same with the two purple wires.
The red wire in the loom that goes from the rectifier to the battery would need to be omitted.

This is likely to work, but this is all from memory, I currently have no scooters or books to check connections.

But there's a good chance it'll have the desired effect.

Make sure you fit the correct recommended voltage and wattage bulbs, or you will have problems with bulbs blowing or very poor lights.
Check the official workshop manual for the correct bulbs. I do have a small stock of 6 volt bulbs that would work perfectly, but like I said at the moment, I have no access to any scooters, parts or lambretta workshop manuals.

Wired this way with the ac stator there is no chance of harming any of your electrics, the only real difference will be how the switch gear changes circuits.
If the horn fails to work because its not wired into the purple wires electrical circuit then replace it with a wire from the purple at the headset down to the horn.
If the purple doesn't supply enough current the take the feed from the brown in yhe headset instead of the purple.

Good luck, Mark

[Fast n Furious]

Hi Martin,
Thank you for your thoughts and options. Much appreciated.

With this particular scooter. I would very much like to keep it as much to factory spec as possible. I'm not interested in 12v conversions , Full AC systems.
I wish this scooter too look fully UK Spec when looking under the panels. But without the hassle of battery use.
(With the option to convert back to Battery DC should I wish at a later date)
Having already sourced and fitted a new wiring loom ( Original Factory Spec ) GP200 6 Pole DC.
And sourced an Original Ducati 6 Pole AC Stator wire colours : Pink , Green , Brown , Purple.

As already mentioned Rectifer is the Large Ducati 6 Pole type.
AC Horn
DC Original Ignition switch

I look forward to any feedback , advice on the matter.


Best regards
Bruce

Hmm....."Original Ducati 6 Pole AC Stator wire colours : Pink , Green , Brown , Purple." The whole point to these stators was to avoid the need a for any voltage regulator and the performance of the lights was of no critcal concern. When the back light blew the extra voltage would then take out the headlamp. Why people would ever want to ride a scooter in the dark was unimportant to designers.
Not the best choice here. These were the stators fitted to series 3 and GP125's etc. The lights will likely be crap cos they are only powered by 2 seriesed coils on the stator (the brown wire) The horn was traditionally connected to this circuit also which was pathetic with the lights on.
The puple wire from coil 4 was used to power the side lights
The pink from coil 5 was used to power the brake light.
The 4 lighting coils on these stators can be reworked into a series/parrallel arrangment but then it needs an aftermarket 6Vac regulator, which are very uncommon.

[Adam_Winstone]

Sorted

[Moonlight-Lover]

Thank you all for your input.

With a little help from my good friend and Club mate.

I now have full working electrics. ( Cheers Adam )
Just as I wanted.
DC Loom , Large square rectifier , AC Stator on points. ( No battery )
Good lights & strong horn !