Electrickery question

[MK Monty]

No wonder people get confused..... my brain hurts
MOST lambretters run AC Lights
If it has a battery your headlight will also be AC but the horn and brake light are often supplied by the power off the battery. The tail light will still be AC and Bugger me it's the same bulb just 2 filaments. It even uses the same earth point, its all magic.
It may or may not have a regulator to help stabilise the output.
If it has a battery the AC regulator will normally have an EXTRA output to trickle charge the battery at wait for it....at DC.
The output at 12vDC is very low and not good enough to power anything like a rear brake light or horn by itself without a battery. Remember the bucket analogy, full bucket with a hole as long as the tap is filling it up more than is being used, it will not get empty soon.
A long time ago some one looked at the Greasers of the time with shit British bikes and looked at how good the light were. They had only slightly better stators but had battery's and often used Zennor diodes often fitted with large aluminium heat sinks coz they get ##### hot but basically had a similar set up to a car. Everything is running DC. The battery works like the bucket but most of the power supplied by the stator is going to the lights. What's left tops up the battery.
Those that have seen the light, opt for the modern equivalent of the Zennor diode.
With an extra wire on the stator and a regulator like the Wassel or Podtronics they do the same job as the Zennor.
All your 12v lamps will run on DC you will have to change the duck quack AC horn.
You don't have to buy DC lamps unless you want to use LEDs. The light switch ignition switch and believe it or not the loom will all work on DC.
Not having a go at anyone but this thread is very confusing, trying to explain it simply meant I had to keep filling holes so it may be one more confusing post.

[johnnyXS]

No wonder people get confused..... my brain hurts

If it has a battery the AC regulator will normally have an EXTRA output to trickle charge the battery at wait for it....at DC.
.
Not having a go at anyone but this thread is very confusing, trying to explain it simply meant I had to keep filling holes so it may be one more confusing post.

well I don't mean to take issue but for the benefit of future visitors to this thread from searches it would be helpful if you were clarify your statement about the AC current from the stator coils charging the battery with DC

It doesn't and it can't
I think what you meant to say is that the AC output from your Stator lighting coil is rectified into a DC current by your rectifier which then charges the battery. The regulator then adjusts the charging voltage according to load and battery condition.

[MK Monty]

Not getting into a I know more than you spat here. Shall we call it a box of tricks be it a regulator or rectifier a BGM unit unit will give you a regulated AC output that will save you the race of blown bulbs and the basis of the original post. A good fit to any bike even if not designed that way. The same electrickery box will charge the battery. Your choice to connect or not. So it's a modern version of the old 4 pin Vespa one.
My preferences for the Wassel system and full DC is well known on here and this reminds me of a discussion with a scooter shop owner lecturing me on full wave and half wave rectification and on how a Vespa DC horn would not no could not work on a Lambretta. The same goes for my digital speedo phone charger HID headlight etc.
What ever. Merry Christmas guys

[sidepanel]

I've just encountered this very problem on my S3 125 Special 1966. Opened up everything and all the bulbs were 12V ! Anyway, 12v Speedo Bulb installed along with new 6V stop & tail and headlight. All worked well, for about 5 minutes. Now back to square one or rather just a little bit better off than square one No tail light, brake light works, only one filament of the headlamp working. When I switch the headlight switch over to the circuit or dipped beam the scooter cuts out dead ! Short circuit ? I didn't rev it on any occasion, but I note that the headlight and for that matter the speedo are way too bright like they are taking a major surge ? Hooter works fine and has done all the time .............any thoughts ??

[coaster]

I've just encountered this very problem on my S3 125 Special 1966. Opened up everything and all the bulbs were 12V ! Anyway, 12v Speedo Bulb installed along with new 6V stop & tail and headlight. All worked well, for about 5 minutes. Now back to square one or rather just a little bit better off than square one No tail light, brake light works, only one filament of the headlamp working. When I switch the headlight switch over to the circuit or dipped beam the scooter cuts out dead ! Short circuit ? I didn't rev it on any occasion, but I note that the headlight and for that matter the speedo are way too bright like they are taking a major surge ? Hooter works fine and has done all the time .............any thoughts ??

If you are saying that you bought your scooter already fitted with 12 volt lamps then changed them to 6 volt and they are blowing, I'd say your electrics could well have been converted to 12 volt by a previous owner. Does it still have points ignition?

[sidepanel]

Yes, definitely 6V and still on points. I've a feeling previous owner tried 12v bulbs because they kept blowing maybe ?? I'm going to try and remove the bulbs in the next couple of days (trying to find time at this time of year ) and see if they have definitely blown again. Thanks for the reply, i'll get back on here when I think I've found anything suspect ??