1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

Vermont Pete /

Hi All,

My trusty 103SP blew it's bulbs. Digging in, it was easy to see that even at idle, the 13 volts that were going to the lights was waaay too much. Rev it up and it easily hits 20 volts. This is supposed to be a 6 volt system! The brake light is fine - just the headlight circuit is messed up.

What's weird, is that there is no transformer or anything on the moped that I can find that would drop or smooth out the voltage. It's a no-battery system. There's no transformer, no set of resistors, not even a rectifier to go from AC to DC. And the wiring on this moped looks pristine - the 5 coil stator is in gorgeous physical shape - I see nothing mechanically wrong.

I've read a few threads on this topic - but nothing helps. Any thoughts?

-Pete

Re: 1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

hows your running light bulb?

i think the non air coil transformer harness runs the headlight, speedo, and tail on the same circuit? i have run a 10w as the tail, which dims the headlight due to the higher load on the circuit overall but keeps the nla sealed beams from blowing.

trailtech voltage regulator works, or just a ballast resistor / coil will work as a regulator.

Re: 1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

Vermont Pete /

My tail light is running at the same high voltage and was blown. The speedometer, according to the wiring diagram, is on the same circuit and probably blown as well. It was hard to see in the daylight.

I don't suppose you have a link to the voltage regulator or ballast resistor?

Thanks!

-Pete

Re: 1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

i lied about the trailtech one , it works on 12v great, but no guarantees on 6v stuff.

A reactance coil like this is what i am talking about. in series, it is a load that will draw on the system enough to keep voltage down.

do you have these under your rear fender/rack ?

having all good bulbs is step #1.

Re: 1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

Vermont Pete /

That's very interesting! I actually ordered the voltage regulator - but it will take a while to arrive. This weekend I put new bulbs in - even went up to 12v and no joy, the system is putting out way too many volts. At idle, the lights are at 6v, but by 3/4 throttle, it's up to 16v - under a full 12v headlight and taillight load! (And it doesn't have any problem powering them, either!)

The reactance coil is something I'll look into. You mention "under the luggage rack". I'll check to see if I find anything in that area - but I don't have a luggage rack. Mine has the long (two person) seat and there's nothing under it, nor under the rear fender. I can follow the headlight/running lights wire directly to the rear bulb as well as to the front bulb and there's no extra hardware in there. (But, I'll double check.)

Thanks, Jumpsuit!

Re: 1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

the wiring diagram for your bike is not represented in the wiki, but i believe it is this one:

IMG_6440.jpg

it seems like there was a transition from the 2-coil stator with one, dual-filament rear bulb, then to the 5-coil with the same rear bulb but no transformer, then ultimately to the 5-coil, separate tail/brake bulbs and transformer setup shown here:

so it looks like you might have the in-between setup - do you have a dual filament bulb back there, or two bulbs?

the only SP i worked on had a 5-coil, but did have two (i believe) "reactance" coils under the rack like this:

what kind of wire colors do you have- do you have the 3 conductor plug with grey/black/white coming off the stator, or bullet terminals? and at the taillight?

peugeot explicitly lists "add a voltage regulator" for blowing lights, so who knows.

Re: 1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

If you measured the voltage with all the bulbs blown and no regulator the. Of course your voltage is going to be through the roof. The system is balanced when the load of the correct number and type of bulbs draws down the output. VxA=W. If you are not drawing watts you are going to have excess voltage.

Re: 1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

Vermont Pete /

Yes, the voltage is high under load. I burnt out a couple more bulbs just testing. Yes, I had both bulbs in. :)

I have hardware arriving in a day or two (including new sealed bulbs).

I’ll reply when I have more info.

Re: 1980 Peugeot 103SP 5 coil stator running lights at 13-20 volts!

Vermont Pete /

Well, it looks like the problem is simply that the new sealed bulb I was using was a 12V bulb. Lower resistance...

For what it's worth, this particular righ (as Jumpsuit mentioned) is in-between designs. It's a 5 coil stator, but has no voltage regulation whatsoever - it seems to depend entirely on the properly balanced load being in place.

So, in the end, I have a new bulb on the way and it's very possible there's absolutely nothing wrong with my bike other than I put in an improper bulb.

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