Hi Chuck
Great to hear the green LEDs worked out nice and bright.
Are you aiming for some filament
lumins loomens lemings light bulbs to load up the alternator when you beef it up some more?
The circuit with 18 Green LEDs sounds like you calculated that out to be just right for using the alternator windings as your LED current limiter.
If you don't mind me stealing your thunder Chuck, I'll explain (for those interested) how you would have arrived at that magic number 18.
A typical forward Bias voltage for green LEDs is about 2.2V - the internal impedance of the alternator was measured at 22 ohm (IIRC) therefore out of the 4V measured at the alternator output (unloaded), 1.8V (=4v-2.2v) must be across the internal impedance of the windings when LED load is applied.
1.8V over 22 ohm will pass 80mA.
That should give about 9mA through each of the 9 conducting LEDs during each half wave of the AC cycle (close to the typical 10mA required)
Setting the circuit up this way there is no need for the usual current limiting resistor. Neat trick Chuck
I'm looking forward to seeing your next mods
Cheers
Bez