What I was meaning or trying to say is on the china girl magneto with 3 wires, the white wire is output voltage, I'm just not sure if that output voltage from the white wire is ac or dc voltage.
I've seen that before but I took the more durable and waterproof route since I ride in the rain more often than not and a 100 miles a week. Never installed the voltage regulator just to see how it work out without. I run a 44 during the winter and 40 during the summer so im constantly in the upper rpm 7-9k 37mph
They have a back light too I'm guessing the battery couldn't handle the voltage at that speed. Great light though. It has a special connection so you can wire the tail light right off the head light.