Yes, not sure what is going on. The LED headlamp I got was recommended by another member. By specs on box it should handle up to 12volts. So, not sure how these would be getting toasted from voltage. You say these things are putting out AC voltage, not DC? Maybe that is part of the issue with these LEDs. Or could be it's cheap Chinese kaka and it just died because it was junk and then the over voltage took out the tail light.
I don't want to mess with this too much. If it's just easier to use old school bulbs and it will be reliable, I'll go back to those. I'm going to get a flashing battery powered rear light for safety, like used on bicycles. A brighter headlight would be nice, but don't really run these at night, so not a big deal in the scope of things.
My Puch is only hitting maybe 30mph at the moment, so it's not "kitted" per say.