aside from the electrical installation problems, a horn? why?
BEEEP!! (i can't stop before i hit you.. get out of my way??)
BEEEP!! (i have right of way and you better let me through or else??)
BEEEP!! (Hey you freakin ***hole!! You cut me off! I'm gonna vote to make it illegal for you to eat a hamburger, talk on a cell phone and put on your make-up all at the same time (??)
Drive defensively.. it's a moped.. we are at the very bottom of the vehicle food chain.. gopeds, skateboards, bicycles.. pedestrians.. ALL are above us and should be given right of way even if the "law" says different. The bigger animals can and do smash us like bugs regardless.
I'd actually prefer that nobody sees me (or hears me), because when they do they act weird and often become totally unpredictable.
But back to the topic, a magneto is amps-challenged and has a hard time just keeping the lights on. Hook one of those horns to a battery and measure how many amps it draws.. i bet it's more than all the bike's accessories now draw.
you really need a horn?? Need to make sure someone hears you? Get an air-horn at Walmart in the boating section.. compressed air/bottle type.. loud as hell .. simple..