Join Date: Jun 2018
Location: Long Island, NY
The second Tsukayu 12V+ wire (the thin one) is a simple trigger. Your battery was weak/dead because there is no off switch for the stereo, and it was pulling full power the entire time the bike was off. There are more things drawing than the radio.
I found a switched 12V+ wire under the side cover (throttle side), removed some of the wire insulation and soldered the wire on. If I want to ride with the radio off (as I mentioned there is no main off for everything), I just disconnect the wire disconnect between the batwing and where the wire goes under the tank.