Look...you need to break out a $100 bill and buy ANY 12V deep cycle battery. You're gonna need one immediately and there is NO better or cheaper solution that won't end up costing your more money. Your existing battery is TOAST. Trying to charge it can only turn other things to toast. Autozone, and AAparts or Napa will all carry deep cycle batteries. A Group27 wll be $90-110 bucks typically. Good luck!
2015 Georgetown 280DS
2014 Vespa LX150 2014 StellaAuto 125