If your scooter battery won't charge, the first thing you should do is check the charging port for any dirt or debris that may be causing a connection issue. If the port is clean and clear, then you'll want to check the battery terminals for corrosion and clean them off if necessary. Next, check the voltage of the battery with a multimeter to see if it's above 12 volts; if not, then it's likely that the battery needs to be replaced. Finally, if all else fails, you can try jump-starting the battery with another power source like a car battery.