This is what’s giving me pause on the battery, you had it in a trickle charger and it was only 70%, then you gave her a charge, still bike is dead per say, then they check battery which has been on a trickle charger and you gave her a charge and the battery is 80%, that battery should go to to full volts on trickle charger and definitely once you charged it I presume stand alone real deal charger. The smell in your garage more than likely that battery making the smell. Anyway get the skunk running and you can diagnose better.