I think I have a dead battery but don't know for sure. Green light turns on when I plug in charger but no other lights. If so where can I get a replacement and could I up to a 36 volt. I have a 24 v now
I would be very careful over-volting that older bike design, it could be very dangerous and a fire hazard. I assume you have the original SLA battery, in which case you will never be able to revive it, you'll need to rebuild it.
Court did a review on the 36 volt SLA version where the owner installed a new rear rack battery:
I think I have a dead battery but don't know for sure. Green light turns on when I plug in charger but no other lights. If so where can I get a replacement and could I up to a 36 volt. I have a 24 v now