I bought my wife a Sunl T12 150 street legal scooter and it starting having problems starting- appearing to have no power or dead battery. It started happening more and more.

NOW- it wont start at all, I plug the battery charger in and it shows a green light indicating a full charge. however with the key on and if you pull the clutch handle it looses all power. Does the same thing if you pull the brake handle it looses all power.
Any ideas