Ezip dead : was working then throttle light went out when plugged into charger green throttle light came on until I hit the throttle

The light came on because the charger brought voltage up to full, but when you hit the throttle, the voltage dropped since the charger cant power the motor. While checking the wiring (which I assume people automatically do), bypass the power switch with a screwdriver or a jumper wire. If it works, replace the switch. Check the battery with a multimeter...you should get > 25.2v full charge, no load. If you get 0v, check the fuse in the battery case. If all of the above check out ok, and it's totally dead, you probably need a controller.