I ordered this 500w controller to go with the 48v battery. A good thing about this controller is it works with the Sondors LCD display.
https://bmsbattery.com/ebike-kit/552-s12s-500w-torque-simulation-sine-wave-controller-ebike-kit.html
https://bmsbattery.com/ebike-kit/552-s12s-500w-torque-simulation-sine-wave-controller-ebike-kit.html