Is it the magic pie? or a motor with external controller?
Nearly all the 36v external controllers supplied with direct drive motors can handle 48v batteries. That's a maximum of 60v when fully charged, such as a 48v lifepo4 or 14 cell lipo batteries.
The motor should be good for at least 1000-1500 watts of power, provided it's not 1500 watts up some killer mountain.
With minor modifications to the motor, controllers up to 3000 watts and 100v is not unusual for us hotrodders at ES. For big watts, the wiring into the motor is generally swapped for a larger size.
That's for the generic 500-1000 watt direct drive motors. The pie is a bit different, with it's internal controller. I belive some of those have been hot rodded too, with external controllers instead of the stock one inside.