There are a number of posts in the history showing folks modifying controllers to handle 48V. Since then Goldenmotor has changed some of the controller boards, but the process will likely be similar. You need to verify the components will handle the peak voltage of a fully charged pack, check the supply to the low voltage components to ensure it can convert the peak pack voltage down to ~5V, and adjust the Low Voltage Cutoff sense pin to ensure it gets the right voltage. A bit of electronics knowledge is needed. Otherwise, just buy a 48V / 20A controller. The motor should handle the voltage without any problems.
