Yes, just do it. The mini motor will work very well with the 48v battery. You may want to restrict the amps going to the motor via the external controller/usb lead, but as they are already very restricted maybe lower the peak and continuous amps a little, otherwise you could potentially put too many amps throught the wiring/motor and burn them out - potentially. My advise would be not to do standing starts without pedalling as the mini motor gears can be fragile. Under full load (especially if you are trying to start on a hill going up) they are known to strip, but as I have said above always assist the motor with pedalling when taking off.
Andrew
