I have a 30 amp infineon controller,i know if you add solder to the shunt of a controller you can up the amps,can you do the opposite and file away bits of the shunt to lower the amps to 20 or 25 amps,or maybe put in a 3 or more speed switch,running at 48v with a 30 amp controller on my ezee torq mk 2 motor is probably wasting energy,i would like to be able to save some power for longer runs.