Hi and
to the forum.
That controller would require some pretty hefty gauge phase wires combined with a high output battery to handle up to 150A, which is a lot more than the motor will handle for any length of time without overheating.
You would also need some very secure torque arms to prevent the axle from spinning with the extremely high torque that these motors can produce.
My modified 26" Magic Pie drew 97.75 Amps on a 51.8V 5Ah LiPo pack would simply flip the bike over backwards from a standstill:
GM had an external controller modification for the MPIII, but I don't know if this was just a one off for their own test purposes or whether they were actually mass produced for customers:
It should be possible to convert the MP4 in a similar fashion, but you will need to make a cover plate to fit in place of the existing controller. I would suggest making a paper template and transferring the shape and hole positions onto a piece of 3mm Aluminium.
As the windings and magnets are all pretty much the same
(Although I think that the MP4 has a slightly different winding pattern) a cheaper option would have been to use the external MPII or even convert an MPIII rather than modify the more expensive MP4.
Alan
