Hi keratea
I used this 12AWG cable from alphawire
http://alphawireonline.com/Products/Wire/Hook-Up-Wire/EcoWire/6718.aspxThis 12g cable is very thin and 3 fit perfect along with the cat 5 sized hall wires! I had to buy a full role of black as I could not buy off cuts! I used yellow, green and blue small cables ties to identify them. Then write down the hall wire colours to the cable you use.
I used cat 5 networking cable and cut the wires off I didn't need.
Okay first of all if you are not used to this, then you need to be very patent indeed! And take off the sprocket side cover off the motor. You will need to remove the motor stator. And that can be quiet hard. I got a length of wood and placed the axle on it and pushed very hard on the wheel and it popped out, Putting it back, well, just make sure your fingers are well out of the way! Use heatshrink to insulate where you make your connections in the motor. Put some tape on the cables and tie them to the axle to stop the force of the motor going back from damaging them.
How you connect the controller end of the cables is up to you, I got a bag of matching connectors for the controller I used to make connecting and disconnecting simple, Or you can just solder and heat shrink!
There are 2 circular clips on the cable side of the axle, and you will need a special tool to remove them, it can be a pain. I could not find any of the right size, so I did not put them back on. Just make sure you use a cable tie on the outer part of the axle to keep the cables from rubbing off the motor. It has worked fine for me. Oh yeah I got the matching throttle and ebrake, simply because they had the connectors for the controller!
Remember the external magic controller will only output 20 amps max, some say less. I got the 40 amp infineon controller from ebikes.ca and the direct plugin cycle analyst, with external speed sensor. The cycle analyst gives a very accurate indication of what you have left in your battery + you can adjust your current limits and speed limits. For the pie I really recommend that controller or similar.
Anyway good luck and keep us posted on how you get on
Mark