This post is about how to double the phase wires copper to allow more amps to be used on this motor.
On the stator with phase wire terminations facing up, going clockwise with the halls at the bottom, the phases wires from left to right are Yellow, Blue (center), Green. The three screws holding the shaft onto the stator core are common M5 thread. Each phase wire is 19 strands.
Hollow shaft ID: 0.300" / 7.6mm
BPM axle flats width: 10mm
Two 0.060" copper-diameter 16Ga wires that have been stripped of insulation and then twisted together equal a roughly 0.090" diameter of copper, which is approximately equal to Hobby King 12Ga.
The stock wire insulation is thin, but is actually quite good. I tried stripping a few inches of the stock insulation on the paired wires, and re-insulating the two of them with a single sleeve of heat-shrink, but the result was slightly bulkier than just the paired wires with the stock insulation still intact. I then tried taking the six phase wires (with the stock insulation intact) and covering that 6-stock-wire bundle with a sleeve of 6mm heat-shrink. This worked well, and even passed through the axle fairly easily with a small amount of lube on the outside of the 6mm heat-shrink sleeve.
The six-wire bundle inserted so easily, that I wondered if I could do that again with three of the original hall wires added to the bundle to be used to connect to a temp-probe. It worked! There was enough air-space between the fatter wires that three of them easily worked. The original sheath over the wire bundle is quite thick, and the 16-Ga wires are easily adequate for 500W, which allows a diameter of bundle that still easily and quickly inserts through the hollow axle on an assembly line with no lube. By using lube, removing the thick-walled sheath, and removing two of the hall wires...the phase wires can easily be doubled.
In this phase-wire upgrade, the stock cable length was cut in half to result in two equal-length sections. This also results in ten shorter hall wires, instead of the stock 5.
It might be possible to double the phase wires,
retain 5 hall wires for sensored operation, and also add three of the extra hall wires for the temp probe operation, since the hall wires are very thin.

- Fold the cable in half and cut, so you have two equal-length sections.
- Bafang6 001.JPG (57.61 KiB) Viewed 37521 times

- Put foam under the stator, and use the impact-driver to loosen the 3 screws that are holding the shaft onto the aluminum stator core.
- Bafang6 002.JPG (77.25 KiB) Viewed 37521 times

- Cut off the heat-shrink sleeve that holds the cable anti-kinking metal coil in place, and then remove the coil.
- Bafang6 003.JPG (120.7 KiB) Viewed 37521 times

- Spray a small amount of lube-oil down into the cable, and let it flow downwards for a few minutes.
- Bafang6 004.JPG (75.6 KiB) Viewed 37521 times

- Flip the stator over and put the 12mm axle-nut on the tip of the axle to protect the threads. Then, tap the end of the axle-nut until it comes loose from the stator.
- Bafang6 005.JPG (116.54 KiB) Viewed 37519 times

- Untwist and remove the three twist-ties that hold the phase wires onto the stator spokes.
- Bafang6 006.JPG (52.95 KiB) Viewed 37519 times

- The cable is held in place by an "Omega" shaped steel clip (a "U" with the ends bent outwards). Push the ends towards the center and downwards to release it.
- Bafang6 009.JPG (85.17 KiB) Viewed 37519 times

- Flip the stator over, and cut off the 5 hall sensor wires. I suggest cutting them where they attach to the ends of the green half-circle circuit-board, and leave a short stub with some of the colored insulation. That way, hall wires can be easily identified and re-attached in the future if desired.
- Bafang6 007.JPG (58.03 KiB) Viewed 37519 times

- After the hall wires are cut, the axle can be lifted out of the stator. Take a black felt marker and mark the aluminum stator with a Y, B, G...for yellow, blue, green. Place the marks next to the corresponding phase wire to make ID fast and easy. Note that the yellow phase wire shown has black insulation near its top, and the yellow can only be seen near its root.
After cutting off the section of heat-shrink that covers the soldered joint between the phase-wires and the axle-wires, cut the phase-wires while leaving a short stub that still has some of the colored insulation, so identifying each phase will be easier (note the yellow phase wire being handled has a short section of black heat-shrink over it's tip). That way they will go back together exactly as they came apart, and identification will be fast and easy. Note the Omega clip at the top right of this picture, place it in the parts jar immediately, since it can be easily lost. - Bafang6 010.JPG (77.01 KiB) Viewed 37519 times

- Three phase wires and 5 hall wires cut.
- Bafang6 013.JPG (76.38 KiB) Viewed 37519 times

- The wire-bundle is easier to pull out in this direction.
- Bafang6 014.JPG (50.2 KiB) Viewed 37519 times

- There was a dried glob of silicone goop, remove it to make re-insertion easier.
- Bafang6 017.JPG (55.3 KiB) Viewed 37519 times

- Two stock 16-Ga phase wires have the same copper cross-section as one 12-Ga wire from Hobby-King (measured with a caliper)
- Bafang6 020.JPG (59.58 KiB) Viewed 37519 times

- After several experiments, this is the recommended configuration for max amps and high-heat survival. No halls due to sensorless operation, three stock hall-wires to operate an internal temperature probe, and the stock phase wires have been doubled. The new bundle is covered by a single 6mm heat-shrink sleeve. A small black section of heat-shrink was put over the wire tips to smooth insertion and pass through the axle before the wires begin insertion.
- Bafang6 024.JPG (115.26 KiB) Viewed 37519 times

- Re-attach the axle in preparation to re-solder the axle-wires to the phase-wires.
- Bafang6 026.JPG (72.55 KiB) Viewed 37519 times