For this weekend's project, I upgraded the phase wires in my 3T V2 MXUS.
The original Plan was to use 10AWG PTFE wires. However I had some difficulties getting the 10AWG PTFE wires through along with the hall wires. So I back-pedaled a bit, and ran 12AWG PTFE wires through the axle.
I still wanted 10AWG or larger wires to carry the bulk of the high phase currents from my controller to the motor, so I oped to splice 8AWG silicone wire to the 12AWG PTFE wires immediately once they existed the MXUS' Axle.
I saw this technique for end-end splicing on another thread here, and thought I would share it again, because I think it is the Cat's Meow.
How to make a kick-ass End-to-End Splice on Heavy Wires that will take a LOT of current
Start by stripping off a good 3/4" of insulation on both wires you wish to splice.
Unravel & splay the strands out slightly on each wire.
Slip the two Splayed wire ends together so they intertwine with each other. It helps if you hole the strands somewhat snug in your fingers so they don't just mash into each other, but really slide in between each others strands.
This next step is the key: Use a very thin strand of bare copper wire (I used a 4" long piece of Ethernet cable (28AWG maybe) with the insulation stripped off) to bundle the connection together. Wrap it around in a spiral, and as you do so, you pull all the loose strands of the wire ends tight together. (This is exactly what madin88 did on his phase wires inside the motor in the beginning of this thread.)
Once your slice is sufficiently snug and tight, solder everything together, This takes quite a bit of solder, so just let the strands soak up that solder, until the whole thing is saturated, all around.
Following the soldering, and after letting the connection cool, feel the surface for any sharp or pointy parts. File or press down any sharp or pointy areas (especially the wrap ends) so the bare surface is more or less smooth, and Apply Shrink wrap.
And Voila... You have a very neat and insanely beefy splice. This method works well for Both Phase wires and Battery Mains.