hello im new to this forum but certainly not new to electric bikes and i seem to be a little stumped and hoping someone can help shine some light. I have a 1500 watt hub motor and stock it came with very small phase wires like probaby 18 or 20 gauge. its pathetic. I have a kelly controller and i juiced it to the point where my bike goes 53mph and the phase wires got so hot that they melted together and shorted inside the motor where it connects to the coils. No biggy i assumed i need to increase the size anyway given they were so small. I bought 12 gauge wire and there was no chance i was getting all 3 to fit inside the axle. So i settled on getting 2 in the axle and leaving one original phase wire in place but once it exited the axle i spliced in the 3rd 12 gauge wire. Now im having bad vibrations on acceleration and massive loss in torque.... All the phases are soldered and heat shrinked together. I feel okay about the soldering but not great because for some reason i couldnt really get the solder to really melt with the wires that well even with flux...but none the less i feel okay about it. Im wondering if maybe these issues are due to that short section of the phase wire thats really thin? or could it in fact be a bad solder connection? any input would be great. I know this is long and thanks in advance for any help.