Originally Posted by Little-Acorn
I rigged the 2-connector harness on the 60A ESC's battery cables last night, to connect two LiPo batteries in series, and tried it. Now my wattmeter can read only one battery's voltage, but the current of both batteries of course since they are in series. Plugged two 4000mAh 2s LiPos (nominal 7.4V each) from an R/C car, into the harness, started slowly, and revved it up.
Sorry if you think I am picking on you but I do not think you understand what you are doing or how brushless motor power trains work. OTOH the fact that you are open to posting exactly what your have tried is a good thing, because hopefully it means that you are willing to accept suggestions and learn.
"Starting slowly" with a brushless motor ESC does nothing to limit the current going to the motor. A brushless ESC sends a string of current pulses to the motor, each one of which is the same amplitude as WOT, even at low throttle. That, combined with your inappropriate motor and prop combo, is why things are getting hot.
Pleasel get yourself a proper RC power meter and learn how to use it..