Now I am thinking to DIY a switching power supply unit (PSU) to test the BLDC motors, instead of using a real Lipo 4s ~ 6s. The PSU will have (1) a variable output voltage, (2) limiting current output, and most important of all, (c) A flyback Schottky diode to prevent back EMF damaging the Pico MCU.

200VAC to 24VDC PSU to evaluate Lipo 3s~6s PSU