title_body: What happens if i select the wrong number of motor poles in BetaFlight? what kind of effect has on my gear and flights to have set a different number of motor poles that I actually have installed. for example, my motors have 14 poles but I set 12 on BetaFlight or vice-versa.
upvoted_answer: This is a setting that is needed for RPM sensing and RPM filtering. An ESC can not sense the RPM of your motors directly, but can sense how often the magnets in the motor bell pass by the coils in its stator (this is called eRPM), and will report that number to the flight controller if you've got bidirectional DSHOT enabled. If your motor bell has x magnets (or poles) in it, then they will pass a coil x times per full revolution of the bell. Thus, 
      eRPM = x * RPM. 
  
  In other words, to calculate the RPM of a motor, the flight controller will read the eRPM value reported by the corresponding ESC, and divide it by the number of poles. This means that if you set the wrong number of poles, your flight controller will read the wrong RPM from the motors, and the RPM filter will not work properly.
  
  If you don't use RPM filtering, you probably should not care. If you do, it won't work as intended (and may cause your copter to fly worse) unless you put in the correct number.