Arducopter extreme spool up


I’ve been running into severe issues with my APM 2.8 board. Since I upgraded my battery from a 5S to a 6S LiPo and went from an 4 in 1 ESC to 4 single LittleBee ESCs the copter suddenly turned out as unflyable.

If I arm the copter and give it a minimum amount of throttle (RC_PWM_Input ~5%) the motors immeadiately jump to 30% - but only motors 2 and 3, motor 1 is always lower than 2, 3 and no matter how much RC throttle input I give, motor 4 always remains at arm throttle. Motors 2 and 3 further accelerate without increasing RC input, until the drone starts to shake heavily.

I calibrated each ESC (and in calibration mode, they behave normal), RC and all sensors are calibrated. Motor and RC wiring is fine.

And I know, that a “spool up” state is defined in the ardupilot copter code, but this is far from normal, it looks like a jet-engine which is about to blow up…

Thanks in advance. If I’ve missed any required informaiton, please let me know.

You never stated the motor Kv(RPM per volt of electricity) rating, or the prop size. HINT: Motor RPM is a function of voltage. Increasing battery voltage raises motor RPM…

APM 2.8 firmware (ArcduCopter 3.2.1) does not support ESCs that use BlHeli.

If you are bench testing the motors with out the props on you must use the Motor Test function in Mission Planner > Initial Setup > Optional Hardware > Motor Test. Testing prop-less motors by arming via your RC transmitter enables PID controllers. The motors are acting weird because APM is trying to stabilize the aircraft.