Hot Motors & Video Noise on Piroflip Team Edition Combo Package

by Corey Snyder

My Original Query:

Hoping to get some help on my Team Edition Combo Package. I got it all built up and tested it a race Saturday. I only flew 2 packs on it b/c I noticed at higher throttle situations I was getting pretty bad video noise, and I could hear that something was "off". It has a high pitched wharble sound that is accompanied by the video noise. Also when I landed I had motors that were too hot to touch.

Worth Noting:

  • I swapped to the Hyperlite 2207 1722 HV Motors.
  • This is my first 6S rig and I set it up the exact same as my 4S stuff.
  • Betaflight / PYRODRONEF4 (PYRO) 3.4.0 Jun 10 2018 - Diff
  • HQ 5x4.5x3 Props
  • I skimped and used 26g wire to my 2 450uf 35v Caps on the arms. (Maybe related?)

If I missed anything let me know. Thanks.

Answers:

Build Feedback

  • Use thicker gauge wires OR put caps directly on board.
  • Put Cap on same connections as VTX to handle noise there.
  • Try moving your camera to 5v as well.
  • 1000uf caps with 18g wire.
  • Power Cam off Unify 5v Out instead of off the board.

Flight Controller Settings:

Filters
  • @EvanTurner on BF 3.3 (Not ok on 3.4)
    • Also I turn off all notch filters and activate the gyro lowpass 2 and deactivate the 1st one.
    • Gyro Lowpass 1 to 0.
    • set gyro_lowpass2_hz = 90
  • @CoryIbanez on 3.3
    • The easiest solution is to go to 3.3 and turn the stage 1 gyro lowpass off by setting it to 0 and to turn the gyro stage2 lowpass on by setting it to 90 in the cli.
  • @CoryIbanez on 3.4
    • I suggest trying the first gyro lowpass set at 90 and the gyro_lowpass2 set at like 150-180 and to turn off the d term lowpass 2
  • @CudaKeer - Too much D gain might be causing the warble noise. Try 18 roll/20 pitch.
  • Baseline for 3.4:
    set dterm_lowpass_type = PT1
set dterm_lowpass_hz = 120
set dterm_lowpass2_hz = 240
set dterm_notch_hz = 0
set anti_gravity_gain = 3000
set setpoint_relax_ratio = 0
set dterm_setpoint_weight = 100
set iterm_rotation = ON
set smart_feedforward = ON
set iterm_relax = RPY
set p_pitch = 48
set i_pitch = 45
set d_pitch = 20
set p_roll = 38
set d_roll = 18
set p_yaw = 65
set d_yaw = 10

Tune:

  • @Michael Huddleson - Lower p and d a couple points.
  • Try d first 8k/8k
  • accelerometer off

ESC Settings

@Harrison Gale's Recommendations:

Set motor timing to auto. If you’re running dshot 1200 (or 600) set min throttle 1000 and max throttle 2000. Prefer DSHOT1200. Also set pwm freq to 48hz

@Mike Novak

Auto timing will dial back the timing to a quite conservative point. It will clear up a lot of issues in low throttle situations, but you also lose a ton of power in the top end. A local friend did some testing and found that you get an almost 70% thrust gain going from med-low (18-20 deg) to med-high (27-30 deg) timing, but power draw more than doubles (23A max draw vs 51A on high timing)

What Worked for me

Sofware Changes

To start I just made some software changes in both Betaflight and BLHeli32. These included most of the stuff above including:

  • Setting the BLHeli32 ESC timing to auto.
  • Reflashing to Betaflight 3.3 instead of 3.4 and I did a full chip erase since so much was different between the two builds.
  • Setting the first gyro lowpass set at 90 and the gyro_lowpass2 set at like 150-180 and to turn off the d term lowpass 2

This worked to solve my crazy wharble sounds and hot motors. It did not however fix the video noise issues under mid to high throttle situations. The noise was especially visible in big throttle changes. In order to fix those, I had to make a few changes to the build.

Wire Thickness to Caps

I swapped from 26g to 18g wire to my Capacitors from the main battery pads. This meant less resistance and I could really take advantage of the low ESR caps that I had already installed.

VTX Wiring

I moved my VTX from being powered right off the main battery pads, to being powered of the VBAT on the FC. I doubt this had much of any effect since I think those two are wired together with no caps/components between.

Camera Wiring

I also moved my camera from being powered off the battery to being powered off of the Unify Pro's 5v Out. This is the change that made the biggest difference I believe.

After making all of these changes the quad was flying smoothly