Effect of capacitor wire length

Conclusion first: The shorter the capacitor wire and the closer it is to the ESC, the better the filtering performance.

Let’s start with a comparison. The data shown in the following images comes from the same drone, with the only difference being the length of the capacitor wires.

• Noise graph with a long capacitor wire:

微信截图_20230518175240.png

• Noise graph with a short capacitor wire:

微信截图_20230518175300.png

As you can see, shorter wires result in cleaner overall noise (less yellow area), and the gyroscope data becomes much clearer. This helps reduce motor heat and lowers the load on the ESC.

Finally, let’s talk about how filtering affects the drone as a whole, highlighting the importance of having a capacitor and keeping its wiring as short as possible, close to the ESC power input:

1. Better filtering reduces unnecessary motor signal output, making flight actions cleaner and more precise.
2. With more effective signals, motor heat is reduced, current demand is lowered, and the system becomes more power-efficient.
3. Lower temperatures help prevent magnet demagnetization in the flight controller due to overheating, which can lead to motor desync. (Bi-directional DSHOT with RPM filtering is effective at filtering out motor noise.)

Therefore, we recommend enabling bi-directional DSHOT when experiencing motor desync.