too long battery wires will kill ESC over time: precautions, solutions & workarounds - RCG
- Solution I & II, rules of thumb
- Capacitor type & polarity (orientation!)
- How & where (not) to add extra capacitors
- DIY capacitor pack pictures
- Capacitor & pack suppliers
- Expert/manufacturer opinions, they all say the same ... & their rules of thumb.
- Explanation, water hammer/knock analogy, theory, references, measurements
All RC controllers with block or trapezoid commutation need extra caps, not only Castle. Also Schulze, Yge, Jeti, Shock, Markus, Scorpion etc. and the Chinese OEM manufacturers. That leaves us one controller that doesn't need extra caps, SLS controllers .
You guessed it, that controller uses sinussoidal commutation, therefore less/no harmonic frequencies. They tested the SLS-60-100 for one hour with a 70m (seventy meter) battery cable at 1500Watt load. One of the developers, Rolf Zimmermann, is user RogerZ at RCGroups. Some people in Japan are working on a RC sinussoidal controller too.
More discussion, also about cooling the input caps: