Interesting thread here. I used to design large (50HP~400HP) Three-Phase, Variable Frequency motor controls for industrial use, so I'm quite familiar with the principles involved.
What you're doing here (and some of you have correctly pointed out) is providing a "current reservoir" to supplement the battery during periods of high current draw when the ESC switches between windings on the motor. Being able to source additional current helps keep the voltage input to the ESC more constant, meaning you get smoother power delivery.
Every time the ESC switches, there's a huge slug of current drawn from the battery, and the capacitor bank provides what it can.
Keep in mind that bigger is not always better, and if the capacitor bank is too large, it will never fully recover to support the next time when the ESC switches. I don't know how big "too big" is, but just keep it in mind.
Since the capacitor bank is constantly charging and discharging at a very high rate, low ESR caps are a must. Don't buy cheap ones, either. I like Panasonic and Nichicon; both make good caps.
And considering you've got LOTS of electrons getting stuffed into and sucked out of the capacitors, which will generate heat, 85*C temperature ratings would be a "Best Buy".
What you're doing here (and some of you have correctly pointed out) is providing a "current reservoir" to supplement the battery during periods of high current draw when the ESC switches between windings on the motor. Being able to source additional current helps keep the voltage input to the ESC more constant, meaning you get smoother power delivery.
Every time the ESC switches, there's a huge slug of current drawn from the battery, and the capacitor bank provides what it can.
Keep in mind that bigger is not always better, and if the capacitor bank is too large, it will never fully recover to support the next time when the ESC switches. I don't know how big "too big" is, but just keep it in mind.
Since the capacitor bank is constantly charging and discharging at a very high rate, low ESR caps are a must. Don't buy cheap ones, either. I like Panasonic and Nichicon; both make good caps.
And considering you've got LOTS of electrons getting stuffed into and sucked out of the capacitors, which will generate heat, 85*C temperature ratings would be a "Best Buy".
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