doesn't tantalum have much higher esr?

So far I know a lower ESR compared with normal polarized capacitors. But from what I can remember from school is that they have a faster response.

Roelof, do you have a part or model number for the capacitors you used?

These: https://www.ebay.com/itm/100pcs-1206...Cclp%3A2334524

Low ultra low ESR capacitors are typically used in low noise amplifiers to increase efficiency, audiophiles, and other shaman devices. Used in Switching power supplies output stage with relatively high frequencies in the kHz-MHz range. Low ESR capacitors are not really needed at the mains filtering.

Equivalent series resistance, due note I2R heating and may actually cause more DC ripple or feedback.

What kind of frequency is being seen here as ‘lossless‘ low esr capacitors are not a dime a dozen, putting a low esr Capacitor on a rectifier that is not running at high frequency would be pointless as most half, full, or doubling rectifiers run at mains frequency.

You should use a low ESR capacitor when the expected I^2 R heat loss (ripple current, squared, times the ESR), is too much heat for a standard esr component.

I have been working on a capacitor setup that uses a small heatsink as I think it is important it seems that they get hotter the more people are out causing interference.

I'd expect ripple to correlate with motor RPM as the rotor switches between the 3 phases, and also the switching frequency of the ESC as it performs PWM speed control. So, easily in the kHz range.

Yes, each phase is PWM controled and can go up to 40khz to get a decent PWM signal that does a voltage control. Remember thjat 60.000 rpm (+/- 5.5 to 6.5 turn motor) has a rotation frequency of 1khz..

Thank you Sir ;)