I've seen a lot of info about caps. I've worked with electronics for 23 years, on all sorts of things. Everyone has said things that are correct, but the main idea of caps is to smooth the spikes out. Not the large dips in voltage, as there is simply not enough storage space in the sizes we can use to proved any amperage. A 47 Micro farad cap will supply power to an L.E.D. for about 1 second thru a 500 ohm resistor drawing less than .1 amp. Our motors pull large amounts of amps, so any voltage stored in the cap is quickly gone with no benefit to the motor, but to the ESC. The cap will keep the esc collectors on the transistors flowing more amps since the input voltage will be just a few thousands higher and so the forward bias will keep the amps flowing just a tiny, tiny bit more. Caps cannot store more voltage than the battery, without a diode in series to block reverse flow, and that will take an even larger voltage drop and pull away from the battery voltage. In fact all devices connected to the batter will have a voltage drop, and take a little from the total peak voltage. Any cap will be installed on the ESC input leads and so will be in parellel with the battery, and so if the battery or the CAP are higher in voltage, a potential difference is created and the electrons flow to the other device and balance out. IE, if the cap was 8.4 volts and the battery was 8.2 there will be a difference of potential of .2 volts between positive charged devices, but still that electrically would allow electons to flow to the other device and even out until there was no potential difference. That is exactly why we balance charge our lipos, so that there is not current flowing internally from one cell to the other.......
Also, connecting any cap directly to the motor will Decrease performance. only the smallest fastest discharge type should be used to limit spikes created from the brush moving off the comm. Any large cap will take voltage from the battery to charge, and lower the overall voltage to the motor all the time, and since the cap is directly on the motor, it will discharge as fast as the voltage is reduced from the esc since it is a direct short across the motor windings. No performance gain with a larger cap on the motor at all. Only the ESC will perform smoother and supply a bit higher voltage under load to the motor. But then again, anything connected to the ESC/battery will have a load and pull voltage away, so bigger or more is not always better in this case.
By the way, gates are normally switched on and off via +5 or 0 volts. TTL transistor logic using gates called xor, nor, andor, etc.... in a or gate, either input can be +5 and the out put will turn on or off. Others require both on or off to change the output state. A cap will change the voltage curve, to a better square wave rather than a sort of rounded square wave. That will reach the +5 just a bit quicker and the gates will change state just that much faster.
So, anyway, blah blah, blah........... Remember anything added to the system electrically will take from the total power output, you cannot get something for nothing in electronics. Caps only smooth the flow and allow for more precise voltage output, which can be a bit higher than if no caps were installed. ( in fact caps tend to leak when they go bad and will have a constant current flowing thru them and take more power away than they can store!!) something to think about................
