Capacitors on ESC wires.

[miniconverter]

I am getting the bits together for my 680 build so I am going to start wiring the power feeds for the ESC which will be mounted under the motors.

Having read loads on the internet it seems some people say you must put extra capacitors on long power wires whilst others say its totally unnecessary. Sort of understand the reasoning for both.

Now the big question is can any one give me a definitive answer and there reasoning, and if they are needed a value for them.

Thanks Stephen.

[teslahed]

I';d suggest wiring up an ESC and motor and sticking the prop on then testing it on the bench. Make sure the wire lengths are similar to the lengths you';ll use on the quadcopter itself.

Sorry i can';t give you a definite answer without actually testing it for myself.

Capacitors are very cheap though.

[Oakie]

What tesla said. In my opinion DC long AC short to keep interference down?

Making shore the dc cable is of a good size. 14g maybe for the dc and 12g if you go long. I guess deminishing returns would end up the winner. Then again what current draw are you expecting the esc to draw.

Paul

PS if it helps i would keep the AC side below 800mm and test each motor esc pair independently as you may start to see stalling going any longer

[guest325]

If you make sure you';re cable sizes are thick enough you shouldn';t need capacitors, all capacitors really do is smooth things out (stop surges).
I would suggest that you find out the draw on full throttle on the standard length wiring and calculate the extra thickness needed for the extra length.Make sure you up the thickness both sides of the esc, it does make a difference!

[Oakie]

In the end though it';s a fight between weight of the additional cables and the advantage gained through larger cable.

I would be interested to hear from you.

The caps may be useful in helping a quick surge from the motor, allowing for a thinner cable to be used to supply the esc maybe?

Paul

[guest325]

If it were on a small acro model I would agree but with a bigger camera platform the extra weight of thicker cables is less of an issue.

[Tean]

I';ve no knowledge with this on multis, but I can offer my experience with helis.
Before 2.4Ghz radios came along, interference from the ESC and its wiring was a real problem for 35Mhz radios with large electric helicopters. I spent lots of time trying to find ways of minimizing it. Extra capacitors didn';t really seem to help much. Gently twisting the battery cables together, adding a ferrite ring in the ESC to receiver cable and moving the receiver aerial as far as possible from the big current wiring were the things that did work.
When Spektrum radios appeared, the problem went away completely and I never bothered with any precautions again.
I would think that the extra soldered joints required to stick capacitors in all your ESC feeds would reduce reliability more than the RF noise they might save, but if you';re using a power distribution board you could maybe add a couple of low ESR caps of around 50uF there. Be aware that more and/or bigger caps will increase the connector sparking when you connect the battery.