TRF415boy

Well he should then review his ESC basics. As long as you're not to full throttle you wil always have a moment when your motor is off power and sending a back emf to the speedo. Anyway power caps are not here to provide power, but to smooth out the gate opening when the fets get warm bu the end of the run.

pucho

I don't use one on my Twister 2.1 for stock and some 19t racing with no problems with fade/spkes or anything of the sort.

rcnewb2004

A capacitor will give the vehicle more punch and a smoother acceleration for sure. Its not a requirement, your equipment will function 99% well most of the time because the quality of ESCs today are far better. But if your driving style/track requires you to accelerate and brake constantly, it maybe benefical for you to add a cap.

I have a twister 2.1 and run 19T, adding the cap has definately helped me exit corners a bit quicker. Suits my style of driving (I jam the throttle too much). Infact I have 2x 4700uF caps on mine linked in parallel. Does wonders for acceleration.

TRF415boy

Get back to earth mate, caps aren't capable of providing high amps, and the energy they stock will only make the motor turn slightly as has been said earlier. As an example, your 4700 µF caps are capable of stocking 0.12 Joules, this is completely useless to provide power for more than a nanosecond to a motor.

rcnewb2004

They are not able to provide higher amp draws, but they are capable of providing voltage during the off cycles on the esc.

I am interested to know where you get your numbers. 0.12J and 1 ns.

Can you elaborate on that a bit more?

Guo Chean

iTrader: (4)

where we can get this capacitor? it should be very costly

TRF415boy

W= 1/2*C*V˛ for any capacitor. nanosecond is an estimation, it just means a time so short you won't notice it.

How can they provide voltage if they don't provide energy ? As soon as they're discharged they're not providing any energy anymore. During a ESC off cycle the batt voltage goes back up and that's when the cap gets charged, it can't provide voltage at that moment.

rcnewb2004

I am not sure if all the energy in the capacitor is drained through one off cycle of the esc. if it can last more than 1/9300s (the lowest frequency on the hara twister is 9300hz) there may be energy left in the capacitor such that it can provide voltage through the off cycle...?

Can they provide voltage during the moments while battery voltage is going back up but it is still below the voltage in the capacitor?

I am sure it charges while the vehicle is free rolling. Therefore after a couple seconds of free rolling... the capacitor should be full again...

I have troubles believing that what I am seeing w/ additional capacitors on my ESC is some kind of illusion.

robk

iTrader: (22)

Doesn't the shottky control back emf? I thought the cap went to the battery?

XrayFK

iTrader: (1)

You are correct, a capacitor helps smooth out voltage spikes (dips, actually) from the motor.

seaball

iTrader: (9)

i put one of these on my car last night. i had to go from aluminum dog bones to STEEL. and this is with a stock motor.

yeah, oddly enough, the capacitor has made more people exhibit the placebo effect than any other product ever created. it's truly absurd.

rcnewb2004

where can i get one seaball? i am interested in testing it out.

if it doesn't speed me up, don't matter to me, it certainly hasn't slowed me down.

Z.Hallett

a website to show and explain the true science behind these claims would be welcome. i as well as an electrical engineer would like to examine the scientific background to see if this is truly plauseble to get such a high charge/current into a very minute package. this seems highly unlikely (no matter how low a voltage you go) to have 3F in a package less than 40mm X 20mm. a capacitor for car audio can hardly keep a 1 1/2 F cap from being less than a foot long and approx. 4-5 in in dia. and still keep it under 20 - 30 lbs.

so for the sake of us all:
please elaborate on your truly spectacular (if true) claims.

THE DARKSIDE

iTrader: (2)

Nope, that's the matcher.....

AustinTX

http://en.wikipedia.org/wiki/Supercapacitor