Anybody else tried using the capacitor in place of the Rx pack technique?

[WheelNut]

I've found one thread on this, the guy used a 0.47F capacitor plugged into the battery slot in his Rx, this compensates for the voltage drop in the batteries and apperentally eliminates cogging. I'm going to order a 0.10F and a 0.47F to try the two of them out, supposed the 0.47F is pretty high capacity so there could be the possiblity of damage to something? Anyone have any thoughts on this, seems like a very nice alternative to using a Rx pack!

[ducati777]

Don't know on that one. I use a 4700 uf cap on my battery wires. I've always done this, but on 6 cells after the pack runs out of punch, it will cog. On the lipos the setup runs perfect.

I haven't heard of doing that to the Rx. Considering I really like caps, maybe I'll try it. To my knowledge theres pretty much no way to damage anything with caps. They're just a place to store energy, if the voltage drops, the cap kicks in, but since its charged off the same voltage its replacing, it never comes in higher. Thus if your BEC is at 6 volts, the cap is at 6 volts.

There was a little cap that came with my mamba, maybe I'll throw it on the rx. When holding the car off the ground I get a tiny bit of glitch when I rev the mamba, might as well try the cap.

[OptimaMan]

A .47 farad is 470,000 uF! So, he's talking about a capacitor that is about 100 x larger capacity than yours. 1 F capacitor has the energy to power 1 amp for 1 second or 2 amps for 1/2 second or 4 amps for 1/4 second etc. etc. etc. It sounds reasonable to assume that the receiver could momentarily use the power of the capacitor to power it - but maybe you'd need a diode from the BEC to the receiver to prevent energy from the capacitor going back to the BEC.

Somebody try it and tell us how it works! One thing.. how HEAVY is that .47 F capacitor? It probably weighs more than a UBEC!!!!

[bomb-proof]

1F is all you should need, the guys at Bk have been doing that for a while.

[WheelNut]

The .47F weighs like a few grams, its very small. I'm going to try the /10F first and see how it works.

[AtomHeartMother]

I read the thread posted a while back about this. I got some.47F capacitors from digikey.
It does seem to smooth some cogging though it isn't eliminated. I did notice that Rx glitches seem to be reduced as well.
I run 7 cell nimh 3000's on a feigao 8s with a warrior 7018 esc.
Yes, they're small and light...no weight penalty on anything but the smallest of vehicles.

[ducati777]

This is how I do it, right at the batt plug. I think they're 4700 uf but I can't remember exactly.

http://www.freepixhosting.com/uploadedfiles/100_0802.jpg

http://www.freepixhosting.com/uploadedfiles/before01.JPG

[standard_63]

I used to have cogging on my hacker master comp esc until I got a UBEC, and now it's smooth as ever. Glitches only occasionally now, but the difference with RX pack vs. UBEC is amazing, at least on my setup. I also notice better performance on my other cars using lipos over nimh, maybe more voltage helps, or better current draw?