ESC braking causing spike?

[snellemin]

BTW, the caps are kind useless at the plug. They are suppose to be as close to the power input as possible and not visaversa.

[Nick]

Originally Posted by zeropointbug

I guess we should have told you this before, but are those low-ESR caps, and are they rated for 105 C? If not, then they wil lnot do anything for you, and they will most likely fail if pushed hard at all.

Please tell me they are low-esr.

Yep they are 105C.

@snellemin, how will they not do anything there? Where should they be?

I put them on the battery side like people said.

[brian015]

Originally Posted by snellemin

BTW, the caps are kind useless at the plug. They are suppose to be as close to the power input as possible and not visaversa.

Now that's an overstatement. I would guess that the resistance of those cables from plug to esc is less than the resistance of the actual capacitor leads.

[BrianG]

They are supposed to be as close to the ESC as possible. So really, on the wires right before they enter the bullet connectors would be ideal.

[snellemin]

Originally Posted by Nick

Yep they are 105C.

@snellemin, how will they not do anything there? Where should they be?

I put them on the battery side like people said.

You did put them at the battery side, but what was meant was to put them near the ESC itself and not the plug.

[Nick]

Ah cheers guys, couldn't of soldered them that close anyway.

They'll still something where they are I am sure.

[BrianG]

Originally Posted by Nick

Ah cheers guys, couldn't of soldered them that close anyway.

They'll still something where they are I am sure.

Sure you can, it just takes a little thinking. Here are a few pics from a Quark. It's different than the MMM obviously, but should give you some ideas:

http://scriptasylum.com/forumpics/quark_cap_1.jpg
http://scriptasylum.com/forumpics/quark_cap_2.jpg
http://scriptasylum.com/forumpics/quark_cap_3.jpg
http://scriptasylum.com/forumpics/quark_cap_4.jpg
http://scriptasylum.com/forumpics/quark_cap_5.jpg

And yes, the way you have it does provide some benefit, just not quite as much as if they were closer to the ESC. They are there to help the FETs, and the further away they are, the more wire resistance is present which reduces their effectiveness. Yeah, wire has little resistance, but it does have some, and at the currents we run (well over 100A), any resistance produces voltage drop.