esc capacitors

[team n.o.m.a.d]

on some esc's ive noticed that they have cylinder type capacitors on them mainly black in colour what do they do? are they necessary?

[chris_dono]

generally you shouldn't run without a power cap in place. They help make up for the current drain on acceleration.

If you're lacking punch/brakes, it might be worth trying another cap to see if your current one is damaged.

[team n.o.m.a.d]

im gunna be running a mamba max pro with a novak 4.5hv motor 2s lipo will this need one and how many of them is one enough?

[Huckster522]

Originally Posted by chris_dono

generally you shouldn't run without a power cap in place. They help make up for the current drain on acceleration.

If you're lacking punch/brakes, it might be worth trying another cap to see if your current one is damaged.

If the cap is faulty, would it affect one or the other or both at the same time.
I have a 70a team orion vortex, which powers the car well, but the brakes only work when they feel like it.
when the car is moving slowly, they dont ever work, when under race conditions, sometimes they work other times the car just over shoots the bends etc.
also how can i test the cap to see if faulty or not.
amy help appreciated.

[Matt-h]

My LRP has not got a power cap.

It gets no hotter or has less performance than the one with.

My opinion is that those power caps are too small to make any difference at all

[chris_dono]

Originally Posted by Huckster522

If the cap is faulty, would it affect one or the other or both at the same time.
I have a 70a team orion vortex, which powers the car well, but the brakes only work when they feel like it.
when the car is moving slowly, they dont ever work, when under race conditions, sometimes they work other times the car just over shoots the bends etc.
also how can i test the cap to see if faulty or not.
amy help appreciated.

the only time i've personally seen if a cap is dodgy is that the end has a bulge in it. I think you can test them but I'm not sure how to do that with a multimeter.

[Richard Lowe]

Originally Posted by chris_dono

generally you shouldn't run without a power cap in place. They help make up for the current drain on acceleration.

They are to counteract the inductance of the power wires. When you turn the car off your ESC is running off the capacitor, it doesn't stay on long does it

If it struggles to keep the LED's in the ESC lit up for more than a couple of tenths of a second it won't really do much for the motor

[Northy]

Originally Posted by Richard Lowe

They are to counteract the inductance of the power wires.

Inductance?

[ianhaye]

mamba max pro i beleve have one inside the casing already, this is why the esc is so big as its all inclosed

[JonyNitro]

I will be running my CC 10 amp bec and turn the internal one off,on my new MMp just to be sure

[DCM]

The capacitor(s) are there solely to push and pull the FET Transistor gates shut, when the FET starts to get warm. Thats why the FET needs to be as close to the +ve and -ve terminals of the ESC, the further away, the more/bigger the cap needs to be. You can run them without, if the application isn't to power hungry, but if you are pushing the limits, to help with ESC temps, you can add more.

[Richard Lowe]

Originally Posted by Northy

Inductance?

I'm just repeating what my electronics savvy Dad told me

[pugs]

Originally Posted by team n.o.m.a.d

on some esc's ive noticed that they have cylinder type capacitors on them mainly black in colour what do they do? are they necessary?

If anyone would like the correct answer:

The mosfets in speedos switch on and off very quickly and with a high current on load, the switching causes "spikes" and the voltage varies up and down very quickly,the power caps help to stop the voltage jumping around and keep the voltage more steady to make it smoother and run cooler, the gtb set up also has diodes across the power cap,these are to help a bit more and to act as some protection if some idiot did manage to plug it in the wrong way round, Rich your dad is along the right lines because a brushless motor is an inductive load, it's basically coils of wire that are swiched on and off very quickly to turn the rotor

[R.C.Hole]

Guys I'm also running a MMp with a 5700kv brushless but I can't get any punch from my motor even with a 18T pinion.

My batteries might be screwed but do you think putting a (or more) capacitor(s) will help?

Or isn't that what they do?