esc for HV

[jayt]

Adding capacitors to a well-designed ESC does nothing for performance, this simply is a bandaid for poor wiring. If you have to use long power wires with high impedence, then adding caps can help a little - but the best solution is to use short power wires of adequate gauge. I once added caps to an ESC for SAW use, and the ESC still blew! The problem was the ESC, not the caps.

If the caps go bad - no spark when plugging in the packs - then replace them. I had the cap on an Aquacraft ESC go bad, so I replaced it with what I had available. Doubtless it is overkill, but it works.

 

[hugh hargett]

Jay I have to disagree. No caps in all scenarios wont save an esc but they definately improve the stability of the power supply and thats what the esc's like. If this werent the case you would not see castle as well as schulze recommend them on there WELL DESIGNED esc's. Im so sorry but iIl have to disagree with you. Schulze even has a tutorial telling you how to install them. Jay you used to run them on your striker remember?????

capacitors do exactly what they are designed to do. Bulk capacitance is just the thing for starting surge on a motor or an amp spike. Thats it nothing more. My escs are well designed and I use them . Can you expalin why you see them hanging off every esc on the market from 29 dollar skywing to 900 mgm comp pro???

 

[gil sonsino]

I added a pair of caps to my 180A ver3 and tested the boat yesterday ..quick runs and no issues.guys the debate is open and the more you trade the more we learn. Gill

 

[MarkTanski]

Caps are there to smooth the ripple current from the switching of the esc, not anything to do with "storing current" for spikes or takeoff, an impossibility with the size of caps we use. PLus they never actually discharge in this application.

Some capacitance is required for filtering, more won't hurt anything at all. It won't take away from performance.

A number of smaller caps dissipate heat better than one big one does, in parallal they act like a cap of higher value anyway, just more cooling surface.

Adding caps is half band aid half not, they share the workload and run cooler appearing to fix something BUT they haven't really solved the problem of WHY are they working so hard to heat up in the first place, which is batteries and wiring. If you're at the absolute limits of available power delivery more caps can give you a little bit extra protection for a short time before they begin to heat up and bulge, then blow, and the damage is cumulative. Thats why they can all of a sudden blow under almost no load.

Who'd have thought knowing how to repair guitar tube amps would come in handy to rc boating!

 

[hugh hargett]

CC CapPack is useful in all brushless motor applications, where it serves to give just that little boost needed to overcome ripples in the battery voltage caused by hard acceleration or long battery wires. Remember, ripple voltage is hard on an ESC, adding the CC CapPack can help reduce the load on the controller's on-board capacitors.

from castle

BOOST. HARD ACCELERATION . The battery is the power supply where do you think the power comes from? smaller caps rc time is faster than one large cap and lower resistance as there are more paths for the current to take. No need for any debate gill . More caps have nothing to do with cooling surface smaller caps in parallel simply have a lower resistance just like two like value resistors in parallel will have a lower resistance period. A guitar amplifier has totally different topology and amplifier design than a BLDC motor controller hence the big difference in size and power. A BLDC is essentailly 3 class d amps 120 degress out of phase with a dc battery power supply.A tube amp is just that it uses tubes not transitors is monaural and is an entirely different beast . Make sure you get caps in a 105c rating and a higher voltage than you will see ever.Rod if ripple(voltage drop) can be cause by longer motor wires to the dc battery doesnt that tell you that they have to give something back? They cant do that without storing something my friend and the cant give it back unless they discharge. Also theoretically too much bulk capacitance CAN introduce more amperage load without the addition of low esr ceramics or npo supplementation's . I would pull up the the lecture notes on that, but wats the point? Gil just add your caps if you choose and get your boat back in the water asap so you can test it.

Hugh

 

[Jim Caldwell]

Hugh, where do you get your 63 and 100 volt caps??

Part numbers?

 

[MarkTanski]

God you're arrogant, the cap on a esc is a plain simple low pass filter no matter how complex you attempt to make it sound! Look it up! You don't think that applies to an amp? I'm pretty sure all the ones I've worked on have low pass filters! The math and theory is the same!

 

[hugh hargett]

Jim just make sure they are low esr type. I usually fish the audio amp parts suppliers on ebay. Digikey or Mouser

Dr Wayne(EE) from ose sent me some 848c2(m) 470 uf tk series jamicons 105C . The 100 volters are a result of an ebay search for 100 volt low esr capacitors # GXE 100volt 330uf caps 125c temp rating.

 

[hugh hargett]

Arrogant! Mark there just simply two different style amplifiers. If you wont take castles word for it you wont take mine. A filter yes by stabilizing the power supply ripple which is considered as noise. Mark you free to voice your own ideas. But the charge of arrogance is based on me not agreeing with your assessment of more caps as more cooling area?????? that just not the point of them sir. You have to look a little deeper than a diy tube amp repair. They are both amps but of a different kind. They have many different style amps Mark with different topologies and different supplemental components to bring them all together. A crossover is a filter right? show me an electrolytic in a audio crossover network please. You wont see it what you will see is an op amp with a ceramic not polar that open at dc and closes as it approaches an infinite frequency dependent on the topology of the rc circuit in relation to the op amp will decide if it a high pass low band pass or notch filter but you will not see an electrolytic there. Electrolytic s store energy and release it sir.

 

[hugh hargett]

Arrogant! Mark there just simply two different style amplifiers. If you wont take castles word for it you wont take mine . A filter yes by stabilizing the power supply ripple which is considered as "noise". Mark you free to voice your own ideas, but the charge of arrogance is unfounded and based on me not agreeing with your assessment of more caps as more cooling area?????? Thats just not the point of them sir. You have to look a little deeper than a diy tube amp repair. They are both amps but of a different kind. They have many different style amps Mark with different topologies and different supplemental components to bring them all together. A crossover is a filter right? show me an electrolytic in a audio crossover network please. You wont see it what you will see is an op amp with a ceramic caps and resistors (not polar) that open at dc and closes as it approaches an infinite frequency dependent on the topology of the rc circuit in relation to the op amp will decide if it a high pass low band pass or notch filter but you will not see an electrolytic there. Electrolytic s store energy and release it sir. Ive been repairing audio amplifiers for some time now. Car audio was my trade for over 20 years. Im an avid audiophile.

 

[hugh hargett]

Mark why would a"guitar" tube amp have a low pass filter on it???? is it a bass guitar amp? if not that really makes no sense to me :huh: . Nevermind youre right sir. Im wrong.

 

[hugh hargett]

About Ripple :

" surge currents can also be limited using lower-value FILTER capacitors. lower-value caps charge in a shorter

period of time. The relationship among capacitance,current and time is given as "

C=I(t)/ change in voltage

taken from Introductory Electronic Devices and Circuits seventh edition page 100. Figure. 3.35

a first year EE college text.

Gregory Mimmack, the director of the EE program at school that helped develop some of the newer fairchild mosfets while working for fairchild, even suggested small electrolytic ceramic caps across the legs of the bigger bulk electrolytics to handle small transients that were too fast for the bigger caps to capture because of rise and fall time of the larger barrels.

I havent tried this yet as I dont know how useful it will be in our app. It will almost certainly lead to an even flatter ripple. A better supply side seems to point to a better output side in most cases unless there alot of loss in between somewhere ^_^ . Gil you can always use your data logger on the same setup with caps then without then go compare the ripple in each - a real simple way to find some truth.

Hugh