Cap pack?

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Interesting thread here. I used to design large (50HP~400HP) Three-Phase, Variable Frequency motor controls for industrial use, so I'm quite familiar with the principles involved.

What you're doing here (and some of you have correctly pointed out) is providing a "current reservoir" to supplement the battery during periods of high current draw when the ESC switches between windings on the motor. Being able to source additional current helps keep the voltage input to the ESC more constant, meaning you get smoother power delivery.

Every time the ESC switches, there's a huge slug of current drawn from the battery, and the capacitor bank provides what it can.

Keep in mind that bigger is not always better, and if the capacitor bank is too large, it will never fully recover to support the next time when the ESC switches. I don't know how big "too big" is, but just keep it in mind.

Since the capacitor bank is constantly charging and discharging at a very high rate, low ESR caps are a must. Don't buy cheap ones, either. I like Panasonic and Nichicon; both make good caps.

And considering you've got LOTS of electrons getting stuffed into and sucked out of the capacitors, which will generate heat, 85*C temperature ratings would be a "Best Buy".
 
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Can a cap pack help on cogging? My exb is still giving me a headache theres no transmission issue or electronic issue and its cogging on 14t under acceleration. My hobbyshop has a 50V castle cap pack for 30$
And i heard it reduces speed control heat and my esc overheated on normal conditions and wasnt abusing mh exb
Thermal 2 times on the same pack
I find hard to belive that hrb lipos and zeee are inferior to awanfi because the awanfi don't cogg as bad or berely noticable but i cant do stuns with the awanfis and is less reactive it doesn't make any sense!!
 
Can a cap pack help on cogging? My exb is still giving me a headache theres no transmission issue or electronic issue and its cogging on 14t under acceleration. My hobbyshop has a 50V castle cap pack for 30$
And i heard it reduces speed control heat and my esc overheated on normal conditions and wasnt abusing mh exb
Thermal 2 times on the same pack
I find hard to belive that hrb lipos and zeee are inferior to awanfi because the awanfi don't cogg as bad or berely noticable but i cant do stuns with the awanfis and is less reactive it doesn't make any sense!!
I agree with you on that last part, that it doesn't make any sense. Cogging shouldn't be present with one battery pack over another unless you have some packs that need to be thrown out. Especially with non-speed run gearing like you said 14t should be zero cogging.

In some cases the ESC is to blame. Maybe if a friend has an ESC you could try in your car?
 
I agree with you on that last part, that it doesn't make any sense. Cogging shouldn't be present with one battery pack over another unless you have some packs that need to be thrown out. Especially with non-speed run gearing like you said 14t should be zero cogging.

In some cases the ESC is to blame. Maybe if a friend has an ESC you could try in your car?
I swaped the esc to another brand new blx 185. Changed the arrma motor to the firma motor that comes on the felony now. Idk what to do anymore. I checked the center diff play there is a little bit up and down play but the cap who secures it is well seated
You can hear the gearmesh jumping a bit at low speed
 
I swaped the esc to another brand new blx 185. Changed the arrma motor to the firma motor that comes on the felony now. Idk what to do anymore. I checked the center diff play there is a little bit up and down play but the cap who secures it is well seated
You can hear the gearmesh jumping a bit at low speed
Slide the motor back where the pinion does not make contact with the spur gear (or just pull the pinion)
Roll the car and make sure there are no issues with bearings or binding.
 
Slide the motor back where the pinion does not make contact with the spur gear (or just pull the pinion)
Roll the car and make sure there are no issues with bearings or binding.
Already did that car rolls freely
I feel like im trying to understand why its miss firing i wont start dumping 200$ on lipos. The other option would be to get the firma 150 esc but thats another 150$ down the drain
 
It took a lot to get my kraton 4s to missfire one bullet connector was just destroyed when it started missfiring i just move the connector arround and it started running again
I really don't know man, that is bazaar.

Pick up a Castle Mamba Monster X 8s ESC and you will never hear cogging again ?
That thing is like 500$ here lol
Im going to run it today its the last day of heat here in montreal canada. 23 degres celcius and tomorrow we are going to be in the low 10 again and almost bellow freezing afterwards
 
I really don't know man, that is bazaar.

Pick up a Castle Mamba Monster X 8s ESC and you will never hear cogging again ?
It was even doing it with the awanfi lipos. Im going to junk the v4 diff and put an exb diff i need to buy another diff yet again and screws because my 2 exb cups i bought melted on the steel insert my luck??‍♀️. What i think is happening is suddenly the drivetrain seizes because i don't understand how tf my motor is cogging at a such low gearing. What a massive facepalm today the car at times didnt want to wheelie at all i wont be suprise if it destroyed a side wall in my rear diff sun gears
Can i try a glitch buster?
 
It was even doing it with the awanfi lipos. Im going to junk the v4 diff and put an exb diff i need to buy another diff yet again and screws because my 2 exb cups i bought melted on the steel insert my luck??‍♀️. What i think is happening is suddenly the drivetrain seizes because i don't understand how tf my motor is cogging at a such low gearing. What a massive facepalm today the car at times didnt want to wheelie at all i wont be suprise if it destroyed a side wall in my rear diff sun gears
Can i try a glitch buster?
It wont hurt anything, but a small capacitor like that wont fix the issue.
 
Going to have the parts monday im almost at 300$ of figuring out whats wrong with the cogging
I noticed no matter what the sun gearboutdrive just keeps getting loose but the diff spins smoothly.. so well i thought. At first it spins smoothly but when you push the drive cuo towards the bearing and pushes the sun gear more foward by hand i can feel a really hard spot.. thTs just by turning it by hand. Imagine a motor. Well now i find kinda stupid honestly. Im almost 100% is the stupid diff who is causing this madness. I found the diff was spinning happily but turns out in reality while its running it not spinning smoothly. Idk what kind of load it puts trought that motor that makes it studder like a cogging
 
I noticed no matter what the sun gearboutdrive just keeps getting loose but the diff spins smoothly.. so well i thought. At first it spins smoothly but when you push the drive cuo towards the bearing and pushes the sun gear more foward by hand i can feel a really hard spot.. thTs just by turning it by hand. Imagine a motor. Well now i find kinda stupid honestly. Im almost 100% is the stupid diff who is causing this madness. I found the diff was spinning happily but turns out in reality while its running it not spinning smoothly. Idk what kind of load it puts trought that motor that makes it studder like a cogging

Gremlins I tell you.
 
Sorry I am a bit late to the party here but wanted to chime in since I have built 4 cap packs and done a fair amount of data logging of ripple voltage. (also have an Electrical Engineering degree) I suspect sadlerbw above might also.

To answer some questions, I personally believe you will not "feel" any difference.
These capacitor packs cannot power more than the servo on their own without the battery. Hitting the throttle would drain the caps almost instantly. (With the exception of some monsters over 20,000uF)
All of our ESCs come with capacitors built in already and are there to smooth out the ripples in the voltage supply. The problem comes up more so related to large motors and or aggressive gearing, which create larger amperage loads on the system.

The cap-packs purpose is to smooth out the oscillations in power, the ultimate goal is to provide a smoother power level. Having an oscillating dc power supply "stresses" the ESC and will greatly shorten its life. It could also blow the caps that are pre-installed on the ESC. That is the whole point, save the ESC from power supply stress.

During a speed run with an 8s system I would often see data logs of voltage drops of nearly 1v per cell. My 8s system (4.2v * 8 = 33.6 volts turned into nearly 25.6 volts. ) Prior to installing the cap packs data logs showed oscillations in the power supply of up to 20%

I have always built my Cap-Packs with low ESR caps from the Panasonic FM line. I have used 35v caps from 1000uF up to 2200uF wired in parallel depending on the car and room available. I have found that around 6000uF total is sufficient in most cases. On larger RC's where you have more free space, fit in as many as you can within reason. It is also noted that you should wire them as close to the ESC as possible. I like to install them with an battery connector to make it easy to remove during repairs on the RC. I also use clear shrink wrap because it is easy to inspect the cap tops for swelling which is the #1 sign of a cap on its way out. Like batteries caps have a certain number of cycles for their life span and heat tolerance, so considerations for mounting location should be made.

Ideally you may want to test the capacitor pack with your multi-meter initially and then test it every 6 months to make sure it is still healthy.

-Liberty
I've found a 1, and 2 farad cap pack (super caps) that will fit, how will this work? Will it help acceleration?
 
Going to be running a tp 4070cm 2200kv motor with hw max5 esc on 6s in my Kraton. It may be necessary to keep voltage spikes down Idk...

What is the cc cap pack rated at compared to others like em, poseidon, or kill mode?

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/272697996673

http://poseidonrc.com/capacitor.html

https://www.killmoderc.com/online-store/4-PACK-8-800uf-CAPACITOR-PACK-p84360571

Justin
You probably want a cap pack with at least 3-4k microfarads combined to be functional. However, it is truly NOT needed in your rig and running 6s.
I make my own cap packs. From 35v Panasonic Gold caps. Best ESR's from what I seen. Rubycon caps are commonly used by HW in general and other brands and probably whats in the Max5 already with out any external one. The designer brand Cap packs, Like Killmode and Ripple Killer don't publish their specs. But thats easily found by dissecting them. I only use a cap pack on my HW XR8 Plus sensored combo/2200kv (4074 can)geared tall for Speed running only. Lim. The caps do get hot, so they are working with sustained pulls. The gearing in the Kraton doesn't pull sustained amps like a speed runner does. If it does, you have more issues than just high ripple volts. Just my thoughts.
I've found a 1, and 2 farad cap pack (super caps) that will fit, how will this work? Will it help acceleration?
NO. Does nothing for acceleration at all. Cap packs keep ripple volts low within a threshold based on a percentage of the lipos total volts under load.
It is something you really cant observe short of pulled data. It maintains ESC efficiency. And Caps don't help a battery function any better.

I use a narrow bread board for soldering/mounting my 6 Panasonic Gold's. Shrink wrap so the tops of the Caps are visible. Clear works also. But I prefer to leave the tops exposed to cool off as well. And, you want to know/see when those tops split. They pop when they fail.
 
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I use a narrow bread board for soldering/mounting my 6 Panasonic Gold's. I use hot glue to keep the Caps tight. I use Liquid electrical tape over the solder joints. Shrink wrap so the tops of the Caps are visible. Clear works also. But I prefer to leave the tops exposed to cool off as well. And, you want to know/see when those tops split. They pop when they fail.
 
I've found a 1, and 2 farad cap pack (super caps) that will fit, how will this work? Will it help acceleration?
As @SrC mentioned this will not improve acceleration.

Is this a cap pack that is ready to buy? I'd be curious of the price and configuration. The problem with super caps is that they are rated for very low voltage. I see variations but generally they fall into the 3v to 5v range. You then have to wire them in series so they can handle higher voltage. Capacitors behavior is interesting at that point. Each additional capacitor in the series reduces the capacitance. For this reason you often see series parallel configurations to bring back up the capacitance. All of this typically means more size and weight.

I made a 500,000 uF pack using super caps and was not impressed with the results. I have since gone back to standard Panasonic FM caps. The pack I run right now is 21,000 uF and is honestly overkill. I think something in the 3k to 12k range is plenty.

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I do wonder if a parallel cap pack works better if all wirelength from cap's to battery are equal. I've made two designs with this in mind, but i didn't order enough caps to make a third one with all caps in line(and thus different wirelength) to make a real comparison.
 
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