Why use a Cap Pack on an RC Car? (Capacitor Pack)
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- เผยแพร่เมื่อ 19 ม.ค. 2020
- In this video we get an understanding as to why we would want to use a capacitor (cap) bank on an RC Car. We look at what specific RC Car application is best suited to use these cap pack banks.
Cap packs are not installed to increase the top speed of our RC car, or to increase the acceleration we can achieve from our car. They can not do this as there is not enough power capability in the capacitors. Capacitors at this size do not store enough energy to be useful in this way.
The main purpose of a capacitor is to fill the void in voltage as the ESC is switching the motor on and off. RC Cars that pull a lot of power and are pushed very hard for short duration of time tend to be the offenders that are hard on ESC's.
Using a Cap pack in these applications can only help your ESC. There is no magic solution as to the exact specifications you require in your application. Therefore, it is recommended to choose a Cap pack that has a minimum of 800μF.
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#RCcar #CapPack #RCexplained - วิทยาศาสตร์และเทคโนโลยี
Great work in this vid! I’ll have to remember to share it every 5000 times I see people asking what a cap pack is, if it will help with my esc cutting out or when they think they will gain speed.
Thanks for the comment Stew- Mac! I certainly appreciate the support by sharing any of the content!
Great info man. Of all the youtube channels I watch yours has the most solid, well explained information. Keep up the solid work! 💯🙏🏻👊🏻
I appreciate that! Thanks for the awesome comment King Stoeck!
I have been binge watching your videos and decided to subscribe. It's the least thing I can do. Thanks for the info.
Hey LusoiHardware, That is awesome to hear. Thank You for the sub!
Thank you for being such a great knowledge mine, and for sharing all that cool stuff with the community 🙏
No worries!
Thank for clearing that up for me! Just order a Arrma Limitless and don't plan on doing crazy speed runs and I wasn't sure if I needed a cap pack for some basic track usage. Thanks!
Thanks for the comment! Glad I could help!
Very helpful! I'm old school we didn't have this fancy stuff back then.
Clear to the point and precise...subscribed!!!👏👏👏👏
Appreciate it Kowlessur Rajiv!
subbing after watching this, exactly the information i was looking for explained clearly and efficiently. thanks
Thanks for the sub!
I´m impressed about your knowledge as an engineer. You relly know what you are talking about! Many thanks!
Thanks for the awesome comment Johan!
Very clear, thank you!
Thank you Remko!
Always pleased with your content from motor kv to timing to series and parallel keep it up👍
Hey Racing Rivals, thanks a ton for your comment. Really Appreciate it!
@@RCexplained no prob
Very informative. Funny enough though I was just wrapping up on reading about cap pack use
Thank You for the comment Caribbean Mafia, I'm glad the video can help!
@@RCexplained Your videos are amazing. Thanks for share your knowledge. Will be good enable the auto subtitles in english even better in other languages too like Portuguese. Thanks.
You missed one. Some servos have very high Amp draw. They are very fast and we use capacitors plugged into the receiver to help with glitching that occurs because of the high amp draw. This can cause your car to be momentarily unresponsive. I used a capacitor that was actually Called a glitch Buster. It totally corrected the problem and I continue to use savox servos till this day.
I think servo brown out is one of the main reasons to use a capacitor.
You have the best videos on this stuff
Thanks Mike!
Im new to the rc world This video was very informational...subscribed 👍
Thanks for the sub! and Comment!
Great info bud.....👍👍👍
Usually after 7-8min of race i felt theres power drop from the car. I cant clear some jump when that happen. Will adding cappack solve or myb reduce that effect?
informative, in the process of putting on 8s cap great video.
Awesome! Thanks for the comment!
Very good information thank you. Do you think that it would be helpful to install the cap pack that came with my hobbywing max 8 that going in my upgraded arrma kraton V4 using it for normal bashing. Or would it not be necessary?
Hey Ed, if the ESC came with a cap pack, I would use it. If you were to choose not use it, the life of the ESC would be reduced.
@@RCexplained Thank You
Thank you!!!
Hey Dex Andrews, thank you for your comment and watching the video!
Can you explain how this can affect the crawlers, like TRX 4 ? I want to install this on my 3 lipo castle mamba x esc and castle 2280 kv motor .
A capack will assist in ripple voltage. If your setup has a high ripple voltage, a cap pack can help.
So is a cap pack really that usefull? For a normal basher or onroad 1/7 scale
I already knew of the use of capacitors on receivers but just today i found that it can be also used on the escs. My question is if a single 3300uF 16v cap might be enough for my aplication, it's for a trx4 running 3s max... Very good explanation btw, first video i found about this and it really cleared almost all my doubts about it... U earned a new subscriber... 😉
Hi Silvio, thanks for your comment, I'm glad you liked and found the video! Your capacitor selection is sufficient for max 12.6v.
Hi thanks for the info and it make sense because I made one pack with seven capacitors of 1000uF 35v each and I contacted them near the battery connection not to cut the esc wire and I can't note any difference neither in speed, acceleration or temperature.
Yes, no measurable differences there, however your ESC built in capacitors will not be over stressed. This will help increase the reliability of the capacitors in the ESC.
@@RCexplained thanks for your reply, so you don't think I will damage the ESC because I was thinking of trying the 35v 2200uF x7 or the 35v 4700uF x6 or x 7 capacitors, what do you think?
Is it ok if I fit right on connector s going to battery
Question please. If you have an external BEC powering your servos, and the ESC's BEC powering the reciever, will a cap pack still be of any use? Thanks
A cap pack is for the main power going to your motor. This is independent of how your servos are powered.
That was good except i dont understand the last diagram its not very clear. Is it showing that the battery plugs go into the cap pack which then goes into the esc? I thought the cap packs get soldered into the sides of the wires that go from esc to battery, very close to esc. If so how do you solder into the side of the wire? Do you solder it directly wire pushing against wire or do you wrap the cap pack wires aroung the esc wires first before soldering?
You can solder directly to the side of the wire close to the ESC
Very useful info. Will capacitor fitted to the ESC also prevent servo glitching like when fitted to a the receiver and vice versa or should I use one on the ESC and one on the receiver as well?
Capacitors really won't help with servo glitches. I don't use any for the receiver, just make sure you have enough current for your servos and all.
Thank you!!
You're welcome derka5581!
What about the “C” rating of the batteries? Isn’t that also a factor? I put 50C batteries in my Traxxas Spartan boat and the wires/connectors get hot. If I use 80C batteries it stays cool. What good is a “cap pack” going to do if all your running is 25C batteries?
That's a great point. A cap pack will be able to help reduce ripple voltage caused by weak batteries. However a cap pack will never be able to makeup for the voltage drop experienced from weak batteries or an inadequate c rating.
Thanks for the explanation sir. I just got a question.
I am planning to make a cap pack of 6 capacitors with 470uF 35v. That's total of 2820uF. I am running it on 8s for speed runs which has 33.6 volts max voltage.
Would it be enough?
Thank you for the comment. That is a lot of capacitance. It should be enough!
@@RCexplained thanks. Coz I was just wondering if "overcapping" could damage the batteries or affect the performance of the car.
No. Not enough.
You should use twice the voltage caps as the lipo.
So minimal 50 or 63v
On my 6s setup i already use 50v
does this ripple voltage then over time negatively affect any RC car? one thing I wish I knew was a formula for the C-rating of the battery compared to to the motor and ESC your running. It seems that the average C rating is 25C but if your running a 2S pack and a 35AMP speed controller and your motor is say a 540 sized motor there seems to be significant amp draw and the voltage sags especially if your running for 20-30min. Then the motor will get hot, the ESC or the battery and over time this kills them...batteries Puff etc. I had a friend who is an electrical engineer tell me that you should not run less than a 50C battery in most of these RC car applications on 540 motors or higher or any setup that is 2S or greater? So what C rating should you run and should you put a Cap Pack on any car to make it more stable and last longer?
Ripple voltage does affect the ESC over time, however, if it is managed (kept low) you should expect a long lifespan making it a no issue.
The C rating can be calculated from the maximum continuous current you will draw multiplied by 1.3 and then divided by the capacity of a battery pack measured in Ah.
Hye sir..if i use the 120a esc with 3670 motor 2650kv..can i use 35v 2200uf ×4..its means the capacitor volume around 35v 8800uf..its is ok to my set??
2 much man 3000uf enough
Hi, that's good info for Cap Pack. Very clear and good explanation. I want asking how to buy RCexplained t-Shirts
Hi Thanks for the comment!
www.radiocontrolinfo.com/ first tab is the Shop
I have a question, my 80amp readytosky esc had 3x 330uf 35v capacitors, one of them got knocked off, the highest volts I give is 25v, and the 70mm edf unit draws 65amp peak, am I fine with only 2 of the 3 capacitors? Or do I need to replace it?
I would replace it if you can't measure Ripple Voltage with the esc.
@@RCexplained ok thank you 😁
Great video as always. And this is from a Cap Pack maker. ;-)
Hey rhouse21, thanks for the comment bud! Yes, you have some good cap pack vids on your channel as well!
@@RCexplained Thanks! You've gotta try to get good info out there somehow. 😊
Can a capacitor pack help keep lipo batteries from swelling and getting hot? I run 80c + batteries and they get very warm time to time when racing.
No, caps would not help
Warm the lipo's To 35 Celsius. At least 2 hours before until you use them( inner cells will also need to be warm) . That will drastically lower the internal resistance of the lipo. Otherwise you damage them. Don't think the lipo's already get warm. That is because of the high resistance. It will also give you more punch. Because the lipo transfers the amps way easier.
You can make or buy a lipo heater/warmer
Niels
If you get a super capacitor the same size as a 6s battery in the other tray in a limitless could that reduce the voltage ripple completely?
Not necessarily. There's a few factors that come in to play. Making sure you can dump the required amount of power certainly will help though!
@@RCexplained it would be an interesting experiment to try. the car audio guys have a similar problem when pushing massive subwoofers, they have to add cap banks or more batteries. You can get some massive caps so I wonder what would be better in an arrma limitless, 1 battery with a super capacitor or 2 batteries in parallel 🤔
I've had to cap my car stereo, the capacitors that would be HUGE for any of these cars. Like the same size for an OK cap, but 2-3 times or more. Higher C batteries, good cables an connectors. The esc also needs to carry the current demanded by the motor without heating too much too fast, or hitting an amp limit by the esc. Aerodynamics, and weight really kill this as a solution to getting instant power to cover voltage or current drops. And, I believe that supercapacitors deliver powe at a more steady rate and wouldn't discharge fast enough to be viable eather. I don't have much experience with them. I've seen batteries with a good bit higher than100c. I'm planning on no lower than100c, the little extra cost has got to be better than putting any kind of limit or strain on the power system at all, it will certainly diminish performance. In speed running, you want to tune the system, not work around bottlenecks. We probably have the most control of the power flow than anything. I take my time, research the options, and think about it all, having a better idea of what is available to work with, rinse and repeat until your just not changing the setup/design anymore, then I feel better about searching price a bit more. I can extend my $ savings time hunting for price as I wait, but I'm not entirely boxed in in my head about price. Said price still being in range. I can't get a thousand dollar esc, but I can get the $200 esc instead of the $120 one because the $120 was lacking somewhere I had to keep working around. The $200 hits your bases correctly, and $300 I was drooling over isn't missed So much. Or, just wait a bit longer for the $300 one. Same with batteries and the rest of the power system, not a place to cut corners, and a real pain to chase the problems that come with it.then your left with gearing, aerodynamics, bearings, weight, ect, power systems can make your vehicle, break your vehicle or completely make it go up in smoke. I'm currently entertaining the idea of a boat or jetboard esc, they run some high extended current pulls. Heatsink it well with high speed fans, could work. Gonna experiment. It's just my little opinion. Been fabricating and repairing much in a half century, and my opinions come from experience. That doesn't mean it's right, just where I got my opinions from. And I do ramble on in the comments section late at night, I'm working on it.
IF I'm correct, then, may it help others in the quest for performance.
Or, I'll shut up, eventually...
Ok, after many minutes of scouring the web for information I have come to the conclusion that I won't be running the supercapacitors either. Gotta hook too many in series to get the required voltage, and for current draw, but the power delivered is just not justified as a solution for me. That, and to hook them up to be even marginally effective will decrease service life. I still believe that high discharge batteries, proper wiring and connectors to handle more than my actual draw, and an esc that can let the current demanded by the esc is the best way to deal with voltage sags and current drops for instant and sustained purposes. If the motor isn't the onl serious draw on the power system, there will be a limit to performance best case, and a melted puddle where your car used to be. Both RC vehicles, and full-size alike.
Although, if you haven't seen a good car fire, it's one heck of an experience!
I built my losi 8ight 3.0e to do 100mph. I crashed it. Had to replace motor mount and battery tray. Now its fixed. I use a 5000mah 6s 100c battery. I switch between 2 that i have. Before crash it would do 100mph. Now it wont go over 80mph. After your video im wondering if cap pack maybe bad not smoothing out ripple effect. Valley going too low causing esc to smooth out and not keep increasing motor rpm ? Im trying to learn this side of electric rc. Not sure if this makes sence;)
Hey Mike. It's unfortunate your car was crashed and needed a rebuild. It's going to be tough to say what is happening within many of the components on your car.
You can verify the battery is ok with a resistance check to ensure it has not changed since the crash. If the battery pack changes shape, resistance can increase. The second battery can be a close comparison as well as long as both pack were capable of 100mph prior to the crash.
Another quick area to check is driveline resistance. You will want to confirm that the resistance within the driveline has not increased over time.
I would not suspect the ESC to be an issue, (nor a capacitor issue) however it would be best to review a datalog if possible to see what is going on with the entire system as a whole. Another thing you can do if possible is swap to an equivalent ESC to see if there is a difference.
@@RCexplained hi. Ok. Thank u for your reply. Both battery packs did take it to 100 mph
So strange for it to be happening with both packs. I cant see how both would have same issue. I checked shafts and they are straight. It pulls awesome tons of power gets up to now its new peak of just 80 mph and doesn't pull to higher speed.
Can’t tell if your Standing or sitting? Haha very informative video
Can one big capacitor be used vs four small ones?
A larger capacitor can work and help, however smaller capacitors placed in parallel is best.
Thanks for the good information.
I have a question.
Most high-performance RC cars have a voltage drop because the battery cannot handle the motor's output.
If we put a 100F super condenser in here,
I think batteries can accelerate battery failure because they need to send power to super capacitors and motors.
What do you think?
I'm not sure what you mean here: "I think batteries can accelerate battery failure because they need to send power to super capacitors and motors."
@@RCexplainedI'm sorry, it's a translator.I mean, if the capacitor is depleted while driving, the battery will have to send electricity to the motor and capacitor at the same time, so I think the voltage drop will get worse.
The capacitors and the battery pack will both be at the same voltage. If the capacitors have been depleted, that would also mean that the battery would be depleted.
@@RCexplained Thank you for your answer.
Can I think that the more capacitors the better?
Except for spark when plugging in.
@@RCexplained Sorry, that was a stupid question.
What’s the difference between a glitch buster and cap pack?
Glitch buster has been used for the receiver vs a cap pack being used on the esc. A cap pack used on an ESC is for a very specific and important purpose for the reliability of the ESC.
In the distant future I'll have a video on these glitch busters.
I noticed you said parallel how do I know which one to really get can you please explain to me ..
Have you tried looking at a diagram? You should be able to pull one up on Google.
Can cap packs help stop low to no rpm cogging?
A stronger LiPo with a high C rating will help with startup hesitation. Cap packs will not reduce startup hesitation.
RCexplained ok thank u for the knowledge sir.
What can I do to protect esc from burning out when it's close to it s motor limit please
Keep it cool
@@RCexplained found solution I gonna run 9.6v nimh instead of 3s on my old school brushed gorgon
How come LC filters are not used here? The drone guys have been using LC filters for ages now.
Hello Isogen, I'm not experienced with their use in drones. I would expect the reason for their use to be more for FPV guys who are trying to filter out higher frequencies to avoid interference or RF issues in the FPV feed. Especially if the power system is operating off of the same battery the FPV gear is. In this case, LC filters are reducing noise that affects video quality. Instead of an LC filter, one could just run a separate battery for the video feed with improved results.
Much different purpose vs a cap bank to protect the ESC.
hi wiche cap pack i need with hobiwing max 5 , i run with 8 s , on losi 5 b, tnx!
Are you going to be making speed runs or pushing the system very hard? Stock configuration as the manufacture lists in the manual would be sufficienct for bashing the car around.
@@RCexplained i pushing the system very hard and wont protect the esc grom verbal volteg,
but i dont know wiche cap pack i need, can yyou help me?
You can use a standard cap pack that has a minimum of 800μF.
@@RCexplained TNX!!
I’m using a smaller pinion then stock , will a cap pack help ? (It’s getting hot at)
Do you have a data log of the run? What is getting hot?
@@RCexplained I don’t have a data log but the motor gets crazy 160+ definitely, and the esc gets really hot in pretty normal weather gets hot even on the street and ect
A cap pack will not help the motor getting hot. Reducing load or moving to a larger motor and ESC will help.
@@RCexplained will it help esc heat?, I can’t really go any bigger on the motor , and with the esc I can’t find a 8th scale esc small enough
Yeah I have a glitch on a crawler on the lights when I use the servo cap pack don't work
Yes, just not enough storage energy to fill massive gaps even on the radio side of any RC.
I'd rather think your bec insufficient for lights AND a high torque servo
@@ChaosRC666 correct
I bought a 1:32 scale car and tore it apart, I found a single capacitor and thought that it might be the battery, I took a good look at the circuit board and found no battery so that's why I concluded that the cap is the battery. Is my conclusion correct or incorrect? I'm just curious because I'm planning to upgrade the battery life of the car.
What is the make and model that you bought?
It's a virhuck "cracker" rock crawler.
@@RCexplained It's the same as this video here: th-cam.com/video/ix5zBKDUmXk/w-d-xo.html
@@radunit4805 I'm not familiar with the crawler. I'd have to see a picture of what you are looking at. I would expect there to be a battery. I would suggest asking the individual who is taking it apart in that video.
@@RCexplained it really is a capacitor, I unsoldered it from the board and saw a print saying "Lithium Capacitor 3.7v"
Okay if this helps smoothing out the power and doesn't drop as fast I would think you get consistent speed runs out of it helping it to go faster than one ESC without it
You kind of answered your own question. You are correct you will get a more consistent speed run but at the end of the run will not see a higher top speed.
the reason good escs will last longer than cheap ones are that they are using fets that are rated at a much higher voltage than you ever will get with 6 or 8s batteries.
cheap ones run right at the edge of their ratings, any overvoltage will break them. overcurrent is usually not the cause of failure.
when a back emf voltage spike occurs which exceeds the max voltage rating of the fets, you get a fire brick in an instant.
the worst causes of high back emf is running the motor without load at max speed.
good batteries with low isr and low-esr capacitors will try to catch that before it exceeds the fets absolute maximum rating.
Flopaks cap packs are the best they can run the car for 30 seconds after being disconnected from the battery its awesome
👍🏽
I followed you regarding what cap packs do not do… increase top speed & acceleration. They do reduce ripple. I do have a basic idea of what ripple is, but what is the benefit of reducing ripple…reliability? Reliability of what? What becomes more reliable? The motor? The ESC? The batteries? How does this “increase in reliability” affect performance?
I'm no expert but from my understanding, the cap packs only reduce the amount of ripple voltage which can damage the esc hence increased reliability of the esc . It does not protect batteries, it doesn't affect performance (No speed increase, no acceleration boost).
I agree with you. From what I got it prolongs the life of an esc and should definitely be applied.
800uf 35v or 50v?
Hi nts 323, the easiest way to determine the best voltage spec is to look at the specifications on the capacitors of your ESC. If your ESC hides these specifications, a 35v capacitor bank would work for 6s and lower. 50v for 8s and under.
@@RCexplained thank you👍👍
I’m new to racing r/c
Welcome to RC Racing Everett
So in other words, cap packs help to protect the capacitors in speed controller’s from overheating and they reduce ripple voltage which could result in more severe voltage sag
I think in general you got it. Cap Packs help the capacitors so that the grouping of capacitors can protect the FETs from seeing too much ripple voltage, otherwise the FETs could turn to smoke before the caps. Capacitors reduce the ripple voltage, however they won't be able to make up for any voltage sag caused by weak low C rated batteries.
@@RCexplained Ah ok. Thanks for responding. Love the videos man! Keep up the good work.
Caps connected in parallel, no matter how you use them, resist a change in voltage, thereby "smoothing" DC. They act like an accumulator to limit instantaneous voltage changes during instantaneous current loads on a circuit. If you have a high powered stereo in your car, put a 1 farad capacitor across your battery terminals so your headlights don't dim every time that bass hits...just saying.
Installing my flux capacitor right now lol
Sweet I need one of those!
tom brady ?
14 people feelings are hurt lmao
No they are not worth the hassle!
If you are experiencing significant Ripple Voltage, they are necessary, otherwise the esc is at risk for failure.