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Adding caps to esc???
I have heard of adding caps to ESC to improve things, since I am new to EP boats I don't know what this means?
Do you solder them across the battery leads going into the ESC from the battery or do you replace the caps on the ESC with bigger ones? I have read that if the ESC overheats the caps can puff and need replaced. I know there are some simple rules about adding caps in series vs parallel. I will be working on a Proboat Stiletto, I don't expect to change much but I will be changing the battery connections to 6 mm bullets. Thanks for any Help! Harry<br type="_moz" /> |
RE: Adding caps to esc???
Well, I have never seen a schematic of an ESC yet but I worked as an Electronic Engineer for 15 years in Silicon Valley and I have seen a lot of power units. Some take the DC input and create an AC waveform that is then Pulse Width Modulated, called a chopper stage, that can be cut on and off so the total effective power is controlled. Other things happen in the middle stages like timing and then the output drive has to match the poles of the motor like 3 phase brushless motors we have on a lot of these EP boats. This is not the place to go into details but the values of a capacitor are usually made on two considerations 1) Voltage Rating and is usually twice the voltage it will be exposed to so for 14.8 input stage you would want about a 30V part but to be cheap they may have shipped with a 25V part, internally the voltages may be as high as 100V so the internal caps could be rated as high at 200V; and 2) Capacitance and this is based on how it is designed to work with other components for filtering, wave shaping, and possibly in a network to prevent back-EMF from letting spikes hit the battery or the control signal output from the RX. A chopper power supply is very noisy electronically and has to be designed also to limit the RF that would disturb the communications signal as well.
So when someone in another forum said they added a cap to the ESC, ???are they talking about? I am left clueless as to what it improves and if they are not replacing the main caps ones with ones of a higher voltage rating, which I probably wouldn't waste my time doing because I would probably destroy the damn thing in the process, then I have no idea? THX and sorry about the long message but yesterday was a weird day for disinformation and I was hoping for some clarity on a few things. I have posted this question on other forums and I have gotten directions on how to build a necklace, LOL Thanks for all the Good information I usually always find on RC Universe! A Bright Fella from the truck forum clued me in! In the past the brushed motors caused a lot of interference on the AM / FM radios so they added filter caps to cut down on the electrical noise. If I am right the older the bruses get the more interference they cause. As he said, with the brushless motors and 2.4 GHz radios why would you bother, I agree.<br type="_moz" /> |
RE: Adding caps to esc???
The reason for adding caps has 0 to do with interference. Take a after market car stereo with subs that pushes a lot of watts your not going to add a large cap for interference reason, you add a extra cap to support the system. The cap stores voltage, the larger the cap the more it can store, with sudden voltage spikes i.e a boat getting on/off plane or in the example above large bass point the cap makes up the difference. In boats with the large amp spikes can destroy caps or the esc itself. You add them as kinda like a extra bag of stored energy. Most brushless car systems come with a little side cap board the reason is to help support the constant on/off throttling that you would have in a car. Has nothing to do with interference. </p> |
RE: Adding caps to esc???
That makes the most sense of anything i've heard yet.
It is like having a micro electrical power reserve. So, double the voltage of 4s, ~30V and someone said about 1000uF. THX, Harry |
RE: Adding caps to esc???
Radio Shack has what you need. Also most online rc shops such as ose http://www.offshoreelectrics.com/pro...k-cap-35v-1000
The etti cap banks are also very popular http://www.offshoreelectrics.com/pro...lv&cat=136 Castle also now makes a cap bank: http://www.offshoreelectrics.com/pro...ck&cat=136 ORIGINAL: amrharrymac That makes the most sense of anything i've heard yet. It is like having a micro electrical power reserve. So, double the voltage of 4s, ~30V and someone said about 1000uF. THX, Harry |
RE: Adding caps to esc???
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RE: Adding caps to esc???
ORIGINAL: Diesel6401 The reason for adding caps has 0 to do with interference. Take a after market car stereo with subs that pushes a lot of watts your not going to add a large cap for interference reason, you add a extra cap to support the system. The cap stores voltage, the larger the cap the more it can store, with sudden voltage spikes i.e a boat getting on/off plane or in the example above large bass point the cap makes up the difference. In boats with the large amp spikes can destroy caps or the esc itself. You add them as kinda like a extra bag of stored energy. Most brushless car systems come with a little side cap board the reason is to help support the constant on/off throttling that you would have in a car. Has nothing to do with interference. </p> Thats not how these caps. work at all, hey I might be wrong. can u back up your statment with facts or a link? from Novak's web page Using a power capacitor dissipates noise, smooths harmful voltage spikes and decreases ESC operating temperature by 10-15 degrees Fahrenheit for improved efficiency The capacitor filters out all of the ripple on the input voltage. This ripple is due to the high frequency operation of the speed control The Cyclone speed control uses extremely high-speed switching circuitry for the drive power MOSFETS, which are used to control the power to the motor. This method of control is called PWM (pulse width modulation). To deliver 50% power to the motor at a PWM frequency of 5000 Hz, power is applied for 200 micro-seconds (µs) and then turned off for 200µs, repeatedly. In between being turned on and off, the transistors go through a transition period where they are inefficient. To minimize this inefficient period, the transistors must be switched on and off at a fast rate. Therefore, the speed of switching, which determines the overall efficiency of the speed controller, is important to the design of the speed control. The cyclone's switching speeds are the fastest in the industry, with a Rise Time (off to fully on) of less than 1 µs and a Fall Time (fully on to off) of less than 0.8µs. There are several side effects with high speed switching. The more dangerous of these effects are the creation of high voltage spikes and radio noise. The value of these voltage spikes is determined by the current draw, the internal impedance of the battery, and the length of the wire connecting the speed control to the battery. During PWM switching, the battery voltage fluctuates up and down several volts (sometimes decreasing down to just a few volts during heavy acceleration). This fluctuation is called "ripple voltage," and can damage or cause improper operation of the radio system. To provide smooth power to the speed control and the rest of the radio system, a very low impedance high-frequency capacitor is placed across the battery wires. This capacitor also delivers a large surge current during the valley portion of the ripple. Our test results have shown that at 50% power level, the use of a power capacitor adds about a 7-10% increase in motor RPM, reduces radio noise and increases the radio range. When the power capacitor is properly performing, it gets hot and must dissipate this heat or it will fail. As you have observed, the power capacitor is round in shape. Therefore, placing it inside the speed control would waste a large amount of space and prevent the heat from being dissipated. PS they are used in car audio systems to save the alternator from excessive spikes in demmand...... nothing els... Come on guys, u all have the internet, google it |
RE: Adding caps to esc???
Did you read anything I said, you just repeated what I said and re-worded it. Your digital camera flash has a capacitor in it. The time you are waiting for your flash to "charge" you are waiting for the cap energy to restore, you explain to me what that has to do with interference. It's obvious google makes you think you are more intellengent than you actually are.
Caps have NOTHING to do with interference. Do you people not understand what the purpose of a capacitor is... Unbelievable. Theres a little something on certain esc's called a RF filter, it's a little green donut, THAT is a interference filter. The PRIMARY PURSPOSE OF A CAP IS TO STORE A CHARGE AND HELP SMOOTH OUT POWER. If it does happen to filter out some noise, o well that's NOT it full PURPOSE! Now that this phmaximus dude is on this thread im sure him and his google searching skills will help you. After all google makes everyone smart! I'm done with this thread and RCU for that matter. Have fun guys. I'm thinking your forum troll. Google that! Capacitance is the property of a circuit or device that enables it to store electrical energy by means of an electrostatic field. A device especially designed to have a certain value of capacitance is called a capacitor. The capacitor has the ability to store electrons and release them at a later time. The number of electrons that it can store for a given applied voltage is the measure of capacitance. A capacitor is an electronic compoenent that can sore electrical energy in the form of an electric field Quoted from the Concepts of electronics text book that I own, people do still own books you know, and there's this magical place called School that teaches you certain things that may not be found on the internet. Have fun on Google! <br type="_moz" /> |
RE: Adding caps to esc???
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RE: Adding caps to esc???
ORIGINAL: phmaximus That is a incorrect statment, with brushes setups on AM/FM it has everything to do with interference... its all about placement... Thats not how these caps. work at all, hey I might be wrong. can u back up your statment with facts or a link? Not to mention electrical noise reduction is best reduced by ceramic capacitors not Electrolytic Capacitors. ORIGINAL: phmaximus In short they dont supply that voltage spike with boats, it helps to reduct it PS they are used in car audio systems to save the alternator from excessive spikes in demmand...... nothing els... Come on guys, u all have the internet, google it |
RE: Adding caps to esc???
ORIGINAL: Diesel6401 Did you read anything I said, you just repeated what I said and re-worded it. Your digital camera flash has a capacitor in it. The time you are waiting for your flash to ''charge'' you are waiting for the cap energy to restore, you explain to me w t f that has to do with interference. It's obvious google makes you think you are more intellengent than you actually are. Caps have NOTHING to do with interference. Do you people not understand what the purpose of a capacitor is... Unbelievable. Theres a little something on certain esc's called a RF filter, it's a little green donut, THAT is a interference filter. The PRIMARY PURSPOSE OF A CAP IS TO STORE A CHARGE AND HELP SMOOTH OUT POWER. If it does happen to filter out some noise, o well that's NOT it full PURPOSE! Now that this phmaximus dude is on this thread im sure him and his google searching skills will help you. After all google makes everyone smart! I'm done with this thread and RCU for that matter. Have fun guys. I'm thinking your forum troll. Google that! Capacitance is the property of a circuit or device that enables it to store electrical energy by means of an electrostatic field. A device especially designed to have a certain value of capacitance is called a capacitor. The capacitor has the ability to store electrons and release them at a later time. The number of electrons that it can store for a given applied voltage is the measure of capacitance. A capacitor is an electronic compoenent that can sore electrical energy in the form of an electric field Quoted from the Concepts of electronics text book that I own, people do still own books you know, and there's this magical place called School that teaches you certain things that may not be found on the internet. Have fun on Google!<br type=''_moz'' /> Wow, I hope he never comes back, Honestly the RCU comunity would be better of with out people like this, He obviously has no respect or people or forum rules. I will be complaining about this, As i think its unacceptable. Im just trying to post facts, not my interpertaion of how components are used, & im trting to help other people understand. Obviousle this guy belives he know better than Novak. All he can do is quote text books and insult people. Little does he know His camera caps. work in a diffrent maner. with a camera the battery cant supply the required amps for the flash so it uses a cap. to store the extra energy needed. This is not the case in a ESC. with a ESC they use Caps. for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies, in electric power transmission systems for stabilizing voltage and power flow, and for many other purposes. ESC uses a cap to smooth ripples out so that the average voltage available to the ESC is close to the battery voltage. THATS A FACT hence all ESC have one He can argue this as much as he wants.... good luck with that. If what he was saying about how ESC use a Cap, wouldent the Cap be part of the "punch/burst amp ratings"???? well its not, it would be cool if that was the case, but its not ok it seems u guys are lost on the whole interferance thing.... Excessive noise causes interferance and glitching, do u disagree??? Now there are lots of forums on RCU and others dedicated to resolving this issue with caps. All u have to do is look, im not going to argue with u. so like that link that Dan S posted, when u extend the ESC battery wires u add a cap. its got nothing to do with voltage supply, its all about reducing magnetic feilds right? [youtube]http://www.youtube.com/watch?v=vqapTwk1Rpw[/youtube] here is proof about ESC & Motors causing interferance. |
RE: Adding caps to esc???
Just a reminder to you. You brought this on your self. "Come on guys, u all have the internet, google it " comment was starting the fire. If you can't take the heat I don't know why you would want to start the fire.
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RE: Adding caps to esc???
ORIGINAL: ryan_t888 ORIGINAL: phmaximus That is a incorrect statment, with brushes setups on AM/FM it has everything to do with interference... its all about placement... Thats not how these caps. work at all, hey I might be wrong. can u back up your statment with facts or a link? Not to mention electrical noise reduction is best reduced by ceramic capacitors not Electrolytic Capacitors. ORIGINAL: phmaximus In short they dont supply that voltage spike with boats, it helps to reduct it PS they are used in car audio systems to save the alternator from excessive spikes in demmand...... nothing els... Come on guys, u all have the internet, google it Capacitors have more than one use on ESC, do u disagree??? What are we talking about Brushless ESC & Motors or Brushed???? im a little bit lost are we debating that Caps have been used on ESC to reduce noise? IMO they have been but not all the time Allso with the end part, From what i understanded he was saying people installed Caps to audio system on the sole pursose to help power the sub. Where i belive its to save the alternator from excessice voltage spikes and to stop ur lights from dimming,. some people have a boot full of batterys. each to there own Did u know u can have a voltage spike in a alternator thats under its max output, wont damage the ALT but it can damage the BCM, PCM etc thats why they sam leave any EFI vehicle connected for at least 10min after jumpstarting. IF the BCM & PCM had a cap on it u wouldent have to worry about that. this has been a really vauge thread, nothing is specific |
RE: Adding caps to esc???
ORIGINAL: ryan_t888 Just a reminder to you. You brought this on your self. ''Come on guys, u all have the internet, google it '' comment was starting the fire. If you can't take the heat I don't know why you would want to start the fire. These days I try to keepthe peice and not stoop to his level. |
RE: Adding caps to esc???
I dont need that BS from him, im trying my hardest to keep it clean & follow the RCU rules... what did u want me to explode and say what i really think????
I like to think im better than that. |
RE: Adding caps to esc???
Like I said, your comment initiated it. Accurate information was provided. You disagree with it and pretty well told them they don't know what they are talking about so go and google it.
With a comment that can be taken in that way, I expected something to be said. If you did not, I can't understand why you would say that. Nonetheless, I'm not here to sort out the personal stuff. As far as the discussion goes, it seems to me it's quite clear it concerns brushless setups. You can determine this quite easily by the characteristics / information provided in the original post. The second post confirms this. Saying this: From what i understanded he was saying people installed Caps to audio system on the sole pursose to help power the sub. Where i belive its to save the alternator from excessice voltage spikes and to stop ur lights from dimming,. For the exact same reason he has said, we do not desire voltage fluctuations in our ESC. Capacitors will help out. However, when there are severe fluctuations it can destroy the caps and once the caps are gone or weak, the ESC may fail. This is why I highly recommend a 2p setup on demanding systems, as it increases reliability for this and just about everything else without the need to add caps. |
RE: Adding caps to esc???
Thanks for clearing a few things up for me. Honestly i dont want to offend anyone, by debating it it makes it more clear in my mind.
have i stated anything that u belive is incorrect? I need to know to expand my knowledge |
RE: Adding caps to esc???
<div>That's directly from wikipedia and seems like you are using it as your own statement. JMHO</div><div></div>
<span style="background-color: rgb(251, 252, 255); font-family: Verdana, Arial; font-size: 13px; ">for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies, in electric power transmission systems for stabilizing voltage and power flow, and for many other purposes.</span> <div>That's not even close to what I said. I said "support" the system, where did I mention power the sub at? Support the system meaning help the battery and alternator handle the amp spikes. The system meaning battery, alternator, audio amp i.e severalcomponents working together as a unit or system. Ryan had no problem understanding that.</div><div></div><div> <span style="background-color: rgb(251, 252, 255); font-family: Verdana, Arial; font-size: 13px; ">From what i understanded he was saying people installed Caps to audio system on the sole pursose to help power the sub.</span> <span style="background-color: rgb(251, 252, 255); font-family: Verdana, Arial; font-size: 13px; ">ESC uses a cap to smooth ripples out so that the average voltage available to the ESC is close to the battery voltage. THATS A FACT hence all ESC have one</span></div><div> You just agreed to my whole statement, so why are you arguing with me? <span style="background-color: rgb(251, 252, 255); font-family: Verdana, Arial; font-size: 13px; ">He can argue this as much as he wants.... good luck with that.</span> <span style="background-color: rgb(251, 252, 255); font-family: Verdana, Arial; font-size: 13px; ">can u back up your statment with facts</span></div><div> <span style="background-color: rgb(251, 252, 255); font-family: Verdana, Arial; font-size: 13px; ">All he can do is quote text books</span> <span style="background-color: rgb(251, 252, 255); font-family: Verdana, Arial; font-size: 13px; ">Wow, I hope he never comes back, Honestly the RCU comunity would be better of with out people like this, He obviously has no respect or people or forum rules. I will be complaining about this, As i think its unacceptable.</span> |
RE: Adding caps to esc???
I'm here to share information. Sorry this thread took such a bad turn and I apologize to the OP for that. You asked for information and it went south very quickly. It's obvious me and phmaximus DO NOT see eye to eye on anything and sorry your thread got caught in the middle of it!
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RE: Adding caps to esc???
FWIW Diesel yer fine, don't let one person bug ya so much...I did LOL at busting on the plagiarism. I think the OP got what he was looking for. I know until recently I would have thought glitchiness in our servo's or the older brushed motors was from interference of sorts, but after having my issue with a new servo I realized that the glitch was because the BEC in the RX was not puting out enough so had to add a cap to the RX to smooth it out.
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RE: Adding caps to esc???
caps can do a range of jobs depending on where there placed and how there connected, Don't believe everything on wikipedia. Teachers put duff information on so students can't copy and paste for homework. My old teacher done that and i know of other teachers doing the same.</p> to the op this might help with what caps do on a brushless esc.</p> http://www.teamnovak.com/tech_info/power_caps/power_caps.htm</p> http://www.castlecreations.com/products/cc-cap-pack.html</p> i would avoid wikipedia for anything and try to search a site that does what your searching for, sorry for butting in buds.</p> </p> |
RE: Adding caps to esc???
I think this thread needs some clarification, so here comes my opinion, as a Bc. S. on electrical engineering.
1. The sole purpose of the capacitor is to protect the FETs from induced voltage spikes from motor and wiring harness. The energy storage effect is neglible in this situation, because each capacitor stores so little energy, and the motor consumes heaps of it. The capacitors has no practical effect whatsoever on the boat getting up on a plane, when you slam open your throttle. The huge power surge will drain the capacitors nearly instantly and the voltage drop will happen anyway with no practical effect whatsoever from capacitor choice. The capacitors task is to work as a 1st order filter together with the resistance of the wiring harness. http://en.wikipedia.org/wiki/Low-pass_filter 2. The inductance on the wiring harness is NOT dependent on wire length. You do not have to use more capacitors if you use longer wires. Inductance is determined by the closed loop area of the wiring harness, and if you use long wires, all you have to do is to strap the wires close together to keep the closed loop area small, and hence keeping inductance unchanged. http://en.wikipedia.org/wiki/Inductance Strapping the wires together also has the effect of creating greater capacitance in between the wires, further eliminating the need for any extra capacitor. http://en.wikipedia.org/wiki/Capacitance 3. Do not ever buy a capacitor from Castle, or Etti, or anything like that. All they have done is soldered down some very generic electrolytic capacitors to a PCB board, stuck a badge to it, and charging you 50 times the price of what the chinese OEM does. There does not exist any "hobby grade" or "hobby brand" capacitors, so don't throw any money in that direction. 4. there is a very significant difference between brushed and brushelss here aswell. A brushed motor will produce much higher voltage spikes than a brushless because of the way that an ESCs FET will allow internal closed loop bleeding of the voltage spikes, which the mechanical commutator of a brushed motor does not. CC, which of course is very keen to sell their capacitors, fail to mention this. CC also fail to mention that the inductance of extended motor wires is very easily kept down by simply strapping the wires together, keeping the closed loop area down. |
RE: Adding caps to esc???
ADVICE NEEDED , i am running a cat on 8s i have a 4s pack on each side of the boat i have had to extend the battery wires and have a connecting wire across so i cant strap both wires together i am looking at fitting some 220uf / 63v capacitors
how many do i need to fit ????? thanks in advance phil |
RE: Adding caps to esc???
MADPHIL none required lol
Guys Diesel and PHmax you are both right and both wrong. Von Ohain has the best description here. The caps in a BRUSHLESS speed control are to protect the speed control thats it for us normal guys. The real engineers can play with caps some to tailor the effects to thier desire but nothing for the performance of gaining more speed of your setup. Diesel Dont let all the car mags and car audio installers fool you with the capps help your system for max output. (they can have benifets but most of the time for short bursts) Example: you have a 1000 watt system and your car lights dim under heavy constant bass. you go out and buy a 10-200 farad cap system thinking it will improve things. think of a cap as a storage battery. they fill quick and disharge quick also. you car audio power supply system ( alternator and battery set up) only puts out so much power. Now while at low power settings those 200 farad caps will be charged and have a large quick power burst waiting for you. your favorite song comes up and you turn all the way up. for about 2-3 seconds you will have a high output power untill the caps are drained. now your audio power system ( that wasnt up to the task earlier) now has to supply power to the car amps and is also trying to fill the caps back up. This would work great while watching a movie in your car as the caps would have time to recharge, but under constant bass there is no point in it. you also add more wires and conncetions by hooking up these caps. Now this is with AMPS that are unregulated. most amps are regulated in that they give the same output power no matter what the voltage input is. Some competiton amps are unregulated so that you can run 16-18 volts input and have a high output (cheater amps) as most amps are rated at 13.8 volts Also a lot of you guys may not have been in the hobby long enough to know about BRUSHED motors (non brushless ie with only a positve and negative motor wire) the BRUSHED motors had two very small caps mounted on the end bell of the motor. one to negative and the case of the motor and the other to the positive side and then to the case. These were installed for INTERFERENCE on 27,50,72 MZhz systems in the days of old. The BRUSHED motors would have high em because of the "sparks" coming of the brushes and the comunicator of the motor. |
RE: Adding caps to esc???
airraptor you also just repeated what i said about helping in short burst and as a storage for support against voltage sag, i believe they do work and help alot im not fooled by magzines, i use to be in heavy into stereo systems until i realized i enjoyed my hearing. 200farad cap would be overkill on a 1000watt system. Typicall for every 500watts 1/2 farad is enough.i didnt mention anything about max output, thats not there purpose.hopefully that didnt come of aggressive wasnt the intent, just conversation. My point is you pull up to a stop light and the stereo is full blast, with the car at idle the battery and alternator will not handle the demands, in return your headlights will dim badly, add a sufficient cap, it will handle supply the neccessay voltage to support the system temp under load and the headlights won't dim. Voltage lag. This thread has gone wild. I don't feel I posted any wrong information and not sure how my words where read wrong and the power the sub or max output with the cap not sure how that happened but I think I am going to gratefully bow out of this topic for now. Good luck genetlemen.
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