I can't believe that it took me this long to find your channel. I've been preaching the same Gospel on my TH-cam and Facebook pages for a while now. Excellent Video! I look forward to seeing what you come up with in the future.
The capacitors effectively lower the source impedance for the mosfets in the esc's, At high frequency and current, all wire has inductance and some resistance, and even the battery's internal series wiring contributes negatively, along with cell resistance, and effectively they are all in series, then that naturally degrades progressively to a higher value as the battery pack ages. Instantaneous current demands by high speed mosfets result in reduction in switching transition time when the source voltage sags, and it's compounded when multiple esc's all overlay the same demands on wiring/battery, that resistance results in heat which is just wasted energy. it's the art of losses. The value of the capacitors used should be a factor of esc frequency with minimal esr for that value. You will not get a boost, just a significant reduction in loss when it's correct. Anyway, good video Nick.
Hi Alasdair I agree, the capacitor is essential to minimise switching losses. The large capacitors are sold as power boosters for the models with a single speed control and high power lipo with high power wiring etc. And in my opinon do very little, if the speed control already has a low ESR capacitor as supplied with the speed control. However many racers believe (in their minds) that it is boosting performance, and that effect may actually result in them performing better. Thanks for your input. Nick
Alasdair McC Alasdair, would you say that a very high capacity capacitor would help braking or punch in a stock racing class like 17.5 blinky? OR would you say their use is simply to protect the ESC? What about ESC temperature reduction? Great explanation btw, even though I am not sharp enough to grasp it all!
Jay, the optimal size as strange as it seems would increase (in capacitance) as the performance of your battery decreases, so rather than lugging huge caps around when you would not likely gain much from their size most of the time, i would suggest maybe some trial and error if you don't have a scope to measure the switching sag and the effect of increasing value with your setup. One thing though, anything beyond about 1500uf with very good low esr performance is not likely to yield much more gain, and any cable length between the esc and capacitor is effectively an inductor, lessening the capacitors ability to sustain instantaneous source current to the mosfets. Imagine the cap as a shock absorber on a car driving along on railway sleepers, a long wire is like mounting it with rubber rods, lessening the effect of what it should be doing. Not to bomb you with more tech babble, but heat in the esc is nearly all generated in the transition time of the mosfet junction (switch) turning from fully off, to fully on, when fully on the resistance is so low no heat is made, but in that transition time it is effectively a resistor turning increasing current into heat. It cannot be infinitely fast due to things like gate capacitance and source impedance, but the lower that source impedance is (rigid supply current) it's like bouncing a pogo stick on concrete, vs. high source impedance (soft supply current) is like bouncing it on soft mud. The punch out is likely helped by caps, as the effects I just listed will help prevent de syncing, but motors, esc's and batteries are a system which all rely on each other for maximum performance, the caps really just make the battery look better to the esc.
Hi Jay A capacitor must be used to help the high frequency on/off switching, to keep the switching losses low, and minimise heating. If you do rock crawling or very slow running, a large capacitor may be beneficial. With high speed racing with fast on and off throttle and braking a larger capacitor will have minimal effect on either. However some report better braking and faster top speed, which may be an effect in the brain rather than in the car.
Hi Ronnie I agree it is confusing, and not sure it is of much use. In theory the highest frequency would give the smoothest control and action. However, the higher the frequency the more losses will occur in the speed control as the pulses struggle to switch on and off, but the motor should run more efficiently. At the lower frequency the response , especially at high speeds becomes less defined and less smooth, but the speed control should run cooler. Most speed controls would compromise and fix the frequency in the middle range. The most advanced speed controls would use automatically varied frequency, thus operating at the best at all speeds. Allowing the user to select the frequency seems a marketing ploy, with the result that the racer thinks he has a good thing going on, but has no idea if it is the right thing. I have tried these variable frequency controls, and can tell very little between the settings. I have asked others who use them, and they say the same, they are not sure there is any difference. I suggest you use the middle setting, say 3 to 5Khz and don't worry about it. Or you can keep adjusting it, and hope you find the setting that appears to be the one. Hope you race well. nick
Would love to see a video comparing the normal silver wire we mainly use in RC to the MuchMore copper looking wire. I’v started installing MuchMore wire in all my cars because I think the copper looking wire will have less resistance.
+Juwan Hunter Hi The LRP capacitor is very good, with low ESR. No need to change it. The 4 in a row small capacitors give low ESR. The KO 45558 is the best I have tested.
Hi Nick, thank you for posting your video’s. You were talking about the length of the wires. Do the wires from the esc to the battery (for example) need to have a equal length. It’s often safer to make one shorter to avoid mistakes (connecting + to - and -to +).
Hi Mushroom. The wires do not have to be the same length, but the shorter the better. Your suggestion of one shorter than the other is what I recommend to try and stop connecting the battery the wrong way. The wires to any capacitor should be kept as short as possible . Racve on. Nick
The disadvantage to the Tekin capacitor is the radial leads make it very difficult to work with regards to placement. I run a 1/10 scale buggy on carpet and need to place my battery as far forward as possible. If I mount the Tekin cap as Tekin suggests, the placement of the battery is impossible.
I can vouch for and agree 100% with everything said in this video. You know your stuff I fly fpv racing quads where voltage spikes (noise) can be a very real issue and even spikes of up to 30v on 4s have been seen in some cases which is the reason why tend to opt for 35v caps to cover nearly all bases for 4s... as most of us dont have access to a scope. It can affect the fpv picture and adding some low esr capacitance can help absorb these spikes and improve the fpv analogue picture being transmitted by the VTX. A welcome side effect is that it will likely improve the reliability of all the electronics on the quad by removing high voltage spikes that may be above the specs of some individual electrical components used on the various quad components. I'm new to the rc car side but I'd say its probably quite likely to be a potential issue worth protecting against here too. We tend to use high C lipos so none of us have ever experienced any performance boost of the quad itself, we just use them for smoothing. Too see the transient spikes created by escs that we quad guys are experiencing see- th-cam.com/video/RIBph5eDuIk/w-d-xo.html
I have not heard of putting capacitors on the DC (battery) input to an Electronic Speed Control (ESC). I have only used capacitors on the Battery Eliminator Circuit (BEC) output to keep the receiver from browning out from momentary dips, usually caused by high servo demand. I have actually observed this on an oscilloscope. Even then the voltage will only be held up for several milliseconds. That is also with only a few amp current draw. Not even enough power to give you an electrical shock much less power an RC vehicle.
+John Lytle Hi John The capacitor is needed on high frequency brushless speed controls to help with clean switching of the control FETS. The receiver capacitor is useful, as you say, to prevent low voltage glitches .
I agree, long wire? I don't consider a 30 CM wire for a DC battery connection to be long. I don't mess with capacitors in these circuits and I'v never had any issues with speed controllers. These are still DC input lines even if they switching device. Not enough AC effect to make a difference. I'm not buying it.
Hi Yes, you can add the new one with the original , or remove the original capacitor. Or if the capacitor is inside, then you can add an external one. make sure the voltage rating of the external capacitor is higher than the maximum Lipo voltage.
Hi Tuck Yes, the voltage must be higher than the fully charged maximum voltage of the highest voltage Lipo that will be connected. So a 3S Lipo will charge to 3x4.2=12.6V Therefore the 14.8V capacitor will be ok
Hi Nick, recently I have been running a SkyRC Toro 120 amp ESC for modified on road touring car. I thought I'd try as a cheaper alternative to HW. The problem has been when I accelerate at full throttle with Turbo timing the power delivery is on and off or delayed almost as if it is going to cut out or cannot handle the power, not to mention the handling issues it causes. Now I had it in my head that I could fix this with a better cap but from your video it seems like I can't. Any suggestions? Is it because it's just a cheaper ESC?
The Toro does have some issues. In this case a larger capacitor may overcome the hesitation. I recommend the 4 bank capacitor module as sold by KO, or Hobbywing. Keep the wire lenght to a minimum to the capacitor.
what's the life span of this capacitors? I'm assuming it takes a lot of abuse.. good idea to replace them if you race a lot ? like replace them after 3 months of racing a lot
Hi This type of capacitors do not change their ESR over time, but I have found that they often fail open circuit and are no longer doing anything. Some inadequate capacitors overheat, so look for split heatshrink or distorted case. Some capacitors fail totally and burn out, but that normally happens when you plug in the battery. Also if you plug in the battery the wrong polarity, then the capacitor will be badly stressed and will probably fail then or next time you use it.
Hi Vince Not sure what you are looking for. Are you trying to see what voltage is lost through the speedo? If the speedo is held on full speed, it should not drop any voltage if perfect. However all speedos have resistance and switching losses which make them heat up. So, one way to test a speedo is to see how hot it gets under load. You can feel the speedo after a race and see how hot it is. The more powerful speedos should be cooler.
Nick Adams is there any way you can email me at Vinced1201@netzero.net, I will try to explain in detail a little more what I am trying to do. I race oval. I have just viewed some of your posts and you know I lot more about electronics than I and I would like to talk to you about a few things. Thanks
Hi Nick, great review. I'm using a cap bank. It works great for rcdrift in my opinion. What do you think about Acuvance Photonic stabilizer acutron? Some people claims it makes the motor ran smoother, some gives extra punch and longer battery. To me it sounds like if you have a low quality capacitor, acutron might help. But having a good capacitor may not have any difference. I just don't want to spend $40 just to do the test. What do you think? Thanks. Jon
Hi I don't know an easy and accurate way to test ESR with a normal multimeter on its own. New capacitors have the ESR stated, and you can get low ESR ones quite cheap now. Also low ESR capacitors are used on speed controls, so they should all be low. Unless of course you have an old or damaged capacitor, in which case I would buy a new one.
Ok. I have a brand new one here, from Turnigy. I just wanted to make sure it was ok/low resistance. The weirdest thing about this is that the ESC directions don't mention a single word about the capacitors, installation or otherwise. My initial concern was if I even needed them. It seems that I do.
This is the "Turnigy Trackstar GenII 120A Sensored ESC" I just finished soldering the cap(s) on. Do you think it will it hurt if there are caps already built-in?
Caps on speedo are always a nightmare to position in the car! they really dont stick well with servo tape and always seem the oddest of shapes to try and secure somewhere. would be good to see speedos with them integrated into the main FET boards.
+clarkie005 Hi, I agree, but there are some speed controls with the capacitors inside the case, such as the Maverick ones, but it makes the control larger.
The best way to deal with this is to replace the flexible cap wires with solid copper wire. Not only is solid wire lower resistance but it it's rigid enough to keep the caps suspended in air without needing to tape them to anything.
I'm here for the invaluable information that Nick is providing!! 👍👍 I mainly run Crawlers, so some things a bit different.... One advantage that extra Capacitance provides is "Brown Out" protection, from High Amp Draw, 20-27mg Servos in a 25lb plus Beast - while running 3S or 4S Batteries. The ESCs onboard BEC can't cope with the high draw, and Drains Motor power Straight from the ESC! ....... We've got PLENTY of room for as much Capacitance as we can fit, and of course, weight is not a big penalty. Unless it's up high on the Rig! We even run separate BECs, wired Straight from the Batry leads, bypassing the ESC altogether. I'm considering getting back into Rally Cars, where a lot of the information here will definitely be relevant. You Sir, are a wealth of information!!
He was talking about ESC caps, not Rx caps. And if you're getting brown outs, it's likely due to having a weak BEC. If you plan to run power hungry servos and your ESC's BEC isn't up to the task, the smarter option is to run an external BEC with more amperage. Brownouts where nothing more than voltage drops on older gen 1 spektrum. Besides throwing all your spektrum garbage in the trash where it belongs, I'd recommend using Castle external bec that will outputs 8-10 amps and what ever voltage you set it to from 4.8-7.2v . The down side is you need the castle programming card to adjust it from stock 4.8v setting. I run Futaba 9352HV servos and they can use all 7.2 volts and need that much to operate like they should, but most don't need more than 6v to be perfectly fine.
I've run nothing but Futaba since 1986.... I do know I need a BEC. Waiting to afford a good one (Castle). In my case, I'm running 12,000uF of Capacitance on the RX. It's a stopgap, and I know it. Hopefully I can get it right, soon.
Nick: you explained why you need them and then said the battery was better which is wrong. You need a quick cap because the cap catches the wash off the battery. do you get instant battery flow?? NO you don't, that's why the cap is so important
Yes, actually you do get instant battery flow. Much quicker than the caps can take it in. As we all know, the caps are simply a noise buffer not an energy storage. But you don't seem to understand what he meant by the battery being better. He made the statement to reaffirm the notion that getting a lower IR battery to begin with will eliminate much of the IR and is the only way to generate more power. Many people don't understand this when it comes to caps because they don't understand their purpose to begin with, hence why companies dupe people into buying caps thinking they will see some form of power increase.
Yeah but only temporarily. They will bleed current over time and discharge them selves without needing to spend the power. I make things from microwave caps all the time to. They have enough voltage/current to kill you quick!
naught point 02 ohms ESR.... at what frequency?? and by the way, what's the ESR of the battery? I'd wager, you're never going to get a "low ESR" cap with less resistance than even the worst of the lipo packs. More miss-information and snake oil. Show me a scope grab of these transient spikes you speak of, then I might believe this B.S.... for now I think I'll just keep with EE theory.
I agree 100% with everything said in this video. I fly fpv racing quads where voltage spikes (noise) can be a very real issue and spikes of up to 30v have been seen in some cases so we tend to opt for 35v caps to cover all bases as most of us dont have a scope handy. It can affect the fpv picture and adding some low esr capacitance can help absorb these spikes and improve the fpv analogue picture being transmitted by the VTX. A welcome side effect is that it will likely improve the reliability of all the electronics on the quad by removing high voltage spikes that may be above the specs of some individual electrical components used on the various quad components. I'm new to the rc car side but I'd say its probably quite likely to be a potential issue worth protecting against here too. Too see the transient spikes created by escs that we quad guys are experiencing see- th-cam.com/video/RIBph5eDuIk/w-d-xo.html
![Electronic Circuitry Diagnosis And Fault Finding! [Repair]](/img/n.gif)
I can't believe that it took me this long to find your channel. I've been preaching the same Gospel on my TH-cam and Facebook pages for a while now. Excellent Video!
I look forward to seeing what you come up with in the future.
Soldering directly to the esc, that is an excellent idea that I've never heard mentioned before. That will also help with space constraints. Thanks!
The capacitors effectively lower the source impedance for the mosfets in the esc's, At high frequency and current, all wire has inductance and some resistance, and even the battery's internal series wiring contributes negatively, along with cell resistance, and effectively they are all in series, then that naturally degrades progressively to a higher value as the battery pack ages. Instantaneous current demands by high speed mosfets result in reduction in switching transition time when the source voltage sags, and it's compounded when multiple esc's all overlay the same demands on wiring/battery, that resistance results in heat which is just wasted energy. it's the art of losses. The value of the capacitors used should be a factor of esc frequency with minimal esr for that value. You will not get a boost, just a significant reduction in loss when it's correct.
Anyway, good video Nick.
Hi Alasdair
I agree, the capacitor is essential to minimise switching losses.
The large capacitors are sold as power boosters for the models with a single speed control and high power lipo with high power wiring etc.
And in my opinon do very little, if the speed control already has a low ESR capacitor as supplied with the speed control.
However many racers believe (in their minds) that it is boosting performance, and that effect may actually result in them performing better.
Thanks for your input.
Nick
Alasdair McC Alasdair, would you say that a very high capacity capacitor would help braking or punch in a stock racing class like 17.5 blinky? OR would you say their use is simply to protect the ESC? What about ESC temperature reduction? Great explanation btw, even though I am not sharp enough to grasp it all!
Jay, the optimal size as strange as it seems would increase (in capacitance) as the performance of your battery decreases, so rather than lugging huge caps around when you would not likely gain much from their size most of the time, i would suggest maybe some trial and error if you don't have a scope to measure the switching sag and the effect of increasing value with your setup. One thing though, anything beyond about 1500uf with very good low esr performance is not likely to yield much more gain, and any cable length between the esc and capacitor is effectively an inductor, lessening the capacitors ability to sustain instantaneous source current to the mosfets. Imagine the cap as a shock absorber on a car driving along on railway sleepers, a long wire is like mounting it with rubber rods, lessening the effect of what it should be doing. Not to bomb you with more tech babble, but heat in the esc is nearly all generated in the transition time of the mosfet junction (switch) turning from fully off, to fully on, when fully on the resistance is so low no heat is made, but in that transition time it is effectively a resistor turning increasing current into heat. It cannot be infinitely fast due to things like gate capacitance and source impedance, but the lower that source impedance is (rigid supply current) it's like bouncing a pogo stick on concrete, vs. high source impedance (soft supply current) is like bouncing it on soft mud. The punch out is likely helped by caps, as the effects I just listed will help prevent de syncing, but motors, esc's and batteries are a system which all rely on each other for maximum performance, the caps really just make the battery look better to the esc.
Hi Jay
A capacitor must be used to help the high frequency on/off switching, to keep the switching losses low, and minimise heating.
If you do rock crawling or very slow running, a large capacitor may be beneficial.
With high speed racing with fast on and off throttle and braking a larger capacitor will have minimal effect on either.
However some report better braking and faster top speed, which may be an effect in the brain rather than in the car.
can you explain the 7.8KHz i have seen esc's with adjustable throttle and brake frequencies and im wondering what that does
Hi Ronnie
I agree it is confusing, and not sure it is of much use.
In theory the highest frequency would give the smoothest control and action.
However, the higher the frequency the more losses will occur in the speed control as the pulses struggle to switch on and off, but the motor should run more efficiently.
At the lower frequency the response , especially at high speeds becomes less defined and less smooth, but the speed control should run cooler.
Most speed controls would compromise and fix the frequency in the middle range.
The most advanced speed controls would use automatically varied frequency, thus operating at the best at all speeds.
Allowing the user to select the frequency seems a marketing ploy, with the result that the racer thinks he has a good thing going on, but has no idea if it is the right thing.
I have tried these variable frequency controls, and can tell very little between the settings.
I have asked others who use them, and they say the same, they are not sure there is any difference.
I suggest you use the middle setting, say 3 to 5Khz and don't worry about it.
Or you can keep adjusting it, and hope you find the setting that appears to be the one.
Hope you race well.
nick
Thanks a lot for explaining that
Caps cover surges and provide more equal and cleaner power , caps aren’t multiplying anything. Helps with cleaning power and short burst stress.
Would love to see a video comparing the normal silver wire we mainly use in RC to the MuchMore copper looking wire. I’v started installing MuchMore wire in all my cars because I think the copper looking wire will have less resistance.
I heard that smaller capacitor in a row will give you better punch out of a corner than one big one, like the one that comes with the lrp flow.
+Juwan Hunter
Hi
The LRP capacitor is very good, with low ESR. No need to change it.
The 4 in a row small capacitors give low ESR.
The KO 45558 is the best I have tested.
Hi Nick, thank you for posting your video’s. You were talking about the length of the wires. Do the wires from the esc to the battery (for example) need to have a equal length. It’s often safer to make one shorter to avoid mistakes (connecting + to - and -to +).
Hi Mushroom. The wires do not have to be the same length, but the shorter the better.
Your suggestion of one shorter than the other is what I recommend to try and stop connecting the battery the wrong way.
The wires to any capacitor should be kept as short as possible .
Racve on. Nick
Thank you!
@@nickadams5411 hi Nick ! It's me Christophe M. Do u remember Gouzat ? And Tom ?
The disadvantage to the Tekin capacitor is the radial leads make it very difficult to work with regards to placement. I run a 1/10 scale buggy on carpet and need to place my battery as far forward as possible. If I mount the Tekin cap as Tekin suggests, the placement of the battery is impossible.
I can vouch for and agree 100% with everything said in this video. You know your stuff
I fly fpv racing quads where voltage spikes (noise) can be a very real issue and even spikes of up to 30v on 4s have been seen in some cases which is the reason why tend to opt for 35v caps to cover nearly all bases for 4s... as most of us dont have access to a scope.
It can affect the fpv picture and adding some low esr capacitance can help absorb these spikes and improve the fpv analogue picture being transmitted by the VTX. A welcome side effect is that it will likely improve the reliability of all the electronics on the quad by removing high voltage spikes that may be above the specs of some individual electrical components used on the various quad components.
I'm new to the rc car side but I'd say its probably quite likely to be a potential issue worth protecting against here too.
We tend to use high C lipos so none of us have ever experienced any performance boost of the quad itself, we just use them for smoothing.
Too see the transient spikes created by escs that we quad guys are experiencing see- th-cam.com/video/RIBph5eDuIk/w-d-xo.html
Hi Paul. Thanks for the technical information. It all helps our understanding. All the best. Nick
I have not heard of putting capacitors on the DC (battery) input to an Electronic Speed Control (ESC). I have only used capacitors on the Battery Eliminator Circuit (BEC) output to keep the receiver from browning out from momentary dips, usually caused by high servo demand. I have actually observed this on an oscilloscope. Even then the voltage will only be held up for several milliseconds. That is also with only a few amp current draw. Not even enough power to give you an electrical shock much less power an RC vehicle.
+John Lytle
Hi John
The capacitor is needed on high frequency brushless speed controls to help with clean switching of the control FETS.
The receiver capacitor is useful, as you say, to prevent low voltage glitches .
I agree, long wire? I don't consider a 30 CM wire for a DC battery connection to be long. I don't mess with capacitors in these circuits and I'v never had any issues with speed controllers. These are still DC input lines even if they switching device. Not enough AC effect to make a difference. I'm not buying it.
How to choose capacitor for esc 120a seaking? Thx
is it safe to add additional capacitor even if the esc came wit capacitor installed to it
Hi
Yes, you can add the new one with the original , or remove the original capacitor.
Or if the capacitor is inside, then you can add an external one.
make sure the voltage rating of the external capacitor is higher than the maximum Lipo voltage.
Nick Adams
thank you
So if i have a 3s 11.1v battery i need a capacitor with 14.8v
Hi Tuck
Yes, the voltage must be higher than the fully charged maximum voltage of the highest voltage Lipo that will be connected.
So a 3S Lipo will charge to 3x4.2=12.6V
Therefore the 14.8V capacitor will be ok
I've got 2 capacitors that came with my ESC and have 2 more the same spare,could I solder those on the positive and negative posts as well.
Hi Nick, recently I have been running a SkyRC Toro 120 amp ESC for modified on road touring car. I thought I'd try as a cheaper alternative to HW. The problem has been when I accelerate at full throttle with Turbo timing the power delivery is on and off or delayed almost as if it is going to cut out or cannot handle the power, not to mention the handling issues it causes. Now I had it in my head that I could fix this with a better cap but from your video it seems like I can't. Any suggestions? Is it because it's just a cheaper ESC?
The Toro does have some issues. In this case a larger capacitor may overcome the hesitation. I recommend the 4 bank capacitor module as sold by KO, or Hobbywing. Keep the wire lenght to a minimum to the capacitor.
@@nickadams5411 Thanks Nick, much appreciated.
what's the life span of this capacitors? I'm assuming it takes a lot of abuse.. good idea to replace them if you race a lot ? like replace them after 3 months of racing a lot
Hi
This type of capacitors do not change their ESR over time, but
I have found that they often fail open circuit and are no longer doing anything.
Some inadequate capacitors overheat, so look for split heatshrink or distorted case.
Some capacitors fail totally and burn out, but that normally happens when you plug in the battery.
Also if you plug in the battery the wrong polarity, then the capacitor will be badly stressed and will probably fail then or next time you use it.
Nick is there a way to measure speedo voltage output without a Blinky buster?
Hi Vince
Not sure what you are looking for.
Are you trying to see what voltage is lost through the speedo?
If the speedo is held on full speed, it should not drop any voltage if perfect.
However all speedos have resistance and switching losses which make them heat up.
So, one way to test a speedo is to see how hot it gets under load.
You can feel the speedo after a race and see how hot it is.
The more powerful speedos should be cooler.
Nick Adams is there any way you can email me at Vinced1201@netzero.net, I will try to explain in detail a little more what I am trying to do. I race oval. I have just viewed some of your posts and you know I lot more about electronics than I and I would like to talk to you about a few things. Thanks
Informative, accurate and to the point, great video buddy, thanks for sharing!
Hi Nick, great review. I'm using a cap bank. It works great for rcdrift in my opinion.
What do you think about Acuvance Photonic stabilizer acutron?
Some people claims it makes the motor ran smoother, some gives extra punch and longer battery.
To me it sounds like if you have a low quality capacitor, acutron might help. But having a good capacitor may not have any difference. I just don't want to spend $40 just to do the test. What do you think?
Thanks. Jon
Hi
I think you should save your money for a Flux Capacitor
Great video Nick. Thanks so much! Best wishes. Rich.
Nick, I was wondering if there was a way to test esr with a multimeter. As always, you provide excellent videos. Thank you for doing what you do!
Hi
I don't know an easy and accurate way to test ESR with a normal multimeter on its own.
New capacitors have the ESR stated, and you can get low ESR ones quite cheap now.
Also low ESR capacitors are used on speed controls, so they should all be low.
Unless of course you have an old or damaged capacitor, in which case I would buy a new one.
Ok. I have a brand new one here, from Turnigy. I just wanted to make sure it was ok/low resistance. The weirdest thing about this is that the ESC directions don't mention a single word about the capacitors, installation or otherwise. My initial concern was if I even needed them. It seems that I do.
Hi
The speed control will need a capacitor.
Some recent speed controls have them built inside.
This is the "Turnigy Trackstar GenII 120A Sensored ESC" I just finished soldering the cap(s) on. Do you think it will it hurt if there are caps already built-in?
Hi
Extra caps will be ok.
Caps on speedo are always a nightmare to position in the car! they really dont stick well with servo tape and always seem the oddest of shapes to try and secure somewhere. would be good to see speedos with them integrated into the main FET boards.
+clarkie005
Hi, I agree, but there are some speed controls with the capacitors inside the case, such as the Maverick ones, but it makes the control larger.
The best way to deal with this is to replace the flexible cap wires with solid copper wire. Not only is solid wire lower resistance but it it's rigid enough to keep the caps suspended in air without needing to tape them to anything.
I'm here for the invaluable information that Nick is providing!! 👍👍
I mainly run Crawlers, so some things a bit different.... One advantage that extra Capacitance provides is "Brown Out" protection, from High Amp Draw, 20-27mg Servos in a 25lb plus Beast - while running 3S or 4S Batteries.
The ESCs onboard BEC can't cope with the high draw, and Drains Motor power Straight from the ESC!
....... We've got PLENTY of room for as much Capacitance as we can fit, and of course, weight is not a big penalty. Unless it's up high on the Rig!
We even run separate BECs, wired Straight from the Batry leads, bypassing the ESC altogether.
I'm considering getting back into Rally Cars, where a lot of the information here will definitely be relevant. You Sir, are a wealth of information!!
He was talking about ESC caps, not Rx caps. And if you're getting brown outs, it's likely due to having a weak BEC. If you plan to run power hungry servos and your ESC's BEC isn't up to the task, the smarter option is to run an external BEC with more amperage. Brownouts where nothing more than voltage drops on older gen 1 spektrum. Besides throwing all your spektrum garbage in the trash where it belongs, I'd recommend using Castle external bec that will outputs 8-10 amps and what ever voltage you set it to from 4.8-7.2v . The down side is you need the castle programming card to adjust it from stock 4.8v setting. I run Futaba 9352HV servos and they can use all 7.2 volts and need that much to operate like they should, but most don't need more than 6v to be perfectly fine.
I've run nothing but Futaba since 1986.... I do know I need a BEC. Waiting to afford a good one (Castle).
In my case, I'm running 12,000uF of Capacitance on the RX. It's a stopgap, and I know it. Hopefully I can get it right, soon.
nichicon fine gold capacitors Japan i like using in audio resotation i ant ever bought cap premad up but i am new to rc but i bet this cost way more
Great information. Thank you .
Nick: you explained why you need them and then said the battery was better which is wrong. You need a quick cap because the cap catches the wash off the battery. do you get instant battery flow?? NO you don't, that's why the cap is so important
Yes, actually you do get instant battery flow. Much quicker than the caps can take it in. As we all know, the caps are simply a noise buffer not an energy storage. But you don't seem to understand what he meant by the battery being better. He made the statement to reaffirm the notion that getting a lower IR battery to begin with will eliminate much of the IR and is the only way to generate more power. Many people don't understand this when it comes to caps because they don't understand their purpose to begin with, hence why companies dupe people into buying caps thinking they will see some form of power increase.
Yeah but only temporarily. They will bleed current over time and discharge them selves without needing to spend the power. I make things from microwave caps all the time to. They have enough voltage/current to kill you quick!
thank you
naught point 02 ohms ESR.... at what frequency?? and by the way, what's the ESR of the battery? I'd wager, you're never going to get a "low ESR" cap with less resistance than even the worst of the lipo packs. More miss-information and snake oil. Show me a scope grab of these transient spikes you speak of, then I might believe this B.S.... for now I think I'll just keep with EE theory.
I agree 100% with everything said in this video.
I fly fpv racing quads where voltage spikes (noise) can be a very real issue and spikes of up to 30v have been seen in some cases so we tend to opt for 35v caps to cover all bases as most of us dont have a scope handy. It can affect the fpv picture and adding some low esr capacitance can help absorb these spikes and improve the fpv analogue picture being transmitted by the VTX. A welcome side effect is that it will likely improve the reliability of all the electronics on the quad by removing high voltage spikes that may be above the specs of some individual electrical components used on the various quad components.
I'm new to the rc car side but I'd say its probably quite likely to be a potential issue worth protecting against here too.
Too see the transient spikes created by escs that we quad guys are experiencing see- th-cam.com/video/RIBph5eDuIk/w-d-xo.html