Why Capacitors Are Important For FPV Drones

by Oscar

Capacitors are a crucial component for FPV drones as they help to reduce voltage spikes and electrical noise in the power system. These voltage spikes and electrical noise can cause harm to electronic components, especially the flight controller and ESCs. Adding capacitors to an FPV drone can protect these components and enhance the overall performance of the drone.

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Where To Buy?

The following suggestions assume you are soldering the capacitor to the main power of a 4in1 ESC. If you are using single ESC’s, you can use smaller capacitors for each ESC (e.g. 220uF or 330uF per ESC).

Both Panasonic FM/FS series and Rubycon ZLJ/ZLH series are great as they have some of the lowest ESR (Equivalent Series Resistance).

For 3S builds (16V or higher, works for 2S too):

For 4S builds (25V-35V, works for 3S too):

For 6S builds (35V-50V, works for 4S too):

What is a Capacitor?

A capacitor is one of the most common electronic components.

Capacitors store electric charge in an electric field between two conductive plates and can absorb and discharge electrical energy quickly just like a tiny battery. The capacitor absorbs voltage spikes, and releases the stored energy when there’s a voltage drop to smooth out the voltage fluctuations and prevent damage to other components.

The Benefits of Extra Capacitors in FPV Drones

The FET’s in our ESC are effectively switches. They turn on and off rapidly tens of thousands of times per second to drive the motors, which can generate a lot of electrical spikes and noise. As technology advances allowing for more powerful motors and ESC’s, and higher battery voltage, the problem becomes even more pronounced. The noise issue is absolutely crucial, it can mean the difference between a fantastic FPV drone and something that is completely unflyable.

Capacitors can help to reduce electrical noise and voltage spikes that can occur when the motors spin up or when the drone is performing high-speed manoeuvres. Additionally, capacitors can help reduce the amount of interference that the power system generates, which can improve the quality of the analog video feed from the drone’s camera.

ESC and FC have surface mount capacitors for filtering, but due to the lack of physical space, they tend to be insufficient. As pointed out in my FPV drone build guide, soldering additional capacitors to our FPV drone is almost always mandatory to ensure optimal performance.

To sum it up, adding more capacitors to our FPV drone can provide the following benefits:

  • Filtering electrical noise generated by ESC and motors, reducing interference to ESC/radio/video signals
  • Improving flight performance by “cleaning up” the noise in gyro signal
  • Protecting electronics from damaging voltage spikes. Capacitors act as a buffer, absorbing any excess energy before it reaches the delicate components
  • If you fly analog, having adequate capacitors at the input power can help reduce video noise in your FPV feed

Here is an example showing how much improvement it made to my FPV video feed after installing a capacitor at the XT60 power input.

If you don’t use capacitors in your FPV drone, you may experience issues such as:

  • Video noise and lines in your video feed, which can make it difficult to fly
  • Suboptimal flight performance and you can’t push PID and filter as high as you could have otherwise
  • Components are more exposed to voltage spikes damage when you power them directly from battery

Do You Need To Add Capacitor?

You don’t have to use caps, but we recommend it. As mum says:

“Put a cap on, it’s noisy out there!”

If you have a noisy quad (lots of oscillations and it’s hard to tune PID and filters) or noisy video feed, adding capacitors would probably be the first thing you should try.

Here is how you can decide whether your quad is too noisy and need a capacitor.

  • Listen to the motors and see if there are oscillation that you can’t tune out with PID
  • Check for hot motors
  • Noise in your video feed is another sign of electrical noise in the power
  • In extreme cases, you can get ESC/motor desync and “roll of death” due to ESC signals being corrupted by noise

Even if you don’t have a noisy build, it’s still good practice to add caps. Better safe than sorry right? :) Bent and misshapen props can introduce noise in your power, adding caps can actually help with that too.

What Type of Capacitor Should You Use?

There are three types of capacitors commonly used in FPV drones:

  • Ceramic capacitors
  • Electrolytic capacitors
  • Tantalum capacitors

Ceramic capacitors are the most popular type used for surface mount because of their small size, low cost, and high capacitance values. Electrolytic capacitors are larger and more expensive but can provide higher capacitance values. Tantalum capacitors are similar to electrolytic capacitors but are more reliable and have a longer lifespan.

The most common type of cap we install on FPV drone by ourselves would be electrolytic capacitor. It’s a small cylinder with metal casing (usually aluminium) and two legs (one positive one negative).

When selecting capacitors for your FPV drone, you should pay attention to the following capacitor ratings:

  • Capacitance: it indicates how much charge a capacitor can store. For an FPV drone, you typically want capacitors with a capacitance between 100uF and 1000uF. Higher capacitance values can provide better filtering, but they are physically larger and heavier
  • Voltage Rating: this is the maximum voltage the capacitor can withstand before failing, it should be higher than the voltage spikes that the drone’s electronics can produce. For example, if the drone is powered by a 4S (14.8V) battery, you should choose capacitors with a voltage rating of at least 25V, and for 6S, that should be 35V or higher. There’s no harm in choosing a higher voltage rated capacitor, but they tend to be larger in size
  • ESR (Equivalent Series Resistance) is the resistance that the capacitor presents to the flow of current, and a lower ESR is generally better for filtering out noise as demonstrated in this video.

Choose voltage rating based on LiPo cell count, voltage spikes can be higher than the battery voltage, so it’s safer to pick a cap with higher rated voltage than the LiPo.

  • 3S: 16V or higher
  • 4S: 25V or higher
  • 5S: 35V or higher
  • 6S: 35V or higher (e.g. 50V if you want to play safe)
  • 8S: 63V or higher
  • 12S: 80V or higher

You could use a lower voltage capacitor but you risk reduced lifespan and performance. Make sure to get a capacitor that is of low ESR (with “low ESR” mentioned on the product page).

Where to Install Capacitor in FPV Drone?

FPV drones typically require capacitors to be added to the power system, either across the power leads or directly onto the ESCs’ power pads. The general idea is to connect the capacitor as close as electrically possible to the MOSFET’s in the ESC can maximize its effectiveness. For 4in1 ESC, that usually means the power solder pads.

 

Eachine Tyro79 Pro Diy 3 Inch Fpv Drone Kit Build Solder Capacitor

If you don’t have space, you can shorten the legs of the cap, then solder some flexible silicone wires for extension and place the cap somewhere else inside the frame. But make sure to keep the wires as short as possible to minimize resistance, and use larger wires (e.g. for 6S 5″ 20AWG or even 18AWG is a good choice).

Capacitor Removes Lead and solder wires

How To Build Fpv Drone 2023 Solder Capacitor Install

It’s extremely important to understand the polarity of a capacitor, the longer leg is positive (+) and the shorter leg is negative (-). The marking on the body (white label) also indicates which terminal is negative. If you make a mistake, the capacitor won’t work, it might even explode, please be careful!

How to Read Capacitor Spec

Solder the capacitor to either the ESC power or XT60 solder pads. Negative to negative, positive to positive.

Cleaning Up Gyro Power

If your mini quad has electrical noise issue, such as oscillations and hot motors, by simply adding a large capacitor to the XT60 or ESC power doesn’t solve it, then you might want to consider adding a small capacitor directly to the Gyro’s power supply. This can target the noise present in the gyro’s power more effectively.

I only recommend this hack to experienced users. It’s not easy finding where to solder the capacitor to, and it also requires decent soldering skills. You don’t have to worry about this if you don’t have issues. If you do, try other easier methods first and treat this as the last resort.

Adding Cap to 3.3V

The Gyro on our flight controllers is powered by a 3.3V LDO regulator, so you just need to solder a capacitor to the 3.3V pin of the Gyro, or the 3.3V output of the LDO. The other end of the cap solder to ground.

Popular options are 4V 220uF, 330uF or 470uF tantalum capacitor: https://amzn.to/3XN4Hhn

The 3V rail should be filtered as close to gyro as possible for the best result.

Very few FC’s share the same 3.3V rail with the MCU and spektrum receivers, so you might be able to access the 3.3V rail on an external solder pad. IMO this is not a good FC design by not having a dedicated low noise regulator just for the gyro, but it does make it easier for you to solder the capacitor to if required.

Adding Cap to 5V

The 3.3V LDO for the Gyro gets power from the 5V rail, so you can also filter the 5V rail which will also clean up noise for the gyro. It might not be as effective as filtering in on the 3.3V rail but it’s worth a try if it’s more accessible.

Popular options: 6V 220uF, 330uF or 470uF tantalum capacitor: https://amzn.to/41blcqv

Capacitor Gets Hot After Flight

Potential causes of capacitor gets hot after flight (or it exploded):

  • Capacitance is too small. For example if you are using a 680uF, you should try a 1000uF
  • It could be a sign of the voltage spikes are too high, you should get a cap with higher voltage rating. For example if you are using a 35V cap on 6S, you might want to get a 50V one.

Is Adding Too Many Capacitors Bad?

Short answer – No.

If you are filtering signal of certain frequency range, then you should control the capacitance and inductance precisely in your circuit. But what we are dealing with here is just DC voltage and a low pass filter, you won’t “over-filter” DC voltage, so you can use as much capacitance as you want and it won’t be a problem. In fact, the more capacitors you use in your drone, the stronger this low pass filtering works.

So, use as many capacitors as you wish, as long as you have space to mount them.

Do Capacitors Wear Out?

Short answer – Yes.

Electrolytic capacitors used in FPV drones have a limited lifespan and can wear out over time due to factors such as high temperature and high voltage stress. When an electrolytic capacitor wears out, it can leak or bulge, and its capacitance may decrease. This can result in instability and noise in the power supply, which can affect the performance of the electronics. It’s a good idea to periodically inspect and replace capacitors in your drone, even when they look “ok”, it’s might be worth to replace them regularly.

LC Filter vs Capacitor

LC filters are often used in FPV systems to combat video noise as well, but it only protects the system after the noise is induced. Adding capacitor at the source of the power on the other hand, protects the entire system by preventing the noise from being induced in the first place.

ESR Testing Results

330uF

25V

Brand Series Size (D X L) Impendance (Ω/100 kHz)
Panasonic FM 10×12.5 0.038
Elna RJF 10×12.5 0.039
Vishay 160 RLA 12.5×25 0.04
Panasonic FM 8×15 0.041
Samwha ML 10×12.5 0.053
Nippon KZE 10×12.5 0.053
Panasonic FR 8×11.5 0.056
United Chemi-Con (UCC) KZH 8×11.5 0.062
Nippon KZH 8×11.5 0.062
Samwha MZ 10×12.5 0.08
Panasonic FC 8×15 0.085
Panasonic FC 10×12.5 0.09
Nichicon PW 10×12.5 0.09
Samwha MK 10×12.5 0.098
Panasonic TP 10×16 0.13
Elna RJ4 10×12.5 0.81

35V

Brand Series Size (D X L) Impendance (Ω/100 kHz)
Panasonic FM 10×16 0.026
Elna RJF 10×16 0.028
Panasonic FM 8×20 0.03
Samwha MZ 10×16 0.038
Nippon KZE 10×16 0.038
Vishay 160 RLA 12.5×25 0.04
Panasonic FR 10×12.5 0.043
United Chemi-Con (UCC) KZH 10×12.5 0.045
Nippon KZH 10×12.5 0.045
Panasonic TP 10×20 0.052
Samwha ML 10×12.5 0.053
Panasonic FC 8×20 0.065
Samwha MK 10×16 0.065
Panasonic FC 10×16 0.068
Nichicon PW 10×16 0.068
Elna RJ4 10×12.5 0.7

470uF

25V

Brand Series Size (D X L) Impendance (Ω/100 kHz)
Panasonic FM 10×16 0.026
Elna RJF 10×16 0.028
Vishay 160 RLA 16×25 0.029
Panasonic FR 8×20 0.03
Samwha MZ 10×16 0.038
Panasonic FR 8×15 0.041
Nippon KZE 8×20 0.041
Panasonic FR 10×12.5 0.043
United Chemi-Con (UCC) KZH 10×12.5 0.045
Nippon KZH 10×12.5 0.045
Samwha ML 10×12.5 0.055
Samwha MK 10×20 0.06
Samwha MK 10×16 0.065
Panasonic TP 8×20 0.067
Panasonic FC 10×16 0.068
Nichicon PW 10×16 0.068
Panasonic TP 10×17 0.13
Elna RJ4 10×12.5 0.57

35V

Brand Series Size (D X L) Impendance (Ω/100 kHz)
Panasonic FM 10×20 0.019
Elna RJF 10×20 0.02
Nippon KZE 10×20 0.023
Samwha MZ 10×20 0.027
Panasonic FR 10×20 0.028
Panasonic FR 10×16 0.028
Panasonic FR 8×20 0.03
Nichicon UHW 10×16 0.03
Nippon KZH 10×16 0.032
United Chemi-Con (UCC) KZH 10×16 0.032
Vishay 160 RLA 18×20 0.035
Panasonic TP 12.5×20 0.038
Samwha ML 8×20 0.038
Samwha ML 10×16 0.041
Samwha MK 10×20 0.05
Panasonic FC 10×20 0.052
Nichicon PW 10×20 0.052
Samwha MK 8×20 0.088
Elna RJ4 10×16 0.5

1000uF

25V

Brand Series Size (D X L) Impendance (Ω/100 kHz)
Elna RJF 12.5×20 0.017
Panasonic FR 10×25 0.018
United Chemi-Con (UCC) KZH 10×25 0.018
Nippon KZH 10×25 0.018
Panasonic FR 10×20 0.02
Nichicon UHW 10×20 0.02
Nippon KZE 12.5×20 0.021
Samwha MZ 12.5×21 0.025
Vishay 160 RLA 16×31 0.027
Samwha ML 10×20 0.033
Vishay 136 RVI 12.5×25 0.034
Panasonic FC 10×30 0.035
Panasonic FC 12.5×20 0.038
Nichicon PW 12.5×20 0.038
Panasonic FC 16×15 0.043
Samwha MK 10×25 0.045
Samwha MK 10×20 0.05
Elna RJ4 10×20 0.27

35V

Brand Series Size (D X L) Impendance (Ω/100 kHz)
Panasonic FM 12×25 0.015
Elna RJF 12.5×25 0.015
Nichicon UHW 12.5×20 0.017
United Chemi-Con (UCC) KZH 12.5×20 0.017
Nippon KZH 12.5×20 0.017
Panasonic FM 12.5×20 0.018
Nippon KZE 12.5×25 0.018
Samwha MZ 12.5×25 0.022
Vishay 160 RLA 18×35 0.024
Samwha ML 12.5×20 0.026
Panasonic FC 16×20 0.029
Samwha MK 12.5×25 0.029
Panasonic FC 12.5×25 0.03
Nichicon PW 12.5×25 0.03
Samwha MK 12.5×20 0.043
Elna RJ4 12.5×20 0.23
  • Panasonic EB, EE, HD, NHG,GA, M, SU, KA and KS series are not low ESR
  • Samwha SD, BH and RD series are not low ESR, WL and WF are mediocre
  • United Chemi-Con (UCC) with KZM series is comparable to KZH
  • There are much more low ESR Vishay capacitors, but they are just too big
  • Rubycon low ESR capacitors go only up to 220uF – thus not show here
  • Elna RJ3 and RJ4 are comparable

Edit History

  • May 2017 – Article created
  • Oct 2017 – Updated cap options, uploaded a video to show the effectively of adding cap
  • Apr 2018 – Added section “Does my Quad Need Capacitor?”
  • Aug 2018 – Added section “Adding Cap to Gyro’s Power”
  • May 2019 – Updated capacitor introduction
  • Jan 2020 – Added info on cap getting hot, cap size consideration
  • Feb 2023 – Revised, added new images and updated product links

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102 comments

Thanh 14th May 2024 - 4:41 am

ESC drivers often have very high motor control phase currents. Therefore, the ripple current is very large. How to choose a capacitor that meets this ripple current? I see that capacitors usually only have a ripple current of a few Amps at 105 *C/100kHz.

Reply
Martin 15th December 2023 - 7:21 pm

In the Audio world, NCC KY is comparable with Pana FC at a lower price… NCC GXE is also a good capacitor suited for more demanding environment…

Reply
J. Sylvester 8th August 2023 - 3:41 am

Hey OSCAR. Long time fan of your write ups! I had an issue with a foxeer 25 unbreakable. Long story short, I power cycled it 3 times in a row pretty quickly and then the FC had a red light. Everything beeped…. But no power to my cam, thumb 4k or vtx. I read up and found I did not get 5v to my pads (blue lights when plugging into PC). I tried to add a 5v setup down thinking it just blew the reg… But no go. I have another on order. My thoughts after reading this is it spiked voltage while cycling. It always “snapped” pretty good when plugging g a battery in. From reading this it sounds like I should instantly add a cap to the new one. Is it normal for power spikes to happen when cycling power? (Elrs with nano required me to do it when wifi mode was not activating so this is alarming). Over 25 flights and not 1 crash! Terrible way for it to die.

Reply
max 10th July 2023 - 1:12 am

hey oscar, heres my issue. one day i plugged in my battery and randomly one motor started spiining up out of nowwhere. now i have 4 seperate escs with a capacitor on each one. i doubt the problem is my esc but it could be. but i suspect its the capacitor thats finished. do you think that may be the cause of the issue or its more likely the esc?

thanks

Reply
Oscar 11th July 2023 - 3:35 pm

It could be, but unlikely to be the capacitor.
I think there could be two main reasons that the motor starts spinning – either the ESC is faulty, or the FC is telling the ESC to spin (maybe a bad FC or buggy FC firmware).
Can you reproduce the issue? is it always the same motor that spins? Try swapping the ESCs around and see if the same problematic ESC is still causing issue, then you’d know if it’s the FC or ESC.

Reply
Graeme 1st March 2023 - 12:20 am

Hello Oscar,

Many thanks for taking the time to help others.

I do have a question, if you don’t mind?
I am using an RC Car with an FPV setup and am getting a lot of interferance. I am wondering where I should put a capacitor. Do I put it on the power leads where they exit the ESC or do I put it on the VTX Power leads?

Thanks again
Graeme

Reply
Oscar 1st March 2023 - 12:47 am

On the power leads.

Reply
Graeme 3rd March 2023 - 11:40 pm

Thank you.

Reply
Jerome Demers 24th March 2023 - 12:55 pm

you place capacitors the closest to the source of the electric noise.

Reply
Charlie 18th February 2023 - 9:02 pm

You and others say you can use multiple capacitors but does it make a difference if they are added in series or parallel? Can I put a smaller 25v 470uf capacitor on the battery pad so that it fits in the quad and then a 35v 1000uf On my xt30?

Reply
Oscar 19th February 2023 - 12:28 am

Never connect capacitors in series if your sole purpose is to filter noise in DC, it actually reduces the total capacitance.
Connecting them in parallel on the other hand will increase it (sum total).
Yes you can mix caps of different voltage rating and capacitance.

Reply
Charlie 21st February 2023 - 4:57 am

Thanks. But is putting a capacitor on the xt30 and another on the battery pad considered in series?

Reply
Oscar 21st February 2023 - 11:02 am Reply
Ben 21st June 2022 - 5:31 pm

Will using a larger cap (1000uf) on a smaller build (3” 4s) cause potential problems or starve voltage from the system at all? Or would it simply be a bit more capable of higher spikes (that likely wouldn’t occur)?

Reply
Merin Kumar 24th February 2022 - 6:07 am

Hi Oscar, I built my 1st 6S setup (mainly iflight electronics), doc mentioned 50V cap for 6S and 35V for 4/5S, but the cap i got in the ESC stack from iflight is 35V (Succex-D mini twing F7, 45A esc). So i checked and only can find Unicon UPL 220uF 50V caps, cant find hight capacitance, would that work 220uF ?

Reply
Rodro 25th October 2021 - 12:54 am

Hey Oscar, thank you for sharing your knowledge. You already helped me out a bunch of times!
So I have this 6S quad where there is no space at all for the capacitor to be correctly mounted soldered to the battery pads on my 4in1 ESC. So I have it soldered on the XT-60 battery-side, at the end of the pigtail.
I’m not having any video noise problems, but I’m concerned about ESC longevity. It’s a LR quad so burning the ESC because of damages caused by the current spikes will almost certainly mean loosing the quad…
Is my solution really bad? Would something like the FETTEC Spike Absorber adeguately compensate for that?
Thank you!

P.S. Does the size of the motors matter? I have 2814 Xing 1100KV

Reply
Vitorio 7th September 2021 - 5:35 pm

My 35v/ 530uf cap burned out on first test of the motor. I’m running a matek f722se, kraman 60a esc, and five33 2207, 1970 kv.
All smoke test where fine. No damage to anything but the cap. Should I just get a bigger cap , or that an indication for other issues?

Reply
Oscar 7th September 2021 - 11:31 pm

I assume that’s a 6S build? But even for 6S it’s very unusual to burn out cap for 35V caps. Maybe you have a very noisy build, try to get the 50V rated cap i linked?
The other thing is to make sure polarity is correct and the cap is in good shape (brand new, no dents etc).

Reply
Marek 15th April 2021 - 5:49 pm

Hello,
I would like to say few words about capacitors for noise filtering. I am going to add 100nF ceramic capacitor in parallel.
A large capacitor like 1000 uF act as a “reservoir” to store energy from the Li-Po out .
When large current peaks are drawn the capacitor supplied surge energy helps the battery not sag in output.
The small capacitor (100nF) non polarized, usually nowadays be a multilayer ceramic capacitor
with low ESR and low inductance giving it excellent high frequency response and noise filtering capabilities.
High value polarised capacitors typically do not have ideal characteristics at high frequencies
, so it’s fairly common to add a low value capacitor in parallel
in situations where you need to worry about stability at high frequencies.

Reply
Gustavo 19th January 2021 - 10:53 pm

It would be interesting to see how to calculate the Farad rating for a build.

Your site is always the first stop when I want to learn something related to quads. It’s often the best source with high quality and comprehensive information.

I’ve read all the comments here and looked online a bit to try to understand how to calculate the uF needed. I get that the more the better, but I’m trying to build ultra-light toothpicks so weight and size are a concern. Also for curiosity, as I love to learn this kind of stuff.

Reply
Mariel Vasconcelos 10th July 2020 - 1:50 am

Hey Oscar, just like one of the 100 people that commented on this article, Im extremely thankful. You deliver clear concise information.

I added a 1000uf 35 cap to my Bat connection on my 5 in. I get no horizontal lines on start up, but still have faint lines after arming.

Do you think it would be a good Idea to put the cap on my 4n1 ESC power pads instead? I also heard that maybe putting the ground on the VTX onto same ground as camera could work as well.

Either way, love your website, thank you again

Reply
Oscar 12th July 2020 - 11:11 pm

As close to the ESC power as possible is always better.
About noise in FPV feed, this guide might help.

Reply
Christian 29th April 2020 - 4:50 am

Hi Oscar,
Hope you see this comment since your post is 2 years old. I’ve run into a weird issue that I’m hoping is capacitor related. I have a newly built 6S rig that exhibits weird glitches at punch out. I’ve swapped every component but the frame. I’ve tuned the quad it it flies perfectly, except when I punch out the throttle and even then, it seems like the glitches only occur when the battery is fresh. Once it’s lost some charge from flying, it no longer has problems punching out. Sound like voltage noice messing with the ESC and motors?

Reply
Martin 2nd April 2020 - 10:30 pm

Hello Oscar
This is a very good article, thanks for going to the time to write it up. Just a simple question, do you know what make/model the esc shown in you article is? i have been asked to help a friend fix his quad but the ESC need to be programmed.
Any information would be appreciated. Thanks

Reply
Miles Mcneill 2nd April 2020 - 8:49 pm

I have an older quad. Rated for 2s. I put a 3s for fun.
Blew 1 capacitor on landing.

Do these older quads with capacitor s need capacitor s?

It had 2 capacitor s next to the battery plug to begin with

Reply
Gennaro 18th March 2020 - 10:19 am

As always very informative article, but I still have some question..

What treshold should be considered to label acapacitor as “Low-ESR” ?

Can I use solid capacitors instead of electrolytic in my builds?
I’d like to build a 3S toothpick and install a 270µF 16V solid capacitor ( ESR 5mΩ ) in the XT30 connector.
Which capacitor would you suggest to use in my case?

Reply
Oscar 30th April 2020 - 4:37 pm

The 220uF or 330uF I linked should be fine.

Reply
Vousie 20th January 2022 - 2:57 am

That’s not actually an answer. Not everyone can/wants to buy from your US Amazon affiliate links. Makes you look like a shill when you just keep advertising your own stuff.

So, as I’d like to know the answer too, I ask again: Is an ESR of 5mΩ low enough for a small quad?

Reply
Oscar 20th January 2022 - 5:32 pm

It’s like asking “how short is a short string”.
Having any capacitor will help, but lower ESR is always better. So get the lowest one you can find.
The Amazon link I provided is linked to “Panasonic FM” Capacitors which is known to work well.
So yea, I hope this shill answered your question.

Reply
Axel Jebens 9th December 2019 - 6:55 am

Just wanted to tell you that I really love your blogs! Everything is reduced to the amount of information that you really like to have.
The best blog for FPV.

Reply
Harry Murphy 22nd July 2019 - 3:16 pm

I have read the article and reviewed the spreadsheet, but could not determine what capacitor that I need. I have several quads that use “Whoop Lite” flight controllers with Silverware and 8520 brushed motors. These are 1S (3.7-3.8v) setups. There is so much noise that the video is next to useless. I would like to try adding a capacitor where the power leads attach to the FC, but can’t determine what to buy. Will a 25v work? what uF?

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netmonk 9th July 2019 - 11:00 pm

Well it this whole article and all comments, it is never said how to solder with polarity to respect.
So is it ok to solder +leg of the capacitor to the + pole of the esc 4in1 and the negative leg of the capacitor to the negative pad of the esc 4in1 ???

Why so basic things are not even said in this page ?

Reply
Oscar 15th July 2019 - 5:15 pm

Yea, your assumption is correct.
basic things are not said because it only takes 10 seconds to google “how to connect a capacitor”.

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Slava Chrome 19th May 2019 - 5:11 pm

What about 22 awg as extends?

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Oscar 23rd May 2019 - 6:39 pm

yea it’s fine. but thicker is always better.

Reply
Larry Bryans 13th May 2019 - 7:32 pm

Hi Oscar. Love all the info you share with us. As a newbie I hope you can help. I have a R239 Diatone and the little capacitor at the rear of the stack fell off. I’ve only had a few flights, but the canopy front came loose and that was an easy fix, but the capacitor has been recovered and has extremely short leads. Do you know where I could get one the same size? Banggoods was of no help! It’s only a couple of months old.

Reply
Oscar 14th May 2019 - 11:16 am Reply
Justin 25th April 2019 - 4:08 am

Can i put an capacitor on each esc on an Aikon AK32 V2 32Bit 35A all in one esc?

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Slava Chrome 7th April 2019 - 8:37 pm

If I don’t have so much space for installing Panasonic FM 1000mf 35v right on solder pads, but added 6cm 18awg wires and moved capacitor back the fpv camera (between camera and FC). Is it really bad???

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Oscar 8th April 2019 - 5:44 pm

it’s okay to use wires, obviously, you should keep it as short as you can.

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Kamil 2nd December 2018 - 1:00 am

I would add Jamicon TL low esr series capacitors, 1000uF has 0.038 impedance. They are popular and available where i live. They are pretty good, i’m using one 1000uF on battery pads, and i have much better video on no camera restarts anymore after snappy movements of motors :) so it is doing it’s job very well

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Manjulal 28th October 2018 - 1:56 pm

Hey Oscar,
I was planning to add 470uF 35V capacitors to my ESC power points, but only 470uF 25V is available here. I am using a 4S batt pack. Should I be concerned?

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Mike Williams 17th October 2018 - 2:55 am

I HAVE NOISE IN MOTOR #4 AND ITS IN MY FPV …I BOUGHT A IC FILTER BUT DONT KNOW WHERE TO CONNECT IT IN THE RACE QWAD??? IN YELLOW ON CAM AND GROUND ??? OR – AND+??? HELP PLAESE THANKS MIKE

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All Day Air 13th September 2018 - 6:18 pm

Has anyone tried the Matrix PDB with 4800uf super low esr caps on board? I am going to be installing it soon and just wondered if anyone else had experience with it. Thanks!

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Justin 9th June 2018 - 8:06 am

Hi Oscar. Thank you for all the valuable information. Aishi capacitors seem to be quite common in central Europe. Here is a spec sheet. Is Impendance (Ω/100 kHz) on your spreadsheet the same as dissipation factor or tano? capcomp.de/fileadmin/Webdata/partner/AISHI/catalog_seriegroup/ASH_2014_WH_Series.pdf

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Stephen Shoemaker 9th April 2018 - 9:01 am

hi, just wondering……..
I soldered in a cap backwards (polarity). On a new build, on the initial smoke test, it started making a hissing noise and I could see it was getting hot. I immediately disconnected the power and discovered that I had soldered the cap in wrong. I’m guessing the cap is done but am needing to know if there could be further damage to additional electronics. The cap was soldered to a hglrc f428 all in one board where it was designated to be. I replaced the cap with a new one, plugged in again and now have motor#1 get hot very quickly. Any idea whether this could be related??? I’m new to building and not sure where to go from here……any help would be greatly appreciated.
Sttephen

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dafunk 24th May 2018 - 12:24 pm

I mounted mine and shorted it. It went in flame and it projected a lot of black smoke in the shape of a cone, relatively easy to clean.
I have been flying it for 3 months now, all electronics are fine

I guess you can be lucky and get away with it… just be safe on your first 2 or 3 packs

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tim 1st June 2018 - 11:40 am

Capacitors when they blow will do a good job of exploding… be careful :D

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Bj0rn 13th June 2018 - 7:11 am

Hi Stephen,

soldering a cap the wrong way only damages the cap. If you hear hissing, you cap is already done for. If it bulges out and smokes, it’s already past that stage. If it explodes into a thousand pieces, well, you get the point.

Now, the cool thing is, the damage will be limited to your capacitor. By reverse connecting the capacitor, you actually shorted it out. So there was a high current going from the battery through the capacitor back to your battery, heating up the cap and damaging it.

In extreme cases, you may damage the battery because it discharges at a high C load and if it stays shorted for multiple minutes the battery may discharge down to a voltage that it’s bricked. But since you disconnected it quickly, that kind of damage is very unlikely.

A motor getting hot is typically related to a worn out motor. I assume yours are brand new since you’re starting in the hobby. You can test using a process of elimination. Swap motor #1 and motor #3 (assuming a quad copter) and see if #1 or #3 gets hot. If now #3 gets hot and #1 doesn’t, it’s probably your ESC. If #1 gets hot again, there’s something wrong with the motor. Electrically, there is not much that can go wrong with a motor. I would expect worn out bearings, a manufacturer error or if it’s electrical in nature, a screw that has protruded part of the windings during assembly. In any case, I expect the cause of hot motor#1 to be not related to the cap.

Bottom line, your other electronics (flight controller, etc…) will be fine. :-)

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Moritz Beyer 9th April 2018 - 7:09 am

Jesus! Lots of comments!
Well, I hope mine will be new.
So how does the size of the capacitor matter?
You recommend 1000 uF at the Power plug. The Bolt32 comes with 2000 uF.
Should we do 2000 as well? Are there any downsites? What happens with a 500 uF? Just not enough filtering?
Thank you!

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Test 15th April 2018 - 12:41 pm

The value means “capacity”
The higher the better for filtering

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Oscar 17th April 2018 - 6:44 pm

The bigger the better if size isn’t an issue for you. I find 1000uF generally can fix most of my issues that’s why I recommend it.

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Bill 9th March 2019 - 11:26 pm

Have you tried any other cap types, ceramic,mylar,poly, tant.,etc? I might fire up the scope and see what ripple I can find.

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Pierre 28th February 2018 - 1:05 pm

Hello Oscar.
Great article here..
But i have a question:
On a 6S build what caps do u recomend??
And what Voltahe should they be??

Cheers

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Oscar 6th March 2018 - 6:00 pm

I think 1000uF 50V would be a good choice.

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Simon Ireland 13th February 2018 - 7:45 am

“Cut the legs of your caps as short as possible for the best results, and to minimize ESR, these tiny leads don’t conduct high current very well.”
Oscar with all due respect, the filtration Capacitor is not intended to handle high current, nor does it need to. It’s intended to filter out “ripple” voltage spikes within the low frequency spectrum. Adding a few inches of wire will have absolutely negligible impact for the intended purposes. This is particularly beneficial for quads where you need to position the Capacitor away from the FC or battery. It is erroneous to suggest the Capacitor leads must be short.

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Stephen Gibb 4th March 2018 - 1:02 am

No its not he is actually referring to the capacitors legs which are in fact quite poor conductors especially at high frequencies.

The purpose of these caps is to smooth voltage transient spikes not ripple this isn’t a bridge rectifier. The active braking dumps a lot of charge quickly into the system resulting in high voltages if there isn’t enough capacitance to soak it up.
The instantaneous current can be very high.

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Bill 9th March 2019 - 11:30 pm

short leads always, they also radiate less rfi/emi

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Roddy 17th January 2018 - 7:44 am

How about installing the capacitor on XT60 when PDB is equipped with current sensor?
As far as I know the current sensor has some resistance as well to obtain current by measuring voltage drop. I assume that from FC and FPV supply point of view the sensor’s resistance will add to ESR. So, can this resistance affect filtering performance?

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maczar 15th May 2018 - 10:02 am

I think you cannot install capaitor on battery lead when using AIO FC or FC with PDB integrated that is equipped with current sensor.
In my quad there was no filtering with this kind of connection, same as without any cap.
When I have soldered caps to ESC power leads ad FC, capacitor are now doing their job – quad is now perfectly tuneable and fly great.

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Jake 7th January 2018 - 12:46 am

So far lots of useful info here!
In case anybody doesn’t already know and is paying hiked up prices for passive components like capacitors on sites like Amazon or Ebay, check Mouser – very fast shipping, industry pricing on a lot of useful stuff. They don’t mess around and you can trust their technical information and specs.
Just as an example – Amazon pricing on qty of 6 Panasonic FM 330uF 50V caps, $11.68. Mouser has them listed at $0.75 ea., or $4.50/6 (with 100% technical data so you know all the little details and can easily compare!). Of course you have to weigh shipping costs (around $8 where I’m at – Amazon and others typically have free shipping), but if you deal with a lot of quads then you’ll be best served in the long run picking up higher quantities and other useful parts/supplies in one order. You can save a lot of money, and put it back into your quad. ;D

Curious about one thing here, aside from plugging an electrical parts supplier: Is it a good idea to do an ESC calibration after adding capacitors? I’ve fixed a few issues with unexpected flipping by calibrating, so I’ve been starting to recalibrate ESCs almost every time the quad goes on the bench. I figure it’s easy enough, but wondering if it’s necessary after this little mod?

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Walkeer 22nd November 2017 - 3:26 pm

If low ESR is critical, which I agree, why not use the best capacitors for the task, which are Aluminum polymer capacitors, such as KEMET A750MS567M1EAAE015 or Panasonic 35SEF120M OS-CON SEF Series, which have ERS 0.015 Ohm

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seb 3rd December 2017 - 9:46 am

Price!

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Simon Ireland 13th February 2018 - 7:54 am

ESR capacitors are not critical, they are desirable. You can use regular electrolytic capacitors and still get effective filtration. The low ESR capacitors are better but you can’t quantify the difference between the two off this video. It’s just a simple demonstration, not a definitive comparison.

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Stephen Gibb 4th March 2018 - 1:03 am

Low ESR whilst still having a sufficient capacitance to do the job poly caps tend to have a low capacitance for there size and weight.

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Skywalker 20th November 2017 - 10:22 pm

Hi .dear oscar
I buy rubycon 470 uf 25v zlh series cap . Can i use this cap for my esc s to decrease noises. In google spreadsheet that you say this cap was located. Can i use ?
Thank you -skywalker

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Gogi 10th November 2017 - 8:38 am

Hi!
Question: i have recently built a quad and i am getting flips of death and i can see via the fpv feed that the fc restarts. Its been made clear that its a power issue. I have increased the idle and all that jazz to no success.
So my question is would a capacitor fox this?
ThanX in advance :D

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Roderick Heal 29th October 2017 - 6:17 am

Haven’t tried this before on any of my quads but want to try it.

Which way round should the caps be connected?

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Jesse 26th October 2017 - 6:26 am

Can you put 1000uh Capacitors on your ESC if that’s all you have? Or will it cause a problem?

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Oscar 30th October 2017 - 5:33 pm

Yea that should be fine if space isn’t an issue for you.

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Jorge 11th October 2017 - 6:56 pm

Hi, I bought a second hand quad with the same red ESC in a picture of the article, and it broke dawn yesterday, I hope yo can tell me which model is, so if yo please can answer this comment as earlier as you see it, I will appreciate.

PD: Very interesting article.

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Oscar 19th October 2017 - 3:16 pm

those are really ancient ESC’s (probably more than 3 years old), you are better off getting some latest ESC’s. I don’t even think you can find them anymore from shops.

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Jorge 19th October 2017 - 9:04 pm

OK, thankyou, I finally found a similar ESC from Eachine of 12A, I wanted to know because, yea is old, but is the best drone to learn racing with Acro mode and nothing happened if it broke
down.

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Fred 9th October 2017 - 10:03 pm

Hello Oscar
From my experience with tekin esc on rc car, they are using either the rr or rnu series of nichicon capacitor
Would they be better than your recommended list ?
330 uf 25v digikey.ca/product-detail/en/nichicon/RNU1E331MDN1PH/493-6635-1-ND/3466049

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Justyn Markland 12th September 2017 - 3:23 pm

I am using Panasonic fm 270uf 50v caps on my esc’s. I also use the 2 of the same caps on the pdb. This is for a 6s setup. Multiple small caps are better then one large capacitor. The 50v rating gives plenty of head room. 35v would do, but the 50v caps have a lower esr and higher ripple current.

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Joe D 6th September 2017 - 12:50 am

Anyone use 470uf Panasonic cevss series?

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spek121_fpv 19th August 2017 - 5:25 am

what about a pdb and fc in one like the DYS f4 pro

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Oscar 21st August 2017 - 3:01 pm

what about it?

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Kai 18th August 2017 - 10:10 am

Is this list of low ESR capacitors comprehensive?

I found some ‘Sanyo High Frequency Low ESR Radial Electrolytic Capacitors’ for 35V & 50V rated at 470uF & 1000uF (105-deg C) going pretty cheap on eBay. But they’re not on your list.

Can I use them?

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Oscar 21st August 2017 - 2:53 pm

It’s likely that it’s missing a few. You can certainly try them although I don’t really trust sellers on ebay for quality products.

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Ben T 16th July 2017 - 1:46 am

Hi Oscar,

Thanks for doing all these videos and sharing the knowledge.

I put 4 330f Panasonic FM capacitors on my 5″ quad. Emax 2205S, 2300 kv with Aikon 20A ESCs.

When I plug in, motor 4 will start to spin on its own, even with the quad unarmed. Do I need to re-set the end points or do some sort of recalibration somewhere?

Ben

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Ben 1st August 2017 - 11:35 pm

Anyone?

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Buzz 3rd August 2017 - 4:19 pm

Usually, a motor that spins up on its own means that you have a malfunctioning MOSFET on that motor’s ESC.

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Matt E 27th September 2017 - 7:49 am

lower your endpoints manually by 10 or 15. should solve the issue. Mine has done this before but its usually seen as motor twitches. if you still have issues make sure you calibrate your ESCs. Google should show many results on the subject.

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Cyril MARTINEZ 19th June 2017 - 1:06 pm

Very nice article and explaination.
As i am willing to build micro quad, i was wondering if the use of capacitors is necessary, du to the increasing weight, and the lack of space inside those frame ?
What about using capacitors when using 2 in 1 or 4 in 1 ESC’s ?

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Oscar 25th June 2017 - 4:19 pm

for a micro quad? I don’t think it’s necessary. But it wouldn’t hurt to add one in if there is space.

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Shamsher 7th June 2017 - 3:35 am

Will adding the 4 smaller caps to esc’s also clean up the power going to the 5v and 12v bec, or should I use one 1000 micro farad cap on the battery lead? Also will the 4 smaller 25v caps add up their voltage incase the spike is greater than 25v? ( E.g. for a combined 100v protection with the 4 caps)

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Oscar 12th June 2017 - 4:24 pm

Yes. Either way would help. No the voltage rating is for each Cap, they don’t add up.

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NickB 29th May 2017 - 6:00 am

Hello Oscar. What about dshot and adding extra capasitors? Are they also needed? I assume that you also have spikes, but people are removing caps from their escs? Or this is irrelevant.

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Oscar 30th May 2017 - 11:49 am

People are removing caps to run DShot because it was connected to the signal.
The Caps we are adding here are connected to the power, so different caps.

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Scott Cline 28th May 2017 - 1:40 pm

Thanks for this article Oscar. It helps explain a lot of things about adding a capacitor to your build that I would have spent days/weeks/months trying to figure out.

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Ronald Kotila 25th May 2017 - 1:32 pm

Help I have capacitor Says CKHM 1000uf 25v B105degrees c with number 17 on it and ic circled r will these work on my Quads

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Lusetti 23rd May 2017 - 7:36 pm

In example 1 where you have the cap on the XT60 can the cap go on the batteries connector ?

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Oscar 28th May 2017 - 4:35 pm

yes but it’s better to place the caps closer to the ESC as possible

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Ruben 22nd May 2017 - 6:47 pm

I read a lot if the size of the caps. Some say 1 470 uf on pdb is enough, other say 1000uf is needed. Does it matter how much caps on the esc itself is placed? Like a total uf on the whole quad?

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Oscar 28th May 2017 - 4:25 pm

there is no rules on total uf required, it depends on how noisy your quad is.
But generally speaking 330uF on each ESC, or 1000uF on PDB works for most people. 470uf on ESC would even be better, but a little bigger.

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Ben 22nd May 2017 - 1:48 am

Gee it would be nice if there were non cylinder shaped Capacitors. Maybe rectangular/cube or circuit board style that could be mounted in line with an esc on the arm of quad.

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Justyn Markland 12th September 2017 - 3:28 pm

You could make a small pcb board with ceramic capacitors, but you would need a bunch of them. The uF rating is lower on the ceramic caps.

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Erwin 21st May 2017 - 9:56 am

Hi oscar, Is it okay to install capacitor on each esc even if theres already a lc filter

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Oscar 28th May 2017 - 4:20 pm

LC filter reduce noise getting into your FPV setup… capacitors “clean” noise in your power, so yes, it’s okay.

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1337Flite 20th May 2017 - 6:48 pm

No “might” about caps saving your electronics.
I lost at least 2 x FCs, 1 VTX and an RX for no apparent reason before I found out about spikes, ESC braking and capacitors.
I now run a single 220uF 25v cap on each ESC and my video is better, but more importantly I have not lost a single component since (except the Tramp I bent in half in a crash – not spike related).

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Dean Buckner 20th May 2017 - 4:34 pm

What size caps would you recomend when using 2 6s lipos to feed a heavy life six rotor? Not sure what the escs are,,,I would say 40amps

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