Reducing RFI - Four simple methods - 12v Solar Shed

[@RWBHere]

Thanks for the follow-up, Adam. Glad you've sorted it out. For reference, it's good practice to add a small disc capacitor (1,000pF or so) in parallel with an electrolytic. This is because the larger capacitor is quite inductive and an RF signal will 'see' a high impedance. The small capacitor has much less parasitic inductance, particularly if lead lengths are kept short, so the RF noise sees a near short circuit, and is dissipated. Both parts of a screening box need to be connected together properly, forming a Faraday cage, and a short ground lead needs to be connected to it, preferably to a proper ground, not just the Earth connector in the plug..

[@AdamWelchUK]

Thanks for the note on the capacitor - I will definitely try that. I've connected the inverter to my house ground and it was physically touching both halves of the 'box' but this wasn't really a serious attempt due to the lack of a suitable container. Too big for a biscuit tin!

[@RWBHere]

I know the feeling! There's almost never a case of the right dimensions when you need one. They're usually an eBay away, but that usually takes too long. ;-p

[@Viking_X]

I have bought the Epever Shi1000 24volt 1000 watt and been using it for a few weeks. At first i thought it also had RF problems also as i had some flickering on my Computer screen when i was using my computer but it turned out to be a loose gfx card. So far no issues with my Shi1000 in any regards but it is also placed outside and connected to my room with a wire. I think its about 5 meters and a wall apart from my PC and no RF or other issues. I highly recomend this inverter. Much more powerful than most others and not much more expensive than the cheap ones that dont match the promised output, or does so with unstable and unreliable running.

[@AdamWelchUK]

Mine definitely lives up to it's claims. It will deliver the constant and surge power suggested. Glad you're happy with yours and you're not seeing any ill effects.

[@Viking_X]

I just hooked my computer up with the Shi 1000 and had grafik problems again. tried many times with different cables. Its not a loose gfx card but my Shi 1000 that has similar problems. It causes small flickers on my pc screen and the display switches on and off. It seems ill have to order some of these Ferrit rings and hope the so the job. About the capacitor? If i want to try that option also, what capacitor should i get? Its a 24 volt system running at a 1000 watt.

[@michaelthomas3105]

Hi Adam, interesting video. Us electronics guys need to minimise any R.F. interference not just for ourselves. Problem is neighbours will often blame the 'radio ham type bloke' in the shed, for any interference problems, when in most cases the shed gear is not responsible at all.

[@AdamWelchUK]

+Michael Thomas Yeah I agree. Theres so much electronic kit in everyone's home and a simple faulty component or badly designed circuit in any one of them can cause interference. As soon as we identify it we should be attempting to reduce its negative effects for everyone's benefit.

[@thewalkingtrade2678]

In RC hobbies I used to make 5 turns with ferrite it was the optimum to reduce interference in video.

[@AdamWelchUK]

That's useful to know - I'll have to buy some bigger ferrites.

[@alexandreesquenet3736]

The interferences also makes the rs485 data transfert difficult to the epever tracer A charger. A bit a pitty because this inverter works fine otherwise. I use the hsi 3000 W.

[@StrixTechnica]

1:24 The bad news is that those cutouts, at the right frequency act as very good "slot" antennas! Even when not resonant, the shielding effect of a metal box relies on fairly complete closure. Any hole, including an unwelded seam, that is about λ/4 or larger will conduct noise to the outside surface of the box, where it will radiate. 3:16 Filters are really some combination of inductors and capacitors. Each capacitor has some amount of parasitic inductance, particularly those with wire legs (as opposed to surface mount), past which it ceases to be a useful filter. There is always a frequency at which a particular component is resonant. Wires also present a normal resistance, too, and especially electrolytic capacitors of the sort you used tend to have a maximum ripple current. So although capacitors can work, an LC filtering network needs to be designed with all that in mind. 5:09 ah yes, the bane of every audio engineer's life. That cable is for unbalanced audio which suffers from several different types of noise. One is entirely conducted (ground loops) where especially mains AC noise currents in the shield/ground appears as noise relative to the signal, which the input stage faithfully picks up and reproduces. This situation is most likely to be a problem of common-mode noise on the cable (ie, noise currents on both conductors going the same direction). The right sort of ferrite ring can help with that, too. (And note that choking impedance is proportional to the _square_ of the number of turns.) For this reason, professional audio uses balance (XLR) audio cables where possible. These still pick up common-mode noise currents, but the complementary wire picks up the same amount of noise as the true wire, which the audio input stage cancels out by subtracting the signal on the complementary (aka 'cold') wire from the true ('hot') wire. The result is clean audio, but it doesn't mean the noise isn't there. In this case, the inverter is still very much to blame.

[@oldtimeengineer26]

yep that was good process of elimination thanks

[@AdamWelchUK]

Cheers OTE

[@akhurash]

This video is old but I want to comment to maybe help others... I designed a 12V to 230Vrms power inverter for automotive applications before. The first method in the video didn’t work because you need to connect the ground of the inverter to the shield. But you have to becareful because if the low voltage and high voltage sides are isolated then you can create an isolation fault (isolated inverters should protect for this). In our module we did couple of things to reduce EMI noise. We had a large LC filter on the front end. This will reduce the noise going out to your system. This is applicable if you have other electronics connected to the same source as the inverter. If the batteries are only powering the inverter then it doesn’t matter much. Adding a capacitor like you did at the input will help some with the noise going out to the power source but won’t help much on the AC side (for isolated systems). You can also add ceramic capacitors on the input to help with the noise. We had a ceramic and a electrolytic right at the input of the module. The electrolytic will form an LCR pi filter with the inductance of the input wires. Second we placed X and Y capacitors around the input and the output and connected them to the module housing. The housing was the heatsink and also acted as a RF shield. Thirdly we created a sudo faraday shield around the PCB by ensuring we always had a ground plane all throughout the edge of the PCB. We had a four layer board and tried to have ground on all four layers around the PCB and they were sitched together using via’s. This helps with radiated emissions. I know you can’t do some of these things on a ready made module but hopefully this will give some ideas.

[@offgriddreaming5403]

Well done. Victory in the end

[@AdamWelchUK]

Well yes and no - I've reduced the issue but it's not eliminated really.

[@offgriddreaming5403]

Adam Welch That's true, partial victory maybe 😊Have you hooked it up to the Epever software yet? They seem to make decent gear, especially for the price. Your vids were a big help with choosing the tracer. I also did your cable hack, thanks for sharing that!

[@kd5fjf453]

For proper metal enclosure shielding both halves must be electrically attached, and grounded. Try procedure for EMP protection, nothing in, nothing out.

[@paulabristow948]

I am looking for a solution to the noise I hear from my solar inverter ... it has a high picked humming that drives me nuts

[@richardsandwell2285]

Me too, my house runs on an inverter, with it being only a 3000-watt pure sine wave I am thinking about a supply filter unit on the mains out lead from the inverter which I robbed out of a washing machine, it drives me insane, today I bought an antique MW/LW radio, it sounded great until I put the inverter on, the whole house wiring seems to become an antenna for this noise and it ruins enjoyment listening to radio's. And the electro-smog generated cannot be good for humans either, even if my £2.75p winter electric bill does compensate for it a little.

[@pcmalek5]

hi i have a problem with the output of my EPEVER UPOWER inverter/charger i correctly connected my inverter to ground but when i test with a multimeter i have 115 volts between neutral and ground also 115 volts between live and ground !! it is very dangerous what is the problem and what is the solution ?

[@xanataph]

Seems like your mic extension cable was not properly shielded (or perhaps not at all). Many posters have already covered the "capacitor thing" so I won't comment further there. The other thing to consider of course is proximity. If you can move the inverter further away you'll get less direct radiated RFI and then you can treat the mains output easily with a commercial in-line noise filter. Often the best approach for getting rid of RFI is to use *all* the methods at once!

[@xanataph]

As as aside to the chat going on here: If you're operating really sensitive equipment from an inverter the only real choice is "low frequency pure sinewave". These inverters create a 50 Hz (or 60 Hz) low voltage / high current signal and simply feed it though a step-up transformer. They also tend to have a lot more "grunt" for starting difficult loads.

[@alanknight2204]

Many years ago I used a spray on conductive paint on the inside of plastic boxes . My memory is that it was Zinc based but I may be wrong .

[@AdamWelchUK]

Interesting idea - I'll see if it is still available.

[@alexandreesquenet3736]

You can reduce a bit the interference by selecting 220V setting instead of 230V.

[@mrjohhhnnnyyy5797]

Seems like the noise from a DC-DC converter inside of the unit. Not sure if you can decrease it much without going inside the inverter and modifying it.

[@AdamWelchUK]

I think I've reduced it a little but I also think you're right. I've asked EPEver to consider that I have a faulty unit. Other owners don't seem to be reporting the same issue. Cheers

[@mrjohhhnnnyyy5797]

Usually, there's a capacitor between primary-secondary side of the PS, which is there to cancel out the noise which is coupled to the output by inter-winding capacitance. Maybe in your unit it's not fitted or faulty.

[@Viking_X]

Ive just ordered the shi1000 and watching this carefully. Not sure i will notice the RF noise if its there because my unit will be outside from where im living. I dont have a scope to test it with though. Currently im running a cheapo 500 watt pure sine inverter with a cooler mod but even with cooler mod its not running 450 watts reliably continuously without some hickups that is making my computer reboot :( And the stability and power is why i choose Epever inverter since i dont want something partly unstable like i already have. And the price seems very reasonably.

[@AdamWelchUK]

+Resist Dk The wave is extremely good and the build quality seems good for the price. Most people won't notice this issue if it's like this by design. Or I could have a faulty one. I can only report on what I find. I hope you get good service from yours.

[@Viking_X]

I dont have a scope so i cant test that aspect but ill let you guys know if theres any issues with the shi 1000 when it arrives or it behaves as rock stable as i expect :)

[@Viking_X]

Since mine is outside but im experiencing this RFI noise also ( cant use it on my pc because it makes my screen flicker and switch on and off) my guess it that it isnt as much as "radiation" from the unit itself as it is disturbance in the 230 volt power its putting out. A guy on Facebook just wrote to m from a solar group that he has same inverter and he cant use his iphone while charging it near the inverter due to noise. It seems EPever has a general problem with Noise on these and its a shame since quality of it seems very good for the price ( despite the fact that it has much RFI noise and my old crappy 50 dollar tin can "600" watts inverter didnt)

[@makomk]

Hmmm. One would expect that to already have much more capacitance on the input than could be provided by such a tiny capacitor.

[@RWBHere]

For RF, a small capacitor (1,000pF, for instance) is much better than a large electrolytic one. This is because the rolled-up metal plates are inductors, so RF encounters a high impedance, preventing the capacitance from shorting it out, and thus dissipating it. For the same reason, keep all filter conductors as short as possible. Electrolytic capacitors work well as good filters only at low frequencies.

[@tedmichael160]

Have you found a solution to the noise? This looks like a great inverter otherwise.

[@deslomeslager]

An old microwave will do. Remove the inside and you will have a nice cage of Faraday. Of course you could also build one using aluminum foil. But Rf is very annoying. My laptop power unit disturbs my radio receiver. As well FM as higher bands are effected. And I do as well have an inverter supplying back into the grid, that one as well has a lot of RFI. I seem to have got used to it, and just listen to the radio stations which I do still can receive. We live inside RFI! My WiFi is on all the time, I have 2 telephone stations and my mobile phone is somewhere in my neighborhood as well. My neighbors also have WiFi and they all use amplifiers! It is just that our mobile phones and tablets need WiFi or else I would shut it down all the way. (sorry for all the chatter).

[@AdamWelchUK]

Now I did consider wrapping the metal box in tin foil but thought I would be laughed at! You're right the modern world is very 'noisy'. Sadly radio hams are having a hard time with it all. Testing and adjusting circuits to reduce the effect has a cost though - and the consumer demands the lowest prices. And then only a handful of customers will notice the difference.

[@Doazic]

Try tin foil!

[@graplingurty]

Dang gone good one. I never thought of that. What a good what to isolate a small rfi problem

[@mikepeck880]

Hi Adam thanks for the update on the EPever. pls can you advise where to connect the earth from the Inverter if mounted on wood in my caravan thanks

[@AdamWelchUK]

That's an interesting question. Best solution is a ground rod hammered into the ground but this might not be practical if you move frequently. I bet the steadies of your caravan use plastic or wood feet too don't they? I'm not entirely sure what's best I'm afraid.

[@dennisolsson3119]

shouldn't the cables (positive and negative) be fead through the same ferrite?

[@AdamWelchUK]

Probably best yes but I didn't have one big enough - although I guess they could pass through just once each. I might try that!

[@PE1MR]

haha, the RF is pressing the capacitive touch buttons on the scope... removing the extension audio cable seems a bit symptom control? Wouldn't want that RF generator in my shack/shed.

[@AdamWelchUK]

Well the ferrite rings and the capacitor seem to help with the oscilloscope, but yes - much of the noise is still there, I've just controlled the symptom as you suggest. Cheers

[@PE1MR]

Adam Welch indeed :) As I a "ham" I need to be very picky about what stuff I put in my shed - too bad, because I think solar power is the way; strict EMC tested solar stuff is quite expensive...

[@AdamWelchUK]

+Michel Honig Yeah I'm sorry - this isn't the product for you then.

[@graplingurty]

Michel, I have been looking for an affordable QUIET pure sine inverter but I haven't found one I can both afford and is silent enough to have in my radio shack. Every one I have checked out sounds like a Mexican pirate AM station overloading the front end of every receiver in the ham bunker. Changing the mic cord didn't make it go away. I hate RFI but I really like solar and power. My field deployable solar ham shack is completely self sustaining but inverters and noisy solar charge controllers are shut down while on the air. I have had luck with a combination of caps and torroids you can knock it down below the noise floor but the real junk inverters and controllers there is no way that I have found to shut them up except by pulling the plug........KC0ZQB said that......

[@basspig]

away. Have an 18,000 w split phase pure sinewave inverter, but the wiring is 2awg. I've tried ferrites with zero effect. 20 over s9 noise.

[@pbox9642]

when converted to 24 volt did you get lower charge in the winter vs 12 volt

[@MrBrymstond]

The ratings on the capacitors are way to high well into the audible range.

[@MrBrymstond]

Replace capacitors that are out of normal range

[@jay-rus4437]

Having the same issue with a Giandel

[@Marcos_Ledinich]

Hi Adam how can I use this inverter in my country which we use 110v as epever only sales the 220v version? also is there a way to make modified sine wave inverters a little "better" and by that I mean using some type of filter or rectifier to make them produce a more clean sine wave? thanks and sorry for the tricky questions I love your videos by the way

[@AdamWelchUK]

+Marcos Figueroa Hi Marcos. You might be able to step the voltage down using a step down transformer - but it seems like over kill. I'd be just tempted to use another model of inverter - one designed for 110. Modified sine waves are exactly that and there's no way to make them cleaner that I'm aware of. Some are better than others (more differential steps in the wave) but many are three step and pretty poor for many devices.

[@antpowell5974]

Just wondering if the device has a CE mark.

[@Raaaphael]

Yes it does . I saw it in the owner's manual

I have the shi600... but no noise or any problem

[@AdamWelchUK]

Useful to know thank you - I have put it to EPSolar that perhaps I have a faulty unit. They've been helpful up to this point so hopefully they'll get it sorted.

[@laukudvasios9605]

Would you recommend this inverter over a renogy pure sine wave one?

[@Luke-san]

I might have missed a couple of things, sorry for that, having seriously issues with my eyes again, what frequencies do you see on the scope and are they the same that disturb the microphone? If it is really HF freq via the cable then it might help to put a smaller capacitor in parallel typically 100NF. They suppress HF noise much better in some cases. Also placing both cables through ferrite with different winding might help more. A nice video about it is this one kzbin.info/www/bejne/bmKmZXychLOnadE

[@AdamWelchUK]

Cheer Luc. When I put my scope into FFT mode there are a number of frequencies showing up. 50Hz - and some harmonics of this are the overwhelming readings - which makes sense. I will add a 100n cap and see how that improves things and I'll look at a getting a larger ferrite ring. I had those ones lying around and they just about worked! Cheers for the link - I'll add it to my watch list.

[@chronobot2001]

Removing the cable from your microphone did not reduce the rf coming from the inverter. Turn on a shortwave receiver and you will hear the havoc. This is why I need to know how to stop the rf.

[@Viking_X]

The RFI on my Shi1000 24 v version is driving me crazy! I cant use it on my pc, which it was intended for, because it makes flickering on my pc screen which makes the display turn on and off on random. Tried with some homemade ferrit rings out of metal strips but sometimes it works and sometimes not, so im ordering both real ferrit rings and capacitors now. Just not sure what capacitor values to use on a 24 volt 1000 watt Shi1000 ? Capacitor 35v 1000uf ? Higher or lower uf value ?

[@Viking_X]

Adam what size is the ferrit rings ? You made just one loop? I made some homemade ones out of metal strip. Gave them 2 loops at first and it solved some of the problems. Then tried 3 loops and a tighter fit to the rings with plastic strippers. It made it worse again :(

[@AdamWelchUK]

My rings were too small really for the cable. I got one loop through. Also it may be better to loop the positive and negative through the same ring in opposite directions. But whatever works really...

[@Viking_X]

It might be too early to draw conclusions but i suspect this interference comes from either the charging process some way, the controllers or the batteries when charging, because yesterday at mid day when i tried a new approach with one ring, one twist and opposite ways trough the ring for positive and negative. it was flickering so much i couldn't use the pc. Last night and this morning with a lot of clouds there was no flickering. Now when the sun starts peeking out from the clouds the flickering starts again slowly. I will try adding a capacitor also but im unsure what values to use for a 24 volt 1000 watt system? I might try and get a special cable for my pc also as it seems only to cause problems with my pc ( television works and laptop work fine). Im getting a 3000 watt inverter soon to go all off-grid but if this problem isnt solved it wont be an Epsolar/Epever :( Btw a user from a danish solar group messaged me some days ago and said he had problems with his Shi1000 also. When charging his Iphone there was so much audio inteference that he could not have a conversation while the phone was plugged into the inverter for charging. Clearly Epever has some issues they need to address regarding these inverters :( My "cheapo" "500" watts, 50 dollars pure sine inverter has no such problems but its crap regarding delivering power

[@thomashrb]

Hi Adam, thanks for another quality review. I really enjoy watching your videos. Short of using a balanced xlr setup, I have found that using a high quality audio extension cable such as this one from Rode www.rode.com/accessories/vc1 makes a significant difference. It's not perfect, but it's pretty much as quiet as an unbalanced cable gets.

[@AdamWelchUK]

+Tom Rodgers Yeah - I have seen the ride one but cheaped out. Guess I'm paying the price! Cheers

[@GroovyVideo2]

Aluminum foil

[@wouternet94]

Ground the system...

[@AdamWelchUK]

It is - you can see the ground lead attached to the inverter in a number of shots in the video.

[@zogworth]

Great stuff! Any sign of those AC filters? If you need the audio extension then an isolation transformer for the audio cable? Big clive has a video on them fV_hsFK1MnA

[@AdamWelchUK]

On the slow boat I think - hopefully it'll arrive before long. I'll take a look at the video, thank you.

[@kruppin]

aluminium foil. ;)

[@chronobot2001]

This video should be called... 4 simple methods that don't work.

[@daikiryoku]

Did EPever reply to your email about the rfi?

[@AdamWelchUK]

We're in discussions. There support have been pretty quick to reply, friendly and they've offered some suggestions but I do wonder whether I have a unit with a small fault.