5 minutes ago, DiSiNTiGR8 said:

Did you Install this on your main live inverter output line or only in front of specific appliances? 

Both will work. However it will probably be best to use multiple filters on different plug lines to distribute the load across multiple filters. If you are only going to use one filter on the main live inverter output, it's going to be huge!

Alternatively (probably the best option) is to use one filter just before the appliance that causes the most frustration. That way you can keep the size and cost of the filter down.

Oh an an important note, the inductor can cause big voltage spikes when a load switches off. It is best to add a surge protector on the appliance side (or both sides if possible). So the setup would be Inverter/Filter/Surge Protector/Appliance.

My Deye 8kw is running for 2 years now none of the above noise not on the inverter not on pc or any appliances. Sunsynk and Deye are manufactured in the same factory i believe so how come

2 minutes ago, TaliaB said:

My Deye 8kw is running for 2 years now none of the above noise not on the inverter not on pc or any appliances. Sunsynk and Deye are manufactured in the same factory i believe so how come

Many people cannot hear the frequency it emits as it is very high in the human audible spectrum at 15000Hz.

Unfortunately for the rest of us this is an extremely annoying frequency to be exposed to if you can hear it, its like a constant ringing in the ears from some electronics in the house. 

 

 

8 minutes ago, Wiggly Electron said:

Both will work. However it will probably be best to use multiple filters on different plug lines to distribute the load across multiple filters. If you are only going to use one filter on the main live inverter output, it's going to be huge!

Alternatively (probably the best option) is to use one filter just before the appliance that causes the most frustration. That way you can keep the size and cost of the filter down.

Oh an an important note, the inductor can cause big voltage spikes when a load switches off. It is best to add a surge protector on the appliance side (or both sides if possible). So the setup would be Inverter/Filter/Surge Protector/Appliance.

Thanks for the input.

In my case it is my PC and its screen that are the most annoying in the house so I would try this on their plug. The PC might not have a sudden drop in amps when it turns off but I'll still play it safe with a surge protector. 

6 hours ago, Wiggly Electron said:

Hi everyone

I have found a solution to the problem. Before you get too excited, I need to say that it isn't an easy nor cheap fix. It also only gets rid of the 15kHz whine on your appliances (output side of the inverter), while the noise from the inverter itself remains unchanged. That being said, it was still worth it for me. Our microwave was driving me insane!

Anyway without further ado, to fix the issue you need to place a big filter inductor on the live line between your inverter and your appliances. The inductor must have a ferrite core (preferably the MnZn type as they have a higher core saturation point). Iron cores wont work as they will filter out the 50Hz power as well and probably cook itself within minutes. I got my E-cores from Mantech Electronics (about R350 for two half cores), although they seldom have stock of these large cores. With these cores you will need between 50-100 turns (resulting in 1-5mH) and the wire size is determined by the amount of current your load is going to draw. I used 10m of 3.14mm^2 enamel wire (sourced from Communica @ R210) which got me about 50 turns and 1.25mH. At 1.25mH it should attenuate about 14dB of the 15kHz noise. After I installed it, I couldn't hear the whine at all. So it definitely works.

Also, another note to those who haven't wound an inductor/transformer yet, it took me a whole day to wind that thing. A solid core wire with a 2mm diameter is quite difficult to work with...

Hope this might help someone.

Regards

Hi Wiggly

I have the same issue but only in one room at home. Everywhere else in the house seems to be fine. Do you think these Ferrite sleeves would help with the annoying sound at all? From Communica: https://www.communica.co.za/products/0443167251

I have no chance of creating and connecting this filter like you have done myself so looking for any other way to stop this sound. 

1 hour ago, theaveragegamersa said:

Hi Wiggly

I have the same issue but only in one room at home. Everywhere else in the house seems to be fine. Do you think these Ferrite sleeves would help with the annoying sound at all? From Communica: https://www.communica.co.za/products/0443167251

I have no chance of creating and connecting this filter like you have done myself so looking for any other way to stop this sound. 

Hi there

When looking for a filter in this application it's all about inductance. The bigger the better. If you look at the specs of this ferrite sleeve it is specced to be 225Ω @ 100MHz. So if we use the formula Z=2πfL we can solve the inductance to be 358nH. That is very, very small when trying to filter 15kHz. At this frequency it will only offer about one thousandth of a decibel of attenuation (0.001dB). Or in simpler terms it will only filter 0.02% of the noise we are struggling with.

These sleeve ferrites are designed to filter out much higher frequencies in the AM and FM radio bands. The design issue with these inverters are very unfortunate. I believe most inverters have similar noise emissions, although at slightly higher frequencies that are out of the hearing range for humans. I have measured an Axpert 5kW  VMIII and it had similar noise levels but only at 19.5kHz which is basically inaudible. The problem with the Dye/Sunsynk inverters are that their switching frequency is just a bit too low at 15kHz where we can hear it.

I am still on the lookout for more off-the-shelf solutions, if I stumble across anything I will be sure to post it here.

Regards

Excellent work @Wiggly Electron and thanks for sharing with the community. The most reliable way to objectively know if your appliances are squealing at 15kHz is to use a sound spectrum analyser app on your phone. Most good cell phone microphones are sensitive to frequencies up to 20kHz. The older you are, the lower the frequency threshold of your hearing, this is a natural process. My kids can hear sounds above 20kHz. I used to be able to hear those. My hearing limit is now around 16-17kHz, so I can just make out the Deye/Sunsynk hum on our appliances. This is a screenshot from an app on my iPhone, you can clearly see the spike at 15k when the phone is near an appliance.

On 2023/01/30 at 9:31 AM, Wiggly Electron said:

Hi everyone

I have found a solution to the problem. Before you get too excited, I need to say that it isn't an easy nor cheap fix. It also only gets rid of the 15kHz whine on your appliances (output side of the inverter), while the noise from the inverter itself remains unchanged. That being said, it was still worth it for me. Our microwave was driving me insane!

 

Would it be possible to share a simple wiring diagram showing how to wind this inductor and connect it to the live wire? Also, if you have specs or a model of the surge protector you deem adequate to pair with the inductor?

Lets assume I would like to add this to a PC setup with max power usage of around 700W, (3.5A), what size wire would you recommend?

thanks

I used the same method to show Sunsynk / Deye that there is an issue... This is a sample taken next to my computer screen. 

 

To compare when I temporarily had the Growatt ES5000 I took the same reading at the screen:

 

Then at the Growatt inverter itself you can see they chose a better (higher) frequency to switch at, however what is also interesting to me is that the frequency is not really emitted in the devices in the house, only at the inverter, which is what I would expect, unlike the Sunsynk.

Reading at the Growatt inverter around 18000 - 19000Hz which I can't hear:

Edited February 1, 20233 yr by DiSiNTiGR8

21 minutes ago, mneeth said:

Excellent work @Wiggly Electron and thanks for sharing with the community. The most reliable way to objectively know if your appliances are squealing at 15kHz is to use a sound spectrum analyser app on your phone. Most good cell phone microphones are sensitive to frequencies up to 20kHz. The older you are, the lower the frequency threshold of your hearing, this is a natural process. My kids can hear sounds above 20kHz. I used to be able to hear those. My hearing limit is now around 16-17kHz, so I can just make out the Deye/Sunsynk hum on our appliances. This is a screenshot from an app on my iPhone, you can clearly see the spike at 15k when the phone is near an appliance.

Which app exactly are you using?

My 5kW SunSynk shows nothing at 15000 Hz. Maybe only some inverters have this issue. 

 

1 hour ago, PowerUser said:

Which app exactly are you using?

My 5kW SunSynk shows nothing at 15000 Hz. Maybe only some inverters have this issue. 

 

Now this is interesting, I also went and tested at a friends house with an 8KW and with my same phone and app and even plugged my PC screen in there and there was no noise. This made me think the 8KW maybe does not have the noise but then I saw this thread on the forum where the 8KW is reported to have the same issue.

Where are you measuring with your app, next to an appliance such as a TV or PC? What does it measure at the inverter?

 

16 minutes ago, DiSiNTiGR8 said:

Now this is interesting, I also went and tested at a friends house with an 8KW and with my same phone and app and even plugged my PC screen in there and there was no noise. This made me think the 8KW maybe does not have the noise but then I saw this thread on the forum where the 8KW is reported to have the same issue.

Where are you measuring with your app, next to an appliance such as a TV or PC? What does it measure at the inverter?

 

I did several measurements now. I measured by the laptop and a big monitor connected to it. Measured by the TV and by inverter. Nothing!

Then simulated load shedding by disconnecting the mains, so everything runs from the inverter - still nothing.

BUT I only have the inverter and a battery connected to it at the moment. My solar panels are not installed yet, so no PV input on the inverter.

it could be a bad batch of SunSynks with faulty filters inside, or it could be related to the PV input.

 

Edited February 1, 20233 yr by PowerUser

36 minutes ago, DiSiNTiGR8 said:

Now this is interesting, I also went and tested at a friends house with an 8KW and with my same phone and app and even plugged my PC screen in there and there was no noise. This made me think the 8KW maybe does not have the noise but then I saw this thread on the forum where the 8KW is reported to have the same issue.

Where are you measuring with your app, next to an appliance such as a TV or PC? What does it measure at the inverter?

 

I also have a friend with the 8kw and it does make the noise at the inverter itself but only when its working hard ,it also does not seem to send the sound through to appliances like the 5kw . On my 5kw the sound also is the loudest when its working hard ,at the inverter and appliances.

Interesting indeed.

My inverters (2 x 5kW Deyes) are pretty new. I see the physical appearance of these inverters changed a year or 2 ago, primarily at the back where the heat sinks are. Perhaps there was also a change on the inside along with this, I don't know.  I can put pictures of the inverters here or we can try and use model numbers / serial numbers to try and figure out a pattern of which units are prone to the noise and which are not.

The 15kHz sound emission is present both at the inverters and some appliances. The notable ones are:

• Microwave oven
• Induction stove
• Desktop PC power supply
• 1kVa UPS

I think a common denominator here is that these devices all have some inductance component to them? @Wiggly Electron, what is your take?

I use this app below.

14 minutes ago, mneeth said:

Interesting indeed.

My inverters (2 x 5kW Deyes) are pretty new. I see the physical appearance of these inverters changed a year or 2 ago, primarily at the back where the heat sinks are. Perhaps there was also a change on the inside along with this, I don't know.  I can put pictures of the inverters here or we can try and use model numbers / serial numbers to try and figure out a pattern of which units are prone to the noise and which are not.

The 15kHz sound emission is present both at the inverters and some appliances. The notable ones are:

• Microwave oven
• Induction stove
• Desktop PC power supply
• 1kVa UPS

I think a common denominator here is that these devices all have some inductance component to them? @Wiggly Electron, what is your take?

I use this app below.

Interesting! Your app does show a peak at 15000 Hz at the inverter and at all other devices - laptop, TV, microwave but nothing with the other app. My SunSynk is not working hard at the moment. And I’m never able to hear that noise myself. 
 

Later, I’ll do another test - switch everything to Eskom on the changeover switch and measure again at the appliances. 
 

Thanks for posting, I think this just shows that

1. all these inverters run at 15kHz, we don't have to hunt around to see if some does and others doesn't

2. this will not be "fixed" by Deye, this is how they are designed to operate. Anyone hoping for a firmware update in the future to change this, is going to be disappointed.

 

My situation is a bit different;

My flat is being fed from my landlord's house with two 5kW Sunsynks in parallel. 

I have also used an app called "Sound Analyzer" by nobapp (the free version is Sound Analyzer Basic I think). It works quite well in picking up the more subtle noise emissions or emissions in noisy environments. Sometimes something like fan noise will drown out the 15kHz noise from the ear, but with the app you can clearly see it. 

In my experience I always hear the 15kHz noise, even during night time when the solar DC/DC isn't doing anything. The noise would seem to come from any appliance with a transformer in it (which is the same as @mneeth suggestion as the appliances having some form of inductance in it). I believe the magnetic field created by the noise induces Eddy currents in these components which then vibrates the enamel wires or the core at said frequency. 

The appliances where I noticed it the most was my UPS, inverter microwave, laptop charger, inverter fridge and inverter washing machine. Some sound worse than others.

 

So my question remains, are they not able to adjust the switching frequency of the inverter to something in the 18000 - 20000Hz range (like Growatt uses for example) with a firmware update, or is this a hardcoded hardware related thing that cannot be changed? This would fix the problem. 

 

On another note, anyone seen the Growatt SPH range stocked anywhere in SA? A SPH6000 for example could replace the Sunsynk feature wise if I would look at selling off the Sunsynk to someone that can't hear the noise emissions... What would be other trusted Hybrid options? 

I can only hear this 15kHz when I take the front panel off my 5kW Deye.  It drives me bonkers to the point where I cannot work on there unless the machine is switched off.  If the panel is closed though, it is just a lowly hum - not at all intrusive.

It shows up on a spectrum analyser just like in the above pictures, but nowhere else in the house can I detect this 15kHz harmonic - or if I can, it is tiny compared to at the inverter, and definitely not at an audible level.

Could this effect have something to do with the existing wiring in the house?  Maybe if the wiring length is a certain factor of the wavelength it might amplify or mute the noise?

4 hours ago, mneeth said:

Would it be possible to share a simple wiring diagram showing how to wind this inductor and connect it to the live wire? Also, if you have specs or a model of the surge protector you deem adequate to pair with the inductor?

Lets assume I would like to add this to a PC setup with max power usage of around 700W, (3.5A), what size wire would you recommend?

thanks

See the attached diagram I made below.

You can have the filter in multiple locations but I would recommend the placements I marked as options 1 and 2. 

Option 1 will be the easiest to implement as it will require the smallest inductor (as it will have a smaller current requirement). The downside is that it will only silence that specific appliance that is connected right after it.

Option 2 will be more expensive and also more difficult to build as it will need thicker wire due to a larger current requirement. The upside is that it will cover an entire room's (or multiple rooms') appliances.

 

The surge protector should be placed between the filter and the load in both options. An inductor has two wires, so you would cut the live wire and join it again with the two inductor terminals.

For option 1 I would recommend a simple Ellies surge protect plug:

https://www.takealot.com/16a-high-surge-protection-3-pin-plug-top-for-electrical-devices-/PLID73912362

https://www.takealot.com/high-surge-protection-8-way-multi-plug-with-r30-000-warranty/PLID27971525

 

For option 2 I would recommend a DIN rail mount surge surge protector to be installed in the distribution board. I couldn't find one online from a reputable retailer now but they usually sell them at general electrical suppliers such as ACDC Electrical. They look something like this:

https://www.chamberlains.co.za/lear-din-10-20ka-2-pole-surge-protector-385v-blsd-10-2-1086674

 

I will make a post that details the technical and practical inductor design later on this week. For now I'm a bit swamped with work.

 

Hope it helps!

 

37 minutes ago, DiSiNTiGR8 said:

So my question remains, are they not able to adjust the switching frequency of the inverter to something in the 18000 - 20000Hz range (like Growatt uses for example) with a firmware update, or is this a hardcoded hardware related thing that cannot be changed? This would fix the problem. 

 

On another note, anyone seen the Growatt SPH range stocked anywhere in SA? A SPH6000 for example could replace the Sunsynk feature wise if I would look at selling off the Sunsynk to someone that can't hear the noise emissions... What would be other trusted Hybrid options? 

This is usually not something that can be changed with a software or firmware update. Even if it could, it wouldn't be advised as the components that the engineers chose were specifically chosen to work at 15kHz. Changing the switching frequency might damage the components or cause efficiency problems.

Exactly, don't expect a software update to fix a hardware design problem, we'll have to learn to live with it.

This is all above my head, but this link ( https://www.portablesolarexpert.com/how-to-eliminate-inverter-noise/ ) says it could just be size of battery cables.

They call themselves "experts" so ......

So I followed the path Sunsynk recommended as some others with the noise issue have done before and collected the filter they advised to use. 

Wired it in on a lead to plug my PC in through the filter as a test as the computer is the main device I am concerned about. 

Here is the filter they provided (recommended by Deye engineers) :

 

Test without the filter at computer, you can see the spike at 15000Hz:

 

Test with the filter, now the 15000Hz is lower however there is now a new way more audible noise at around 7500Hz so half the original frequency with the filter in use:

 

Definietly won't be running this filter as the new noise with the filter is way more annoying than the original noise.

Will feed back the same to Sunsynk and Deye who advised on an email trail to use this filter. Will see what they advise next...

 

Hi @DiSiNTiGR8

 

Most of these off-the-shelf filters are not very likely to work unfortunately. I have wasted a couple of bucks to try these out too. Almost all of them are designed to filter out frequencies in the CRISPR defined conducted emissions band, which starts from about 150kHz and ends at 30MHz.

Some do seem to have good filtering properties at 15kHz on their datasheets, but one should be careful for the "50Ω/50Ω symmetrical" condition the tests were run at. This condition refers to the characteristic impedance (transmission line theory) of the test system and is usually only applicable to RF circuits and not mains power. The test condition for an inverter would be closer to something like 0.1Ω/100Ω. Under this test condition most of these filters perform very poorly or can even cause resonances making the problem worse as in you case.

If you are looking for an off-the-shelf solution, you should get a filter with an inductance in the 1-5mH region (the higher the better but past 5mH it would be overkill). Just be careful, some datasheets also list the Common-Mode inductance, which wont be helpful in our case. A differential inductance (aka a normal series inductor as everyone knows it) is needed.

I am yet to find an off-the-shelf solution that has a large enough inductance and current rating. Usually you get to pick either or, but not both.

Regarding a DIY solution, I am looking for a supplier of a large toroidal core, which will make the whole winding process very easy. This will make it a viable solution for the general hobbyist. Will make a post as soon as I find something.

 

Cheers for now

Wiggly