audio-talk

Hi,

A friend of mine asked me if I knew whether the inverter associated with PV panels would have any detrimental effect on hifi systems in the house.

I don't know enough about the equipment to comment so thought I'd pass it over to the assembled wisdom on here.

I'd think there was probably a good chance that noise would be generated but how much? Would it be noticeable?

Cheers,
Tony

There are at least two (only two?) ways of feeding the 'new electricity into the mains supply' . With our's the new electricity joins the junction box an dis not fed directly out into the mains supply out in the street. I cannot hear any noise on my hi-fi (eh, what's that you say, sonny!?) hi-fi, don't make me larffff.

So I'd say, 'No!'

There are very strict standards for all parts of the green environment equipment which it must pass before the government approves the feed in tarrif or RHI.

But many people including myself can hear significant improvements in hifi when we filter out noise.

I imagine there is some additional noise but it could be picked out by the various power supply cleaners whether proprietory or home made.

I don't think you are wasting your time and money attending to noisy power sources.

My household mains always has been very noisy and I always use a cascade of rfi filtration in the first instance in a box of it's own then each component of the hifi has a double cascade of it's own. This is because noise generated by a component of our own (like the RF heating of filaments, or the computer power filament supply).

By the way laptop power supplies put out gargantuan amounts of noise compared to electronic solar PV inverters.

Indeed, I've not noticed any detrimental affect Tony, in fact my system may even sound slightly better when generating power but that could just be down to me feeling better when the sun shines!

One thing to look out for though is the voltage level, I'm in a high mains area and when the panels are generating I sometimes see 255v, this is due to the mains impedance I'm told. I have a couple of Turntables rated for 220v and have had to implement a bucking transformer for them to get the voltage down.

Yes the inverter senses the mains voltage and adds +5v to it, whatever it is.

That way your home consumes what you have generated before it takes power from the incoming.

We are already over voltage compared to what equipment manufacturers design for those of us with Pv are making that situation worse for ourselves.

There is a whole aftermarket industry (enphase for one example) of gadgets which reduce your mains voltage that they claim save their cost in the first year.

In brief they are autofromers with multiple taps that are switched to accordingly, but they cannot coap with a full 32 amp ring so they have a shunt for when current exceeds their spec.

The devices you save money on are fridges freezers washing machines vacuum cleaners turntables.

Anything with a transformer or a motor in it. this is because with the stupid high voltages we suffer these inductive items saturate and run inefficiently.

Bit puzzled by this. We too are in a high voltage area - typically about 250 - 255VAC.

Are you saying that we'll be using MORE power (kWh) because the voltage is higher? Surely modern appliances with a PF very close to 1 will register identically say between 220VAC and 260VAC in terms of kWh on the utility meter...

No I am not saying anything. The manufacturers of Vphase are saying it. I am relaying.

As I said already if you had read it properly before jumping in with argument.

Paul Barker wrote:
The devices you save money on are fridges freezers washing machines vacuum cleaners turntables.

Anything with a transformer or a motor in it. this is because with the stupid high voltages we suffer these inductive items saturate and run inefficiently.

What they are saying is that any motor or transformer will saturate and so be less efficient. your saving comes from operating inductive equipment within the designed voltages.

YES after so called "harmonisation" we in the UK are effectively over voltage for this type of equipment, since most manufacturers are outside the UK and they think that when we specify a nominal 230v we mean it.. But what happened in reality was we kept everything the same and just relaxed the tolerances. So our voltages is higher than Europe.

Paul Barker wrote:As I said already if you had read it properly before jumping in with argument...

Hang on a sec! I am just trying to understand the rationale, not start an argument

This would be an interesting claim to test - I have some decent mains monitoring devices (but, regrettably, not a Dranetz of my own) - I know from careful checks I did a year or so ago that all our white goods and PCs etc. have a PF of extremely close to 1 (they are all fairly new).

The main consumers of power are the heat pump (50% of all our electricity), the freezer and the fridge - the washing machine and dishwasher are secondary consumers as are the various PCs etc.

So, how to I test this theory? I could put in a CV transformer, but that would have losses of its own - they have insertion losses and seem to run at between about 85% and 90% efficiency - pretty poor really - and it gets worse, as when driving motors etc. with surge starting currents, the CVT has to be sized for that, therefore it runs normally at maybe 40% or so capacity and its efficiency can drop even more, e.g. down to below 60% (they just get warm).

The heat pump is a 3-phase beasty - I will ask the supplier about its energy usage with high mains voltages.

EDIT: Just spoken with ICE Energy's technical support line. They claim to have recently done tests on the system I have (an IVT Greenline), moving between +10% and -10% of nominal (230VAC) with no discernible difference in efficiency or energy consumption.

has this got anything to do with Tony's question about noise and hifi?

I have solar panels and although I previously thought they might be negatively impacting on my quality of sound, having explored this I have concluded this is not the case. Infact, at present my system sounds the best it ever has, being played night or day, sunshine or overcast sky

ed wrote:has this got anything to do with Tony's question about noise and hifi?

No.

However, to get back on track, all PV etc. systems use inverters which are notoriously bad when it comes to shoving crappy artefacts down their outputs and into the aether generally. Especially cheap inverters.

Having anything switching large currents anywhere near HiFi is a tricky combo...

..."combo" rhymes with "mambo", which give me an opportunity to include one of my favourite tricky mambo scenes:

Actors 'being' musicians.... never an easy task...

witness....


Its just not right y'know


DTB

PS. Yes I know its Ry Cooder really, no not the karate kid, the guitarist playing the sad sounds, oh shurrup Dave....!

Thanks for all your help chaps!

Hello, audio friends - and Nick for inviting me in. I'm new today: spotted the old thread about solar panel intrusions: an increasing issue, as many more panels go up.
My work, home-based, is quality sound recording. The 20 kHz switching oscillator of my Fronius inverter gets in everywhere. I cannot at my age hear it, but every track used to be disfigured by a spire which had to be software filtered, twice. Now my neighbour has installed solar... but his runs at 19 kHz so I cannot efficiently filter both. Ironically, he can hear his whistle, as such.
The twin whistle currents reach my recording gear via mains: 'common mode' - i.e. all three conductors carry same signal, same phase. So, probably, I can block it by winding a ring ferrite plus some grounding capacitors. Thin triple wire is at the ready, awaiting a ferrite from China.
I've written to Fronius to ask if their industry might look into pushing those oscillators up to 24 kHz, where the inbuilt sharp cutoff in standard recording software would most likely eliminate it. Also queried RSGB because radio amateurs encounter terrible inverter harmonics, but very few have any interest in communications around 20 kHz!

What would worry me most is there being some non linearity somewhere in the system giving you a 1kHz beat frequency.

i.e. all three conductors carry same signal, same phase

An isolating transformer might be a solution, though it may get in via the common earth, One question I have to ask is if its actually on all three conductors how does the kit notice it?

A nice big EI 1:1 transformer should stop a lot of it if you can solve the earth problem. Or maybe a balanced transformer with a local earth point in the ground. Though that would be hard to do safely, you would have to have an inside and outside protective earth and prevent the two meeting.

20k is nice and low so should be simple enough to filter out and it won't get everywhere like a RF signal would, but I would do some work checking exactly where the signal is and relative to what. Battery power scope might be of use here to allow isolated inspection.