Roundtuit Posted May 23, 2018 Share Posted May 23, 2018 Hi. My pv has been generating for several months now, but as the weather has got sunnier and the family has spent more time at the build, it has become apparent that the inverter is producing some high-pitched noise. It is at a frequency that I can't hear, but both teenage kids (and friends) can hear it, and I suspect it's pi$$ing the dog off too. The 'plant cupboard' doesn't have doors on yet, but it strikes me as not something you want in the house. The installer and manufacturer are both claiming not to have come across this issue before, but are offering to try replacing the inverter foc to try and resolve the problem, which is fine. But; I can't help feeling that the manufacturer should know what noise emissions their kit makes as it is a measurable, and they should, with the aid of a noise meter if necessary, be able to tell me whether my current inverter is in or out of acceptable limits. Any thoughts please? Link to comment Share on other sites More sharing options...
Temp Posted May 24, 2018 Share Posted May 24, 2018 (edited) Many power supplies including those in a PC or laptop use high frequency switching. Usually it's above 20kHz to try and prevent it being audible. Explains why only kids might hear it. You might be able to google the make and model to find out what your uses. Sometimes it's more audible on one example than another so switching the inverter might help, but could conceivably make it worse. Occasionally manufacturers have an issue with a component like a capacitor vibrating and will use some hot melt glue to stick it to another component or the pcb to try and prevent it. I don't recommend doing this yourself for a bunch of safety reasons. eg could cause overheating, fire etc PS: Sometimes the switching frequency is modulated by the load and that can make it even more annoying (You could conceivably make it play tunes not that this helps any). Edited May 24, 2018 by Temp Link to comment Share on other sites More sharing options...
Onoff Posted May 24, 2018 Share Posted May 24, 2018 https://www.nhbs.com/magenta-bat-5-bat-detector? :) Link to comment Share on other sites More sharing options...
Temp Posted May 24, 2018 Share Posted May 24, 2018 (edited) More from google.. https://aaltodoc.aalto.fi/bitstream/handle/123456789/12007/master_Mal%E9n_Joni_2013.pdf?sequence=1 Quote "Analysis of noise emissions of solar inverters" "Eight on-market solar inverters were examined to fnd their noise emissions and the voltage- and power-related variability in those noise emissions. Additionally, a Generic Device was partially disassembled to reveal the contributions of various noise sources." "For the majority of devices, noise above 10 kHz represents a signifcant portion of total noise, and must be included in sound power measurements. Emission sound pressure levels exhibit great variability in space and thus must be determined empirically at specified positions." Which suggests relocating the inverter or perhaps even mounting it to the wall in a different way can effect the noise produced. Edited May 24, 2018 by Temp Link to comment Share on other sites More sharing options...
Roundtuit Posted May 24, 2018 Author Share Posted May 24, 2018 10 hours ago, Onoff said: https://www.nhbs.com/magenta-bat-5-bat-detector? Interesting idea, might give that a go. Just need to clarify that there are no bats here. Nope, no siree. No bats, no newts. ? Link to comment Share on other sites More sharing options...
Roundtuit Posted May 24, 2018 Author Share Posted May 24, 2018 @Temp Sorry, the link doesn't seem to work, but I get the gist thanks. The proposed replacement model is the next generation, so if nothing else, I'll have a slight performance upgrade. If the noise is intrinsic, I guess I'll just have to bump the plant room doors up the priority list! Link to comment Share on other sites More sharing options...
Temp Posted May 24, 2018 Share Posted May 24, 2018 Might have to copy and paste that link. Link to comment Share on other sites More sharing options...
Onoff Posted May 25, 2018 Share Posted May 25, 2018 (edited) @Roundtuit, there is another way... You need to find the noise frequency first. Then build (buy?) an anti-noise emitter/amp at the same frequency & amplitude but inverted phase of the nuisance sound. Ideally adjustable to fine tune it. Active noise reduction basically. Like this but guessing lower frequency: http://cambridgesound.com/products/qt-emitters/ Maybe a cheap "try", some acoustic tiles in there? Like this: https://www.studiospares.com/Studio-Gear/Acoustic-Tiles/Acousticheck-30-Absorption-Foam-Tile-100mm_465500.htm? I bought a few second hand off eBay to hopefully quieten my concealed wc. Test flushing and it is very, very quiet but that might be as much to do with the way the "box" round it is close fitting and sealed at the joints. I think more noise will come from the Richards hurtling down the soil pipe in the wall that's only encased in gun foam! Off the wall but it's not a transformer breaking down somewhere but if it's a mains trannie I'd guess about 100Hz. Edited May 25, 2018 by Onoff Link to comment Share on other sites More sharing options...
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