RE: Domestic PV solar inverter noise
VK5PJ > 02-02-2024, 08:17 AM
Hello Nev,
roof top micro inverters can be a gamble for RFI, once they are in they are almost impossible to work on or do suppression work on as there are so many of them and mounted behind the panel on your roof. As Steve mentioned one of the good brands of inverters is Fronius or SMA,, both from the heart of the EU where EMI and radiated interference is taken seriously.
Shop around, ask questions about WHAT Inverter they provide, many of the inverter brands now are sourced from China where they do not care about RFI. One brand sold into VK4 had an 'optional' RFI section on the PCB but it was never populated with components as they worked out no one cared about it as long as it cut the costs, so they left all of the RFI suppression off the PCB and put links in instead.
Please do not be drawn in by the cheapest price as it will probably result in a life of terror for you each time you want to listen to the radios. I have had an SMA inverter (very quiet) and currently have two Fronius inverters here, one only a few metres from the shack and tower, no RFI detectable from our two solar systems. There are many people on the forums or the VKspotter with horror stories about roof top solar noise I hope your not the next one.
Workmanship when installing will be important, they are required to earth thing properly but often these steps get done with the thinnest cable possible or just not at all. The way they run / route the DC cable to the inverter can also be of interest to you as typically the most noise is radiated from the long DC lead from the panel to the inverter so this can be a make or break part of the build, this is where the better inverters have good filtering on the DC leads to stop the switch mode noise products going up the long DC leads to the panels (perfect antennas for noise radiation). A lot of Modern inverters have FANS in them for cooling, so do not site the inverter (if you go with a traditional inverter) close to a living area window where it might annoy you during the day.
As both Steve and I mentioned, micro inverters can be a gamble, I am told there are good ones but I have not ever seen a reference as to which are good or bad, where as the traditional inverters are less risky if you go with one of the 'safe' brands. I know it will cost more but in the long run the extra I paid for my choice of inverter has never been a regret and has served to re-enforce that it can be done right if you take some time at the beginning.
hope this in some way helps with your choices.