Solar-Powered RFI

It's quite common to come across hams making use of solar energy to run their stations.  It kind of goes with the territory, really - all off-grid stuff and independence.

Being of much the same mindset, I've been slowly developing a very small-scale solar energy system for the house.  It started with lighting only, but the problem isn't so much a lack of energy, but too much of it!  Or, at least, a lack of adequate battery storage.  Perhaps Elon Musk's latest battery pack may solve this problem.

For now, I decided the best way to make use of all that sunshine falling on the panel whilst the battery was still healthily charged, was to grab a micro grid-tie inverter.  This is a plug-and-play device, very widely sold all over the world, cheap, and in fairness, works very well.  There is uncertainty as to the strict lawfulness of connecting these things to the domestic circuit, but the protections have been tested, and all seems well.

Yet another Chinese RFI-generator.  Where will all this end?

Where the Chinese-made inverter falls down is, once again, RFI.  On all bands from 20-10m, it produces slightly modulated RFI raising the noise floor from S0 to S3, varying according to the amount of light falling on the panel.

The authorities seem to have a big problem on their hands.  Whilst politicians are worrying endlessly about terrorism and the threats thereof, the UK market is already flooded with cheap and poorly-made electronic equipment that cause RFI at best, and are a safety risk at worst.  They even go so far as to fabricate false 'CE' and 'FCC' marks, which I've found and previously reported on with a CCTV system from Argos, of all people!  And the response from Trading Standards locally?  No response at all.

I suppose the defence for the sellers of these devices - and it is a perfectly reasonable one - is that even fully-approved, rooftop and grid connected solar systems under government schemes, installed by certified electrical contractors, also frequently give rise to serious RFI problems.  So, maybe the inverter isn't so bad, after all?

So, if you want to make the most of solar on a small scale, connect your panel to a battery, not the mains, and hope your neighbour doesn't install a much bigger system and connects it to the grid!