Reducing RFI from solar systems

  Reading this very useful and detailed post from fellow blogger KA7OEI. 

https://ka7oei.blogspot.com/2024/06/reducing-qrm-interference-from-renogy.html

I extended my solar energy production with 5 extra solarpanels a while ago. It really was a bargain getting these as I bought the 260Wp panels at a cost of €50 (€10 per panel) from a colleague. The inverter was searched for on the dutch internet marketplace and I bought one for another €50. Most of the costs were the mounting rails, wiring and the #31 ferrite to make shure no RFI would reach my antennas. The last items were an additional €300. 

The open line of the inverted-V doublet is just about 1,5 meter above the solarpanels. I even got a quarter wave CB antenna near the panels to listen to some chats on CB when in the garage. I really did take all precautions to make shure I would not have any RF coming from the inverter or the panels. On the pic at the right you see that I used big #31 FT240 ferrite rings in both AC and DC lines. The earth wire is fitted with a big #31 snap-on ferrite. DC wires are mostly fitted in earthed Alu tubes were possible. Everything is earthed to a central earth point, the tubes, the mounting frames and the inverter.

At the left a pic from the Alu tubing used. Yes, it is made of old antenna left overs. I always use what I have at hand. I seldom throw away scrap Alu tubing. Over the years I collected some ;-).

Well to keep a long story short I can recommend the page from FerriteShop about this subject. I followed most from their tips and used #31 snap-on ferrites below the panels. The only difference at my installation are the FT240 ferrite rings below the inverter.

https://ferrite-shop.com/prevent-solar-panel-interference/?v=796834e7a283

For Dutch readers it could be interesting to read the Dutch Telecom recommendation:

https://www.rdi.nl/onderwerpen/tips/voorkom-storingen-door-zonnepanelen

Well, I don't have any RFI from my own solarsystems. I see QRM in the waterfall of my IC-7300 from my neighbours solarsystem on 50MHz. Just to be shure it isn't my own I checked when I switch my own systems off. Of course there was no change, the QRM stays there and is not from my property for shure. Luckily the QRM is only there when I turn my beam over their house.

The 5 solarpanels harvested 165 KWh in less then 2 months. Approx 3 Kwh average per day. It is not much but anything helps. The system can be extended easily when I find another 5 or 6 secondhand solarpanels.