LiFePO4 12V DC INVERTER TO 230V AC - Noise on input rails

[Gebrey]

Hallo everyone,
I have a NANO V3 (chinese arduino nano clone) that can't work properly (supplied with 12V DC) when INVERTER is on, idle or load doesn't matter. With a scope analysis, I found that 12V DC INVERTER PURE SINE WAVE 2500W/5000W PEAK, that makes a beautiful sine wave on AC, make a very intense (2.5-5Vpp) HF noise on input rails (up to 60MHz).



I'm trying two things:
- operate on input connection of INVERTER to stop the noise at origin
- operate only on arduino nano board andbrelative 12V DC connectors


FERRITE BEADS ON INVERTER: counterproductive
Someone suggested ferrite beads. I lucky had already got the perfect bead (30x30 15mm inner d) exactly for my 70mmq 12V+ wire that goes to inverter. Well, in idle mode nothing happens at all (in scope). In load mode, the inverter, that still works flawless, start to make an audible resonant noise (like 400~Hz). A bit scary but I doubt to have damaged it* (*expert opinion required).


REGULATORS AND DCDCs: need filters
Any of thesr devices needs filering the input rails noise to ensure it won't pass trought. I tested LM317 DieNoiser, L7805 reg, DCDC no isolated of any kind, to achieve 5V DC and supply it to arduino trought USB port. While all these methods work when inverter is off, when turn on nothing makes arduino working correctly.

Next steps:
- SB140 diode in series to arduino Vin (this should cancel lower half wave)
- SMD 1206 100uF ceramic cap between arduino Vin and GND (the new 0.1uF ceramic decoupling cap method)
- damping resistor allowed is max 20ohm, the same resistance is the limit for any LC filters

Crazy ideas:
- earthing the ferrite bead (the VAC earth is not connected to battery GND or any other thing. It goes to a steel braid scratching the asphalt (yes is a camper van))
- wrap a coil (and a counter coil) to inverter rails and connect it to earth. My inverter rails goes up to 5000W peak power so I need an expert opinion.

Any other suggestion is really apreciated. I would ideally solve the probmem on inverter rails... if not I would operate only on arduino rails. Since now, I never analyzed the inverter noise. But now, since that huge Vpp I think it could damage other 12V devices (diesel heater, water pump, led strips, GPS tags, tuya relays, engine battery charger, etc..)

Thanks in advance