Solar panel RFI

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K3RW, Jul 27, 2016.

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  1. KD0CAC

    KD0CAC Ham Member QRZ Page

    Give a list of gear , make & type of charge controller can be a biggie , also same with inverter ?
    Then how its installed , try to keep batteries & gear away from shack , and any shack wiring / feed-line .
    Depending putting a faraday cage around the electronics and ferrite / chokes on wire , cabling .
    But 1st is to find source to see if eliminating source , and covering up last , is always my preferred way .
    NH7RO likes this.
  2. WA7ARK

    WA7ARK Ham Member QRZ Page

    The biggest RFI source that I cannot control is my neighbor's grid-tie roof top solar that back-feeds into the AC grid. She has the el-cheapo Chinese micro-inverters, so instead of having one, well-shielded inverter box downstairs, with DC wiring going to it from the roof, she has 13 micro-inverters and AC wiring all over her roof, each of which makes about the same amount of RFI as one big one would.

    The system is leased and monitored over the internet by a company that owns the system. If she where to shut it off, she would soon get a phone call because the company would see the system stop producing...

    To add insult to injury, she and I are fed from the same power-company distribution transformer secondary, so not only does the RFI radiate, it is also conducted from the micro-inverters along the AC power line to the transformer, and back to my distribution panel...

    My advice, if you want to be a ham, forget grid-tie roof-top solar...

    otoh, I have a large solar panel that runs my ham station and charges 200Ah batteries, but it is all DC. I tried a switching MPPT charge controller, but it generated RFI, so I built a linear charger (no switching).
  3. W0AAT

    W0AAT XML Subscriber QRZ Page

    I have 2400 watts of installed solar. Morningstar MPPT 45 charge controllers. A couple f HF birdies but nothing that would stop me from operating. I am not grid tied and use a pair of Samlex PST 1kw inverters that have been pretty RF quiet also.
  4. NH7RO

    NH7RO Ham Member QRZ Page

    Moral of the two widely differing accounts above: YMMV;)
  5. AB6RF

    AB6RF Ham Member QRZ Page

    We live in a house on a small suburban lot. Both of our next-door neighbors have large PV arrays on their roofs, both tied to the grid via an unknown brand inverters.
    The RFI here is horrendous, all HF bands are near useless for me here at home, 2m and up are ok.
    I can open the main breakers to our house but still get S9+ noise across the HF.

    I’m sure all the switching power supplies, Plasma TVs and LED lights create lot of this suburban noise, but I’d be surprised if most of it is not coming from these large PV system inverters.
    NH7RO likes this.
  6. W0AAT

    W0AAT XML Subscriber QRZ Page

    Inverters are the culprit. I went through several before I found some that were rf quiet. And they are not grid tie, I use what I produce... grid tie inverters you would have to look close at the UL listing codes to see what is going to be acceptable...

    These companies doing solar leasing where they use your roof, it cuts your bill etc do not use top of the line equipment. A lot of it shouldn't even be allowed in the USA but good luck getting the FCC to act. I have been fighting power line RFI for years. Complained to the FCC 4 years ago... nada, zilch, an email saying we received your complaint... then no action whatsoever. They finally came out and fixed one source when it started to interfere with the police radios when the deputies were in town...
    NH7RO and AB6RF like this.
  7. VE7PJR

    VE7PJR Ham Member QRZ Page

    We have 45 panels on a 40-foot pedestal, a dual-axis solar tracking array with bifacial panels so they also generate power "off the backside" from snow albedo. Each panel has a dedicated micro-inverter and there is a master combiner that puts it all in phase (240VAC) and throws it up to the house 100 feet away.

    We also have "smart meters" in the neighbourhood that operate their own cellular network to transfer data down the valley, and I'm sure we have PLCs. In other words, lots of potential sources.

    I don't get any noise that I can conclusively say comes from the electronics on the array, but I notice some occasional pulse-type noise on 30m. I can't say if it was there before -- I've been a lot more active lately, using a different rig, etc. Too many variables. It's not objectionable, and it doesn't seem to matter if it's day or night, so likely not coming from the inverters because they shut down at low light level.
  8. NH7RO

    NH7RO Ham Member QRZ Page

    I suapect a DXE NCC-1 or 2 (or even an old JPS ANC-4 or similar) might be able to null some or most of this noise if it is coming from one source.

    Egads, though---what a ham nightmare! The only RFI I've experienced with my own mobile/portable 83-watt system was from a battery voltage booster in the "always on" mode.
  9. KC8VWM

    KC8VWM Moderator Volunteer Moderator QRZ Page

    Pulse charging is only intended for lead acid (wet cell) type batteries and the theory is pulse charging helps to prevent sulfate on the battery plates. However, you can't use PWM (Pulse Width Modulation) chargers on lithium battery chemistry because the "pulsing" could result in damaging the battery management circuitry the lithium batteries have built inside.

    MPPT also provides up to a 30% increase in charging efficiency and that's why people use them instead of PWM schemes.
  10. W0AAT

    W0AAT XML Subscriber QRZ Page

    MPPT is PWM but it matches the load demand so the panels stay at max efficiency. Plus it allow running higher voltage to the charge controller. My system is operating at ~80 volts so instead of running 24volts back and needing really heavy cable for the 100 foot run I could run #6 THHN and only have ~15 amps versus 60 amps for running low voltage. The difference in wire cost paid for the difference in inverter price!
    KD0CAC likes this.

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