MPPT Charge Controllers that don't produce RFI - For Ham Radio and Shortwave Users

I'm currently in the market for a new MPPT charge controller. Since one of my favorite hobbies is ham radio, I am searching for a controller that does not produce a bunch of radio frequency interference (RFI). I operate the high frequency bands between 1.8 - 30 Mhz, as well as VHF 50 Mhz and 144 Mhz.

I've been looking at the Morningstar TriStar MPPT 60. Do any ham ops use this controller and if so, how does it work in regards to RFI?

I have been searching the internet and have not been able to find much information regarding MPPT charge controllers and the radio frequency interference (RFI). Some of them are FCC Type B certified, but that really doesn't tell me much - especially real world experiences. I would really like to hear from people who are actually ham radio ops or folks who are into short wave radio and are currently using a MPPT type charge controller.

I realize most folks also run inverters. Inverters are also notorious for causing RFI. If you have one that works well and doesn't produce RFI please list it as well.

To really benefit myself and others in the future, please respond with the following

1) Make and model of your charge controller
2) Panel array voltage
3) Battery System voltage
4) Does your MPPT charge controller produce RFI? If so please describe RFI including frequencies and strength if possible
5) Inverter make and model
6) Does your inverter produce RFI? If so, please describe RFI including frequencies and strength if possible


  • VicVic Solar Expert Posts: 2,984 ✭✭✭✭
    Re: MPPT Charge Controllers that don't produce RFI - For Ham Radio and Shortwave Users

    Hi SJ,

    Please carefully review the Sticky on RFI on this Forum:

    You have posted in that Thread, and several others, it may be difficult to keep track of them all ...

    There is NO piece of switching Power Electronics that is immune to the production of RFI/EMI.

    FCC Class B for DC devices like CCs begins at 30 Mhz.

    Here the OB MX-60 CC is not that noisy (discontinued now). The Classic is not bad at all. Inverters that meet FCC B are tested in the MF/HF range. Xantrex SW+, XW, and Context SW Inverters claim to meet FCC B. The SW+ inverters used here are not that bad at all, even on 160 M.

    Not to completely rehash all that has been posted in that RFI Sticky.

    Probably the most important single thing to do for emission reduction are:

    1. Separation of antennas from emission sources.
    2. Run power conductors in tight metal pipe
    3. Run AC power cables underground, about 24" deep or so. PVC seems OK for these underground conductors. Transition to metal as the conduit emerges from the ground. This transition could be a Code no-no.
    4. Place directional antennas such that the main directions of interest do not have PV arrays between the antenna and these areas of interest
    5. Place Common-Mode Chokes on all power cables, as close to the RFI generator as practical.
    6. Use tight metal semi-rigid AC conductors in above-ground locations, such as in your Radio Shack, residence, shop, etc. Coleman Corra-Clad is such an MC type cable that has a continuous Aluminum corrugated tube around the THHN type conductors.

    And so on. The above measures here have virtually eliminated RFI. If I point a directional antenna at the PV array, there is a nominal S1 signal from an MX-60 CC on 17 M (for example). These carriers are spaced about 20 KHz nominal. Would be a bit stronger on 20 M, but not an issue 99.99% of the time.

    My experience. The Off-Grid locations were constructed ONLY for Hammie Radio reasons. There is no local noise to speak of. The inverter noise is essentially non existent. ON 160 M, there is a small bit of inverter noise. About S1- S2, but Band Noise is far above this value. The CC may generate a bit of noise on 160, but, this is a night band, and the power converter is Sleeping then.

    In town, the noise is now about S7 - S9 just from all of the CRAPO Switchers from the lowest-possible cost supplier. Radio became essentially useless for DXing there, so built a couple of off-grid radio QTHes.

    Opinions, YMMV, GL Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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