Victron MPPT EMC issues

[team karst]

time for an update, since I have made some progress.

First off, the Victron MPPT controllers are not easy to work with. They are semi-potted, so just getting the cover off is an issue. And, of course, not having design documentation/schematics has led me down an independent path. ie: don't modify the device.

First step is a site survey to see how bad the issue is, if its an issue at all for your install. My survey includes the 40m and 20m ham band, the aircraft AM band, the WX VHF service, and the AIS service. Here is a easy to duplicate example: Take your VHF handheld marine band radio and tune in a weak, but fully readable weather channel. It should have some light noise on the signal. Place the radio in a typically used position, perhaps the nav station or the helm.
Activate your solar charging system, either by using the PV panel disconnect switch or even a blanket over the affected panels. You must know what panels power the MPPT's, in case there is >1 unit. Notice that the issue, if any, turns the WX station into unreadable noise.
If you have AIS targets between 6 and 20 miles out, that will also be a good test. Look for significant range reduction. Mine was 20 miles to 4 miles with one MPPT on. If your vessel checks out, no mitigation is necessary.

For mitigation: see next entry

[team karst]

My site survey (the BEFORE data) results:
SSB on 7MHz and 14MHz bands show 1 full "dash" of noise with some associated audio present. l don't know how the SSB is calibrated, but this noise was significant. Airband AM was more significant, with even full squelch unable to quiet the receiver; from 118 to 130MHz. Again, note that AM radio squelch works just the opposite from FM radios, as far as squelch response to noise.

Without belaboring what did not work (I tried even dual section line filters), here is my current fix:

It took one each high frequency ferrites on the +Batt, and + PV lines.
Two ferrites on the B- (GND) line.
Two feedthru caps are also required, one on each POS line. Tie the B- side to the copper strap. Note the PV- and Bat - on the Victron are tied together internally.

Only using ferrites were not effective. I am using THK ZCAT3035-133 clamp ons. I even tried 12 ferrites on one MPPT, with poor results.
Note the copper tape to mount the caps. I used Cornell Dubilier CBFT40. Unfortunately, only available on the NOS market. Also, they have a 50Volt DC max spec, so will not work for higher voltage systems. It would be best to find a different cap. Its a shame that Victron was not responsive to this issue. An internal fix would be far better.

[CatLove]

Very interesting update for me, because I am in the early stages of selecting components for a solar refit of my boat and Victron MPPT's were one of the options.


I am an old EE , worked on many such electro magnetic interference issues , both on new designs and in retrofitting old stuff for mitigation. All sorts of devices, UAV's , medical devices, spread spectrum radios etc. Also designed and got thru FCC several radio transceivers , some long range, others micropower.


Your location is indicated as Flagler County, which is not far from Orlando, where I am currently. I own sufficient test equipment (Agilent/HP/R&S , spectrum analyzers, VNA's , near field probes etc) to get to the bottom of this Victron interference issue.

I'd be interested to see what's going on , hopefully find a simple solution that would be applicable for many Victron users on this forum .



Depending on the Victron internals, worst scenario is if it radiates massively thru whatever switcher inductances it uses internally . There isn't much that could be done short of putting it in a Faraday cage to prevent this radiation.
However, it is likely that either or both the input and output conductors are radiating , or conducting or both. That scenario could be dealt with using input , output appropriate filter topologies. I've designed and produced such filters for similar power and voltage range switching supplies in the 100kHz to 2MHz . My interest in this issue is purely as a hobby and my free time is free so why not put it to some good use. Let me kow if you're interested in my offer , either here or DM me.



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