Victron MPPT EMC issues

[stgermain45]

Originally Posted by team karst

Interesting. Is the AIS/VHF at masthead? I see more of the hf issue at 10M. 40M no effect, although the atmospheric qrm has been bad lately.

Yes, AIS/VHF is at masthead 65ft up and very far from the solar controllers, whereas SSB is a lot closer. So no mystery there why we don't experience AIS/VHF problems.

[Justin Cook]

Originally Posted by Kolchac

Simple physics:
100/30 is designed for a series connection of panels. Using it for one panel is a mistake (if you use 18 V for 12V).
Connecting panels in series increases the voltage (like 18V + 18 V = 36 V), but the amount of current would be the same as from one panel.
To convert extra voltage to extra current they use an electrical transformer (it is not innovation!). The transformers work only with AC. So they convert high voltage DC(36V) to high voltage AC(36V), then, using the electrical transformer, they transform high voltage AC(36) to low voltage AC(12V), then convert AC(12) to DC(12V).
Using these three transforms they lose ~30% of power theoretically, and practically more. The size of the electrical transformer depends on AC frequency - higher frequency - smaller size. So they use probably approximately 100 KHz transformer.
So why do you see 100-200 MHz? Because instead of generating sinusoidal AC, they use square pulses, which have a lot of high-frequency harmonics.
As an emc engineer, you should understand, that this HF emission 90% goes through the wire, not by air through the box. So even the battery cannot suppress it. You cannot do anything with that.
The solution is simple:
Use parallel connection of the panels, and use a $20 controller (which has the same Taiwan microchips as a $300 one), which does not have any transformers.
If you have a sun shade problem (for what Vicron offers this design), much better to use several small panels instead of a big one.

Just for a little bit of clarity here, Victron MPPTs are DC-DC converters, there's no AC - none at all. That's why they can run up to 99% efficient (admittedly in practice, depending on circuit efficiency and other factors, usually more between 95-97% efficiency).
And no, the 100/30 is not "designed for series connection"; it's designed for up to 100vDC input. How you get your input voltage, whether it's with a single panel at 70vDC or 4 panels in series at 22vDC for 88vDC total is irrelevant; and, for that matter, if you choose to use it to only control a single 100w panel at 22vDC that's fine too - it makes no difference to the MPPT and certainly isn't a mistake. The only relevant consideration there is that panel voltage must be 5v above battery voltage for the controller to start charging... as is the case with just about any MPPT on the market from any manufacturer.
The bulk of the information in the comment appears to be taken from a "Leonics support" page from 2009 that's (oddly) the first thing that pops up when you Google "how does an MPPT work" but is, regrettably, wildly incorrect for the application being discussed. That may have been how MPPTs worked 14 years ago, but we've thankfully come a very long way since then!

[wholybee]

I have a 75/15 and 100/30. I note significant interference with my SSB. The simple solution is to turn them off before a scheduled call. I have not noticed any other significant interference, my VHF and AIS reception range is exceptional, I've not made any tests to see if it is more exceptional with solar off.

I have also not yet installed any ferrites. I plan to and even have some, but have just been too lazy for the amount of interference I have.

[team karst]

Originally Posted by Justin Cook

Just for a little bit of clarity here, Victron MPPTs are DC-DC converters, there's no AC - none at all….!

Negative. The input dc is chopped up by a FET, switching into a transformer at high frequency. AC.
the windings on the secondary feed are into rectifiers and then capacitive filters to smooth the waveform. The operating frequency is set by a regulator/gate drive IC, and can vary from 20 kHz to 100kHz and more. The fast switching of the fet is the root cause of harmonically related unwanted spurious. Research: step down SMPS.
The added trick with MPPT is optimizing the solar panel output power. And, shutting down at full charge. [emoji106]

[Karanga]

I'm hoping that someone else with expertise and knowledge is going to contribute to this discussion. These last couple of posts each sound so knowledgeable, but so completely contradictory...

[K1MGY]

Originally Posted by Justin Cook

Just for a little bit of clarity here, Victron MPPTs are DC-DC converters, there's no AC - none at all.

Assuming a buck converter, there's pulsed DC working at a specific duty cycle, satisfied by an LC circuit. Switching these high currents creates noise.. a lot of noise.

[ejs]

Team Karst is correct, there is absolutely AC in the inner workings of a DC to DC converter. They chop the input DC with FET switches, use a transformer to change the voltage and rectify the result back to DC. The process does generate RF noise but a good design can eliminate it escaping to the outside. There is some regulation circuitry too, but that is low power.

BTW I have 6 Victron solar controllers (3200 watts total) and I have not been able to find a noise difference with them on vs off in the HF or VHF radios.

-E

[GordMay]

Have you tried running it through a Turbo Encabulator?
"... Now basically the only new principle involved is that instead of power being generated by the relative motion of conductors and fluxes, it is produced by the modial interaction of magneto-reluctance and capacitive diractance ..."

Here's a good explanation, from General Motors ➥ https://youtu.be/Ac7G7xOG2Ag

by Chrysler ➥ https://youtu.be/MXW0bx_Ooq4

by Rockwell Automation ➥ https://youtu.be/RXJKdh1KZ0w

[team karst]

Gord. U nailed it [emoji1362]

[FlyingScot]

For those who are noticing EMC issues, what input voltage to the MPPT do you have as compared to the output. In our case our panels are about 40v and we charge 12-14v. We have one MPPT per panel.

I wonder if the large differential creates more EMC.

[team karst]

My summary to date:

The Victron 30/100 has been linked to various radio service interferences, though not affecting all users.
A scan was published on the Victron community postings, showing strong noise starting at near 30MHz, presumably repeating at harmonics thereof.
The scan done by Victron supporting its CE mark EMC directive will not be released by Victron.
re: AIS. Interference is notably absent when the AIS antenna has significant vertical separation from the MPPT converters, and/or the solar panels themselves.
When such separation is not afforded, as much as a 4:1 reduction in AIS receive range has been experienced.
For the airband service, an increase in interfering noise is experienced at 122MHz, increasing with frequency, peaking at 137MHz, where the receiver looses squelch effectiveness altogether.
All MPPT noise appears to stop when the panels are not producing power.
The affect on marine VHF comms has not yet been quantified.
Up to 6 mix 61 ferrites have some, but not significant impact, when applied to both Batt and pv terminals, close to the converters. 30 Amp rated line filters will be tried on the next round of mitigation.

My pv system consists of two sets of series connected panels, 18V each. Thereby providing a max of 36V into each MPPT.

[tanglewood]

Are these MPPT controller tested to FCC limits with certification numbers? The point of those regs is to minimize EMI emissions. They aren’t a guarantee, but a good baseline. I have never checked for this cert

[team karst]

FCC Part 15 generally excludes transportation.

a) A digital device utilized exclusively in any transportation vehicle including motor vehicles and aircraft.

Curiously, Victron claims emc compliance to a Euro wheeled vehicle R10 standard. ??

[tanglewood]

Originally Posted by team karst

FCC Part 15 generally excludes transportation.

a) A digital device utilized exclusively in any transportation vehicle including motor vehicles and aircraft.

Curiously, Victron claims emc compliance to a Euro wheeled vehicle R10 standard. ??

They are equally useable in a dirt dwelling, right?

[team karst]

Compliance is kind of a funny thing. Much rest on the marketing and instructions for use documentation. If the paperwork talks marine only, then “marine” rules apply. OTOH, if fixed residential use is implied, then stricter rules apply, at least for emissions.