Enphase microinverter efficiency

[fresnoboy]

Tyab, thanks for the recap. Just to be clear, microinverters in the past have also been the source of a ton of RFI. There are examples of folks with M215's using toroids on the output leads as referenced in an enphase application note (which is no longer apparently on the enphase website) reducing the interference adequately, but there are no examples that I can find on any modern enphase units being deployed and not causing noise either.

Hams and those caring about AM reception have traditionally gone with string inverters, which seem to be out of favor for the reasons cited here, esp in California.

I am now thinking I need to actually test a bunch of units and see empirically what happens. This would be a good thing for a university to actually do a report on, and maybe the FCC as part of an enforcement action. I don't think the Trump FCC is likely to soft pedal enforcement on solar companies if interference is deemed a problem. Unfortunately it could give the anti-solar forces a new lever to pushback on solar deployment, all because the inverter companies got sloppy.

thx
mike

[SunEagle]

Tyab, thanks for the recap. Just to be clear, microinverters in the past have also been the source of a ton of RFI. There are examples of folks with M215's using toroids on the output leads as referenced in an enphase application note (which is no longer apparently on the enphase website) reducing the interference adequately, but there are no examples that I can find on any modern enphase units being deployed and not causing noise either.

Hams and those caring about AM reception have traditionally gone with string inverters, which seem to be out of favor for the reasons cited here, esp in California.

I am now thinking I need to actually test a bunch of units and see empirically what happens. This would be a good thing for a university to actually do a report on, and maybe the FCC as part of an enforcement action. I don't think the Trump FCC is likely to soft pedal enforcement on solar companies if interference is deemed a problem. Unfortunately it could give the anti-solar forces a new lever to pushback on solar deployment, all because the inverter companies got sloppy.

thx
mike

As far as I know most electrical equipment must meet a specific FCC standard (listed in their specifications) so that it does not emit a spectrum of frequencies above a specific magnitude.

Of course some radio equipment may be more sensitive to that RF but then it falls to the Ham operator to install filters or shielding on their equipment.

[fresnoboy]

Argh... Something weird with the site is preventing me from posting the my note.

Take a look at part 15.5 of the rules, which you can see here on page 6: https://www.gpo.gov/fdsys/pkg/CFR-20...ol1-part15.pdf

Complying with part 15 limits does not mean you are allowed to cause *harmful* interference to any licensed service, whether it's amateur radio or AM broadcast. The operator of the equipment is the one that is responsible however, since equipment could be configured in a number of ways, and in this case it's the homeowner with the solar equipment.

The reason I am am trying to find a solution to the RFI problem is that I have to make sure my equipment doesn't cause harmful interference, to me or to my neighbors.

Hams can't install filters on their own gear to solve the problem because the inverters are transmitting directly on licensed frequencies, and not they are suffering from adjacent channel interference. They are also not required to filter other people's equipment that is causing the interference, anymore than an AM broadcast station is responsible for installing filters on equipment interfering with their service. Amateur radio and AM broadcast are not part 15 services, and have no responsibility to tolerate harmful interference from Part 15 devices.

thx
mike

[bcroe]

EMI test results of many units would be interesting; something mfrs don't talk about. Likely all meet the FCC
requirements; this is probably not an enforcement issue. Tests with any legal weight are quite complex to
set up. But regulations are a compromise between what is usually tolerable and what is economical to build.

Some of us need better than "just barely" meeting legal requirements. The string systems are the easiest to
"fix" if required. And a simple toroid isn't going to reduce EMI enough DB to satisfy the unsatisfied; one of the
available filter networks should do it. Bruce Roe

[fresnoboy]

Here are the regs I tried to post earlier.

[SunEagle]

Here are the regs I tried to post earlier.

I am not sure why your posts keep getting stop for review. Most times it has to do with a weblink or some other component that automatically gets flagged.

[sensij]

Here are the regs I tried to post earlier.

You are running into forum software that truncates messages on characters that are not accepted. If you want to cut and paste text, you'll need to look for dashes, apostrophes, quotation marks and delete / replace them within the text editing window. The "preview" button will not show this problem.

Edit... looking at the text you are trying to replace, it looks like the "Section" symbol is what is triggering the truncation.

[fresnoboy]

Sigh...

Ok, here we go:

15.5 General conditions of operation.
(a) Persons operating intentional or unintentional radiators shall not be deemed to have any vested or recognizable right to continued use of any given frequency by virtue of prior registration or certification of equipment, or, for power line carrier systems, on the basis of prior notification of use pursuant to 90.35(g) of this chapter.

(b) Operation of an intentional, unintentional, or incidental radiator is subject to the conditions that no harmful interference is caused and that interference must be accepted that may be caused by the operation of an authorized radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator.

(c) The operator of a radio frequency device shall be required to cease operating the device upon notification by a Commission representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected.

(d) Intentional radiators that produce Class B emissions (damped wave) are prohibited.

[ 54 FR 17714, Apr. 25, 1989, as amended at 75 FR 63031, Oct. 13, 2010]

[PNPmacnab]

Speaking of Enphase, I was just given sixteen M215 modules. These were used on 280W panels. The story is that these were hit by lightning and are all bad. I think one or two may still be good. If you are ever thinking about tearing one of these apart, forget it. They are potted in a hard rubber compound. I have repaired other potted assemblies and I wouldn't mind even just using the case of these. The only thing salvageable are the MC4 connectors. I'm looking for the actual pin out of the connector itself so I can test them.

[max2k]

... The story is that these were hit by lightning and are all bad. ....

just curious- what happened to the house below the array?

[jflorey2]

Speaking of Enphase, I was just given sixteen M215 modules. These were used on 280W panels. The story is that these were hit by lightning and are all bad. I think one or two may still be good. If you are ever thinking about tearing one of these apart, forget it. They are potted in a hard rubber compound. I have repaired other potted assemblies and I wouldn't mind even just using the case of these. The only thing salvageable are the MC4 connectors. I'm looking for the actual pin out of the connector itself so I can test them.

Why not just get a cable and a panel and test them functionally?

[fresnoboy]

BTW, I see Darfon (part of the big Korean BenQ group) has a microinverter that actually outputs 300W AC instead of Enphase's 280W. Has anyone used these anywhere?

thx
mike