Sunpower system performance

[lockem]

I am having trouble with the performance of my Sunpower system. This started after an FW update that was installed last year as part of a snow-damage repair.
Before the damage, my 14 panel on grid microinverter system installed in the high desert (where solar intensity is between 108% and 120% of standard conditions) would report 5.16kW power produced in full sun. This is perfectly aligned with the 366VA rating marked on the microinverters.

With one panel destroyed, the system reported 4.8kW in full sun.

With the broken panel replaced, but the FW updated, the sunpower monitoring system reports 4.38kW in full sun.

I made some independent measurements:
20.84A * 247 V => 5.147kVA
However, the SCE power meter with all breakers in the house tripped shows -4.3kW power consumption

The difference must be caused by a steep-ish power factor of 0.83

The inverters are also marked 1.45A max each and 14*1.45 = 20.3A, so measured current is a little higher than the max rated current.

So is this behavior expected and the FW update changed reporting VA as W to reporting W properly? Or did the update reduce the max current the microinverters to their rated specification?

Is anybody else having a similar issue?

[lockem]

Shortly after posting this, Sunpower updated my system (a total of 6 months waiting for this) and it now is reporting normal power production. I need to make some power and VA measurements to see if they actually fixed anything, or if they are just "fudging" the numbers.

I did double check SCE power meter readings as reported on my power bill and see that according to the SCE power meter the pre-messed up system was producing 5.16kW, not 4.3kW.

[Raymond Enriquez]

I did encounter some issues with my solar power before, fortunately I was able to resolve it through the help of the company.

[Raymond Enriquez]

It might be worth reaching out to Sunpower or try consulting with a solar technician familiar with their systems for potential solutions.

[lockem]

It might be worth reaching out to Sunpower or try consulting with a solar technician familiar with their systems for potential solutions.

Try one was to contact the installer (they did not know and had not observed this behavior with any of their other installations). Try two was to ask the installer to get some information from Sunpower (nothing useful provided). Try three was for me to call Sunpower (Sunpower provided a mix of stonewalling and misinformation); I ended up close to yelling at them on the phone due to their stonewalling and/or incompetence.

Sunpower insists:

System is performing adequately.
It is only an instrumentation problem.
Snow cannot possibly increase solar yield.

Of those, the only item that is true is that even crippled the system is producing more power than Sunpower expects, but that is because of my location and not because of the Sunpower equipment.

I do keep in mind that it is quite possible that the people who answer the phone and their supervisor really are not knowledgeable, so were literally unable to answer my questions and made up answers in an attempt to keep me happy.

Some other Sunpower issues:

At least for me, "MySunpower" records that are more than 3 months old are reduced to once an hour readings rather than the every 5 minute readings in "fresh" records. This hides details that may be needed to "see" problems relative to historic performance.

The microinverters are rated 350VA continuous, 366VA max. Sunpower cannot tell me if running the inverters at 366VA for hours at a time is likely to cause reliability issues.

Sunpower claims that they opened a problem report regarding the peak power issue, but nothing showed in "MySunpower".

[lockem]

So I finally got up here with the sun shining, and VA ~= W, unlike before. Sunpower called this a reporting problem, but it is clear that they fixed something in the microinverter to correct the power factor/current phase.

If you have Sunpower or other enphase microinverter equipped panels (I was told that Sunpower branded microinverters are still the same design as enphase, licensed from enphase), I recommend that you check your power factor and see if you are getting ripped off by the microinverter. My procedure to estimate power factor was:

Wait for the middle of a sunny day with constant max power production (adjust the TOD as needed if your panels are not oriented well). Make the measurements in as rapid a succession as possible.

Use a clamp ammeter to read the AC current = A produced by the solar system.
Use a DVM to read the AC voltage = V at main panel.

Trip all circuit breakers except the solar system breakers. Turning stuff off is not sufficient, as AFCI and GFCI breakers draw power and it is really hard to find all of the hardwire constant power draws in a typical residence.

Check the power production shown on your power meter = W. Of course this only works if you have a power meter and if you have the only load on that meter. On my meter this will show as a negative number on the digital display. If you have an electro-mechanical meter that only measures watt-hours you will need to make a timed measurement over several minutes and adjust for the elapsed time.

Compare V*A to W. They should be pretty close if your microinverters are working properly.
V*A < W indicates an invalid measurement.

Going out on a limb, I say if W/(V*A) < 0.95 you have a clear problem that the inverter manufacturer should address.
Another forum member indicated that W/(V*A) < 0.99 indicates an issue.