intermittent power loss on some panels

[Lyons77]

I'm having some problems with a new SunPower system with M-410 panels. Shortly after installation, one of the panels started reporting 0 power generation at random intervals. Five months later, a second panel has started doing the same thing. The pattern seems to be random, not every day, and it can be midday, afternoon, sometimes just a few hours during the day. I see there was an old thread on micro-inverter failures on SunPower panels in 2018. Is anyone else having this problem with SunPower panels?

My installer is investigating this but it is taking a long time to get resolved.

[J.P.M.]

My installer is investigating this but it is taking a long time to get resolved.

5 months ? W.T.F. !
I've got a Sunpower system - had it for going on 11 and their support truly sucks, but I've found the old idea of the squeaky wheel getting the grease holds true with them. Nothing can replace persistence. Just keep it professional, daily and do it yourself on the chance that the installer is being less than candid about his due diligence.

BTW, has the installer identified the source of the claimed problem ?

[Lyons77]

It was two months before I noticed the issue, so only 3 months working on repair. The installer came out, and SunPower asked them to take pictures of the back of the panel, and I'm still waiting on the results. When it was only one panel with a problem less than 1/3 of the time, I was not overly worried, but now that a second panel has the same issue, I'm wondering if the micro-inverters are defective, and hoping to find out if others have had problems with the SunPower M-410 panels.

This also highlights the need for the homeowner to monitor system's energy generation. SunPower has a nice app to display generation, but apparently neither SunPower nor the installer monitors the system to see if there are problems.

5 months ? W.T.F. !
I've got a Sunpower system - had it for going on 11 and their support truly sucks, but I've found the old idea of the squeaky wheel getting the grease holds true with them. Nothing can replace persistence. Just keep it professional, daily and do it yourself on the chance that the installer is being less than candid about his due diligence.

BTW, has the installer identified the source of the claimed problem ?

[J.P.M.]

It was two months before I noticed the issue, so only 3 months working on repair. The installer came out, and SunPower asked them to take pictures of the back of the panel, and I'm still waiting on the results. When it was only one panel with a problem less than 1/3 of the time, I was not overly worried, but now that a second panel has the same issue, I'm wondering if the micro-inverters are defective, and hoping to find out if others have had problems with the SunPower M-410 panels.

This also highlights the need for the homeowner to monitor system's energy generation. SunPower has a nice app to display generation, but apparently neither SunPower nor the installer monitors the system to see if there are problems.

Only 3 Months ? 3 days would be more like it for a diagnosis after a service call from the vendor.
As for monitoring, if you expect monitoring, my opinion is that to get it done reliably, you'll need to do it yourself.
Vendors saying "We monitor your system" seems a bit of a stretch to me, particularly with more and more installers crapping the bed.

Sunpower had pretty good monitoring when I got my system, all voltages, currents power outputs and other info including monitor information in 5 minute increments.
But that changed about 6 or so years ago and they stopped supplying most of that info.
I suspect cost had something to do with eliminating that detail, but I also suspect limiting the info to end users had more to do with keeping those mostly solar ignorant users from calling installers and Sunpower every time they (the users) saw something that looked like but was not a problem.

[Lyons77]

So, I got this response from SunPower on the bad panel:

Based on our checking, the system encounters high voltages ranging from 250-262V from time to time.

With this findings, RMA will not be process as the reason why the MIs are not producing is because of the said issue.

As per our recommendation, please check with the utility regarding the voltages onsite.

If the problem is high voltage with the utility, why would it only affect one panel?

[azdave]

So, I got this response from SunPower on the bad panel:


If the problem is high voltage with the utility, why would it only affect one panel?

My guess would be that the micro inverters have tolerances and maybe you found the one that is most sensitive to over-voltage? If it goes up a few more volts maybe another one or two might reveal themselves as well. What do I know, I have a simple string inverter in the garage.

[bcroe]

What might happen, is the inverter most sensitive to high voltage
trips first. But that lowers the current being pushed back into the
line, causing less voltage built up in the local wiring, and the rest
might stay on.

Certainly do petition the PoCo to maintain a within range voltage
at the entrance. And determine how much higher the line voltage
is at the micro inverter output for max power. If your own wiring
is part of the problem, you might be able to up the gauge several
numbers to minimize it. 3 years ago I buried a 4/0 aluminum run
to replace a 4 gauge, lowering my back voltage about 7V, and
lowering max loses from 540W to 125W. good luck, Bruce Roe

[scrambler]

In the case this is a grid voltage issue and not just a micro inverter going bad, you should check if the solar monitoring system in place monitors grid voltage, and if it does, it would be easy to see if the panel going down correspond to a high or low grid voltage event.

If not, there are devices you can get to either monitor and record grid voltage, or at least detect overvoltage.
You can also ask the utility company to put a recorder for a period of time.

[Lyons77]

Thanks all for the info and advice. I'll check in with my installer and see if they will work with the utility company, or if I need to do it.

[oregon_phil]

I couldn't find a Sunpower document on microinverter voltage rise but Enphase has a document titled "calculating-ac-line-voltage-rise-tech-brief" that explains design issues that might impact voltage rise.

You should have a schematic of the solar installation. Identity which panels on your schematic that are occasionally faulting.