what to do when your solar PV installer goes out of business?

[bcroe]

As for a 700 foot line, voltage drop exists in AC or DC lines. No difference. In my case all lines are very short.
The microinverters give us MPPT (Maximum Power Point Tracking) for each PV panel, increasing yield by typically 5-20% over
simpler string inverters. String systems have had fires since panel voltages are summed and can be very high, causing arcing.

"Design is a no brainer" is a great feature, allowing easy system expansion, and module level monitoring. It is a little more work since you need to mount more inverters and wire them, but that happens very quickly. And I do not have to worry much about a neighbor's tree getting too tall and causing shading on a few panels or the effect one one panel going bad. Without power optimizers, a string inverter system has a huge output drop because of shading. Microinverter systems just generate more power than string inverters, even when power optimizers are used.

Not everyone needs be concerned with wire length. But if my farthest panel was connected to a microinverter,
the wire loop to the meter would be 1500 feet long. Running that distance at 240VAC would require twice as
much copper as running panel 360VDC for the same losses, I would NOT call that, no difference. But that is
NOT the only issue. The PoCo loves to run the line at or above the legal maximum voltage. Any drop in the
line fed by inverters adds to that, often enough causing inverter monitors to cause overvoltage shutdown. The
DC line losses do not contribute to the effect, so it is minimized by running as much of the length as possible
with panel DC voltage.

Are string systems more fire prone, where is that reported? What about all those micros each a potential fire,
especially if not individually fused?

MPPT may be a point at any given instant, but the curve running very close to that same efficiency is
somewhat broad. I have measured enough panel operating voltages to see that. The only way to approach
20% loss in a string is with extremely mismatched panels or a fault. I doubt I exceed 2% anywhere.

If shade is a serious problem, go with micros. Here I sometimes lose a string at a time sun is fading, the
overall loss is only a few percent, and micros could only recover a fraction of that. Gaining a tiny bit more
is pointless if more is burned up in the power transmission.

In my case expansion was actually easier with a string system, because no inverters or
consolidated power wire was added. Added strings aligned to peak at different times
of day may share the same inverter(s), which also happens under cloudy skies. Micros
are essentially unable to do this, resulting in much more idle equipment. Bruce Roe

[J.P.M.]

Actually, multiple points of failure are a great feature compared with a single point of failure. A single point of failure takes down the whole system. Multiple only takes out a small part of the system, which is a benefit to microinvertors.

Design and build it fit for purpose with as few components that have sufficient quality for the duty will likely produce a system with the GREATEST MTBF - that is, lower failure rate/downtime.

ore stuff, more goes wrong - but only if well designed and built in the first place.

Aside from the idea that for most users who probably look at their output about as often as they look at their electric meter - that is - not much if at all, I'd wager that a zero output system problem will probably get noticed sooner than 1 or 2 panels under producing and gesulting in a few % penalty in output, particularly after day/day out put variation due to weather.

Its' about probability. More stuff - higher probability of something going wrong.

[Ampster]

You didnt mention Rapid Shutdown compliance which will become an issue as jurisdictions implement that part of the code. So far only microinverters and SolarEdge have that capability integrated. SMA has Tigo which can be installed with most string inverters.

[mjlef]

And when an micro fails, you have to take part of the array off to get to the offending inverter. And the hardware has been out in the weather for a couple years, and not likely to easily come apart. Assuming you notice when a micro fails. Unless you monitor daily, one or two could be down for weeks and not have much of an impact on your bill, string inverter is much more obvious when it fails.

The Enphase system alerts you when a module or panel fails, production drops, or anything stops reporting. So it is always being monitored. Removing a panel is easy, just loosen the retaining bolts and slide them down the rail a bit and lift of the panel. This is all very simple and fast. No need to remove anything except lifting one panel and swapping out an inverter, which I will probably never need to do anyway. As for a 700 foot line, voltage drop exists in AC or DC lines. No difference. In my case all lines are very short. The microinverters give us MPPT (Maximum Power Point Tracking) for each PV panel, increasing yield by typically 5-20% over simpler string inverters. String systems have had fires since panel voltages are summed and can be very high, causing arcing.

"Design is a no brainer" is a great feature, allowing easy system expansion, and module level monitoring. It is a little more work since you need to mount more inverters and wire them, but that happens very quickly. And I do not have to worry much about a neighbor's tree getting too tall and causing shading on a few panels or the effect one one panel going bad. Without power optimizers, a string inverter system has a huge output drop because of shading. Microinverter systems just generate more power than string inverters, even when power optimizers are used.

Buyers of systems should examine all these issuers before deciding on what to get, but I think the huge growth in home microinverter systems is not because they better fit the needs of the customers. I certainly studied both before deciding, but then again I am an engineer and always do my "due diligence" before buying anything expensive. It sounds like you like what you have and I certainly like what I have.

[azdave]

For my system in the desert heat heat, I figured one inverter failure in 10 years versus 26 micros potentially signing off in that same time is a far better gamble. If I have to go 30 days without any PV it won't ruin my retirement. What is my time worth not to have to fight the warranty issues again and again or to be at home each time a crew comes to fix a micro when it drops out? How much is a trip charge each time they visit? It was a no-brainer for me to choose a single inverter placed in the garage.

[Mike90250]

Assuming we belive the makers, the Mean Time Between Failure of microinvertors is massively longer than the roughly 10 year life of a string inverter. Most past string invertors require replacement a couple of times during the life of the solar panels, and when they fail, the whole string.system is down.In a system with n microinvertors, a failure in one takes down 1/n of the system. Even if you never replace it it is not a big deal, but replacing them is quite easy since everything is modular. Combined with greater safety due to the lower voltages, and the ability to easily expand the system a panel at a time, and I think they are a great choice.

And when an micro fails, you have to take part of the array off to get to the offending inverter. And the hardware has been out in the weather for a couple years, and not likely to easily come apart. Assuming you notice when a micro fails. Unless you monitor daily, one or two could be down for weeks and not have much of an impact on your bill, string inverter is much more obvious when it fails.

[bcroe]

Assuming we belive the makers, the Mean Time Between Failure of microinvertors is massively longer than the roughly 10 year life of a string inverter. Most past string invertors require replacement a couple of times during the life of the solar panels, and when they fail, the whole string.system is down.In a system with n microinvertors, a failure in one takes down 1/n of the system. Even if you never replace it it is not a big deal, but replacing them is quite easy since everything is modular. Combined with greater safety due to the lower voltages, and the ability to easily expand the system a panel at a time, and I think they are a great choice.

I do not agree with any of that, I think the real reason they are popular is because the design
is a no brainer. I hate to think of all the copper to be required and the voltage drop problems
I would have if micros had to send 240VAC up to 700 feet to my meter. Bruce Roe

[mjlef]

Well that is true up to a point. In the case of a flat roof with no shade that regularly gets to 130F, the multiple electrolytic capacitors in each microinverter are going to get more stressed that the capacitors in a central inverter. That assumes the central inverter has adequate ventilation. Swapping out an single Inverter mounted on a wall can be a whole lot simpler than swapping out a couple of microinverters in the middle of a string on a roof.
I have both systems and have been fortunate to only have to swap out a couple of central inverters over the past 8 years.

Assuming we belive the makers, the Mean Time Between Failure of microinvertors is massively longer than the roughly 10 year life of a string inverter. Most past string invertors require replacement a couple of times during the life of the solar panels, and when they fail, the whole string.system is down.In a system with n microinvertors, a failure in one takes down 1/n of the system. Even if you never replace it it is not a big deal, but replacing them is quite easy since everything is modular. Combined with greater safety due to the lower voltages, and the ability to easily expand the system a panel at a time, and I think they are a great choice.

[Ampster]

Actually, multiple points of failure are a great feature compared with a single point of failure. A single point of failure takes down the whole system. Multiple only takes out a small part of the system, which is a benefit to microinvertors.

Well that is true up to a point. In the case of a flat roof with no shade that regularly gets to 130F, the multiple electrolytic capacitors in each microinverter are going to get more stressed that the capacitors in a central inverter. That assumes the central inverter has adequate ventilation. Swapping out an single Inverter mounted on a wall can be a whole lot simpler than swapping out a couple of microinverters in the middle of a string on a roof.
I have both systems and have been fortunate to only have to swap out a couple of central inverters over the past 8 years.

[mjlef]

Sorry jclimber, I wasn't disparaging the technology itself, but rather the mindless dogmatic insistence of some installers to use it regardless of circumstance. I wholeheartedly agree it has its applications, but when you have a flat roof with zero shade that reaches temps in excess of 130F for weeks at a time, I believe you're asking for trouble with multiple points of failure up there.

Actually, multiple points of failure are a great feature compared with a single point of failure. A single point of failure takes down the whole system. Multiple only takes out a small part of the system, which is a benefit to microinvertors.

[Spektre]

In my case I have some bad shading from a chimney and late in the day from a tall tree. So microinverters were the best choice to maximize power for the whole system. At the time SolarBridge (which I think now has been sucked up by a panel company) wasn't quite ready so I went with Enphase.

solar pete - I'm in Austin,TX area.

Sorry jclimber, I wasn't disparaging the technology itself, but rather the mindless dogmatic insistence of some installers to use it regardless of circumstance. I wholeheartedly agree it has its applications, but when you have a flat roof with zero shade that reaches temps in excess of 130F for weeks at a time, I believe you're asking for trouble with multiple points of failure up there.

[jclimber99]

In my case I have some bad shading from a chimney and late in the day from a tall tree. So microinverters were the best choice to maximize power for the whole system. At the time SolarBridge (which I think now has been sucked up by a panel company) wasn't quite ready so I went with Enphase.

solar pete - I'm in Austin,TX area.

[Spektre]

Yep, been saying it for years. Microinverters are a big reliability risk and servicing them is a big pain for the installers as they fail one by one entailing service trips over and over. Hasn't really been a big problem yet, but I predict a lot of dealer/installers that put these things in will be going belly up over the next few years as they get hit with an increasing level of these microinverter warranty service calls. There is a 25 year warranty on them - but they ain't gonna last no 25 years......

Solarix I really wish you'd make a trip down to North Scottsdale to do my install!!!

I totally agree with the above post, and find it surprising that here in the 'Valley of the Sun' there are several 'microinverter-only' companies. I wonder if they enjoy making service calls, or possibly use it as a mechanism to upsell; 'well your blinker fluid is low, we'll have to replace your entire electrical system'

[solarix]

Yep, been saying it for years. Microinverters are a big reliability risk and servicing them is a big pain for the installers as they fail one by one entailing service trips over and over. Hasn't really been a big problem yet, but I predict a lot of dealer/installers that put these things in will be going belly up over the next few years as they get hit with an increasing level of these microinverter warranty service calls. There is a 25 year warranty on them - but they ain't gonna last no 25 years......

[solar pete]

Forgot to say that in addition to the one panel with lower power I have another panel that is producing no power at all. This seems more likely to be a total microinverter fail so I may just call 512Solar to fix that one since the repair may be fully covered by the Enphase reimbursement (if they approve RMA beforehand).

Howdy jclimber99 and welcome to Solar Panel Talk. Its a pain when your installer goes out of business. Enphase will do what they have to, warranty wise but probably no more than that. You really do need to adopt a new installer so to speak to sort out the issues with your system. Chances are you would have had to pay your old installer a call out fee as well. I assume that you are in Arizona so you might want to check out www.dsire.org and enter your zip code to see what solar incentives are available to you, but it seems like you are doing really all that can be done at the moment.