Panasonic N330 w/ IQ7X vs. LG330 w/ IQ6+

[bnjmnalan]

I've designed a 7.9 kW system for my home and the plans are at the city building department now. I sent my parts list to a few different companies for quotes. My local company sent me two quotes.

The panels I requested but they need to order: (24) Panasonic VBHN330SA16 panels & Enphase IQ7X micros inverters. $11,220
The panels they suggested and have in stock: (24) LG330E1C-A5 panels with built-in Enphase IQ6+ inverters. $9480
That's a $1740 difference! I'm not sure why the huge price difference other than $300 shipping built into the higher quote, wondering what is wrong with the lower priced parts.

What's Better, Worse, or Indifferent with the following differences:
Brand/Co.: Panasonic vs LG
# of Cells: 96 Cell vs 60 Cell
Temp Coeff: -.258% vs -.37% (I see 3 months of 95-106 temps here in Bakersfield, CA)
Efficiency: 19.71% vs 19.26%
PTC Power: 311.75W vs 306.11W
Standalone Micro inverters vs Builit-in Micros
Older Model IQ6+ vs Later Model IQ7X

Should I save the money and resubmit slightly different plans to the city or is the Panasonic setup worth the extra $$?

Also another decision is to buy local for convenience and to support local business or save $800 - $1000 in sales tax and order from out of state vendor?

Thank you in advance for any input, thoughts or advise!

[J.P.M.]

Panels have become a commodity. So, which is better ? Neither one. Once you get into known mfg. names, quality is pretty consistent across the board. Once installed by a reputable mfg., in the same location and duty, equal (electrical) size arrays will produce about equal annual output for as long as you'll likely own them. That makes all the specs/stuff you're listing much less important once the system is properly designed with one possible exception: the inverter(s).

Unless you have a big shade problem, in which case you may have poor potential for getting a cost effective installation, why micros ? Lots more electronics to fail in a hot, harsh and usually less accessible environment. No/little shade ?- skip the micros and put a string inverter in your garage. Fewer parts to fail, in a more accessible and semi controlled environment.

Bottom line: Get a better quality install. Pay more attention to vendor quality and longevity, and don't worry as much about saving a few bucks on panels or on a bunch of specs you know nothing about that will have little effect on the bottom line annual output or system performance.

[adoublee]

Does the panel maker take on the responsibility for the integrated optimizer/micro-inverter warranty? In my experience no. That means if the optimizer/micro-inverter fails, you have TWO companies to work with. I'd be happy to hear this is not the case with LG - I don't know. But there can be a downside to integrated. Otherwise, I'd take the LG.

[solys]

I just want to mention about "string vs micro-inverter" part. String inverters reduce the system's power output to that of the lowest performing panel (due to shades, dirt buildup, etc). They also introduce a single point of failure: if the string inverter is down then the whole system is down. In contrast, micro inverters individually optimize each panel's output and ensure higher overall output in cloudy days when the sunlight distribution over the panels is not cohesive. If one micro-inverter fails the system continues to operate with the rest of the micros. Furthermore, going with micro inverters makes the system modular. Say, you decided to expand your solar panel system with new panels in a year after the install. You can do it easily if you've used micro-inverters in the first place. With a string inverter, you'd need a complete system redesign.

Mod note.
You are now warned, to be very cautious about spouting random nonsense. Several very knowledgeable people have refuted every bit of your post. If you are being a shill for some vendor, you will be banned the next time you spam

[SunEagle]

I just want to mention about "string vs micro-inverter" part. String inverters reduce the system's power output to that of the lowest performing panel (due to shades, dirt buildup, etc). They also introduce a single point of failure: if the string inverter is down then the whole system is down. In contrast, micro inverters individually optimize each panel's output and ensure higher overall output in cloudy days when the sunlight distribution over the panels is not cohesive. If one micro-inverter fails the system continues to operate with the rest of the micros. Furthermore, going with micro inverters makes the system modular. Say, you decided to expand your solar panel system with new panels in a year after the install. You can do it easily if you've used micro-inverters in the first place. With a string inverter, you'd need a complete system redesign.

And yet with Micro inverters you add a failure point at every panel. Considering the heat this equipment sees you have a better chance of losing a few micros then a string inverter. Also expanding a system is not as easy as you think depending on where you live and what the rules are concerning your POCO and AHJ for pv systems.

The choice is up to the individual to decide but if there is no shade issues then IMO a string inverter is the way to go.

[Mike90250]

I just want to mention about "string vs micro-inverter" part. String inverters reduce the system's power output to that of the lowest performing panel (due to shades, dirt buildup, etc). They also introduce a single point of failure: if the string inverter is down then the whole system is down. In contrast, micro inverters individually optimize each panel's output and ensure higher overall output in cloudy days when the sunlight distribution over the panels is not cohesive. If one micro-inverter fails the system continues to operate with the rest of the micros. Furthermore, going with micro inverters makes the system modular. Say, you decided to expand your solar panel system with new panels in a year after the install. You can do it easily if you've used micro-inverters in the first place. With a string inverter, you'd need a complete system redesign.

> String inverters reduce the system's power output to that of the lowest performing panel
You have presented this so poorly, I'll blame some auto-translate

1) panels have a specification window, often + or - 5% or watts. This does not mean that an array of 6, 305w panels will be limited to only 302w because of one panel being at the low end of the spec, it means all panels will be limited to max amps the 302w panel allows to pass through.

2) Failure. When a string array fails, it's known right away. When 1 micro fails, it may be weeks before it's noticed

3) Future expansion. Always requires more permits, and growth depends on how maxed out the system was designed for in the first place.

[bcroe]

I just want to mention about "string vs micro-inverter" part. String inverters reduce the system's power output to that of the lowest performing panel (due to shades, dirt buildup, etc). They also introduce a single point of failure: if the string inverter is down then the whole system is down. In contrast, micro inverters individually optimize each panel's output and ensure higher overall output in cloudy days when the sunlight distribution over the panels is not cohesive. If one micro-inverter fails the system continues to operate with the rest of the micros. Furthermore, going with micro inverters makes the system modular. Say, you decided to expand your solar panel system with new panels in a year after the install. You can do it easily if you've used micro-inverters in the first place. With a string inverter, you'd need a complete system redesign.

The above is considerably exaggerated to simply not true. Sure micros are no brainer easy, and one solution
to an installation with shadow problems. But my system was expanded by increasing the number of panels
in a string from 10 to 12. It was further expanded by increasing the number of strings. That is not even
workable with micros, because the contract and AC wiring would exceed original peak currents, requiring
essentially going for a new additional or larger build. With strings original peak power can be maintained
with the original inverters, using the new strings to boost cloudy output, and facing them E or W to reach
peak at different time than the first.

Failures, I have 44,000 string inverter hours with none, the inverters being sheltered in a much cooler spot
than directly under a panel. If a failure does occur, it will be immediately obvious, and can easily be repaired,
at night, without working outdoors in weather on a roof. The whole wiring system for micros is more complex,
inviting wiring failures (the only kind I have experienced), running much less efficiently at lower voltage.

Given that panels in a string are fairly close together, the idea that only part of a string will have cloud cover
for a significant time is just false. And far countered by use of extra panels for clouds as described above.

And what about the Weakest Panel? Sure I do not recommend panels with different current ratings used
in series. But the negative tolerance of a batch is probably only 5%. If a 5% WP were in series others,
it would slide down its voltage curve enough to match the current of the others. The others in turn would
slide up their voltage curve to match current. Because MPP is somewhat broad, the amount of power
lost would be MUCH LESS than 5%. My own measurements of 100 panel voltages have failed to find any
imbalance worthy of action. Those bent on grabbing that last percent could sort panels so that the best
were in one string, the worst in another. Bruce Roe

[solys]

I was just warned by SPT like "beware when posting nonsense. you are warned" followed by this:
You are now warned, to be very cautious about spouting random nonsense. Several very knowledgeable people have refuted every bit of your post. If you are being a shill for some vendor, you will be banned the next time you spam

Wow, I didn't know I am such a spammy shill.

[J.P.M.]

I was just warned by SPT like "beware when posting nonsense. you are warned" followed by this:
You are now warned, to be very cautious about spouting random nonsense. Several very knowledgeable people have refuted every bit of your post. If you are being a shill for some vendor, you will be banned the next time you spam

Wow, I didn't know I am such a spammy shill.

There are honest differences of opinion around here as to the relative merits/drawbacks of using string inverters vs. microinverters/optimizer systems, with some of the chaff on each side of the discussion coming from those with skin in the game.

Most of the rest of the less helpful additions to the discussion seem to be from what are often uninformed users who mostly seem to be owners of micro equipped systems who usually appear to offer little more than repeats of what the salesperson told them, or anecdotal and parochial observations of tales of magically restored production from microinverter equipped systems that add little to nothing in the way of new and/or useful information. That's about what it seems your posts have added.

There is not a lot of side/side comparison of systems that are otherwise identical but differ only in inverter systems from which to draw any type of conclusions as to relative performance under different field conditions, climates, or perhaps most importantly different shading regimes. I don't think such data exists although it would have been more helpful to users about 10 or so years ago before residential solar peaked.

Until such data exists and it's acquired in a reliable, documented and repeatable way from unbiased sources, we'll all pretty much be doing little more than adding to the calluses on the tips of our fingers.

[jflorey2]

Wow, I didn't know I am such a spammy shill.

I don't think you were spamming - you just had strong and slightly inaccurate opinions about microinverters vs string inverters. Since we often see people here who are trying to sell solar to people, there was a risk that you were doing this to sell something. But I doubt it based on your post. (Hopefully you'll prove me right.)

Now you got some feedback. What you do with that is up to you.

[JSchnee21]

I think adoublee raises an interesting point. Very often we folks who have some issue with their ~1-5yr old residential solar systems -- either SE or Enphase -- or very rarely string if they're Sunrun, NRG, or other similar BigBox solution in which the installer has gone out of business. Frequently this leaves the residential customer in the lurch when they have an issue (like a Micro inverter failure, or SE inverter failure/issue) or other wiring / plumbing related issue.

I'm curious whether the use of "AC" panels (in which the Micro/Optimizer is part of the panel) would help, hurt, or be neutral in this case (installer out of business). For example, if you had an AC panel from a reputable panel MFG like LG or Panasonic. Would LG/Pan step up and cover the entire panel including the Micro/Optimizer? Or do they pawn you off to their "AC" partner du jour?

As we have seen in the case of SunPower, who ostensibly MFG's their own Micros that even though they "cover" the replacement, getting timely and long term resolution can be a real issue as well.

Unfortunately, "AC" panels seem like a niche/fad offering, and given the heterogeneity between different Micro and Optimizer offerings, and the fact that they are all proprietary solutions, it does make long term support a potential issue.

[jflorey2]

I think adoublee raises an interesting point. Very often we folks who have some issue with their ~1-5yr old residential solar systems -- either SE or Enphase -- or very rarely string if they're Sunrun, NRG, or other similar BigBox solution in which the installer has gone out of business. Frequently this leaves the residential customer in the lurch when they have an issue (like a Micro inverter failure, or SE inverter failure/issue) or other wiring / plumbing related issue.

In addition, when a string inverter fails, you call the installer. If he's out of business you call the inverter manufacturer. If THEY are out of business you check the specs for the array, get a new string inverter and install it. (Or call a local installer to do that for you.) You are back up and running.

Compare that to a problem with an optimizer or microinverter solution. You have to get up on the roof, pull that panel(s) and replace it with a new inverter/optimizer. What, they don't make that inverter any more? You have to see if the company has a plug-in replacement. What, they've changed the distribution wiring, or are out of business? You are SOL. (Or are checking Ebay for used ones that _might_ work.)

Or perhaps the company goes out of business. And then one day their central inverter or gateway loses communication with the panels. You are looking at a LOT of work to debug that sort of a system.

(I know, I know, SolarEdge and Enphase would never go out of business. But stranger things have happened.)

[ButchDeal]

I'm curious whether the use of "AC" panels (in which the Micro/Optimizer is part of the panel)

an AC module is one that has a built in micro inverter NOT an optimizer. An optimizer would NOT make AC

[Abe317]

I've designed a 7.9 kW system for my home and the plans are at the city building department now. I sent my parts list to a few different companies for quotes. My local company sent me two quotes.

The panels I requested but they need to order: (24) Panasonic VBHN330SA16 panels & Enphase IQ7X micros inverters. $11,220
The panels they suggested and have in stock: (24) LG330E1C-A5 panels with built-in Enphase IQ6+ inverters. $9480
That's a $1740 difference! I'm not sure why the huge price difference other than $300 shipping built into the higher quote, wondering what is wrong with the lower priced parts.

What's Better, Worse, or Indifferent with the following differences:
Brand/Co.: Panasonic vs LG
# of Cells: 96 Cell vs 60 Cell
Temp Coeff: -.258% vs -.37% (I see 3 months of 95-106 temps here in Bakersfield, CA)
Efficiency: 19.71% vs 19.26%
PTC Power: 311.75W vs 306.11W
Standalone Micro inverters vs Builit-in Micros
Older Model IQ6+ vs Later Model IQ7X

Should I save the money and resubmit slightly different plans to the city or is the Panasonic setup worth the extra $$?

Also another decision is to buy local for convenience and to support local business or save $800 - $1000 in sales tax and order from out of state vendor?

Thank you in advance for any input, thoughts or advise!

Hi bnjmnalan,

Can you share your experience with the brand you finally selected? I installed a 27 panel system in 2018 using LG330E1C-A5.

I personally prefer the LG AC modules for several reasons:

1) Simplified installation with LG AC module - inverter already mounted on back of panel and wired to panel DC output.
2) Enphase provides one-stop warranty support for both inverter and panel - no finger pointing. 25 Year warranty for both panel and inverter.
3) The panel and inverter are matched by design so losses are minimized
4) LG