Is LG front-contact cell technology and susceptible to cracking and corrosion ?

[J.P.M.]

Approx estimation (quick google searches on random sites, close to real retail prices):
30 LG NeON 2 315 = $9,000
30 SE Pnxx opts = $2,070
SE7600A-US = 1,526
Racking, cables, permits, misc = $5,000 (guesstimate)

= 17,596

I'm missing, labor, workman's comp (insurance), etc... + these are retail $$

Out of the bid for $28K for 9450KW, Unclear how much of the $+10.4K difference is eaten by those other expenses to make me feel good about his quote.

This conversation shows up her ~ 1X/yr. or more often. Someone suggested if they can cover the overhead and still do an equal or better install - have at it. One guy - HXguy - got so much free advice here while fixing on a bad install that he started his own solar sales and installation co.

Options: DIY, or accept that a lot of business expenses enumerated here ~ 1X/yr. are things most folks just don't understand. No one's forcing you to do business with any vendor. If you don't feel good about the prices, simply don't buy turnkey.

[JRqwertyui]

sorry, J.P.M., being a newbie to Solar, I've been able to follow your great advice, but i'm not following your comment: " This conversation shows up her ~ 1X/yr "
I'm not adverse to paying for a system that will reduce by electric bill, just verifying with the experts like yourself that I'm not getting ripped off, and that I have some appreciation for the margin the vendor I'm trusting is making... My other goal is whether I should be looking at some other combination of panels, inverter, etc... to achieve better than $2.96/W.

[J.P.M.]

sorry, J.P.M., being a newbie to Solar, I've been able to follow your great advice, but i'm not following your comment: " This conversation shows up her ~ 1X/yr "
I'm not adverse to paying for a system that will reduce by electric bill, just verifying with the experts like yourself that I'm not getting ripped off, and that I have some appreciation for the margin the vendor I'm trusting is making... My other goal is whether I should be looking at some other combination of panels, inverter, etc... to achieve better than $2.96/W.

My apologies for the sloppy printing. Change "her" to "here.

My comment refers to my anecdotal observation that about one time per year or so a poster will question why turnkey solar costs so much - after all, they just KNOW that panels can be bought for $0.50/Watt, and then point to internet sources and magazine/newspaper articles that support that price, and then start with the " - so where is this $ 3.50/Watt crap coming from - what a bunch of B.S. ripoff - I'm getting screwed - it ain't fair - robber barons of solar" kind of talk.

Then, serious and ethical vendors (and probably a few not so serious and ethical vendors as well - hard to separate the wheat from the chaff in person much less in print) post to the same thread and seem to do a pretty fair job of shredding the offended poster's logic - or lack of it.

FWIW, I claim no expertise, just seen and measured a bunch of stuff to verify what I learned and was told at some points. Nothing any reasonable person could not do for themselves. Anyway, none of us is as smart as all of us.

As for your goal of looking at other equipment: Panels have become, beyond some basic level, a commodity. Ways to get electricity conditioned from D.C. at the panel to A.C. to the house or out to the grid in safe and reliable ways (inverters) are at or close to the same state of marketing and technical development. Vendor selection has been and still is, IMO, an area most folks are ignorant of as to importance. Another is the difference between initial price and value. Buy cheap, buy twice, and that's what it seems most folks do.

A third is education. If you know how PV works, what's available and who the go to vendors are, it's a lot more difficult to get screwed. My experience is that most folks have astounding ignorance induced and allowed by astounding mental laziness and that's how vendors make their money. Education can short circuit that process. Do not rely on vendors for answers. That's letting the fox guard the henhouse. Know the answers to the questions you ask of vendors before you ask them. Doing so will get the answers to the important question: Does this vendor know enough to do what I need done in a safe, competent manner for a fair price ?

[JRqwertyui]

JSchnee21 recommends I upgrade the SE7600AUS inverter to a higher capacity unit for the 9450KW system quoted in the LG bid to avoid clipping. What technical spec should I be paying attention to on the DC input side. Oh wait, I see it,,.. "Recommended MAX DC power (STC) is 9600". I'm guessing the overhead above the labeled panel output is not sufficient. Is there a minimum wattage clipping value as well ?
Same goes for the P320 optimizers listed in the bid for the LG315N1C-G4.
i should up-size both for some additional $$$ to the quote,

[JSchnee21]

Hi JRqwertyui, let me look and see if I can find the data that suggested that the Neon2 panels MIGHT be less durable. This was based on some accelerated stability/performance testing that was done by an independent lab (forget whether it was Fraunhoffer or another lab) on behalf of Panasonic. So it very well could be biased. But, honestly, I really won't worry too much about this. Many, many people will tell you that LG panels are very good, myself included, I had been planning on getting them myself until my installer in NJ came up with some great pricing on the Panasonics and Panasonic (at that time) had beat LG to the punch on the 25yr product warranty.

As far as inverter sizing goes. What your installer has quoted is very popular and probably just fine. The DC to AC ratio is a little high for my liking (9450/7600=1.24) but that's just my opinion. Some installers spec up to 1.3 to 1.35 and again it depends on how many strings, orientation, etc. In my case (11.4kW SE) all of my panels face due South so they all reach peak together at the same time. (330*37=12,210 / 11,400 = 1.07). But if you have multiple orientations in your roof, for example, some strings will be producing more than others. In reality, having a little clipping doesn't cost you much in terms of lost production, and can help keep the overall cost of the system down potentially improving your ROI -- OR, it could just be more profit for your installer.

One key advantage of the SE7600AUS is its support for StoreEdge/Tesla Storage etc. for potential future upgrades. Which being in California on an expensive TOU might be appealing one day as battery prices fall. In my case, thanks to Fracking, and community negotiating, my PoCo generation costs have dropped every year for the past 10 yrs. We're down to 8.5cents plus another 3 or so cents for transit per kWH. So storage would never be cost effective for me, other than perhaps as an emergency backup -- for which I already have a generator.

With regard to the optimizers, what your installer has spec'ed is technically fine. The P320 handles up to 48V and 11amps which is within the spec of your LG315N1C-G4 panels (40V and 10amps). The "larger" optimizers like the P370 and P400 handle higher voltages, but the same or less current.

SE Inverters

https://www.solaredge.com/sites/default/files/se-single-phase-us-inverter-datasheet.pdf

SE Optimizers

https://www.solaredge.com/sites/default/files/se-P5-series-add-on-power-optimizer-datasheet-na.pdf

LG Panel

http://www.lg.com/us/business/solar-panel/all-products/lg-LG315N1C-G4

It sounds like your installer(s) are making sound and common recommendations. Make sure you find a shady location for the inverter. Consider the age of your roof. Consider the SE Consumption monitoring option (~$500-1000) if you want to see your personal consumption trended over time in the SE App/Website.

Are you able to offset 100% of your consumption using the 315w panels? Different folks have different views on this, but I like to offset as much as possible (ideally 100-105%) as I'm planning to get an electric car, etc. Also because I live in NJ, I get SREC's per MWh generated so the more I make, the more I make. At current market prices for SREC's (subject to change) I make more on these than on savings from my electric bill.

-Jonathan

[sensij]

A 7600 W inverter will feed into your electrical panel through a 40 A breaker. A 40 A breaker can be installed on a 200 A busbar protected by a 200 A main breaker, which is a common configuration. In that case, going to the next inverter size up probably means either upgrading the panel or replacing the 200 main breaker with 175 A, which can only be done after an engineer looks at your loads.

In other words, going from 7600 W to the next size up can be more expensive than just the difference in inverter and wiring cost. That extra expense might not be recovered by production you gain from eliminating clipping.

To get some idea of what you might be losing to clipping, you can compare your PVWatts results at a DC to AC ratio of (9450/7600)= 1.24 and at a ratio of 1.0. The ratio is entered in the advanced settings. I would run the model at 6% loss to get this clipping estimate.

I hope you see how easy it becomes to "just spend a little more" to get incrementally more output, when those marginal dollars are probably better spent on energy efficiency upgrades that would reduce your consumption and your need for the bigger PV system in the first place. Going from commodity ~280ish watt panels to the high end LG or Panasonic's is already an embedded expense in that direction, and some people can get led far down that road without consciously making that choice.

[Magius]

When considering whether your inverter is appropriately sized, you should also consider your module alignments, whether they're all facing due south, or some are facing east/west, etc. For what it's worth I have two SE-7600 inverters, one with 31 LG 320W panels (9.92 kW), and the other with 26 of the same (8.32 kW). All my panels on the former are east/west facing, while the latter has my 12 south facing panels plus the rest east/west. They end up putting out very similar output, as opposed to the 20% difference in connected STC wattage might lead you to believe. My installer did a fantastic job balancing the system - a benefit of going with the best installer in the area vs. any random solar peddler. Neither inverter has ever shown evidence of clipping to date, and I've peaked at right around 16kW combined output (8kW AC out from each 7.6kW inverter). Note too there is a setting in the SE-7600 inverter that enables it to put out 8.-something kW for short periods, so it's not a hard wall at 7.6kW and then clip. To make an educated decision, you really need to understand how the equipment all works together, and ensure the overall system design is optimized for the purpose. A larger inverter might do nothing but cost you more money in the long run, but you don't know until you work out the details. It's not simply a matter of bigger is better.

[Magius]

Vendor selection has been and still is, IMO, an area most folks are ignorant of as to importance. Another is the difference between initial price and value. Buy cheap, buy twice, and that's what it seems most folks do. A third is education. If you know how PV works, what's available and who the go to vendors are, it's a lot more difficult to get screwed. My experience is that most folks have astounding ignorance induced and allowed by astounding mental laziness and that's how vendors make their money. Education can short circuit that process. Do not rely on vendors for answers. That's letting the fox guard the henhouse. Know the answers to the questions you ask f vendors before you ask them. Doing so will get get the answers to the important question: Does this vendor know enough to do what I need done in a safe, competent manner for a fair price ?

This is a much more concise and eloquent representation of the theme I was trying to get across in my post yesterday. I was using my own personal example to show that I did not start by identifying the vendor with the cheapest price. I didn't even talk price until the very end, and I ended up not even getting a second proposal from another vendor. Instead, I first identified the vendor with the best reviews, a long track record in the industry, great customer support, etc.

Before ever contacting this vendor, I did a ton of research (big thanks to this forum's active members!), got to know how "this solar stuff" works, and did the majority of the system sizing and production calculations for my own home. I then contacted my chosen vendor, and after building some trust and rapport, I shared the work I'd already done and worked with them to refine the design. When it finally came time to talk price, I rejected their first proposal outright, told them what I wanted to pay, and supported my figures with, again, well researched data relevant to the local solar market. They were able to do the job for the price I wanted it done, and we signed a contact. It may not work out that nicely for everyone, but my main takeaway, like J.P.M.'s is that your main goal should be to become educated about solar technology, general principles of solar system design, local market conditions, etc. and be ready to support yourself in this project, rather than rely on the contractor for everything. The way I saw it, if I'm going to invest tens of thousands into something, I better darn well understand what I'm getting into. If you're the type to just trust a stranger with that kind of money you unfortunately "get what you deserve" all too often...

I will say too that at the time, had we not been able to reach an agreement on price, I was ready to walk and bring the opportunity to the "second best" or "third best" installer in town. In retrospect though, having seen the quality of workmanship performed by the company I went with, compared to some friends and neighbors who have done solar with "random cheapest installers", I'm very happy that I went with the top installer. It would have been worth a few cents extra here or there (but not a 15% premium!) to maintain the level of workmanship and support I've received.

[J.P.M.]

This is a much more concise and eloquent representation of the theme I was trying to get across in my post yesterday. I was using my own personal example to show that I did not start by identifying the vendor with the cheapest price. I didn't even talk price until the very end, and I ended up not even getting a second proposal from another vendor. Instead, I first identified the vendor with the best reviews, a long track record in the industry, great customer support, etc.

Before ever contacting this vendor, I did a ton of research (big thanks to this forum's active members!), got to know how "this solar stuff" works, and did the majority of the system sizing and production calculations for my own home. I then contacted my chosen vendor, and after building some trust and rapport, I shared the work I'd already done and worked with them to refine the design. When it finally came time to talk price, I rejected their first proposal outright, told them what I wanted to pay, and supported my figures with, again, well researched data relevant to the local solar market. They were able to do the job for the price I wanted it done, and we signed a contact. It may not work out that nicely for everyone, but my main takeaway, like J.P.M.'s is that your main goal should be to become educated about solar technology, general principles of solar system design, local market conditions, etc. and be ready to support yourself in this project, rather than rely on the contractor for everything. The way I saw it, if I'm going to invest tens of thousands into something, I better darn well understand what I'm getting into. If you're the type to just trust a stranger with that kind of money you unfortunately "get what you deserve" all too often...

I will say too that at the time, had we not been able to reach an agreement on price, I was ready to walk and bring the opportunity to the "second best" or "third best" installer in town. In retrospect though, having seen the quality of workmanship performed by the company I went with, compared to some friends and neighbors who have done solar with "random cheapest installers", I'm very happy that I went with the top installer. It would have been worth a few cents extra here or there (but not a 15% premium!) to maintain the level of workmanship and support I've received.

FWIW, I suspect you and I are pretty much on the same page with respect to design approach and vendor selection. Any eloquence is a matter of opinion, which (opinion) varies a fair amount.

[JRqwertyui]

thanks to all... beyond helpful... sensij, what is the reasoning for going to a smaller breaker, 200A to 175A... I not following you...

[JSchnee21]

Thanks @sensij for raising the busbar limitation concern as it relates to inverter sizing. For those that may not be aware, output from your inverter can be tapped into you existing PoCo electric supply either:

1) Line side -- between your power company meter and electrical panel
or
2) Load side -- by adding an additional breaker in your electrical panel itself

Load side tie-ins seem very popular here on the forum as there are lots and lots of question about them. The issue is that this install configuration could end up supplying more current to the busbars in the electrical panel (say 200 amp breaker from PoCo plus 30-60 amp breaker from inverter). This is especially problematic with bigger inverters and smaller electrical panels (<200 amps). To limit the potential current on the bus bars, the main breaker in the electric panel needs to be de-rated (aka made smaller) to prevent the potential of overloading the busbars into which the individual breakers connect.

What I don't understand is why there are so many Load side tie ins? In this an AHJ or CEC thing? My install uses a line side tie in which was no more work than a load side tie in would have been (all the same conduit, wall penetrations, etc.). It took two electricians about 3-4 hours in total to do all of the AC side wiring (DC was done by the solar company during panel installation).

Now that said, they did not cut and re-feed the 4/0 feeders between the PoCo meter and the panels main breaker (and honestly there probably wasn't enough room to do so). They used some sort of compression spike clamp to puncture into the existing feeders (think water line tap for a refrigerator). This was performed by two licensed Union electricians in NJ who routinely work for a very highly rated local installer which has done over 750 residential and 90 commercial installations in the past ~9 yrs.

While this wouldn't cut it in the commercial world to which I am familiar -- and it wouldn't have been my preference either -- but if it passes inspection (final inspection next week, fingers crossed) then I have to accept that such a practice is "good enough." I'll be sure to do some thermal imaging (IR) on the panel and wiring under full load to make sure there are no abnormal hot spots.

On the interior on my house where the panel is located, there is no visible change, on the exterior, in addition to the inverter which includes the DC disconnect, there is also an AC side disconnect and SREC meter (in addition to the PoCo meter). I'm supposed to be getting the SE Consumption monitoring kit as well . . . we'll see if they install the current sensors in the right location (-: SolarEdge's wiring diagram could be better. My understanding is that they should go between the electrical panel and PoCo meter, upstream of the line-side tap (aka export/import measurement) versus in between the line-side tap and electric panel main breaker (aka consumption monitoring). But perhaps that's the reason for the two different config settings on the inverter.

When I asked my electricians about the intended location of the current meters, they said something about putting an extra breaker in the new inverter AC output disconnect box (which is in between the inverter and line-side tap), which didn't make any sense to me as it would not be able to see either consumption nor export/import. I'll need to follow up with my installer.

-Jonathan

[sensij]

Line side taps are tightly controlled in some places. In Sdg&e territory, they would require use of a "renewable meter adapter"... Less expensive than a panel upgrade but still additional $1300+ cost.

if a line side connection can be made without incurring additional costs, great, but my point was that 7600 W is the magic number for many common panels, in the same way that 3800 W, on a 20 A breaker, is the magic number for 100 A service.

If the loads allow it, and they usually do, dropping from 200 to 175 may be the least expensive path. However, the cost of getting that change approved might still not be zero.

Again, all this is to say that just comparing inverter prices doesn't necessarily tell the whole story, and paying more to eliminate clipping (before panel degradation takes care of it for you) may not make financial sense.

On the topic of consumption monitoring, current measurement is needed for both the inverter output and the grid import. Typically, CT's would be installed between the meter and the line side tap, as well as on the inverter output circuit, ideally getting the voltage reading as close as possible to the meter to account for all wiring loss. Solaredge might just use the voltage at the inverter, though.

[JRqwertyui]

Update: i was going to pull the trigger on this LG system when it was confirmed that these panels only have a 12 year product warranty. LG warranties their production for 25 years. Due to the 12y product warranty, i stated to the vendor that was deal breaker... and should find a replacement panel with a 25 year warranty. Sunpower and Panasonic are the only panels i'am aware of that offers... am i over reacting and should consider these panels ?

When would you claim against the Product warranty that would not be covered under the production performance warranty?

[JSchnee21]

@JRqwertyui,

Yes, that's correct. The LG Neon2's only have a 12yr mfg product warranty. But the new LG NeonR's (which may cost quite a bit more when they are available for purchase and delivery -- TBD) are supposed to have a 25yr product warranty as well.

While this is one of the many reasons I went with Panasonic, the reality of the matter is that successful panel mfg claims are very, very, very rare. Not only are they unlikely, but they are a pain to prove (have to send panel to Mfg, and difficult to win. So while 25yr would be nice, I wouldn't consider it a deal breaker. You'll pay more for the "added peace of mind"

I forget the exact numbers I saw in a European advert for Panasonic but out of like 18 million HIT panels they've produced (as Sanyo) over the last 20+ yrs their reported failure rate was only like 0.00001% or so. So the likelihood of convincing them you have a bad panel is pretty remote. And hopefully it means they have a good product.

[sensij]

Individual panels cost less than $200, maybe $300 for better ones. If one breaks in year 13 and needs to be replaced, does that really seem like a financial deal breaker?