Is Sunpower price difference worth it? -- thoughts, posting as new topic

[littleharbor]

You did say that they are the only company that cuts 5% out of the corners. Where did you get that data?

[LLB]

You did say that they are the only company that cuts 5% out of the corners. Where did you get that data?

I see you havn't gone to post #73 yet.

[LLB]

I got it from my humorous bone. Try it, you may like it. It was suppose to be the hint to make it clear it was a joke.
I guess the joke is on me.

[littleharbor]

Not an isolated incident No, I don't have the only ones.

http://guntherportfolio.com/2013/03/new-sunpower-solar-cell-discoloration-anomalies-at-the-photovoltaic-demonstration-project/

[LLB]

Not an isolated incident No, I don't have the only ones.

http://guntherportfolio.com/2013/03/new-sunpower-solar-cell-discoloration-anomalies-at-the-photovoltaic-demonstration-project/

Your getting a little to cryptic for me. I'm not following you.
That link has nothing to do with the pictures you posted. What is that story? It looks to be a whole roof worth of SP panels and every single cell is orange. How come you don't want to talk about that?

This new link that's 5yrs. old that has 3 cells in Palo Alto...who cares. When your the big dog everyone wants to knock you off the hill. If LG was on top there would be extra people gunning for them.

You aren't showing us anything that can't be found with LG or Pana as well.
Show us a report of a multi-million dollar SP farm were a extra-ordinary amount of panels went bad.

[littleharbor]

Your getting a little to cryptic for me. I'm not following you.
That link has nothing to do with the pictures you posted. What is that story? It looks to be a whole roof worth of SP panels and every single cell is orange. How come you don't want to talk about that?



This new link that's 5yrs. old that has 3 cells in Palo Alto...who cares. When your the big dog everyone wants to knock you off the hill. If LG was on top there would be extra people gunning for them.

You aren't showing us anything that can't be found with LG or Pana as well.
Show us a report of a multi-million dollar SP farm were a extra-ordinary amount of panels went bad.

If I could find the source of the photos I would. Don't remember where I got them, Oh well...Point is it DOES happen. I'm not saying an extraordinary amount of their panels have failures.

,

As far as being the "Big Dog"

well everybody has their opinion. I don't own a Sunpower system, wouldn't own one and don't have to justify overpaying for one. That's MY opinion. Got better things to do now than bicker about who's the better panel MFG. Enjoy your day.

[J.P.M.]

Hmm, I wonder if those cut corners amount to 5%? Need some dimensions to do the
calculations. Bruce Roe

Bruce: Based on what I measured, the S.P. 327's on my roof have cells that are ~ 124 mm square, giving a gross square area of 15,376 mm^2 before the corner triangles are removed. The removed triangle at each corner has a side of ~ 11.9 mm, giving an area for each (removed) triangle of ~ 71mm^2, or ~ 283 mm^2 for all 4. That would give the lost area of the triangles as a % of a square cell as : 283/15,376 = ~ 1.8%. based on cell area alone.

A Sunpower panel has a gross area of 1.63 m^2 based on spec sheet dimensions of 1558 X 1046 mm. So, based on gross panel area, cell area is ~ (15376-283)*(96)/1630000 ~ 0.889 of the gross panel area. That jibes reasonably well with the published spec sheet data that was in effect when my array was installed that lists a cell STC efficiency of 0.225 and an STC efficiency based on panel gross area of 0.2006/0.225 = 0.892

But, as we all know, most all arrays of equal (electrical) size will, in the same service, location and orientation, produce about equal or vary similar annual output. Smaller (physical) size arrays of the same (electrical) size as other arrays using less (area) efficient panels will have one (possible) advantage - taking up less real estate by virtue of a smaller footprint.

Bottom line example: All 5 kW arrays that are competently and professionally installed in the same place and orientation will produce about equal output for probably longer than most folks will own them.

To LLB: Sunpower stuff is good, but no more fit for purpose than other quality PV equipment. S.P. comes with what may be important to the solar ignorant, and therefore needs no further justification: bragging rights, but with little else to justify the premium. S.P.'s success is more than a bit due to their advertising and hype which many see as disingenuous and full of misleading innuendo and hype. Also seems to me that informed folks often see the S.P. B.S. for what it is sooner than others who are less informed. FWIW, thank you for buying S.P. I made a tidy profit owning their stock based partly on the belief that no one ever lost a dime betting on the ignorance of the general public - in this case, and IMO only, but an opinion that seems to be shared by more than a few informed people, the price was run up by folks swallowing the S.P. hype.

[bcroe]

Bruce: Based on what I measured, the S.P. 327's on my roof have cells that are ~ 124 mm square, giving
a gross square area of 15,376 mm^2 before the corner triangles are removed. The removed triangle at each corner has a
side of ~ 11.9 mm, giving an area for each (removed) triangle of ~ 71mm^2, or ~ 283 mm^2 for all 4. That would give the
lost area of the triangles as a % of a square cell as : 283/15,3765 = ~ 1.8%. based on cell area alone.

Thanks for doing the calculations, I like your 1.8% a lot better than 5%. Bruce

[LLB]

Thanks for doing the calculations, I like your 1.8% a lot better than 5%. Bruce

and from #98
"...I personally have a couple of the same failed panels in my possession..."

littleharbor
I thought in the quote above you said you had some of these panels or panels that looked just like them? So just some random picture from the net of some "not even sure if they're dead" SP panels. I'm sure I can't similar pictures of LG or Pana, that seals it, I hate SP they're a much of liars.
Seems my version of the story is more likely than yours, since you're not providing one that is. The picture is more likely from 1970, improperly designed system in the Salton Sea area, that's my story and I'm sticking to it.

And the dealers should take the fall, why should SP? The dealer decides so many things SP has no control over; which inverter, panel location, electrical runs, grounding, etc...

Bruce / JPM
Can JPM or Bruce explain what we learned or the reasoning for doing the math? Obviously it doesn't matter mono to mono as my joke might have been misconstrued as meaning. So were you guys figuring out what advantage poly had in surface area (1.8%) and if it moves the needle in any significant way?

Also I have been meaning to say I think the old guards attitude towards SP has been misguided as I think it is really the installers markup that upsets them. Obviously SP doesn't paint the installer into a corner forcing them to charge higher prices, because we hear of some SP installers (granted not enough) bidding with a reasonable premium. That alone puts it squarely on the installer in my eyes. Again websites assisting in transparency are the key.

What I think I'm resenting is this "don't buy SP" attitude or as some like to say only the ignorant buy SP. When in reality they contradict themselves by saying they make a solid product, its just "they" feel SP stretches the marketing too much. Yet deep down if a newb comes along and says I have 2 bids one from SP and the other "X", they are the same price who should I go with, I think they would say, "you can't go wrong with either of those manufacturers, its the reputation of the installer you want to consider."

You can try to bring bad customer service into this, but to that I say manufacturers are just that. Their job is to provide a quality product (high QC and materials) and brand recognition (marketing). The customer service they outsource (pay for) to the dealer, so lets leave it out. Just because you bought a Ford doesn't mean you get to call the factory and ask questions. They would likely ask you which dealer you bought it from and send you packing. If you picked a bad dealer like I did, then thems the breaks. (It just seems a un-proportionately high percentage of them are bad -from all manu., not just SP) but that's a systemic industry money-grab problem for another day.

[littleharbor]

Tell you what, I'll pull out the panels I have and have already explained the history on and take some pics just for you. See you Tuesday.

[Mike90250]

My feeling of the gist of this, is unless you are really tight on space, and need the extra % that SP offers, they are over priced, with lotsa technobabble in their sales pitch

[J.P.M.]

and from #98
"...I personally have a couple of the same failed panels in my possession..."

littleharbor
I thought in the quote above you said you had some of these panels or panels that looked just like them? So just some random picture from the net of some "not even sure if they're dead" SP panels. I'm sure I can't similar pictures of LG or Pana, that seals it, I hate SP they're a much of liars.
Seems my version of the story is more likely than yours, since you're not providing one that is. The picture is more likely from 1970, improperly designed system in the Salton Sea area, that's my story and I'm sticking to it.

And the dealers should take the fall, why should SP? The dealer decides so many things SP has no control over; which inverter, panel location, electrical runs, grounding, etc...

Bruce / JPM
Can JPM or Bruce explain what we learned or the reasoning for doing the math? Obviously it doesn't matter mono to mono as my joke might have been misconstrued as meaning. So were you guys figuring out what advantage poly had in surface area (1.8%) and if it moves the needle in any significant way?

Also I have been meaning to say I think the old guards attitude towards SP has been misguided as I think it is really the installers markup that upsets them. Obviously SP doesn't paint the installer into a corner forcing them to charge higher prices, because we hear of some SP installers (granted not enough) bidding with a reasonable premium. That alone puts it squarely on the installer in my eyes. Again websites assisting in transparency are the key.

What I think I'm resenting is this "don't buy SP" attitude or as some like to say only the ignorant buy SP. When in reality they contradict themselves by saying they make a solid product, its just "they" feel SP stretches the marketing too much. Yet deep down if a newb comes along and says I have 2 bids one from SP and the other "X", they are the same price who should I go with, I think they would say, "you can't go wrong with either of those manufacturers, its the reputation of the installer you want to consider."

You can try to bring bad customer service into this, but to that I say manufacturers are just that. Their job is to provide a quality product (high QC and materials) and brand recognition (marketing). The customer service they outsource (pay for) to the dealer, so lets leave it out. Just because you bought a Ford doesn't mean you get to call the factory and ask questions. They would likely ask you which dealer you bought it from and send you packing. If you picked a bad dealer like I did, then thems the breaks. (It just seems a un-proportionately high percentage of them are bad -from all manu., not just SP) but that's a systemic industry money-grab problem for another day.

I was simply responding to Bruce's question. We, or at least I, learned that the removed area of the triangles = ~ 1.8 % of a square of 15,375mm^2 area. It doesn't prove anything.

As for being upset (if I'm the old guard), I'm not, particularly upset about vendor markup. Those who can DIY can save a bundle. Vendors have costs that ignorant and simple minds do not have a clue about. One of the few things that does piss me off is ignorance, especially when coupled with arrogance, and especially so when it leads to waste.

Sunpower is a good product. It is just not worth a premium price. That price is not supported by process economics or life cycle costing methods when compared to the cost and reliability of other equally fit for purpose equipment that costs less.

Among lots of things and among many mfgs'. and vendors' practices that I've got problems with, to the degree Sunpower uses peoples ignorance to get a marketing advantage in ways I believe to be unethical and then extract a premium when one cannot be logically justified pisses me off. They are not alone in such practices by any means, but they do seem to have, IMO only, raised it to the level close to that of an art form. To my personal experience, and similar to what can be read on this forum most any day, most who consider and then later buy S.P. over other equally fit for purpose equipment are woefully ignorant of what they are doing, and that ignorance is, IMO only, what S.P. preys on. Most buyers are marks wasting a lot of money buying any PV before other, more cost effective measures that aren't as sexy, but that's a separate issue.

I'm the guy on the HOA Arch. Rev. Comm. that reviews and recommends member solar energy system proposals to the entire comm. for approval and installation. There's a pretty high solar penetration in this HOA: ~ 120 homes out of ~ 550 that have PV. I know all 120 systems on something bordering on intimately. I reviewed each one, spoke with each owner and vendor, watch each installation and spoke with the AHJ for each install. Of those 120 PV systems, 24 use Sunpower panels (including - GASP ! - mine). I also, with the help of cooperative neighbors, monitor about 10 or so of the systems with 3 of them S.P., a few LG's and a couple other panel mfgs. Those systems have orientations similar to mine. All those systems , as best as I can figure it, produce about the same output as mine per STC kW.

The 120 systems in the HOA probably have about 2500 or so panels between them. After 8 yrs. of monitoring things, probably less than perfectly, 1 panel has failed. It was a Sanyo and it died of infant mortality about/less than a week after install. All other ~ 2500 panels are, to the best of my knowledge, operating nominally - S.P.'s and everyone else's . One string inverter needed replacement. Several string inverters have needed service, and maybe a dozen micros, probably/mostly Enphase 190's I think, have failed. There have been a few wiring issues that have been resolved, all early on after install. There have been no big monitoring issues that I'm aware of, probably because most folks in this HOA, being of the old guard, could care less about such things. The S.P. vendors run from among the best to mundane.

Service, when needed is generally best from local vendors as are the installations, although installs are not always perfect. The big, national lease outfits are hit/run, blow & go nightmares for installation.

Most all owners/lessors/PPA users of PV systems in my HOA are ignorant of what they purchased. Those who bought S.P. all 24 of them it seems, sing one tune - and it sounds just like yours: Highest efficiency, best warranty, etc., and after talking to all of them, as neighbors and friends, I'm quite sure none of them have much of any understanding of what they are saying. If I suggest that most every system produces about equal annual output per installed kW regardless of panel, the S.P. owners usually become indignant and what looks to me to be defensive, and display an attitude and opinions that, to me seem not unlike yours. That's understandable to me in many ways, one such way being as a denial or defensive response to avoid the reality of acknowledging a mistake. I have suggested they not take my word but simply check PVOutput.org and offer to help understanding what it has to offer. No takers so far. Only a lot of denial of reality, or at least what looks like reality to me.


Take what you want of the above. Scrap the rest.

No neighbors were harmed in the making of this post.

[bcroe]

Bruce / JPM
Can JPM or Bruce explain what we learned or the reasoning for doing the math?

Determining better accuracy requires no justification. Bruce Roe

[LLB]

Determining better accuracy requires no justification. Bruce Roe

Bruce sorry my query came across the wrong way. Just because I was being spicy with littleharbor (which I assumed was all in fun-apologies to littleharbor while I'm at it) doesn't mean I can't have serious conversations at the same. I was hoping to get more details about the pics you posted on using my identical strings to see if I can tease out if my stepped on panel is under-performing. No worries I will read the post again and certain your explanation was clear enough to figure it out.

It was a serious question and I take your answer to be "curiosity/accuracy". I was certain there was going to be something about poly panels having x amount of more surface area in their modules, making them possibly even a less cost effective choice to mono than previously thought. Obviously 384 (96x4) triangles are going to add up to a few more square inches of real estate, but not enough to make a difference because of polys lower efficiency I'm guessing.

[LLB]

I was simply responding to Bruce's question. We, or at least I, learned that the removed area of the triangles = ~ 1.8 % of a square of 15,375mm^2 area. It doesn't prove anything.

As for being upset...

No neighbors were harmed in the making of this post.

Apparently posts can only be 11,000 words so I'm going to have to break this into 3 posts.
What a nightmare this is to upload. This editor will not take quotes or apostrophes or the three dots after etc, finding more all the time.

From 2015 when I started reading your posts I thought for certain you were some 30-40yr. electrical engineer solar veteran. Who had worked for multiple big brand name companies, knew all the back room conversations and dirty laundry of the solar industry. And now I find out you do not like (despise) SP because the 3 (one being yours) installations you know of that do not out-perform the others like you think they should, because of their marketing techniques. Crikey! You are going to make me pull an all-nighter here because now I have a few things to say/show. Starting with your comment about ignorance, seriously? Ignorance pisses you off? Arrogance sure, but ignorance?

You do know the definition is (a lack of knowledge) it is not laziness, more accurately it is (individuals who do not deliberately ignore or disregard important information or facts). You should feel empathy for them not admonish them. Basically everyone who does not research things as much as you do, you get mad at. I think you might be in for some disappointment. I think you should have stuck with, I hate SP because I think their marketing is unethical and deplorable. I am fine with that, you can have that opinion all day. But to brow beat the newb and then put on the halo of IMO. Nope does not fly with me, not imho.

Believe it or not I hope to make you feel better, because I think you are mad at yourself for buying SP and not getting the performance you thought you should have received. I hope to show you that you did not make as bad a decision as you think you did. I think as the years roll on and your panels hold up better than your neighbors it will be more obvious. But hey, are not these forums great were we get to agree to disagree.

To everyone else who came here because of the title and are still trying to get to an answer, please read on.

I am attaching a few files that I pulled the following info from (2013 NREL, 2013 IEEE conference, Panasonic-HIT 2018, SP Maxeon X/E Gen 2, 3 2013 )

I am just going to do it bullet style, otherwise this post would be 100 pages and no one wants to read that.

These are all the points I was hoping to find and discuss in this forum. Many the original OP brought up and according to my searching of this forum was always met with, IMO Anyone who knows anything and most on this forum, about SP knows they are not worth the hype, its only for the ignorant, sucker born every minute, that is why I bought the stock and did well, etc.

I judge a person by their actions, not their words. I saw no action/facts, just words/opinion.

If any of the snippets peak your interest you might find it worthwhile to look at some of the attachments.

Before I get started I will say I do not like how SP compares their best mono panel to probably a 5yr. older poly panel, but they do state that fact in their document. Also the SP doc is simply a more in depth discussion but definitely not a brochure that is handed out (61pgs.) And they do use some adjective that I would not use, but I do not think it is anywhere near as bad as JPM makes it out to be. I mean seriously would you say you product is a little bit better or your product is measurably better?

I also think they stretch the degradation numbers to the legal limit. They often say conventional panels are .5 to 1.25% and that they are .25%. NREL says mono panels are ~.5% and poly are ~1%.

I think every time SP says conventional you have to think poly, because your brain is going to keep thinking LG/Pana 330 mono and that would be wrong.

So except for some marketing vocabulary and the degradation numbers I think they make the most durable, resistant to fatigue cell out there and it is worth a reasonable premium, less than 10%.

I just do not think it is a commodity like iron or nickel. Even a hot water heater (the closest thing I can think of that should be priced like a commodity is not. You find different prices at HD and Walmart, etc. Why is solar equipment any different? Maybe it should be, but it is not.

OK, lets get started, apologies in advance for formatting issues.

- A 2013 study at the National Renewable Energy Lab (NREL) found that the primary underlying causes of module failures in the field were due to cell/interconnect breakage (40.7%), and corrosion (45.3%)

This is one of the main papers that the SP paper references.
Validation of the PVLife Model Using 3 Million Module-Years of Live Site Data 2012
Ernest Hasselbrink, Mike Anderson, Zoe Defreitas, Mark Mikofski, Yu-Chen Shen, Sander Caldwell, Akira Terao, David Kavulak, Zach Campeau, David DeGraaff

I included this because it is an independent 3^rd party reference.
NREL Photovoltaic Degradation Rates - An Analytical Review Dirk C Jordan and Sarah R Kurtz 6/2012 51664

I hope somebody finds LG, Panasonic, Canadian Solar, etc, equivalent papers. I could not find any.

Some 3^rd party info first.

Failure Rate Data

In addition to degradation rates, failure rates are another important concern. SunPowers installed fleet has not been in the field long enough to provide a good basis for validation, so we shall not attempt to validate PVLifes failure models in this paper. Nonetheless, SunPower, Powerlight, and Tenesol (another front-contact module manufacturer that SunPower acquired in 2012) have significant installed fleets, and a Pareto of failures from these fleets may lead to some insights about what modes cause earlier-than-expected module failures, providing motivation for future modeling.

SunPower is in the unique position of having purchased two companies which deployed Conventional Modules. PowerLight was a project development company which installed 240 MW of modules from 20 different manufacturers before it was bought by SunPower. This fleet has an average age of 6.7 years, and has a failure rate of 8,700 warrantable returns per million modules installed, nearly 1%. SunPower also purchased a relatively high quality European Conventional Module manufacturer (Tenesol) which had installed over 500 MW. This fleet has an average age of 4.6 years and has a failure rate of 1,450 returns per million or 0.14%.

Some general comments and observations on the fleets studied and the overall return rate:
- The overall return rate for the front-contact (FC) fleet is approximately 0.44%, compared to less than 0.005% for the Maxeon II fleet.

- The FC fleet is comprised of about 0.8M modules installed by Powerlight (average age 6.8 years), and 2.6M modules installed by Tenesol (average age 4.3 years).

The weighted-average age of the entire front-contact fleet is 4.9 years.

The Maxeon II fleet is comprised of >8M modules, with an average age of 2.1 years. Thus the Maxeon II fleet is significantly younger (and of a newer design) than the FC fleet. However, given only a 2.3X difference in age, the nearly 100X difference in return rate is remarkable.

Investigating the data for each failure mode in turn, we note the following:
- For the FC fleet, laminate cell/ribbon/solder failures (primarily cell interconnections) dominate the Pareto, resulting in about 66% of returns.

- For Maxeon II, the return rate is more than 1000 times lower for this defect type. We believe this is likely due to significant design differences in cell interconnection.

In particular, (a) FC interconnects are two or three ribbons that connect the backside of one cell to the front side of the adjacent cell. In contrast, the SunPower interconnect is a wide tin-coated copper bar and has cutouts for strain relief. This additional copper can conduct heat away from the cell and the solder joints in case of temporary reverse bias [10]. (b) SunPowers cells have an on-cell busbar which can redistribute current evenly, in event of a solder joint failure in any of the 3 solder pad connections, providing double redundancy.

- For the FC fleet, backsheet and encapsulant are the next largest return category, with about 22% of returns. We note the FC returns are dominated by one particular type of module. The returns data indicate about 1 per million for the Maxeon II fleet attributed to this defect.

The remaining modes have relatively low failure rates, under 100 per million in total. Glass damage has a return rate of ~40 per million. The SunPower Maxeon II fleet has a rate of only 2 per million; in both cases the statistics are based on a relatively small number of observations. FC and SunPowers modules both show very similar low (30 DPPM) failure rates for J-boxes, diodes, and cables. Cell failures, that is, electrical failures that lead to damaged modules, are only a few per million for both the FC and SunPower Maxeon II fleet.

There is reasonable agreement between the Pareto from our FC fleet and those found by previous researchers [11-12]. Wohlgemuth et al [11] found 86% of failures could be attributed to either corrosion (45.3%) or interconnect failure (40.7%). Kato [12] found that 28 out of 32 systems (88%) in a field survey of residential systems of approximately 10 years of age had at least one module in the system exhibiting evidence of solder bond or cell interconnect ribbon failure.

Unlike Wohlgemuths data, our Laminate (cell/ribbon/solder) category does not distinguish corrosion damage from fatigue damage, thus it makes sense to compare our value (66%) with his combined value for both corrosion + cell or interconnect failure (86%, classifying both as metallization damage).

Conclusions
We believe the data analysis method (median YOYPIX) used in this paper is a powerful technique that has significant advantages for proving system degradation rates to investors.
In particular, the methods key advantages are:
- It uses data from real-world systems, and measures system-level AC-power production
- It is tolerant of data acquisition failures and other practical realities of real-world systems
- It is unbiased, and minimal data scrubbing is necessary
- It derives a median degradation rate with low uncertainty, given a sufficient number of sites.

Summary: Design Differences
SunPower modules have several intrinsic differences over Conventional Modules which result in superior resistance against real world stresses.
- The use of n-type silicon prevents early degradation due to LID.
- The thickly plated, tin coated copper foundation of the Maxeon cell is highly resistant against the forces of moisture and oxidation.
- This metal foundation allows for thinner, more flexible silicon, resulting in a cell which can withstand repeated snow and wind loading and can crack without significant power loss.
- Electroplating the metal directly onto the cell ensures a strong and uniform bond with low residual stresses.
- Solder pads and an interconnect that allows for thermal expansion are used to connect the cells instead of a process intensive copper ribbon solder bond.

Reliability Research and Performance Degradation Model (PVLife)
Introduction
SunPower has developed a physical model based on extensive research that addresses SunPowers degradation mechanisms. However, models quantifying Conventional Module degradation is not included, since data and research is, for obvious reasons, primarily focused on the SunPower design. The ability to quantify degradation rate has been vital to SunPower in order to securely offer its current industry-leading twenty five year warranty. Degradation rates cannot be determined through industry standard certification tests such as thermal cycling,