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  • #31
    Originally posted by Duxa View Post

    They have been making panels for nearly 50 years (since the 70's) Im sure its not just a made up number.
    Duxa:

    There's made up numbers and then there are other made up numbers. Without seeing warranty claims and numbers, you have no basis for being sure of anything. Without understanding ways performance can deteriorate, you have no way of knowing if a performance deterioration rate is reasonable.

    If a panel that's on you property experiences an output or efficiency drop over a period of time, how will you even know it, much less go about verifying such a condition ? Well, as a consumer, you won't in any reliable and repeatable way because you, I and every other consumer cannot even reliably measure input, or even understand it, much less deal with the intricacies of PV output and measuring it and then putting all that together and come up with an efficiency drop.

    If you think you can do all that - accurately - please enlighten us all how you would go about it.

    Believe what you want but if you think you can, you are mistaken. Additionally, since you need a measure of input as accurate as output, you and most every other consumer do not have access to the type and quantity or quality of historical meteorological data including site measured irradiance necessary to measure and so verify an efficiency drop.

    Then, there's the whole question of measuring and recording how dirty the panels have been, how often they were cleaned and how effective any cleaning has been. Data of all such things will be necessary for any successful performance warranty claim.

    Point is, while it's not necessarily a made up number, performance degradation is more an estimate based on lab measurements and projections based on accelerated aging rates and other methods than a hard number that's been field verified under varying conditions.

    The main and probably only reason for things like production guarantees is for marketing. Mfgs. know more about performance degradation then most any consumer and they know verifying a performance warranty claim in the field is next to impossible, even with a lot of knowledge and equipment. So, they get to say pretty much what they want knowing performance will almost never be checked in ways required for a successful performance warranty claim.

    Well intentioned but very uninformed folks like you drink the Kool-Aid marketing hype and greenwash media garbage thinking a premium paid for a panel will get extra performance and more reliability. The reality is something different. Folks who have been around for a long time with more experience and education than you know this and also know that beyond a certain level of basic quality and Q.C. panels are mostly a commodity.

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

    Comment


    • #32
      Originally posted by J.P.M. View Post

      Duxa:

      There's made up numbers and then there are other made up numbers. Without seeing warranty claims and numbers, you have no basis for being sure of anything. Without understanding ways performance can deteriorate, you have no way of knowing if a performance deterioration rate is reasonable.

      If a panel that's on you property experiences an output or efficiency drop over a period of time, how will you even know it, much less go about verifying such a condition ? Well, as a consumer, you won't in any reliable and repeatable way because you, I and every other consumer cannot even reliably measure input, or even understand it, much less deal with the intricacies of PV output and measuring it and then putting all that together and come up with an efficiency drop.

      If you think you can do all that - accurately - please enlighten us all how you would go about it.

      Believe what you want but if you think you can, you are mistaken. Additionally, since you need a measure of input as accurate as output, you and most every other consumer do not have access to the type and quantity or quality of historical meteorological data including site measured irradiance necessary to measure and so verify an efficiency drop.

      Then, there's the whole question of measuring and recording how dirty the panels have been, how often they were cleaned and how effective any cleaning has been. Data of all such things will be necessary for any successful performance warranty claim.

      Point is, while it's not necessarily a made up number, performance degradation is more an estimate based on lab measurements and projections based on accelerated aging rates and other methods than a hard number that's been field verified under varying conditions.

      The main and probably only reason for things like production guarantees is for marketing. Mfgs. know more about performance degradation then most any consumer and they know verifying a performance warranty claim in the field is next to impossible, even with a lot of knowledge and equipment. So, they get to say pretty much what they want knowing performance will almost never be checked in ways required for a successful performance warranty claim.

      Well intentioned but very uninformed folks like you drink the Kool-Aid marketing hype and greenwash media garbage thinking a premium paid for a panel will get extra performance and more reliability. The reality is something different. Folks who have been around for a long time with more experience and education than you know this and also know that beyond a certain level of basic quality and Q.C. panels are mostly a commodity.

      Take what you want of the above. Scrap the rest.
      First of, I want to say that Im not trying to argue anything. I am just trying to participate in a discussion and share my own opinion about things.

      Now. I think you are approaching this from a completely different angle than I am. I do not care at all about precision measurements, they are unnecessary in this case. Things like this have a +- margin of error, always. All you have to do, as a consumer is to look at your yearly production during year 1, then if at any point in the future your year over year is significantly lower than the advertised rates you call up the warranty, its up to them to measure and prove to you that the degradation is within the expected range. Otherwise you get a new panel.

      Additionally there is such thing as false advertising. And I do not think top end brands would be advertising something that was blatantly false, especially when it is so easily checked.

      Now, personally, all these things aside, I would trust Panasonic, LG, and other brands that have been doing this stuff for decades, and their advertisements than some random hole in the wall place in China. Why? Well because they are operating 50 years later either because they make good products, or not one of the millions of their customers (including businesses with the proper equipment to check their claims) has ever called them out. And I find it extremely unlikely that their product doesnt match the advertisements, as it is extremely unlikely that over 50 years not one in many millions has called them out on it.

      When you are buying into a company like LG or Panasonic or any other major brand, you are also buying into their warranty, guarantee that they will be around to honor that warranty, access to their service centers etc etc...

      Thats just my personal opinion... participating in conversation. Not trying to prove anything. As with everything in life, you get what you pay for. There is a reason some panels are cheaper and others are more expensive. If the cheap panel could sell itself for more, then it would. Solar panels arent some new unknown technology, its older than cell phones.
      Last edited by Duxa; 01-24-2020, 03:00 AM.

      Comment


      • #33
        Originally posted by Duxa View Post
        ........So I dont think its fair to compare those panels to what we are doing. Completely different environment.
        But the things that make panels more efficient in space, still cost lots of $$ to do. Sure they can be built in that manner for earth, and they might use some of the expensive cells in a panel, but it would likely cost $300 watt . for space use, that's OK. But for terrestrial use, it's not cost effective. For every one of the high efficiency cells that make it to space, about 50 are scrapped for poor performance.
        There is no "secret formula", but rather an expensive process.
        Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
        || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
        || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

        solar: http://tinyurl.com/LMR-Solar
        gen: http://tinyurl.com/LMR-Lister

        Comment


        • #34
          Originally posted by Mike90250 View Post

          But the things that make panels more efficient in space, still cost lots of $$ to do. Sure they can be built in that manner for earth, and they might use some of the expensive cells in a panel, but it would likely cost $300 watt . for space use, that's OK. But for terrestrial use, it's not cost effective. For every one of the high efficiency cells that make it to space, about 50 are scrapped for poor performance.
          There is no "secret formula", but rather an expensive process.
          Yeah, I was just saying that our needs are different than the panels that go in space, they have to worry about things we dont have to worry about, and we have to worry about things they dont have to worry about.

          I do agree with what you said.

          Comment


          • #35
            J.P.M. You make many excellent points. Input is impossible for us to accurately know over time. There are other degrading factors other than the panels themself, like dirt. And you say so much more that is also valid and important.

            With that said, are you suggesting that the panels from one maker which claims 10% degradation over 20 years are similar to the panels from another maker that claims 20% degradation over 20 years? Or is a premium panel really better in some way?

            In my business (not a solar company), our customers rely on us to measure things that they can't measure and we built our reputation on good measurements. We go out of our way to measure to traceable standards and explain the standards that we use. We use superlatives in marketing, but we don't stretch the truth in numbers.

            Whether premium performance is worth a premium price is a completely different question and depends on each situation. Panels for space is an example of a particular situation. Home use is a completely different situation, as others have said. What we haven't said is what we value in a home situation. Some will value dependability - they need the system to be able to deliver a certain power level into the future. Others will value economy. They want to maximize or achieve a particular return-on-investment or or meet a specific break-even time. In addition, there is a value to low risk. How much premium are you willing to pay for things like a lower failure rate, better warranty, or long-term financially-stable supplier?

            Each one of us has to make these decisions for ourselves, and needs some facts to guide us. We're hoping that we can use numbers in data sheets and other facts to help make these decisions. Are we kidding ourselves?
            7kW Roof PV, APsystems QS1 micros, Nissan Leaf EV

            Comment


            • #36
              Originally posted by bob-n View Post
              Are we kidding ourselves?
              If you blindly believe everything you read and are told, yes.

              Duxa is a neophyte who, like many others, including me many years ago, buys into the hype that solar can save the world.

              Those who don't get informed and educate themselves before the commit resources to a project or lifestyle usually waste time, $$ and effort by their persistent ignorance of what's required and the bullheadedness of having their minds made up and not wanting to be confused by reality and the facts as seen by others who have gone down the same path and learned.

              Comment


              • #37
                Considering which panel to buy, efficiency is a factor mfrs can check. I would like to know the
                field failure/replacement rate. The aging rate is low enough to not be much of a factor. AND
                it almost surely varies with average sun intensity at the installation, not ever mentioned.

                It would be interesting to find out how long panels actually are kept in service after setup. My
                guess is, it is a lot less than 20 years at this point. I have seen arrays much newer, which have
                not been kept up. Like a small tree growing a couple feet in front, maybe the original owner
                lost interest/moved/passed away. Bruce Roe
                Last edited by bcroe; 01-24-2020, 01:59 PM.

                Comment


                • #38
                  In my company, field failure rate is critical, but also impossible to get accurately. We report customer return rate and also failure statistics from our own standardized reliability testing..

                  I'm guessing that it's even harder for solar.

                  Panels can have failure due to abuse, storm damage, transportation damage, mis-installation, and perhaps even inverter failure (although not likely). They can also have true manufacturing defects, wearouts and the other issues we want to track. Can we accurately separate these? It's even harder to get accurate when dealing with small numbers, because one or two errors grossly skews the statistics.

                  How many panels fail in the field but are not sent back? How many are sent back to the distributor but never make it back to the factory? How many of those sent back are dissected to find root cause of failure? That work is expensive. How many reported failures are mis-categorized? How many reported failures are intentionally mis-reported (fraud)? Who knows?

                  My opinion is that the best statistics come from large installations where there is relatively little variation in environment and reporting. Second best would be the accelerated reliability studies done by manufacturers.
                  7kW Roof PV, APsystems QS1 micros, Nissan Leaf EV

                  Comment


                  • #39
                    Originally posted by Duxa View Post

                    First of, I want to say that Im not trying to argue anything. I am just trying to participate in a discussion and share my own opinion about things.

                    Now. I think you are approaching this from a completely different angle than I am. I do not care at all about precision measurements, they are unnecessary in this case. Things like this have a +- margin of error, always. All you have to do, as a consumer is to look at your yearly production during year 1, then if at any point in the future your year over year is significantly lower than the advertised rates you call up the warranty, its up to them to measure and prove to you that the degradation is within the expected range. Otherwise you get a new panel.

                    Additionally there is such thing as false advertising. And I do not think top end brands would be advertising something that was blatantly false, especially when it is so easily checked.

                    Now, personally, all these things aside, I would trust Panasonic, LG, and other brands that have been doing this stuff for decades, and their advertisements than some random hole in the wall place in China. Why? Well because they are operating 50 years later either because they make good products, or not one of the millions of their customers (including businesses with the proper equipment to check their claims) has ever called them out. And I find it extremely unlikely that their product doesnt match the advertisements, as it is extremely unlikely that over 50 years not one in many millions has called them out on it.

                    When you are buying into a company like LG or Panasonic or any other major brand, you are also buying into their warranty, guarantee that they will be around to honor that warranty, access to their service centers etc etc...

                    Thats just my personal opinion... participating in conversation. Not trying to prove anything. As with everything in life, you get what you pay for. There is a reason some panels are cheaper and others are more expensive. If the cheap panel could sell itself for more, then it would. Solar panels arent some new unknown technology, its older than cell phones.
                    I'm not arguing anything either. Just sharing opinions arrived at over ~ 45 yrs. after changing careers to engineering as a result of getting the solar bug and then getting fed up with the B.S./lies I was told and then getting educated and possibly better able to find my own answers.

                    You are correct, I am approaching it from a different angle. I trust, but verify. Looks to me like you're one of the typical folks who sees what you want to see and read what you want to read and seem to have your mind made up based on incomplete information and ignorance of what's needed and how things work. So be it and hail the freedom to make the choice.

                    I'm also pretty sure that most residential panel systems I've been around probably exceed their warranted output and I know what's needed to measure it. You do not.

                    Besides being impossible to verify, that most panels exceed their published output as modified by conditions of operation is one reason of several why I'm of the opinion that believing in degradation numbers and basing an equipment buying decision on such things is mostly a waste of time and spending $$.

                    As for your "you could just" dream of how to make a claim, it's an example of your ignorance of the subject. How you imagine you'd spot a problem simply will not yield anything of use. What you think will work to verify output, will not - if for no other reason than weather and irradiance variation - which, in spite of your aversion to gathering data, will be necessary to know and, known or not will have a high probability of making system output different by about the same amount as that weather and irradiance variation - probably something like 5-10 % yr/yr. You're looking at finding a 1 % diff. ? Good luck. Also, has the state of your array's cleanliness been documented and also temporally correlated with irradiance ? Whether or not you care about instruments, precision or otherwise, you'll need some data to back up your method.

                    As for the vendor doing what's necessary to find an alleged problem, how many times do you thing vendors/mfg. get calls from users who think their system is underperforming ? If the traffic around here is any indication, probably a lot. Also looking at such posts leads me to think there's a lot of solar ignorance on the part of users or potential users that's the cause of most of the confusion. Looks to me like you may be one of that group.

                    Look, I don't have a hardon for you or what you want. NOMB or concern. I simply see you spinning your wheels, ignorantly going down roads that don't matter and don't get you a better system or installation. IMO only, you'd be better off with more education before you go further.

                    In that education, since I've seen no mention of what usage (annual electrical demand) you have or how much of that load you want to offset with a PV system. I'm wondering if you've done that bit of necessary basic analysis yet. If not, I'd suggest that might be a good place to start.

                    Comment


                    • #40
                      Originally posted by J.P.M. View Post

                      If you blindly believe everything you read and are told, yes.

                      Duxa is a neophyte who, like many others, including me many years ago, buys into the hype that solar can save the world.

                      Those who don't get informed and educate themselves before the commit resources to a project or lifestyle usually waste time, $$ and effort by their persistent ignorance of what's required and the bullheadedness of having their minds made up and not wanting to be confused by reality and the facts as seen by others who have gone down the same path and learned.
                      I am a neophyte in what? solar? sure. But I am an engineer and work in a field where precision, accuracy etc etc is important. We go through the same processes as these manufacturers. Subject of marketing claims, company reputations etc, span far beyond solar, and this being solar has little to do with it. Panasonic is not a solar company, neither is LG. They have a small division that makes those products. But these companies have good reputation for a reason. Its not something they branded themselves with, its something their customers (you and I and millions of other neophytes) have labeled them. Reputation is hard to earn, but easy to lose.

                      I am starting to get a feeling that you have convinced yourself that any panel is as good as any other, made your purchasing decision based on that conviction, feeling good about the money you saved, and are now trying to convince others (and yourself), that you made a good purchasing decision. If your goal is to convince us that a panel from an unknown Chinese manufacturer is as good as a Panasonic or LG panel, well then everyone that has chimed in so far in this discussion begs to differ.

                      I dont blindly buy a top brand or whatever of any product, I look at reviews, user opinions, and yes marketing material, then I make my purchasing decision based on that. And as we have already established, marketing material from big companies that are always under a microscope (like LG or Panasonic) can be trusted. Marketing material from some company that spun up within last few years in rural China that claims they are just as good as the top brands. Well, thats a red flag. But even if you put a tin foil hat on and throw all that out, sheer number of satisfied customers who at the first chance would crap all over these top brands tells you that they are good products. You literally have zero reason to think otherwise. We have decades of satisfied customers that feel that the performance of the products they bought matched the product that the marketing material sold them.

                      I have a feeling you are not an engineer.

                      Comment


                      • #41
                        Originally posted by J.P.M. View Post

                        I'm not arguing anything either. Just sharing opinions arrived at over ~ 45 yrs. after changing careers to engineering as a result of getting the solar bug and then getting fed up with the B.S./lies I was told and then getting educated and possibly better able to find my own answers.

                        You are correct, I am approaching it from a different angle. I trust, but verify. Looks to me like you're one of the typical folks who sees what you want to see and read what you want to read and seem to have your mind made up based on incomplete information and ignorance of what's needed and how things work. So be it and hail the freedom to make the choice.

                        I'm also pretty sure that most residential panel systems I've been around probably exceed their warranted output and I know what's needed to measure it. You do not.

                        Besides being impossible to verify, that most panels exceed their published output as modified by conditions of operation is one reason of several why I'm of the opinion that believing in degradation numbers and basing an equipment buying decision on such things is mostly a waste of time and spending $$.

                        As for your "you could just" dream of how to make a claim, it's an example of your ignorance of the subject. How you imagine you'd spot a problem simply will not yield anything of use. What you think will work to verify output, will not - if for no other reason than weather and irradiance variation - which, in spite of your aversion to gathering data, will be necessary to know and, known or not will have a high probability of making system output different by about the same amount as that weather and irradiance variation - probably something like 5-10 % yr/yr. You're looking at finding a 1 % diff. ? Good luck. Also, has the state of your array's cleanliness been documented and also temporally correlated with irradiance ? Whether or not you care about instruments, precision or otherwise, you'll need some data to back up your method.

                        As for the vendor doing what's necessary to find an alleged problem, how many times do you thing vendors/mfg. get calls from users who think their system is underperforming ? If the traffic around here is any indication, probably a lot. Also looking at such posts leads me to think there's a lot of solar ignorance on the part of users or potential users that's the cause of most of the confusion. Looks to me like you may be one of that group.

                        Look, I don't have a hardon for you or what you want. NOMB or concern. I simply see you spinning your wheels, ignorantly going down roads that don't matter and don't get you a better system or installation. IMO only, you'd be better off with more education before you go further.

                        In that education, since I've seen no mention of what usage (annual electrical demand) you have or how much of that load you want to offset with a PV system. I'm wondering if you've done that bit of necessary basic analysis yet. If not, I'd suggest that might be a good place to start.
                        Please clarify something for us. Are you saying that marketing material provided by Panasonic, LG and other top brands is a blatant lie? If so, then we are in Alex Jones territory here.

                        And let me clarify, for like the third time. I do not make my decisions based purely on marketing material, but you seem to keep hammering that point, as if that is how it is. You cant argue with brand reputation built up over decades by millions of customers who would crap all over Panasonic, LG at the first opportunity they can get.

                        Did you personally have a bad experience with these brands? Well then enlighten us on what happened and how you analyzed the problem, used your sophisticated measuring equipment (which you keep insisting you "know" how to use). Id love to hear this story. And dont worry, I have multiple engineering degrees, Ill understand it But so far you have been all huffing and puffing and no substance.
                        Last edited by Duxa; 01-24-2020, 03:21 PM.

                        Comment


                        • #42
                          This thread is getting a little heated.

                          Anywayz.... here's a short story on why I got LG panels. When my installer was designing my system he gave me the option between Panasonic, LG, and Hyundai panels. On paper the Panasonic had slightly better specs than the LG but they also cost a bit more, not much. The Hyundai was the cheapest of the bunch but had the worst specs of the three and would require additional panels be placed on my roof. While researching the different options I found a $250 rebate from LG. So that's what we went with. Also my installer was Korean and seemed to favor LG, I suspect for that reason.
                          Last edited by PugPower; 01-25-2020, 02:36 PM. Reason: Spelling

                          Comment


                          • #43
                            Duxa,

                            FYI, my self install about one year ago in Long Beach, CA

                            https://www.solarpaneltalk.com/forum...system-success

                            Comment


                            • #44
                              Originally posted by John_Dumke View Post
                              Duxa,

                              FYI, my self install about one year ago in Long Beach, CA

                              https://www.solarpaneltalk.com/forum...system-success
                              Nice, how long did it take SCE to install the NEM meter and allow you to switch the system on? Also what was your final price per watt? Did you have to make panel changes (you mention the city didnt like that it was center fed). The $14.5k figure you give, does that include all permitting and also after the rebate or before the rebate?

                              Comment


                              • #45
                                NEM - The meter was already NEM capable. I think they just "pinged" it and it then it had the capability. It was done in probably less than two weeks from the application being complete. They were very quick. The $14.5k included everything, permits, electrician, tools.... everything. Rebate???? There was no rebate. I did however take a 30% tax credit for 2019. This would have reduced my Federal tax bill by $4,350.

                                Comment

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