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  • Which panels to get?

    I got a few quotes and the two I am considering are both with Solaredge inverters. The first quote is LG Electronics LG375N2C-B3 panels at $3 per Watt and the second I am considering is Mission Solar MSE300SQ5T panels at $2.77 a Watt. They are both considered T1 panels and I wonder if anyone has experience with the Mission Solar panels. I do live in a hot climate so the LG's will perform better and also will have less degradation, but I am wondering if it would be worth the $3000 dollars. Thanks for any input.

  • #2
    Most every quality panel from a reputable manufacturer when used in a system that's properly designed, installed and maintained will, in all likelihood, be as fit for purpose and have about equal annual output as any other quality panel from a reputable manufacturer under the same conditions in the same location and orientation.

    Be careful were you get your facts and conclusions. The LG's may perform better in a warmer climate, but the differences may well be relatively small, and you'll probably never be able to verify or quantify if or how much better, which means you'll never be able to verify a NPV of savings equal to or greater than that $3K up front cost differential.

    A bit off topic, but just who are the panel rating police that determine, for example, what separates a tier 1 panel from a tier 2 panel ? Without some official sanction or some way to quantify quality levels, that tier stuff sounds a lot like marketing B.S. to me. Maybe my ignorance is showing.

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    • #3
      This is a smaller local company that prides themselves on their installation and quality of components they choose. I think what they meant by a T1 panel is they only use panels that they find reputable and also has a certain warranty. They do sell Sunpower and were trying to sell me on that type of panel, but they also gave me other options which I appreciated. I am just concerned about the Mission Solar company. They are a company based out of Texas and they seem to want to build quality panels. They do have decent warranties on their panels, which means they stand behind their product. However, I don't know if they had quality control issues in the past or have a high defect rate on their panels.

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      • #4
        Part of the decision process is guessing which companies, both mfg. and installation, will be around if service or more equipment is needed in the future, both near and long term.

        Mission Solar may be a good outfit with high standards, but those attributes do not guarantee longevity, nor are those qualities guaranteed simply because someone says so.

        Most folks see what they want to see and hear what they want to hear, and shortsighted first price bottom line on cost influences perceptions more often than not.

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        • #5
          Thanks to the responses. I have one last question. I decided to go with a 11.25 kW LG system and it was right at $2.80 per Watt. The question I have is the contractor wants to use the SolarEdge 7600H inverter. Because I have a N/S/E/W roof I can only put 12 panels on the South, 8 panels West, and the rest of the panels will go East. I have to put panels on the East because the South roof has vents and is smaller. The West direction was design elements that limit the panels.

          The contractor said that the 7600H would be a great inverter because it would keep costs down. I would have to get my service panel modified for a 60 amp breaker. He also said that clipping would not be much of an issue because of the three separate arrays producing peak output at different times. I know the 7600H can accept up to 11.8 kW of panels, but I would like some opinions on this.

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          • #6
            Originally posted by discodanman45 View Post
            Thanks to the responses. I have one last question. I decided to go with a 11.25 kW LG system and it was right at $2.80 per Watt. The question I have is the contractor wants to use the SolarEdge 7600H inverter. Because I have a N/S/E/W roof I can only put 12 panels on the South, 8 panels West, and the rest of the panels will go East. I have to put panels on the East because the South roof has vents and is smaller. The West direction was design elements that limit the panels.

            The contractor said that the 7600H would be a great inverter because it would keep costs down. I would have to get my service panel modified for a 60 amp breaker. He also said that clipping would not be much of an issue because of the three separate arrays producing peak output at different times. I know the 7600H can accept up to 11.8 kW of panels, but I would like some opinions on this.
            I'm not an expert but the 7600 inverter seems a bit small for your system. I have a 10.85 kW system with 4.65kW southern facing and 6.2kW eastern facing. I have 10,000 watt solaredge inverter and would have significant clipping with a 7600 watt inverter. It could be that you'd be ok with your setup because you also have some Western facing panels.

            I'd run 3 separate pvWatts arrays, one for each of your directions. Then pull the hourly report spreadsheet for each and add up each of the hourly outputs. See how often you have over 7600 watt outputs. That will give you a decent estimate of your potential lost production. It's possible that the lost production is minimal and the cost savings is worth it but better to look at the data first.

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            • #7
              Originally posted by NYHeel View Post

              I'm not an expert but the 7600 inverter seems a bit small for your system. I have a 10.85 kW system with 4.65kW southern facing and 6.2kW eastern facing. I have 10,000 watt solaredge inverter and would have significant clipping with a 7600 watt inverter. It could be that you'd be ok with your setup because you also have some Western facing panels.

              I'd run 3 separate pvWatts arrays, one for each of your directions. Then pull the hourly report spreadsheet for each and add up each of the hourly outputs. See how often you have over 7600 watt outputs. That will give you a decent estimate of your potential lost production. It's possible that the lost production is minimal and the cost savings is worth it but better to look at the data first.
              Thank you for the advice. I plugged in everything and the clipping would be very minimal. Kind of surprising to be honest. Even during the peak output days, it would be a maximum of 2 hours being clipped and it is not even by a huge amount.

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              • #8
                Run PVWatts for the 3 orientations/sizes, combine the outputs by hour and look for maximums for a 1st approx. of required inverter sizing.

                Butch: Any thoughts ?
                Last edited by J.P.M.; 01-22-2018, 08:14 PM.

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                • #9
                  Originally posted by J.P.M. View Post
                  Run PVWatts for the 3 orientations/sizes, combine the outputs by hour and look for maximums for a 1st approx. of required inverter sizing.
                  JPM-

                  In your runs with PVWatts, how accurate have you found it to be with regard to estimating system power output at any given set of conditions? When one runs the hourly simulations, estimated power values are available (i.e. not just kWh production) and, based on my very limited experience with my system anyway, they seem to be on the lower end (even using the system parameters generally recommended here such as 10% losses, etc).

                  I have, under STC conditions, 12.24 kWDC of panels and 10 kWAC of inverter, (6 kW and 4 kW) and with my location/panel orientation/angle, etc PVWatts says this should literally almost never clip. But, it does...regularly and quite a bit even in January. This is a good problem to have of course, so no complaints. The load balance between the panels is nearly perfect as both inverters clip at the same time.

                  I could easily solve this with two 6 kW inverters, but my utility limits the maximum AC backfeed to 10 kW (thus the inverter selections).

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