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Help me choose Panasonic vs Sunpower install in Maryland; two different installers

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  • Help me choose Panasonic vs Sunpower install in Maryland; two different installers

    Help me choose Panasonic vs Sunpower install in Maryland; two different installers

    A. Panasonic
    34 x Panasonic 330W 96 cell WHT
    SolarEdge 10 kW HD Wave AC, SE10000H-US & optimizers
    11.22 kw DC; 13240 kwh year 1
    $32000 before any tax grants or credits = $2.417 per kwh
    Year 25 output is 90.76%

    B. Sunpower
    30 x X21-345-C-AC WHT 96 CELL
    SP integrated micro inverters
    10.35 kw DC; 13224 kwh year 1
    $35873 before any tax grants or credits = $2.713 per kwh
    Year 25 output is 92%

    Me: like to buy middle-of-the-road; prefer quality and reliability; able to pay cash for either system; want to do it now or 2019 to lock-in 30% federal tax rebate.

    Are the Sunpower panels and integrated system worth the extra money for the long term?

    Both supposedly 25 year warranty

  • #2
    Prices are usually denominated in terms of $/STC Watt, not $$/kWh of electricity produced per time period. So, A.) = $32,000/(34*330) = $2.852/STC W. B.) = $35,873/(30*345) = $3.46/STC W.

    Where did the estimated annual output come from ? Run PVWatts on your own after you read the help screens a couple of times. Use 10 % system loss factor rather than the 14 % default. Get the orientations correct. Vendors underestimate output to sell more product. No peddler ever got fired for oversizing a system. Users think they're playing it safe by oversizing instead of getting screwed and reducing system cost effectiveness.

    What is your annual usage ? Do you know ?

    Why are you doing this ? Save the most and spend the least ?

    Have you used other and more cost effective measures to reduce your usage before even considering PV - the single most expensive way to reduce an electric bill ?

    Sunpower is overpriced for what you get, often by 20 % or more for no additional annual output. Know too that it seems that Sunpower is having a fair amount of quality problems with the microinverter systems if posters to this forum are some true reflection of reality. Know too, that any reasonable quality equipment when professionally installed will produce about the same annual output per STC watt as any other equipment, Sunpower or anyone else's. That is, annual system output per installed STC watt is pretty much the same regardless of price or equipment, provided it's reasonable quality equipment that's competently and professionally installed. Also, panels don't usually fail. Failures tend to happen early on - a few weeks or months or less and are and are covered by most any decent mfgs. warranty, and in any event, seem to not happen much. Micro inverters seem to have more problems than some other components.

    Comment


    • #3
      I have Panasonic 37x330W (12.2kW DC) with SolarEdge P400's and the 11,400W inverter using a line side tap to my 200 amp panel. I also have the SE consumption monitoring which I really like. I would strongly recommend this solution over the SunPower offering.

      SunPower makes very good panels, but from the posts here on the board their Micros, Portal, and post sales service seem rather lacking. I would compare the pricing of the Panasonics versus LG NeonR (or Neon2, or Hanwha, Trina, or Jinko if you have the roof space).

      Be sure to run an Ethernet line to your inverter, the ZigBee can have issues and Cellular updates are too slow and give less info.

      I'd have to think carefully about the 10kW HD vs. the 11.4kW legacy. No fans on the HD -- going to run very hot. Earlier HD models had some firmware issues, but these seem to be mostly sorted now.

      What orientation and pitch would the panels be? Do you have any shade? Mine is 175 degrees, 20 degrees, with moderate shade and I make ~12 MWH per year

      Definitely out PVWatts and/or Solar Edge Site designer for estimates of production given your particulars.

      What do you pay per kWh in MD? It's going to take a long time to break even without SREC's if your cost is similar to mine (roughly $0.14-0.15 / kWH inclusive of generation and transmission). How many MWh do you use annually?

      -Jonathan

      Comment


      • #4
        To me it is a no-brainer. Panasonic has been around since 1918, makes thousands of products and solar is just a blip on their radar screen as far as financials goes. Pretty darn sure Panasonic will still be in biz 10 or 20 years from now to honor any warranty issue. Panasonic is also less expensive.

        SPE only makes solar panels, only making a real product since 2005, on the edge of bankruptcy, and cost more.

        Who are you going to gamble on?
        MSEE, PE

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