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Request for input on solar proposal - Q Cells and Enphase Microinverters

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  • Request for input on solar proposal - Q Cells and Enphase Microinverters

    Hello, I am new to solar and have been researching and getting quotes over the past month. I am in the San Francisco Bay Area and PG&E is my utility. The leading proposal is for a 9.52kw system comprised of Q Cell Q.PEAK DUO-G8+ panels (28 panels x 340w) with Enphase IQ7-60-2-US microinverters. Cost is $3.13 per watt (before rebates) and includes electrical upgrade to 200 amps (I currently have 100 amp service).

    Preliminary online research suggests those panels and microinverters are good products, but I wanted to turn to the experts on this forum and ask for input / advice before I pull the trigger.

    Thanks in advance --

  • #2
    In the past, there have been issues with Enphase microinverters. The IQ7-60-2-US are a new series, and may be better.
    Insist on several years worth of individual microinverter monitoring. When a microinverter goes bad, you have to pull out good PV panels to get to the bad one, layout to reduce the labor is worth it.
    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

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    • #3
      Ideally get an itemized proposal and a very good description (in writing, preferably with detailed drawings) of how the racking will be mounted to your roof. 7 years ago I had an Enphase/Solarworld system installed for just over $3/watt. At the time the street price with tax for my panels and inverters added up to $1.60/watt. Your Q340/IQ7 can be had for $1.00/watt including tax and shipping to the Bay Area. A quality install and a roof that doesn't leak is worth $$! Just realize the panels and inverters are not the major expense- it's design, installation, permitting, and "balance of system" hardware.

      Regarding potential failure of microinverters vs. string inverters: There are pros and cons to each. One thing to consider is how much work it would take to replace a microinverter. If your 28 panels are in a big 4x7 array on a super-steep pitch 4 story house, access would be expensive! I have low-slope roof with raised racking, so I don't have to remove any panels to access the inverters.

      Finally, if you go with Enphase demand a lifetime full-access Enlighten Manager account. That way you will have lots of data to play with and monitor- such as panel-level output, temperature, voltage, etc.

      In 7 years the only maintenance on my system is washing dirty panels.
      Last edited by jimqpublic; 10-12-2021, 07:57 PM.

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      • #4
        Realize that microinverters will not last the 25 years they are warrantied for. The manufacturers do this warranty as a ploy to match the 25 year warranty of the PV panels (which will last 50 years) They will replace the microinverters under warranty but you need to be clear about who is going to do the replacement as that is not covered under warranty. Enphase already offered a couple years ago to replace all their early generation product for free - so you can figure how good their reliability promises are....
        BSEE, R11, NABCEP, Chevy BoltEV, >3000kW installed

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        • #5
          I just realized the Enphase product line includes both an IQ7 and an IQ7+. I am being quoted for the IQ7. Is that appropriate for my 340w panels, or should I push for IQ7+?

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          • #6
            Originally posted by jonnyboy7 View Post
            I just realized the Enphase product line includes both an IQ7 and an IQ7+. I am being quoted for the IQ7. Is that appropriate for my 340w panels, or should I push for IQ7+?
            Enphase has a table that will give you an idea what they recommend. Personally I have 345 Watt panels and used IQ7+ micros. The IQ7's both have a limit of 295 Watts which is a DC to AC ratio of 1.19 to One. Are your panels 60 cell or 72 cell panels? It may be more about matching the panel voltage and current specs.
            Last edited by Ampster; 10-15-2021, 11:40 AM.
            9 kW solar, 42kWh LFP storage. EV owner since 2012

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            • #7
              Originally posted by Ampster View Post

              Enphase has a table that will give you an idea what they recommend. Personally I have 345 Watt panels and used IQ7+ micros. The IQ7's both have a limit of 295 Watts which is a DC to AC ratio of 1.19 to One. Are your panels 60 cell or 72 cell panels? It may be more about matching the panel voltage and current specs.

              The panels are Hanwha Q Cells Q.PEAK DUO BLK-G8+ 340 watt panels. Please forgive the ignorance, but when I look at the data sheet, I cannot figure out if they are 60 or 72 cell. I assume they are 60 cell because obviously the IQ7 would not work with 72 cell panels, and I don't believe my prospective solar company is incompetent.

              Re the IQ7 vs. IQ7+: The Enphase IQ7 is rated for panels up to 350w, so presumably they should be fine, but . . . I saw a video online that suggested having extra "headroom" to avoid clipping and not to use the IQ7 with panels above 310 watts. I have no idea if that is sound advice or not, hence my question. Thanks in advance.

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              • #8
                Originally posted by jonnyboy7 View Post

                .. . . . I saw a video online that suggested having extra "headroom" to avoid clipping and not to use the IQ7 with panels above 310 watts. I have no idea if that is sound advice or not, hence my question. Thanks in advance.
                I haven't seen the video but I have seen lots of discussions about DC to AC ratios and clipping. To me it is like question of whether the glass is half full or half empty. Then there is always the engineer that will reply that the glass is the wrong size. As far as I know Enphase does not offer a larger Watt inverter so the question is do you want to reduce the capacity of your solar panels or ignore clipping on certain sunny days? I will take the higher DC to AC ratio to get more production during winter and cloudy days.

                9 kW solar, 42kWh LFP storage. EV owner since 2012

                Comment


                • #9
                  Originally posted by jonnyboy7 View Post


                  The panels are Hanwha Q Cells Q.PEAK DUO BLK-G8+ 340 watt panels. Please forgive the ignorance, but when I look at the data sheet, I cannot figure out if they are 60 or 72 cell. I assume they are 60 cell because obviously the IQ7 would not work with 72 cell panels, and I don't believe my prospective solar company is incompetent.

                  Re the IQ7 vs. IQ7+: The Enphase IQ7 is rated for panels up to 350w, so presumably they should be fine, but . . . I saw a video online that suggested having extra "headroom" to avoid clipping and not to use the IQ7 with panels above 310 watts. I have no idea if that is sound advice or not, hence my question. Thanks in advance.
                  These panels are 60 cell panels. If you ask to use IQ7+ it will increase the cost since it will force 3 branches, instead of 2. Max number of IQ7 per branch is 15 but 13 for IQ7+.

                  There are multiple strategies for optimization of PV system design. If the strategy is to squeeze every possible watt of power generation then the advice is sound. If the strategy is to optimize cost/benefit then most likely IQ7 is the right choice. Personally I have 330W LG panels with IQ7 on East/West facing roof planes with 16 degrees pitch. Based on collected data in the last 2 years I could have used 350-360 W panels with the same IQ7 microinverters and have noticeably higher production.

                  I do not think IQ7 has firm range for panel power STC rating. The compatibility is for voltage and current at the lowest recorded temperature in installation location.
                  Last edited by Will792; 10-23-2021, 09:37 AM.

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                  • #10
                    I paid $2 a watt for the exact same setup in NY 6 months ago before incentives

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                    • #11
                      IQ7 peaks at 250W, that is a lot of clipping for a 340W panel.
                      IQ7+ peaks at 295W, sounds like a more reasonable clipping.

                      But ultimately it comes down to how much sun you get where you are, and how much you need to extract all these watts if you have a lot of clear sky sunny days, versus the price premium they will attempt to charge you for them

                      Either way DO insist for full individual panel monitoring, or you will never notice when some of them go bad...
                      Last edited by scrambler; 10-23-2021, 02:24 PM.

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                      • #12
                        Originally posted by Cshama View Post
                        I paid $2 a watt for the exact same setup in NY 6 months ago before incentives
                        I would say that is not remotely achievable in California — at least not in the Bay Area. Even $2.50 per watt (before rebates) for good quality equipment is very rare, and that will certainly not include an electrical upgrade.
                        Last edited by jonnyboy7; 10-24-2021, 01:18 AM.

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                        • #13
                          Originally posted by jonnyboy7 View Post

                          I would say that is not remotely achievable in California — at least not in the Bay Area. Even $2.50 per watt (before rebates) for good quality equipment is very rare, and that will certainly not include an electrical upgrade.
                          I will say you can't find that $2/watt installation cost in Florida either. I have used that value as a reason for not installing solar yet. Unless I can get the price down to that amount I am looking at 12 years or more for any payback. That would put me at 80 yo which is way too long for me.

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                          • #14
                            Originally posted by SunEagle View Post

                            I will say you can't find that $2/watt installation cost in Florida either. I have used that value as a reason for not installing solar yet. Unless I can get the price down to that amount I am looking at 12 years or more for any payback. That would put me at 80 yo which is way too long for me.
                            This is not rocket science. As always, economics rule.

                            Simply put, If the total net present value of the installed cost of any alternate energy equipment (including the PITA factor translated to a cash amount of such equipment - however one values it) plus the cost of maintenance of such equipment, plus the cost of any supplemental POCO power the alternate system doesn't provide is less than the net present value of the cost of future POCO power, then the alternate energy system will - on paper anyway - be the more cost effective alternative.

                            The rub is multifaceted however.
                            - Most folks are ignorant of process economics and the time value of money principle necessary for a reasonably inclusive analysis and are usually so mentally slothful they'll never learn.
                            - Most folks are ignorant about how to make what may be reasonable guesses about future conditions - always a set of unknowns.
                            - Most folks are easily B.S.'d into believing what seems to make life simple.

                            I'd suggest $2/STC W installed cost after rebates/incentives in most of the U.S. is probably not attainable at this time.
                            Where it is - or may be available for cheap - the solar resource is usually not as available - places like the NE U.S - or is heavily subsidized - or both.

                            Comment


                            • #15
                              Originally posted by J.P.M. View Post

                              This is not rocket science. As always, economics rule.

                              Simply put, If the total net present value of the installed cost of any alternate energy equipment (including the PITA factor translated to a cash amount of such equipment - however one values it) plus the cost of maintenance of such equipment, plus the cost of any supplemental POCO power the alternate system doesn't provide is less than the net present value of the cost of future POCO power, then the alternate energy system will - on paper anyway - be the more cost effective alternative.

                              The rub is multifaceted however.
                              - Most folks are ignorant of process economics and the time value of money principle necessary for a reasonably inclusive analysis and are usually so mentally slothful they'll never learn.
                              - Most folks are ignorant about how to make what may be reasonable guesses about future conditions - always a set of unknowns.
                              - Most folks are easily B.S.'d into believing what seems to make life simple.

                              I'd suggest $2/STC W installed cost after rebates/incentives in most of the U.S. is probably not attainable at this time.
                              Where it is - or may be available for cheap - the solar resource is usually not as available - places like the NE U.S - or is heavily subsidized - or both.
                              I agree that the cost of an install will be higher then $2/watt throughout the US but as always the cost and yearly usage of electricity will determine the ROI.

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