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Enphase vs. Solar Edge. What would you go with + interesting input from engineer

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  • Enphase vs. Solar Edge. What would you go with + interesting input from engineer

    Hello,

    Great board. Been reading SO MUCH here and other places about solar. I am going all in for solar here in the Southern NV market.

    I have an interesting installer design. Everything identical as for orientation, roof location, panels, both systems rating:

    Proposed:

    System 1. 44 - Panasonic VMHN340SA18 + 44 - Enphase IQ7X microinverters (MI)

    System 2. 44 - Panasonic VMHN340SA18, SE P400 Power Optimizers, 2 - SE7600H-US Inverter

    Both rated for 14,960 production

    BUT, based on there estimated production (pvwatts.com used and I did some modeling myself)

    System 1. 26,559 kWh per year
    System 2. 27,963 kWh per year

    They are reducing the amount of Enphase MI production due to climate (heat) where the MIs will "stop/under perform" to prevent damage to the MI. Not clip, but actually stop performing or reduce production because of heat here in our market. No where can I find any documentation or claims of this type of performance by Enphase MI products. Based on their experience, they have seen this behaviour here in this market. Claims Enphase knows about this "flaw", but does not officially discuss.

    Cost for either system is the same, I need to choose between an Enphase or Solar Edge based solution. (~$2.80 per kW installed)

    Questions:

    1. Anyone have comments on the Enphase performance claim I mention above, i.e. Enphase will stop or reduce their production in very hot climates (and Solar Edge will not)?
    2. Any comments on pros/cons between these two OEMs, e.g. monitoring, good/bad experiences? I understand installer is key

    Thanks
    Last edited by bird95134; 05-22-2020, 12:18 PM.

  • #2
    I am in California so it gets hot but not as hot as NV and my Enphase microinverters do seem to reduce production a bit with high temperature which I would expect. Many electronics devices throttle back when temperature goes beyond certain threshold so it's not surprising. I would not be surprised if SolarEdge optimizers and inverters behave similarly under high temperature. Enphase sits on the roof and it could be an issue with the NV heat. On other hand, SolarEdge customers have had problems with overheating as well even with indoor mounted inverters. I personally don't like a single monolithic inverter that can fail and take down the entire system for extended time. I have not had a failure with Enphase so far but even if one fails it's a small impact on total system production.

    Comment


    • #3
      Question: Unless you have a shade problem, why not just get a string inverter, get all the electronics off the roof and make the heat problem go away ? Fewer parts = better probability of higher reliability and the heating probelem goes away. String inverters are probably less $$ as well. I'm ignorant of NV requirements, but you may/may not have rapid shutdown capability with string inverters or maybe not even need it in NV.

      On the heat issue, FWIW, panels on a roof under full sun and a meter or 2 per sec. wind velocity will operate at ~ 30 C above the immediately surrounding amb. air temp. On a roof, expect that temp. to be maybe 5 C or a bit more above the ground level air temp.

      Comment


      • #4
        @solardreamer. Totally agree. Heat is enemy of any electronics. My point is that based on IQ7 series specs and literature, competition marketing FUDs (fear, uncertainty and doubts), I have not heard any chatter about this "flaw", as my candidate installer as commented. They offer both SE and Enphase solutions. I see the DC to AC conversion efficiency for Enphase microinverters rated at 97.5% and Solar Edge Inverter rated at 99+% in all the OEM spec docs. When I questioned the difference in projected performance (everything else equal, as per my original note), they lined up their top engineer for me to talk with. He said Enphase acknowledged his observations verbally, but not in writing.

        @ J.P.M.. No shade problem. I like the modular design and extremely simplified approach to add panels later as needed as DC to AC conversion is done at panel and ease to add AC to bus within a close proximity J box. They agreed to match pricing for either system (with SE system technically cheaper, as 1. System is less cost, and 2. I would remove the two LTE comm modules in favor of Ethernet Cat5e to my home Ubiquiti network. I see the DC voltage safety issue is solved with (and included) rapid shutdown inherent within the proposed system. Thanks for observations on wind velocity notes.

        I am now starting to think that may be related to this degragation, i.e. if the microinverters are not installed correctly with airgap between PV panel and microinverter and microinverter and roof. Enphase install specs discuss this as a critical note and list 1.5 to 3 cm distance gap needed on both sides for a proper gap. I brought this point up with the candidate installer lead engineer and he agreed that was an important install item, but also said some roof tile designs do not allow for the required (or recommended) airgap between microinverter and roof.

        Thx for comments!!

        Comment


        • #5
          I still don't understand the attraction to mating a highly reliable PV panel with a much less reliable electronic unit in a blazing hot roof environment. I guess people would rather have less reliable module electronic failures that are visible - rather than invisible but very reliable modules.
          BSEE, R11, NABCEP, Chevy BoltEV, >3000kW installed

          Comment


          • #6
            @Solaris. I also I am not a fan of what you are saying with adding "mating a highly reliable PV panel with a much less reliable electronic unit in a blazing hot roof environment." As a fairly recent newcomer to Solar, I did and continue to research the topic. I came across this installer that pointed this particular data point out to me. I had not heard, read, or saw this point in any documentation or article, anywhere. That's all, and reason to bring comment and question here to you folks. Enphase has a large piece of the US residential market. Thier stock price is doing great and the company is profitable. Other installers I have talked to have either led with either of the two OEMs we are talking about. No one to this point, until your comment, has noted anything critical of Enphase in solar journey (that is my interpretation of your comment). This candidate installer I am talking like Enphase, but pointed out this performance data point.

            Thanks for the comments!!

            Any comments on OEM monitoring, i.e. Enphase vs. SE? Anyone upgrade to the additional cost Enphase Manage capability?

            Comment


            • #7
              Originally posted by bird95134 View Post
              Anyone upgrade to the additional cost Enphase Manage capability?
              I did. It was interesting to look at for about the first two or three weeks after the install, but it was gradually forgotten. It's probably been four years since I've looked at it.

              I only went with Enphase because I have a few shade issues (and I was new and didn't know any better.)

              Comment


              • #8
                If it was my roof and install, my choices in descending order

                1) Panels on unshaded roof with 2 input string inverter. And learn to read the meters
                ( if rapid shutdown is a requirement and you have no detached garage or outbuilding to install panels on )
                2) Panels with optimizers and 2 input string inverter And read the meters
                3) Panels with micro-inverters and decent monitoring system that has no monthly fee

                All installs should have proper 6-9 inches standoff from roof, depending on code and expected weather conditions

                The fewer electronics you have to put up on roof and bake, the better. In 3 or more years, getting panels pulled up and electronics replaced, is going to be a pain for either your wallet, or the labor doing it right. Hardware will likely size and need replacing, dry brittle cables crack......
                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


                • #9
                  Originally posted by bird95134 View Post
                  @solardreamer. Totally agree. Heat is enemy of any electronics. My point is that based on IQ7 series specs and literature, competition marketing FUDs (fear, uncertainty and doubts), I have not heard any chatter about this "flaw", as my candidate installer as commented. They offer both SE and Enphase solutions. I see the DC to AC conversion efficiency for Enphase microinverters rated at 97.5% and Solar Edge Inverter rated at 99+% in all the OEM spec docs. When I questioned the difference in projected performance (everything else equal, as per my original note), they lined up their top engineer for me to talk with. He said Enphase acknowledged his observations verbally, but not in writing.

                  @ J.P.M.. No shade problem. I like the modular design and extremely simplified approach to add panels later as needed as DC to AC conversion is done at panel and ease to add AC to bus within a close proximity J box. They agreed to match pricing for either system (with SE system technically cheaper, as 1. System is less cost, and 2. I would remove the two LTE comm modules in favor of Ethernet Cat5e to my home Ubiquiti network. I see the DC voltage safety issue is solved with (and included) rapid shutdown inherent within the proposed system. Thanks for observations on wind velocity notes.

                  I am now starting to think that may be related to this degragation, i.e. if the microinverters are not installed correctly with airgap between PV panel and microinverter and microinverter and roof. Enphase install specs discuss this as a critical note and list 1.5 to 3 cm distance gap needed on both sides for a proper gap. I brought this point up with the candidate installer lead engineer and he agreed that was an important install item, but also said some roof tile designs do not allow for the required (or recommended) airgap between microinverter and roof.

                  Thx for comments!!
                  On air gaps: For sufficient cooling of the array, particularly in a hot roof in a sunny climate, it's at least a good idea and strong recommendation to keep at least 15 cm. clear between the bottom of panel and a roof deck. Much less than that and the panel will run hotter (very roughly ~ 1 C hotter per 3 cm decrease in clearance) and so less efficient because of less efficient cooling. The micros under them will also run close to that much hotter even with proper micro clearances.

                  Anyway, if the micro has a 3cm thickness, then a 9 cm. ( 3 cm thk. + 2 X 3 cm. clearances) roof clearance ought to do it to meet suggested micro clearances/gaps. Sounds to me that maybe the installers or their engineers are putting arrays closer to a roof than might be advisable, particularly in a hot, sunny climate.

                  Putting all those electronics in a hot and mostly inaccessible location seems bad enough to me. Making the array and so the micro inverter location still hotter and more inaccessible yet by narrowing the array to roof clearance makes me scratch my head. But, NOMB.

                  Comment


                  • #10
                    @J.P.M.. Great feedback!! I have added this topic to my notes (rack mounts, spacing of panels in relation to roof line)

                    Other questions I have for folks here. I wonder if I will get a collective "eye roll" or thoughts "dude, you are really overthinking this...." on this set of questions, lol.....

                    1. Do SE or Enphase active equipment (inverters, optimizers, comm devices, etc.) have software/firmware updates capabilities?
                    2. Does this get done by dealers (be shocked if they do this proactively) or can owner do these updates "easily" vs. whip out a laptop, connect a laptop, a special cable, run a special app, etc..... (easily may be defined like we do for other modern devices, e.g. win10 or macOS device, ios/android -- a guided type wizard?
                    3. I assume if the answer is yes, a different level of management software is needed, e.g. Enphase Manager. Does SE have an advanced software/web interface available to homeowners that dealers or OEMs have access to?

                    Also, I have known a Sunrun sales rep for a 3 or 4 years. Good guy, successful with them. He knows I won't go with them as they are easily 20-25% more expensive for comparable system. Anyway, talking with him in last few weeks, I knew that Sunrun had moved away nationally from using Solar Edge and going with Enphase. He told me "one" of the reasons was quality/service calls on Solar Edge installs for past 2 to 3 years. He added, parts availability also began to be a problem.

                    I have looked at some of the Enphase and SE demo accounts available and do not see anything like described above.
                    Last edited by bird95134; 05-20-2020, 12:27 PM.

                    Comment


                    • #11
                      Originally posted by bird95134 View Post
                      @J.P.M.. Great feedback!! I have added this topic to my notes (rack mounts, spacing of panels in relation to roof line)
                      Opinions on its worth vary. Take all of my stuff FWIW. I also respectfully suggest you consider that it, like most everything else here, is opinion, but some of those opinions have more education and more importantly, experience behind them.

                      Have you downloaded "Solar Power Your Home for Dummies" yet ?

                      Leaving my negative bias about micro inverters and to a lesser degree otimizers and keeping as much stuff off a roof as possible, and KISS aside with respect to design, I spent a large part of an engineering career solving/designing equipment for situations involving heat transfer applications. From what you write, it looks to me (only) that some of the folks you're communicating with are dancing with your leg. If the amb. air temp. on your roof gets to ~ 130 F, which is likely 1X/awhile on a roof in summer in NV, your panel temps. will get past 180 F (~ 82 C), even with good panel to roof clearance. A micro near the backside of a panel by a few cm or so will be a bit lower in temp. than the panel but still maybe above an upper service temp. limit. of the micro.

                      Comment


                      • #12
                        @ J.P.M -- thanks for the note. Yes, I have a copy of the Dummies book you mentioned. And, I have been "in and out" at looking at Solar for the past 5 to 8 years, where ROI did not make sense to me. If fact, ~24 months ago, I pulled the trigger on spending money on more insulation in attic, sealing any recessed lighting/vents in attic ceiling, sealed (as best I could) HVAC ducting, added returns in warm rooms, cleaned evaporator coils, and adding either blinds or radiant glass film (reduct heat through windows). I saw my electricity usage go down in 2018 to 2019 summers (measuring two 6-8 periods from pre 2018, about ~20% AND comfort level went up (as defined by keeping the home cooler).

                        To me, I got started again looking at Solar in past 2 weeks as I am seeing cost going down to sub $3 per kW installed. This is the price range that I always thought it may provide a decent ROI of < 10 years. Also, another project I need to do, which I can couple to the Fed Tax credit, is what we call here in LV NV is "lift and replace" maintenance on the tile roof, i.e. lift and remove the roof tiles, remove the underlayment paper, put down new underlayment paper, replace the tiles. Best practice is to perform every ~25 years (age of my home). So, need to do that anyway and before I would put anything on my roof. Adding that maintenance to a Solar project (for the discount from Fed Tax credit) adds to reasons to look at Solar now. And, here in NV, we have a TIer net metering program and one of the tiers close to capacity (buy back into grid at 81% of cost of kWh, goes down in July, estimated).

                        Comment


                        • #13
                          Originally posted by bird95134 View Post
                          @ J.P.M -- thanks for the note. Yes, I have a copy of the Dummies book you mentioned. And, I have been "in and out" at looking at Solar for the past 5 to 8 years, where ROI did not make sense to me. If fact, ~24 months ago, I pulled the trigger on spending money on more insulation in attic, sealing any recessed lighting/vents in attic ceiling, sealed (as best I could) HVAC ducting, added returns in warm rooms, cleaned evaporator coils, and adding either blinds or radiant glass film (reduct heat through windows). I saw my electricity usage go down in 2018 to 2019 summers (measuring two 6-8 periods from pre 2018, about ~20% AND comfort level went up (as defined by keeping the home cooler).

                          To me, I got started again looking at Solar in past 2 weeks as I am seeing cost going down to sub $3 per kW installed. This is the price range that I always thought it may provide a decent ROI of < 10 years. Also, another project I need to do, which I can couple to the Fed Tax credit, is what we call here in LV NV is "lift and replace" maintenance on the tile roof, i.e. lift and remove the roof tiles, remove the underlayment paper, put down new underlayment paper, replace the tiles. Best practice is to perform every ~25 years (age of my home). So, need to do that anyway and before I would put anything on my roof. Adding that maintenance to a Solar project (for the discount from Fed Tax credit) adds to reasons to look at Solar now. And, here in NV, we have a TIer net metering program and one of the tiers close to capacity (buy back into grid at 81% of cost of kWh, goes down in July, estimated).
                          Well, you're one of the few who keep the horse before the cart and lower the electrical load as much as possible prior to adding energy sources. Hats' off to you.

                          Your PV can be smaller (and less expensive) by about the same 20 %, and most of the conservation efforts won't need much, if any maintenance, but you've probably noticed that.

                          I also appreciate your timeline. 81% of retail is better than the 75 % after the tier fills up.

                          Good luck.

                          Comment


                          • #14
                            Originally posted by bird95134 View Post

                            @ J.P.M.. No shade problem. I like the modular design and extremely simplified approach to add panels later as needed as DC to AC conversion is done at panel and ease to add AC to bus within a close proximity J box. They agreed to match pricing for either system (with SE system technically cheaper, as 1. System is less cost, and 2. I would remove the two LTE comm modules in favor of Ethernet Cat5e to my home Ubiquiti network. I see the DC voltage safety issue is solved with (and included) rapid shutdown inherent within the proposed system. Thanks for observations on wind velocity notes.
                            If you got (2) 7.6kW SMA string inverters that would give you 6 independent MPPT channels so you would have the ability to expand later as well as use different panels. SMA recently published a white paper comparing module level electronics to string level and in unshaded and partially shaded scenarios string level outperformed module level likely due to heat issues.

                            Comment


                            • #15
                              @J.P.M. @ nwdiver -- thanks for feedback and comments!!

                              @nvdiver, specifically to your post:

                              "If you got (2) 7.6kW SMA string inverters that would give you 6 independent MPPT channels so you would have the ability to expand later as well as use different panels. SMA recently published a white paper comparing module level electronics to string level and in unshaded and partially shaded scenarios string level outperformed module level likely due to heat issues."

                              Questions:

                              1. If my current proposed Solar Edge design (qty 44) Panasonic VMHN340SA17 panels + ( qty 2) SE7600H-US Inverters + (qty 44) SE P400 Power Optimizers. This equals a 14,960 kW capacity. I would need to upgrade one of inverters (or both) in this design if I wanted to add panels for additional load, correct?

                              2. If one Inverter of the 2 died/broke, would I still have 1/2 capacity?

                              Update:

                              I have not finalized my decision on selected design. As with 1st post, same panels, roof lines, install company, all aligned with historical -- all of those parameters aligned with historical electrical usage (and future assumptions). I still have not made up my mind on a SE vs. Enphase. Lot's of great feedback thus far here (SE / string is the winner on this thread) and from others. Couple of points:

                              1 I had another meaningful discussion I have had on the Enphase performance issues in high heat install locations like mine (Southern NV), included feedback aligned to @J.P.M feedback about airgap that was related to distance between rooftop and microinverter in real world testing. Comments included that if microinverter airgap between roofline and Microinverter mounted on panel was < 2 in, they saw this problem. If the distance was closer to 4 or 5 inches, there have "not been this problem or very little of this condition" (condition = microinverter shutting down or underperforming [not clipping] due to high heat).

                              2. Confirming from multiple points (even the installer I am working with) did confirm they have seen SE problems/failures -- more than we like to see (out of box, 30-90 days into production, or within a couple of years). A few power optimizers and a few microinverters. Their answer is they have spare whole unit SEs and some FRUs (Field Replaceable Units), like fans that they can replace. Couple this with monitoring they do, they think 3 or 4 days is max a unit would be out "most of the time". Regardless, concerned about this information -- comments on SE inverter experience by anyone here?

                              Thanks for all feedback thus far!!

                              Comment

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