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  • Itemize what's wrong with this idea

    I came across this post on another forum that shocked me. It strikes me as so irresponsible. Besides item 1 that I'm starting below, can you give additional bullet points as to why this a really bad idea?

    Installation is dead simple. plug the panel in the micro inverter and plug the micro inverter in a socket. That's it. Keep in mind of course that the socket is out of the weathers way. This setup generates between 100-300W constantly on a sunny day, depending on the time of day. Not enough to cover large stuff like an AC but it takes quite a chunk out of your usage and your bill..

    1) In the case of a power outage, this panel would energize the incoming line to the house, preventing a lineman outside from safely doing repairs?

    2) The AC generated by the microinverter might be out of phase with the house AC, resulting in distortion? How bad is that to the electronics in the house?

    Please give me your opinions

  • #2
    Originally posted by MichaelK! View Post
    I came across this post on another forum that shocked me. It strikes me as so irresponsible. Besides item 1 that I'm starting below, can you give additional bullet points as to why this a really bad idea?

    Installation is dead simple. plug the panel in the micro inverter and plug the micro inverter in a socket. That's it. Keep in mind of course that the socket is out of the weathers way. This setup generates between 100-300W constantly on a sunny day, depending on the time of day. Not enough to cover large stuff like an AC but it takes quite a chunk out of your usage and your bill..

    1) In the case of a power outage, this panel would energize the incoming line to the house, preventing a lineman outside from safely doing repairs?

    2) The AC generated by the microinverter might be out of phase with the house AC, resulting in distortion? How bad is that to the electronics in the house?

    Please give me your opinions
    Well to answer your questions;

    1. Most micro inverters will stop working if the grid goes down but to use them in the US they must be UL listed or it is illegal.

    2. If you have power being generated that has a different phase orientation then the grid again a UL listed inverter will shut down. If not then the out of phase power generation can cause issues with home loads especially electronics.

    Something you did not mention is that if you do decide to generate power that can go onto the grid your POCO will need to be notified so that a contract is created. If not then you may be in violation of both the POCO and local code rules.

    Oh and by the math a 300 watt panel may generate 1.5kWh a day (300w x 5 hours = 1500wh) Which is about $.18 cents a day or about $5 per month. (1.5kWh x $0.12/kWh = $0.18 x 30 = $5.40) so is it worth that based on the cost of a 300watt panel and micro inverter. Seems like a long payback period to me.
    Last edited by SunEagle; 01-30-2020, 03:04 PM. Reason: added last sentence

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    • #3
      Another potential issue is that it has been discussed that SOME POCO meters measure energy flow whether in or out. SO if you install this illegal setup, power generated that is in excess of your consumption, second by second, will actually add to your bill.

      This is more significant for larger systems where the POCO has not installed or set the meter for net metering.

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      • #4
        I'm assuming that someone is proposing putting a MALE connector (US version is called type B or NEMA 5-15) on the output of the microinverter and plugging that into a mating outlet. Since modern microinverters like an Enphase IQ7 or APsystems QS1 don't put out power until they are connected, that will be safe. It doesn't meet code and won't pass an inspection, but should be safe.

        If the microinverter is a modern inverter intended for solar, like an Enphase IQ7 or APsystems QS1, it will sync to and put out power in phase with the line.

        Curiously, you can technically parallel the power mains with a generator that puts out power out-of-phase with the line and even off frequency, and still efficiently backfeed the grid. I'm not saying it is legal, I'm just saying that current will flow in the right direction and energy will flow. It happens in huge power grids all of the time.

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        • #5
          Originally posted by bob-n
          Curiously, you can technically parallel the power mains with a generator that
          puts out power out-of-phase with the line and even off frequency, and still efficiently backfeed
          the grid. I'm not saying it is legal, I'm just saying that current will flow in the right direction and
          energy will flow. It happens in huge power grids all of the time.
          Now you are showing no understanding of alternating current and its distribution. Long ago
          bringing another generator on, the rpm would be set. Then with light bulbs between the
          the source and the others, the phase would be nudged around till the lights went out. At
          that instant the connect switch is closed and the throttle thrown open.

          This is like a horse running up to a team and connecting. At that point he is not going to
          get ahead because he can not pull the whole load alone. Stays in phase, like those
          generators. I do not know what replaces the light bulbs today. Bruce Roe

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          • #6
            I have heard the thump when some moron did not pay attention to a synchroscope and flipped the switch slightly out of synch. Nothing broken but who knows what long term damage was done. Microinverters get around having to be synched as they use the line frequency to synch to. The UL 1741 standard requires it.

            Most large generators have auto sync but we normally spec a synchroscope on the control panel for manual sync. Its just an analog meter that has the needle pointing straight up when the generator is in synch with the grid. The needle deflects to the left and right when its out of sync. Just watch the needle, figure out when its creeping towards the center and flip the handle to close the utility breaker when the needle hits straight up.

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            • #7
              Originally posted by MichaelK! View Post
              I came across this post on another forum that shocked me. It strikes me as so irresponsible. Besides item 1 that I'm starting below, can you give additional bullet points as to why this a really bad idea?

              Installation is dead simple. plug the panel in the micro inverter and plug the micro inverter in a socket. That's it. Keep in mind of course that the socket is out of the weathers way. This setup generates between 100-300W constantly on a sunny day, depending on the time of day. Not enough to cover large stuff like an AC but it takes quite a chunk out of your usage and your bill..

              1) In the case of a power outage, this panel would energize the incoming line to the house, preventing a lineman outside from safely doing repairs?

              2) The AC generated by the microinverter might be out of phase with the house AC, resulting in distortion? How bad is that to the electronics in the house?

              Please give me your opinions
              We may have seen the same listing. I was poking around on eBay and saw an ad that had wording very similar. The seller was offering an 12 volt AGM battery, a 12 volt inverter and a cord with NEMA 5-15 plugs on both ends.

              Easy peasy. Power goes out you plug it in to an available receptacle and you have power. The only question is: who is going to prison when it kills someone? The eBay seller or the idiot who actually plugs it in.

              It is just stupid crazy when I was living out in the woods we had very frequently power outages. I can't count how many times I was asked to cobble up a similar cable so that they could plug a generator in in the same manner. . Even worse, I stood in the electrical department of Home Depot and overheard an HD employee explain to a customer how to do the same thing. I waited for the employee to walk away and explained to the gent what a bad and dangerous idea it was and showed him the generator transfer switches and recommended a licensed electrician.
              Last edited by PNW_Steve; 01-31-2020, 06:28 PM.

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              • #8
                Originally posted by PNW_Steve View Post
                ......

                Easy peasy. Power goes out you plug it in to an available receptacle and you have power. The only question is: who is going to prison when it kills someone? The eBay seller or the idiot who actually plugs it in........
                Easy, just try to find a flea bay seller if something goes wrong. poof - nobody there, sucker.

                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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                • #9
                  Originally posted by Mike90250 View Post

                  Easy, just try to find a flea bay seller if something goes wrong. poof - nobody there, sucker.
                  Probably so....

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