X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Using Enphase Offline

    Had a power outage for a day and a half and it pains me to have 8Kw offline with the sun shining. Would this possibly work?

    Manually disconnect myself from the grid. Then connect a 240v battery powered inverter to my home wiring to supply a 240v sine wave signal to enable the Enphase inverters.

    Any ideas?


  • #2
    Originally posted by npaizis View Post
    Had a power outage for a day and a half and it pains me to have 8Kw offline with the sun shining. Would this possibly work?

    Manually disconnect myself from the grid. Then connect a 240v battery powered inverter to my home wiring to supply a 240v sine wave signal to enable the Enphase inverters.

    Any ideas?
    That is more or less how the AC coupled Powerwall 2 will work. You'll need some well thought out controls in place to keep the whole system from crashing and/or burning. Enphase put out a white paper to introduce some of what you'll need to consider.

    https://enphase.com/en-us/support/te...-based-systems

    Don't forget to check with your AHJ on the permitting requirements to add batteries to your system.
    Last edited by sensij; 08-11-2017, 04:10 PM.
    CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

    Comment


    • #3
      For a day and a half without grid power a whole house generator will provide much more than any battery system and be about 1/5th the cost.

      But if not having your pv panels do anything when the grid is down is the issue then you can look into something like the Powerwall 2 or one of Tesla's competitor battery systems and see which will work with your Enphase hardware as well as which would be approved by your AHJ.

      Comment


      • #4
        Originally posted by npaizis View Post
        Had a power outage for a day and a half and it pains me to have 8Kw offline with the sun shining. Would this possibly work?

        Manually disconnect myself from the grid. Then connect a 240v battery powered inverter to my home wiring to supply a 240v sine wave signal to enable the Enphase inverters.

        Any ideas?
        More directly answering your question : No that won't work, at least not safely.

        Plugging in at 240v source will defeat the Enphase inverter safety feature and causing your inverter to come online again. Good right? Not really.

        Your 8kw system will come online at full capacity (solar energy). Your inverter will push out all the energy it receive from DC to AC. The problem is, if your house isn't consuming a matching amount, you'll have brownout or overload. Both scenario is bad.

        In essence, the grid goes down, you need a battery system to be the buffer and absorb excess (unused) energy from your PV. Without this buffer, your system will be overloaded.

        Most inverters on the market are only capable of being on (maximize production) or off (safety), with no dynamic load output capability. That's why you can't just flip the switch back on. I know that Solaredge inverters could be configured to limit export power to be zero, in your case to prevent an overload - your system from producing too much power. Assuming your battery has enough power, you could cover both short and excess generation in a de facto off-grid configuration.
        Last edited by inspron; 08-11-2017, 07:04 PM.

        Comment


        • #5
          Originally posted by npaizis View Post
          Had a power outage for a day and a half and it pains me to have 8Kw offline with the sun shining. Would this possibly work?

          Manually disconnect myself from the grid. Then connect a 240v battery powered inverter to my home wiring to supply a 240v sine wave signal to enable the Enphase inverters.
          Any ideas?
          The sun was shining for a very long time before there were any solar panels. I am certainly
          not going to waste time worrying about 1.5 more days of panels not operational. I got a
          generator to cover that decades ago, only used it 4 times. Bruce Roe

          Comment


          • #6
            Originally posted by npaizis View Post
            Had a power outage for a day and a half and it pains me to have 8Kw offline with the sun shining. Would this possibly work?

            Manually disconnect myself from the grid. Then connect a 240v battery powered inverter to my home wiring to supply a 240v sine wave signal to enable the Enphase inverters.

            Any ideas?
            There are many posts about this. It will not work unless you get a rather large and expensive bimodal inverter with a battery large enough to handle the full charge of the Enphase array. A cheap small inverter will not work at best and will crash and burn at worst.
            This is called AC coupling and it is costly and complicated to get working right and safely.
            OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

            Comment


            • #7
              Thanks All. I think maybe a generator is the best way to go. Power out again yesterday for 6 hours.

              Comment


              • #8
                Originally posted by npaizis View Post
                Thanks All. I think maybe a generator is the best way to go. Power out again yesterday for 6 hours.
                Get a generator. Using PV and batteries for power outages is like using two computers as bookends for an encyclopedia.

                Comment


                • #9
                  Originally posted by npaizis View Post
                  Thanks All. I think maybe a generator is the best way to go. Power out again yesterday for 6 hours.
                  Or UPS, if you want short term/low energy backup.

                  Comment


                  • #10
                    A friend tried doing something like this with a propane powered generator to see if it would work in an earthquake siuation where the power might be out for weeks. He has a 16 amp max output on his solar inverter. He turned off the proper breakers, plugged in his EV drawing 20 amps, turned on the appropriate breakers. The generator powered the house/charged the EV fine but the frequency was out of range so the inverter never would send any power out.

                    Comment


                    • #11
                      Originally posted by FFE View Post
                      The generator powered the house/charged the EV fine but the frequency was out of range so the inverter never would send any power out.
                      Good thing too, especially if he likes his generator.
                      OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

                      Comment


                      • #12
                        Originally posted by FFE View Post
                        A friend tried doing something like this with a propane powered generator to see if it would work in an earthquake siuation where the power might be out for weeks. He has a 16 amp max output on his solar inverter. He turned off the proper breakers, plugged in his EV drawing 20 amps, turned on the appropriate breakers. The generator powered the house/charged the EV fine but the frequency was out of range so the inverter never would send any power out.
                        Which is why a generator can't fool a grid tie inveter into believing it is the grid.

                        Comment

                        Working...
                        X