Help me with my system design, solar with generator backup without battery

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  • huge
    Solar Fanatic
    • May 2016
    • 111

    Help me with my system design, solar with generator backup without battery

    I'm fairly new at this and I need help coming up with a design for my system. I think I have the solar panel positions figured out with 3 orientations, ranging from 6-10 panels each. I want to go with a solaredge system because of some shading issues. What I need help with the most now is the wiring becasue I don't know much about it.

    This is what I want to do: I want to have the inverter installed in a way that I can add a generator to the system down the line so that I can have some power during our yearly outages. The generator is going to come a little later after I pass the inspection, but I want to have everything ready for when I get one so that I just have to plug it in when needed. I would also like to add a couple of panels in the backyard mounted on the ground maybe in a year or two for some anticipated increase in electricity need, but this is just secondary.

    How do I need the inverter wired, in general terms? Do I need a switch between the inverter and the electric panel? It makes more sense to have a switch between the inlet from the power company and the electric panel, but I'm not sure if this is even possible. I know I need something to avoid backfeed onto the power lines, but I'm not sure how this is generally done in order to also provide power from the solar system to the electric panel. If possible, I want to avoid having a critical load subpanel to keep it simple and keep cost down. My electric panel is a little unorganized and it would take some work figuring out which wiring goes into which breaker. If power goes out, I would only be using the critical stuff anyway and all I need is to run are the lights, refrigerator and the central AC (and ideally even the internet and security cameras) and having to rewire everything to accommodate a subpanel may be cost prohibitive, but I'm not sure what the costs involved are even going to be so I would appreciate any suggestions.
    Last edited by huge; 06-10-2016, 06:50 AM.
  • ButchDeal
    Solar Fanatic
    • Apr 2014
    • 3802

    #2
    Just make sure that the inverter is done as a lineside tap or have them put in the transfer switch at the time of the solar install, with the inverter on the grid side of the transfer switch. Non-bimodal inverters do not work with generators so they should be disconnected from it when it is operating. Thus putting the interconnect on the grid side of the transfer switch.

    Unless you get a bimodal (hybrid) inverter in which case the generator will attache to the inverter.
    OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

    Comment

    • dex
      Junior Member
      • Jun 2016
      • 31

      #3
      If you're preparing for a battery backup or generator down the line I have spoken to a couple electricians on install crews and they all say SolarEdge is the way to go. You can add to the SolarEdge with a Schneider XW 5548 inverter or just start with the Schneider and use a charge controller

      Comment

      • huge
        Solar Fanatic
        • May 2016
        • 111

        #4
        Does the Schneider replace the solaredge or is it in addition to it?
        What are some good bimodal inverters? Sunny Island seems very pricey.

        Everyone says that getting a generator for backup is much cheaper, but seems like a good 2kw generator will cost around $1000 by itself. Would I be able to add a generator to the storedge version of the solaredge without the Tesla battery?

        I'm just trying to come up with some affordable options to have backup power from the panels in emergency situations. Unfortunately, I can't afford the storedge solution, so I need to come up with a cheap way to do it

        Comment

        • dex
          Junior Member
          • Jun 2016
          • 31

          #5
          You can use the Schneider in addition to the SolarEdge.

          You could go with this Conext as well. I believe the SW2524 can do a 7kW system. I've seen it for $1400 http://solar.schneider-electric.com/product/conext-sw/

          Comment

          • ButchDeal
            Solar Fanatic
            • Apr 2014
            • 3802

            #6
            Originally posted by huge
            Does the Schneider replace the solaredge or is it in addition to it?
            What are some good bimodal inverters? Sunny Island seems very pricey.

            Everyone says that getting a generator for backup is much cheaper, but seems like a good 2kw generator will cost around $1000 by itself. Would I be able to add a generator to the storedge version of the solaredge without the Tesla battery?

            I'm just trying to come up with some affordable options to have backup power from the panels in emergency situations. Unfortunately, I can't afford the storedge solution, so I need to come up with a cheap way to do it


            You can go either way. The schneider or OutBack, or Sunnyisland would AC couple to the existing or you could replace the existing with charge controllers and add the bimodal inverter (generally the same inverters).

            No the SolarEdge StorEdge inverter does not do bimodal without the battery.

            Cheapest is to go with a generator independtly of the solar. Some will say to go with the SMA Secure Power Source but that is hardly backup if it provides power only when it wants and not when you want, and even then very limited, not wired in, and not automatic.
            OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

            Comment

            • huge
              Solar Fanatic
              • May 2016
              • 111

              #7
              Thanks butch. How does the Outback compare with solaredge as far as the actual panel performance?

              Comment

              • ButchDeal
                Solar Fanatic
                • Apr 2014
                • 3802

                #8
                Originally posted by huge
                Thanks butch. How does the Outback compare with solaredge as far as the actual panel performance?

                I have an outback, but I don't have any shadows. It is very nice inverter and good string Charge controller.
                SolarEdge has one of the most efficient inverters
                OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

                Comment

                • huge
                  Solar Fanatic
                  • May 2016
                  • 111

                  #9
                  How big of a generator do I need to power just the essentials, like central AC, refrigerator and lights?

                  Comment

                • SunEagle
                  Super Moderator
                  • Oct 2012
                  • 15124

                  #10
                  If those units are properly rated and can handle the surge of an AC unit starting then I would say either should work.

                  IMO sometimes trying to power a central air unit can be expensive. Usually a whole house generator connected to a natural gas tank is the way to have secure backup power.

                  Or going with a smaller room AC unit and having a generator to power it might be a better choice based on available funds.

                  I have a small free standing AC unit around 14000BTU. It does not take a lot of power to run it and it will cool down my master bedroom and bath. Since there are only two of us in the house that works for me but if you have a larger family or are unable to just cool one room a larger AC unit would be needed along with a generator to power it.

                  Comment


                  • huge
                    huge commented
                    Editing a comment
                    Thanks. That helps a lot. Where do you put the vent for the free standing AC unit? By vent, I mean the tube that blows out the hot air

                  • SunEagle
                    SunEagle commented
                    Editing a comment
                    Mine came with a big plastic tube and a fitting that could go into a window. It allow the hot air to be vented outside.

                    The biggest problem is with the condensation that can collect and would need to be dumped down a drain. Either that or it will overflow and get on the floor.

                    Still the unit I tested seem to keep our bedroom much cooler then the rest of the house. But thank God I have only had to use it once due to not having many long duration power outages.
                • huge
                  Solar Fanatic
                  • May 2016
                  • 111

                  #11
                  what kind of transfer switch would I need to run the house? Would something like the GE Energy TC10323R 100A Outdoor Double Pole Double Throw Safety Switch

                  work?

                  Comment

                  • SunEagle
                    Super Moderator
                    • Oct 2012
                    • 15124

                    #12
                    The transfer switch would be required to have an amp rating equal to what your main panel is rated. It would also have to be wired between the main panel and POCO wiring connection so that you can switch between the grid or an emergency generator. Unless you plan on getting approval from your local AHJ and using a licensed electrician to perform the work you would be getting yourself into an unsafe condition.

                    Comment

                    • Eleceng1979
                      Junior Member
                      • May 2016
                      • 57

                      #13
                      The transfer switch MUST BE service entrance rated if installed at the location sun eagle mentioned. Most automatic switches can be either or...you need to look. This will get you in trouble if you get the wrong one.

                      The manual switch you provided is only 100a and is properly rated, but too small for your home if you have a 200a service. Manual transfer is ok, just silly with a whole house genny these days.

                      Buy an automatic transfer switch. They are practically free (cheap) when buying a genny. Newer switches are pretty full of features and have load shedding which is required by some locale. All automatic transfers have provisions for manually switching too.

                      You are looking for these words, copied from the GE switch you listed.
                      • Suitable for use as service equipment when installed in accordance with the National Electrical Code.
                      • Suitable for use as transfer equipment in standby systems in accordance with Article 702 of the National Electrical Code.

                      Comment

                      • inetdog
                        Super Moderator
                        • May 2012
                        • 9909

                        #14
                        Originally posted by Eleceng1979
                        .... Newer switches are pretty full of features and have load shedding which is required by some locale....
                        Actually if the whole house generator is not capable of powering the entire calculated load of the house, it is the NEC and not local rules that require load shedding to be part of the installation which uses an ATS.
                        If you use a manual TS you are allowed to do manual load shedding too.
                        SunnyBoy 3000 US, 18 BP Solar 175B panels.

                        Comment

                        • huge
                          Solar Fanatic
                          • May 2016
                          • 111

                          #15
                          Thanks for the recommendations. How about getting one of these interlock kits http://www.interlockkit.com/ and just connecting the generator to a 30 A double pole breaker. Seems like a cheap alternative?

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