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Best quality and Best buy for grid-tie inverter?

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  • Best quality and Best buy for grid-tie inverter?

    As I collect my solar panels, I'm nearing 1KW, and had begun to consider battery costs until I took time to email our electric company to ask about a grid tie in. The local power provider is an electric Co-op here in Texas, and has said they will install a "forward and reversing KWH meter" if I complete their insurance requirements and paperwork application for "Under 10KW Co-generation". I emailed them to ask if there were types and brands of inverters they perferred, to which they said they had no company list and it was up to me as most inverter companies have improved because of the push for Green acceptance. I was very happy to hear grid tie is a real possibility, although they have no rebate program like TXU/On-Cor, a large metroplex electric company who is buying wind energy from the large wind farm in West Texas.

    What grid-tie inverter of a 1.5-2KW rating is working for you, and who has the best prices and warranty service? To keep a balanced usage of this small array, should the inverter be a 220v version so it provides to both legs of the incoming power?

    Thanks,
    Bill

  • #2
    I tend to prefer the fanless inverters, like the Xantrex GT series. But to pass inspection and insurance, the PV panels need to be UL certified, no homemade panels.

    http://store.solar-electric.com/xagt25grties.html 2.8KW Xantrex

    http://store.solar-electric.com/fr18wauttiei.html 2Kw FRONIUS

    http://store.solar-electric.com/pv20wagrtiei.html 2kw PV Powered Designs

    http://store.solar-electric.com/suboy70700wa.html 700W SMA

    Also check prices at sunelec.com
    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


    • #3
      Pardon me for butting in here but this is something I'm just starting to look at.

      I'm assuming the 2.8KW Xantrex would work for me? I'm mainly looking at power for my 240v well pump, sump pump and septic pump? Obviously not all running simultaneously. And would it make sense to use this setup or a larger inverter in conjunction with a 120-to-240v transformer? Thanks so much.

      Comment


      • #4
        Grid Tie inverters are nearly always 240V to match the power feed at the house. They do not power any appliances, they only backfeed the active power grid.

        They first sense and monitor the grid power for 5 minutes, and only then, do they start to output power. Every couple seconds, they try a high voltage spike, to test to make sure the Grid is present, and they are not getting fooled by a generator. If the voltage rises (too high of grid impedence) they shut off. If the grid fails, they shut off. They pass every possible watt, into the grid.
        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


        • #5
          Thanks for responding. OK I guess I'm confused. What I'm looking for is an inverter that is monitoring the grid so that in the event of a grid failure backup batteries and/or PV panels can power my devices.

          Comment


          • #6
            Check the Outback 3048, no grid tie in, but can have to circuits/breakers that will allow battery backup to take over so fast it is seamless. Expensive: $1,900+/-

            Bill

            Comment


            • #7
              inverter 5 minute lockout at every utility glitch

              Originally posted by Mike90250 View Post
              ...
              They first sense and monitor the grid power for 5 minutes, and only then, do they start to output power. Every couple seconds, they try a high voltage spike, to test to make sure the Grid is present, and they are not getting fooled by a generator. If the voltage rises (too high of grid impedence) they shut off. If the grid fails, they shut off. They pass every possible watt, into the grid.
              My hope is to find a 'hacker' or better yet, some inverter company that makes their inverter software, open source. I want to be able to config that 5 minute lockout constant. I have utility glitches here every hour or so and I cannot tolerate the inverter being DOWN at every glitch for a full 5 minutes.

              Any other thoughts more than welcome. I have to decide on the inverter purchase today and would rather direct my $$$ to the right place.

              sara dot j at embarqmail dot com

              Comment


              • #8
                Originally posted by Keepsake View Post
                My hope is to find a 'hacker' or better yet, some inverter company that makes their inverter software, open source. I want to be able to config that 5 minute lockout constant. I have utility glitches here every hour or so and I cannot tolerate the inverter being DOWN at every glitch for a full 5 minutes.

                Any other thoughts more than welcome. I have to decide on the inverter purchase today and would rather direct my $$$ to the right place.

                sara dot j at embarqmail dot com
                That will be a difficult one to overcome as you will loose the UL listing as soon as you modify the inverter.
                NABCEP certified Technical Sales Professional

                [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

                Comment


                • #9
                  Depends where you live.


                  All-purpose inverter? You really can't go wrong with SMA although it does have moving parts that might be a concern to some.

                  http://www.sma-america.com/en_US/pro...s-4000-us.html


                  Live in a hot and dusty climate? Power-One is the answer. The only NEMA-4 inverter on the market, also one that won't start to derate until 122 degrees F which might be important if you happen to live in Phoenix, Albuquerque and other assorted hot climates.

                  http://www.power-one.com/renewable-e...outdoor/series

                  Also kind of keen on the Solar Edge system. The inverter comes with a 12 year warranty and comes in a package with a central inverter and DC optimizers all included. Very nifty.


                  Bottomline, if the average temperature rarely or never exceeds 100, I'd go with SMA, if it goes above 100, I'd go with Power-One.

                  Comment


                  • #10
                    Originally posted by GregS View Post
                    Thanks for responding. OK I guess I'm confused. What I'm looking for is an inverter that is monitoring the grid so that in the event of a grid failure backup batteries and/or PV panels can power my devices.

                    So you're really looking for a grid-tie battery backup system. Hope you're pretty handy or got lots of the $$$$ to throw around

                    Comment


                    • #11
                      Originally posted by Keepsake View Post
                      My hope is to find a 'hacker' or better yet, some inverter company that makes their inverter software, open source. I want to be able to config that 5 minute lockout constant. I have utility glitches here every hour or so and I cannot tolerate the inverter being DOWN at every glitch for a full 5 minutes.

                      Any other thoughts more than welcome. I have to decide on the inverter purchase today and would rather direct my $$$ to the right place.

                      sara dot j at embarqmail dot com

                      Is this man your president?



                      Comment


                      • #12
                        Grid tie

                        Sounds to me like you want a back up to run sump pump in case power co fails. I am looking to do the same thing.
                        What I came up with is this. Solar panel, to voltage regulator, to battery, to inverter (non grid tie)
                        Why non grid tie? Because grid tie shuts down if TXU fails, and that is the opposite of what I want.

                        Now if you want to sell excess production to TXU then buy a regulator with a divert circuit, to power the grid tie inverter after your battery is charged up.

                        How many amps does the motor your trying to run use? Example: at 120 volts 10 amps = 1,200 watts. or 1.2 kw.

                        You don't need 1.2 kw of solar panels, but you will need a big battery bank. To properly charge a battery you need ~ 15 amps per. A 400 amp hour battery doesn't deliver 400 amp hours of use, because your inverter is going to shut off when battery falls to 10.5. i.e. you get 100 ~amp hours.

                        However, for my use I am using sump pumps to avoid flooding, and they don't stay on but for a few seconds at a time. I want back up in case I loose power during a thunderstorm. That is best done with out grid tie, but grid tie can be added for no other reason than to sell excess electricity.

                        Comment


                        • #13
                          Originally posted by rrichar911 View Post
                          However, for my use I am using sump pumps to avoid flooding, and they don't stay on but for a few seconds at a time. I want back up in case I loose power during a thunderstorm. That is best done with out grid tie, but grid tie can be added for no other reason than to sell excess electricity.
                          For a short (one or two day max) outage following a thunderstorm, you can just charge your batteries off AC. For a longer outage, get a generator first.
                          SunnyBoy 3000 US, 18 BP Solar 175B panels.

                          Comment


                          • #14
                            I use a Magnum PAE inverter/charger on the feed to my greenhouse. While power is up, the batteries charge / stay in float from the main AC. When power goes down, the batteries and inverter take over that circuit. I've got about 24-48 hours of backup at my current use levels. For extended outages, I can either fire up the generator & feed thru the Magnum or I can rehook up my grid-tie panels to my off-grid charger and keep the battery pack full. FYI, The Magnum inverter is sweet in that it can remotely fire up the generator by itself as the battery pack drains down, then shut the generator off after the pack is charged back up without any outside interaction.

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