Announcement

Collapse
No announcement yet.

Off grid type setup that is on grid?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Off grid type setup that is on grid?

    Sorry, new to solar and I am still in the research stage. I know the title sounds strange, but please let me explain.

    I live in Japan and we have to go through registered dealers to sell electricity back to the grid. So a DIY setup will not be approved. What I wanted to do was build my own system and store any excess electricity made during the day (no one is at home during the day and electricity use is very minimal) in batteries for use in the evenings and night. Problem is with space being an issue going off my calculations I won't be able to make enough power to go completely off grid.

    So , my question is, can you design a system that the house will run off the solar system and when all electricity is depleted from batteries or at night will switch to grid power?

  • #2
    Maybe you can use an automatic transfer switch and set it up so that your "off-grid" solar system is the primary power source. As long as it has power, the switch will use it to power your home. When it no longer has stable power, the transfer switch will change to utility power.

    http://www.electricgeneratorsdirect....er-Switch.html

    I think you will lose power every day though. In real use, it would probably have issues to keep it from being practical.

    Comment


    • #3
      Unfortunately any type of off grid system with batteries will end up costing more to generate a kWh than what you can purchase it from your electric utility.

      The best way to get solar to pay for itself is to install a legal grid tie system. Whenever you add a battery you pretty much are spending more money than just using your grid power.

      Comment


      • #4
        Originally posted by rsilvers View Post
        Maybe you can use an automatic transfer switch and set it up so that your "off-grid" solar system is the primary power source. As long as it has power, the switch will use it to power your home. When it no longer has stable power, the transfer switch will change to utility power.

        http://www.electricgeneratorsdirect....er-Switch.html

        I think you will lose power every day though. In real use, it would probably have issues to keep it from being practical.
        This system would kill the batteries rather quickly, basically fully draining the batteries before switching every time.

        If your goal is to save money then the best bet is a legal grid tie system.
        There are bimodal systems that can be configured to not feed into the grid but they would requier similar permits but not necisarily an interconnect agreement.
        OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

        Comment


        • rsilvers
          rsilvers commented
          Editing a comment
          How about a low-voltage battery disconnect?

        • ButchDeal
          ButchDeal commented
          Editing a comment
          make your own grid zero inverter system, sure. I don't think the OP was looking for a build your own project though. and as specified a grid zero system is unlikely to save OP money. Doing it with disconnects would have reliability issues and permit issues if you tried to use off grid parts (only reason to go this round).

      • #5
        Electricity where I am is about 28-30 cents for a Kilowatt hour. Would you still say that it is not worth it?

        Comment


        • #6
          Originally posted by JapanDave View Post
          Electricity where I am is about 28-30 cents for a Kilowatt hour. Would you still say that it is not worth it?
          Most solar battery systems can cost above $1/kWh. So yes I would say it is not worth it.

          Now a hybrid grid tie system may help someone with that type of electric rates but even in Hawaii where it can get to ~ 50 cents / kWh a battery is hard to justify.

          Comment


          • #7
            Is it the cost of buying the batteries that keep costs up? So should I take it that even if you could make enough electricity to go off grid that it would not be worth it?

            Comment


            • #8
              Originally posted by JapanDave View Post
              Is it the cost of buying the batteries that keep costs up? So should I take it that even if you could make enough electricity to go off grid that it would not be worth it?

              no that is a part of the added costs.
              The inverters that handle batteries costs more
              there are Charge controllers that add cost
              there is different wiring and more labor that adds costs
              to provide the same amount of power, the system must be larger, adds costs
              OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

              Comment


              • #9
                Originally posted by JapanDave View Post
                Is it the cost of buying the batteries that keep costs up? So should I take it that even if you could make enough electricity to go off grid that it would not be worth it?
                Until the price of solar & battery equipment comes down more it will cost more to generate your own power then to just purchase it from your POCO. A solar grid tie system can pay for itself. IMO since you pay a high price for electricity depending on what the cost to install a pv grid tie system you should see a payback much quicker then someone paying only 10 cents/ kWh.

                Comment


                • #10
                  Originally posted by JapanDave View Post
                  So , my question is, can you design a system that the house will run off the solar system and when all electricity is depleted from batteries or at night will switch to grid power?
                  Sure. Outback inverters have a mode called "HBX mode" that does this. It will be pricey, though, as others have pointed out.

                  Comment


                  • #11
                    A somewhat more practical solution would be to simply use a hybrid inverter which has been configured to prohibit sell back and tie it to a very small battery bank and settings that will avoid draining the battery when grid is present.
                    A pure grid tie inverter with an anti-sell-back function would also do the job and some of those are made primarily for sale outside the US.
                    SunnyBoy 3000 US, 18 BP Solar 175B panels.

                    Comment


                    • #12
                      With the Hybrid system, is this what you are talking about?
                      http://www.cleanenergyreviews.info/b...s-hybrid-solar

                      I am thinking of building a 6kw array. Any suggestions as to what hybrid inverters that have a good track record?

                      Comment


                      • #13
                        Originally posted by JapanDave View Post
                        I am thinking of building a 6kw array. Any suggestions as to what hybrid inverters that have a good track record?
                        The Outback GVFX line have a good reputation. They only go up to 3600 watts but that shouldn't be much of an issue.

                        Comment


                        • #14
                          Originally posted by jflorey2 View Post
                          The Outback GVFX line have a good reputation. They only go up to 3600 watts but that shouldn't be much of an issue.

                          They stack.
                          You also have the Radian series, which also stack.
                          OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

                          Comment


                          • #15
                            Can the manufacturer preset the setting to stop power being diverted to the grid , or would I have to do this myself?

                            Comment

                            Working...
                            X