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  • #16
    Thanks Mike im learning a bit more about this as I go,, not hard as my previous knowledge of GT inverters was almost zero..

    The thing is even if I can get it to work I will never be doing it on a real set up all the reasons I have already given

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    • #17
      I have not seen it work when the grid went down but he called me during a power outage in his neighborhood to tell me it was working fine. Also when the installers hooked it up they had to shut off the main power to make sure all four of the inverters were working correctly.

      The SI communicates with SB via a cat5 cable so it "knows" whether to feed the extra power into the grid or during an outage only take from the SB what is needed.

      Here is the manual:

      http://download.sma.de/smaprosa/date...-TUS091012.pdf

      It is 5.6 mb so if u r on dialup good luck. Otherwise check page 117 for a basic overview of how it works. There is more info in the manual so you will have to read through it.

      BTW I use a 5048U for my off grid inverter. But I have Outback charge controllers for my arrays and battery bank.

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      • #18
        Thanks again Trkarl,, Its an interesting read. it was ok I have fast cable to download it. It shows that it can be done and its not "its not possible" as some have said.. Yes I understand it has to have an inverter that is a bit different from most inverters..

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        • #19
          Similar circumstances, newbie with question

          Hi folks - I've got similar circumstances and a slightly different question. This week I'm having a 9kW system installed (40 x 230W panels) and we're using the Enphase M190 micro-inverters, grid tied. Because I already have been using a portable 5kW generator which I converted to natural gas, I've asked them for some sort of transfer switch/interlock that will isolate us from the grid so I can run the generator.

          My apologies, after reading through many messages on here, I am still not clear on whether the inverters will run once I have started the generator or not ... can someone clear this up for me? The system engineer indicated that they should work as long as the generator is close enough in tolerance to grid power, but it depends on the quality of the generator; however it seems like posts on here indicate that it won't work because the house wiring isn't low enough impedance and/or not consuming enough power.

          Thanks!

          Rob K.

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          • #20
            Rob,

            For the most part it not only won't work, it will not work in a fairly spectacular manner -- the generator must be able to accept "sold" electricity and few inverters will.

            The Sunny Island or similar is what you're looking for. And with that you're back to needing batteries, so a hybrid design from the start may be a better solution.
            Julie in Texas

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            • #21
              The choice really depends on how frequent power failures are and geographic location as regards hurricanes etc.

              A couple of short outages per year - the generator is better.

              Hurricane or tornado country - depends on what one thinks they might have left after the storm passes by.

              Many people recommend grid tie with a generator backup as the best of all worlds.

              Russ
              [SIGPIC][/SIGPIC]

              Comment


              • #22
                Originally posted by rklingsten View Post
                Hi folks - I've got similar circumstances and a slightly different question. This week I'm having a 9kW system installed (40 x 230W panels) and we're using the Enphase M190 micro-inverters, grid tied. Because I already have been using a portable 5kW generator which I converted to natural gas, I've asked them for some sort of transfer switch/interlock that will isolate us from the grid so I can run the generator.

                My apologies, after reading through many messages on here, I am still not clear on whether the inverters will run once I have started the generator or not ... can someone clear this up for me? The system engineer indicated that they should work as long as the generator is close enough in tolerance to grid power, but it depends on the quality of the generator; however it seems like posts on here indicate that it won't work because the house wiring isn't low enough impedance and/or not consuming enough power.

                Thanks!

                Rob K.
                Very old thread, but I have the same situation and I'm searching for answers. I have an 8.58 kw system that uses Enphase micro-inverters. I asked the rep what happens if I hook up a generator. He told me to flip off the breaker that feeds the inverters (I always turn off the main panel breaker when using a generator). He said if I leave the breaker on, the inverters most likely would sense that the source is not coming from the grid, and they won't activate. Is this true? If the inverters did fire up, and it's a sunny day, the system would most likely be producing more than I'm consuming. So what happens to the excess, would I wind up frying all of my appliances?

                Thanks for any help with this.

                BTW... I'm a newbie... first post.

                Dave

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                • #23
                  Do not under any circumstances run the Enphase with the generator.
                  Turn the solar off.
                  Best case scenario the inverters don't see clean enough power from the generator and don't start up.
                  Worst case something gets fried and starts a fire
                  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


                  • #24
                    Originally posted by Naptown View Post
                    Do not under any circumstances run the Enphase with the generator.
                    Turn the solar off.
                    Best case scenario the inverters don't see clean enough power from the generator and don't start up.
                    Worst case something gets fried and starts a fire

                    That's what I figured... unfortunately. Appreciate the confirmation though. Could deep cycled batteries be added to the system somehow that would absorb the excess production and regulate the electric flow? If that would require a lot of batteries, then it certainly wouldn't be economically feasible.

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                    • #25
                      Outback makes a radian inverter that they claim will work with Enphase.
                      The issue however is if Enphase finds out about a hybrid install with their micro's they can void the warranty.
                      This has nothing to do with any engineering or comparability issue. It is because of an agreement made with IIRC PGE.
                      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


                      • #26
                        Originally posted by Naptown View Post
                        Outback makes a radian inverter that they claim will work with Enphase.
                        The issue however is if Enphase finds out about a hybrid install with their micro's they can void the warranty.
                        This has nothing to do with any engineering or comparability issue. It is because of an agreement made with IIRC PGE.
                        There is a lot more to putting together a hybrid system than backfeeding a battery-backed inverter with a grid-tied inverter. A system of that size (and I remember when my then-2.8KW system was large ...) requires a fair bit of control to insure that the inverter isn't overloaded and that the batteries aren't over-charged. The Radian firmware will control a motor driven circuit break (not a standard contactor, though one might be usable in a pinch), but that's a pretty blunt instrument.

                        Magnum has apparently modified their firmware to interact with grid-tied inverters to slew the frequency when the batteries are approaching full. I'm not particularly fond of that solution -- don't get me wrong, it's plenty clever -- because too many devices still use line frequency for various purposes, and that includes making sure motors run at the proper speed. Back in 2010 when I was fighting with the PoCo to get them to pay me for the electricity I was delivering I would run for days on end without the grid and the result was a lot of clocks that were horribly messed up. And my twin stack of GVFX 3648's are pretty rock solid at 59.97Hz when running without the grid.

                        The approach I've been pushing with Pantheon (SolarBridge) microinverters is commanding the microinverters to throttle back as the battery voltage approaches Absorb. This avoids the downside of frequency slewing, but requires software which can speak to both products. Fortunately I happen to have software which can speak to both products The downside, for the current poster (besides having already bought Enphase microinverters ...) is that the most stable solutions require DCPV which can act as a buffer against transient loads. The control theory is that once the system reaches Absorb, the maximum allowable ACPV power is equal to the DCPV Absorb power. A traditional DC dump load then provides the 2nd line of protection and a motor driven circuit breaker is the last and final line of protection.
                        Julie in Texas

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                        • #27
                          The problem I have with all AC coupled systems is that if the batteries drop to low voltage cut out it will not start again until either a generator is hooked up and batteries charged or the grid comes back up

                          My preference is the Xantres xw series.
                          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


                          • #28
                            Originally posted by Naptown View Post
                            The problem I have with all AC coupled systems is that if the batteries drop to low voltage cut out it will not start again until either a generator is hooked up and batteries charged or the grid comes back up

                            My preference is the Xantres xw series.
                            Naptown --

                            That's a system design problem, not a system type problem. All PV systems have issues at LBCO -- not just AC coupled ones and the system designer is responsible for protecting the system, especially from documented problems, like LBCO.

                            As for Xantrax systems, I've had issues getting the control interface (CANBus + their gateway) to work in a stable and reliable manner. Were I doing a complex mixed ACPV+DCPV system, Xantrax would be dead last on my list. Enphase + Magnum is another last-on-the-list combination since Enphase won't open the Envoy and Magnum is claiming copyright protection over any 3rd party implementations of their communications protocol. That leaves OutBack + SolarBridge as the only viable home-grown AC coupled combination as OutBack publishes their spec and SolarBridge has the InverterDirect API.
                            Julie in Texas

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                            • #29
                              As I said I am not a fan of AC coupled systems. Particularly if no generator is involved which is what is mostly asked for.

                              Generally when working with folks that do not live off grid as a lifestyle do not pay particular attention to battery use and take the batteries down too far. If the Magnum or whatever is still not firing up in the morning the system is dead until either a generator and charger are used or the grid comes back up.
                              With a DCPV pure hybrid with charge controllers etc they may kill the battery at night but at least it will wake up the next day.
                              Last edited by Naptown; 12-08-2013, 06:14 PM.
                              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


                              • #30
                                I am looking to do the same. In the event of a long black out I do not want to rely on gas powered generators. I want to utilize my solar panels power. There should be a way to switch your panels into a different setting that disconnects power into your main panel bypassing the inverter and swithcing your system into a local powered system with its own off grid inverter. This can be done using switches and once the power comes back in the neighborhood the homeowner should be able to switch the system back into its original state feeding back into the main panel.

                                Does anyone have any ideas?

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