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  • #31
    Originally posted by Markyrocks69 View Post

    Yes. They are 2 separate circuits. Each with its own wires, there are no combiners ect. Theres 2 safety shutoff switches in there so it's not directly from inverter to panel.

    Yes roughly 252v at idle. I highly doubt it has anything to do with solar, solar is not very popular around here. Honestly in this area solar isn't financially feasible unless you DIY. So the only people who have it are either rich and don't care, elderly people who are just getting swindled or someone like me that paid cash for my system and installed it myself. So like I said few and far in between, I only know of one other pv system within like a 5 mile radius from my house. As I said b4 my money is on the fact that it's a rural area and the houses are generally far away from the transformer.
    Turn everything on in your home and see how far the voltage drops. Air conditioner, saws, lights, microwave, etc. 252 is way high.. So you think its that high because of the distance between transformer and customer? I'm in a rural area with homes ranging from 2 to 100+ acres and mine isn't that high.

    Maybe you should call the POCO and see if there's a fix for you?

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    • #32
      Originally posted by Markyrocks69 View Post
      Ok so I knew this was possible but was hoping it wouldn't come to this point but apparently I can dial back the maximum power output until I can get both inverters to stay on. It's not exactly ideal but I'll be able to keep tweaking it until I find a happy medium. Common sense would say that even if both inverters had to be scaled back to only putting out 5kw maximum 5+5>7.7.... hopefully I wont have to scale back that far. I'm hoping I only have to drop it down to 7kw maybe a hair lower but like I said I can't imagine that its attempting to operate that far out of range. Its pretty crappy the only other thing I might be able to do is get the inverters to sync up so they are both outputting the exact same power so they aren't trying to one up each other.
      GT inverters do not sync to the breakers or other inverters. They only care about the GRID.
      With different arrays, no 2 inverters will put out the same power, that is not a goal, to match power outputs 100%, because it can't happen, except in a random condition.

      If you solve the problem by dialing back the power, your issue is either overheating inverters, or driving the line (Grid) voltage too high. My $ is on driving line voltage high. Get a calibrated meter out there, or see if the power company will check line voltage for you. Or you could have a bad connection that has resistance, or a bad breaker with resistance, or a inverter with a bad voltage calibration.

      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
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      • #33
        Originally posted by Salts View Post

        Turn everything on in your home and see how far the voltage drops. Air conditioner, saws, lights, microwave, etc. 252 is way high.. So you think its that high because of the distance between transformer and customer? I'm in a rural area with homes ranging from 2 to 100+ acres and mine isn't that high.

        Maybe you should call the POCO and see if there's a fix for you?
        I'm not saying that it isn't high and I'm not saying that there isn't a problem, the distance being the reasoning is just a guess. When you get down to it though 252 is 2 legs of 126 which is only .5% higher than nominal. I'll call the poco but I'm skeptical that they'll actually do anything and I'd assume that its probably within what they consider normal operating conditions. I feel like I'd probably have better luck trying to get a grid guard code and bumping the voltage up a hair or possibly get the inverters to sync up somehow. I cant really even do anymore testing today. By the time I scaled back the maximum power the sun was already past the prime angle and its already getting gloomy out. Its 5:10pm and it looks like its going to be dark here within the hr lol

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        • #34
          Originally posted by Markyrocks69 View Post

          I'm not saying that it isn't high and I'm not saying that there isn't a problem, the distance being the reasoning is just a guess. When you get down to it though 252 is 2 legs of 126 which is only .5% higher than nominal. I'll call the poco but I'm skeptical that they'll actually do anything and I'd assume that its probably within what they consider normal operating conditions. I feel like I'd probably have better luck trying to get a grid guard code and bumping the voltage up a hair or possibly get the inverters to sync up somehow. I cant really even do anymore testing today. By the time I scaled back the maximum power the sun was already past the prime angle and its already getting gloomy out. Its 5:10pm and it looks like its going to be dark here within the hr lol
          Per google 252 volts (126x2) is the upper limit number of what they are (allowed?). Seems extreme.

          Like I said, turn on a bunch of loads and see if it still trips out. I bet it doesn't.

          You said there are longer than normal distances between your home and the transformer, so I bet when you turn on a big load, that 252 drops fast. You might have to either throttle your array or talk to SMA and your POCO and change some of the grid limits in the inverter.


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          • #35
            With SMA inverters, you can just swap the top halves of the units and avoid messing with any wiring. 6 screws on each cover, unscrew the connectors underneath, 2 screws on each side holding the halve together - 15 minutes tops.
            BSEE, R11, NABCEP, Chevy BoltEV, >2000kW installed

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            • #36
              Originally posted by solarix View Post
              With SMA inverters, you can just swap the top halves of the units and avoid messing with any wiring. 6 screws on each cover, unscrew the connectors underneath, 2 screws on each side holding the halve together - 15 minutes tops.
              Maybe you're thinking of solaredge.

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              • #37
                Originally posted by Markyrocks69 View Post

                Maybe you're thinking of solaredge.
                Not sure which inverter you have, but the designation of 7.7 makes me think you have the same type i do.

                Here you go: The file (PDF) is from SMA on how to replace the top half. Its just 4 screws.
                Attached Files

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                • #38
                  Originally posted by Salts View Post

                  Not sure which inverter you have, but the designation of 7.7 makes me think you have the same type i do.

                  Here you go: The file (PDF) is from SMA on how to replace the top half. Its just 4 screws.
                  That's pretty interesting, I was not aware of that. I'll have to check it out.

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                  • #39
                    Originally posted by Markyrocks69 View Post

                    That's pretty interesting, I was not aware of that. I'll have to check it out.
                    Ya, I felt like an idiot after replacing my inverter and learning I could have done it with 4 screws. It certainly doesn't look like it comes apart, but it does, and quite easily.

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                    • #40
                      You already established that either inverter can run full power by itself, it is the combined
                      power killing you. So switching inverters is a waste of time. 2 inverters push the line
                      voltage higher, anything in the higher 250s risks trip out from any surge or just inaccuracy.
                      Bruce Roe

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                      • #41
                        Originally posted by bcroe View Post
                        You already established that either inverter can run full power by itself, it is the combined
                        power killing you. So switching inverters is a waste of time. 2 inverters push the line
                        voltage higher, anything in the higher 250s risks trip out from any surge or just inaccuracy.
                        Bruce Roe
                        How would you detect an improperly calibrated voltage trip on one of the inverters? I think that's the idea behind flopping them out. If the closest inverter continues to trip, then they are both fine.. but if the inverter that trips keeps tripping even though its been moved, then something is wrong with that inverter yes?

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                        • #42
                          To answer your question I would first check the software setting. If I did not trust
                          that, I would vary the voltage a bit with my large variac and find the trip point.

                          PVviac.JPG

                          Your logic escapes me. Bruce Roe

                          Comment


                          • #43
                            Originally posted by Salts View Post
                            How would you detect an improperly calibrated voltage trip on one of the inverters?
                            Well, he's already established that the trip point isn't wildly miscalibrated because if you shut down one inverter, the other works fine.
                            So they are relatively close in what they consider too high of voltage.

                            I think that's the idea behind flopping them out. If the closest inverter continues to trip, then they are both fine.. but if the inverter that trips keeps tripping even though its been moved, then something is wrong with that inverter yes?
                            IMO it is not worth the time (even if it's only 30 minutes) to swap the innards from one to the other.
                            Even if you find that which one trips off earlier moves with moving the innards, it doesn't get you any closer to solving the problem - which is that the thing is getting to an overvoltage condition.

                            I looked it up, and 252V is above what my POCO has for their standard.
                            They keep it to at most 248V. But your POCO may allow themselves to go up to 252V (5.0% more than the nominal 120/240V standard)
                            I looked at what my inverter reported for the past few days - and it's been between 236V and 241V - varying a bit over the day - but not by a huge amount.

                            If it were me, I might dial back the max production from 7.7 to 5, just to see if that worked a little better for the moment.
                            But I would only do that while I got the POCO to come out and address the high voltage. I would tell them "Hi, it looks like the voltage is too high at my house - it was showing 254V at the main circuit breaker. What's the range for the voltage that is your standard? I'm seeing problems with the equipment at my house because of the high voltage."

                            And in parallel I'd ask SMA for a "grid guard" code so that I could adjust the inverter as appropriate once I had the info from the POCO about what voltage range they try to adhere to.

                            Comment


                            • #44
                              [USER="23318"]foo1bar[/USER] I'm going to explore all options. Like I said I'm going to dial it back to see what kinda sustainable condition I can achieve. Imo moving the inverters around probably wont fix anything. If I have free time down the road and get to my wits end I may try that. Like I've said in a different post I'm still not even getting credit for excess production so it's not overly critical that I get this solved immediately but everyone always wants instant results (me included). Dialing it back is not really a long term solution bc it could result in thousands of dollars lost over the lifetime of the system . I had actually considered adding a 3rd inverter at some point which is (lol) probably not possible given the current situation. That all being said I plan on getting in touch with the poco about getting the high voltage issue addressed. This probably should have been addressed during their ultra thorough level 2 review (lol). I also plan to see what I need to do about getting a grid guard code. I don't see why I wouldn't be able to get permission considering the voltage rise that is required is (going back to a higher voltage line to begin with and) the extra voltage needed to push the current back through the transformer wouldn't actually result in higher voltage actually making it back to the transformer. Only time will tell. At the end of the day any result that lowers my electric bill will be a plus, the system not generating the maximum will probably extend the roi time but.... I think Its only like 4 years or something anyways so even if it pushed it to 5 i could live with that. I don't even miss the money anyways and I'm going to get a healthy tax return in the early spring. I plan on buying an rv, do some light traveling. I also plan on having my meter moved at some point in the somewhat near future so this poco is going to be having to deal with me a fair amount for awhile longer.

                              Comment


                              • #45
                                I had a similar situation a couple years ago with an 8 year old dual Xantrex installation where one of them would consistently have trouble dropping out when the grid voltage ran high. I never saw the voltage above 248Vac yet one of them would have Overvoltage errors. We tried replacing the breakers in the combiner, measured voltages everywhere and finally discovered that the internal voltage displayed by the problem child was sometimes 5 volts different than the measured voltage at its terminals. Long story short - had the unit replaced under warranty but the new one started acting up the same way after a few months. We put three inverters in there over two years and never did solve the problem until we told the Schneider people (who bought out Xantrex) to go stick it and bought an older model Sunnyboy for this customer which has run flawlessly since. I think grid voltage can spike high when you don't notice it causing sensitive inverter circuits to trip off. The POCO was useless in helping us to get the grid voltage lowered, and I've long since quit using Schneider equipment.
                                BSEE, R11, NABCEP, Chevy BoltEV, >2000kW installed

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