Problems with Solectria Inverters

new2solar
new2solar Registered Users Posts: 14 ✭
in General Solar Power Topics #1
Hello. I've got a 10kw fixed ground mount system with two Solectria PVI5000 inverters. On sunny days, the inverters kick out regularly with a DCinjectcurH error message. I haven't had much luck with any warranty service out of Solectria. So far all I've been told to do was to remove them and ship them back for repair. (I sure wish they told me to do that back in December)
The system is 11 months old, and it started from the beginning, was not as bad when the weather was hot, but is real bad now on the cooler clear days. The system design was OK'd by the tech at solectria during the design phase, as the system is 52 x 225w panels = 11700 watts... feeding two 5kw inverters.(four strings of 13 panels) Anyone else had these problems or better luck with the warranty service? Any field repair available? Anyone have any better luck overglassing with other inverter brands?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Problems with Solectria Inverters

    Is each inverter being driven by 36 series panels--Or are you putting all the panels together and paralleling the inverters on the solar input side?

    My inverters, I had to ship back to the vendor and wait for them to be back in stock (took weeks to months) when they failed.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: Problems with Solectria Inverters

    I don't know about Solectria inverters, but it sure sounds like the array Voltage is going too high for them in cool weather. Since they have an input range up to 550 VDC, divided by 13 would be up 42 Vmp per panel (if I read your configuration right: each inverter fed by two strings of 13 panels). This is not a likely number for a panel, so I guess we'd need to know the actual panel specs (and confirmation of the array wiring) together with what kind of ambient temps you're experiencing.

    But I'm not confident it is the panels causing the problem.
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  • new2solar
    new2solar Registered Users Posts: 14 ✭
    #4
    Re: Problems with Solectria Inverters

    The panels are wired 13 per string, two strings feeding each inverter. The panels are Arise F225,( their specs are on Solectria's string sizing site), the sheet I've got says VOC 37.4, voltage 29.6, current 7.8amps, short circuit current 8.4 amps. The local ambient temperatures are above freezing. When the inverters cut out, the dc voltage on the display ranges from 400v on colder days to 350v on warmer days. I don't like the idea of removing the inverters and shipping them back for repair as we are paid .80 cents per kwh on our feed in tarrif, and I've got big payments to make on this very expensive system!
    Thanks for your help!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
    Re: Problems with Solectria Inverters

    That's about what I figured the panels should be. Even up here those strings should not exceed the 550 Volt input on the coldest day. That does not bode well for the inverters.

    How confident are you with wiring? Do you think you could unplug one panel from each and every string? If the inverters start to function normally after that, then there's something wrong with their input specs. If they don't, there's still something wrong with them.

    It sure sounds like the array is within specs but the inverters don't seem to have the right specs programmed in them. :cry:
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #6
    Re: Problems with Solectria Inverters

    I have 5 different gti inverter string charts on my links and only one has a chart for 1 model of arise panel. FRonius has one for 230 watt arise panels and 12 panels per string recomended for the 5000 watt fronius plus which operates at same voltages as the Selectra you have. I would take cariboo coots advice and try 12 panels per string.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #7
    Re: Problems with Solectria Inverters
    new2solar wrote: »
    Hello. I've got a 10kw fixed ground mount system with two Solectria PVI5000 inverters....
    ...was not as bad when the weather was hot, but is real bad now on the cooler clear days.
    ....as the system is 52 x 225w panels = 11700 watts...
    ... feeding two 5kw inverters.(four strings of 13 panels)

    OK, I skip the grid tied stuff for the most part, but it sure sounds like your inverters are having issue when pushed colse to, or past the 5000 watt mark, 5850watts might well produce above the 5000 watts on cool days. from what little I've read, I didn't think this was a problem with grid tied inverters... but I just wanted to point it out.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • new2solar
    new2solar Registered Users Posts: 14 ✭
    #8
    Re: Problems with Solectria Inverters

    With the microfit program here in Ontario, and according to the rules in place when I had my system installed, either the rated panel output or the inverter output could not exceed 10kw. In my opinion, the Solectria inverters were not designed for prolonged maximum output. I'm sure larger inverters would fix the problem if the rules allowed it. I'm still greived at my installers for putting in 5kw inverters that will only output 4.9kw. (but they went bankrupt, so no help there) Solectria was emailed with the panel specs to make sure the system wouldn't fry the inverters, and the installers were given the OK since the voltage produced is within the inverter operating window. Looks like its time to go inverter shopping, any brand recommendation? If I start unplugging panels, the losses over the system life will exceed the cost of new inverters.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: Problems with Solectria Inverters
    If I start unplugging panels, the losses over the system life will exceed the cost of new inverters.

    Except that as it is the inverters are shutting down and producing nothing, right? So if you can get them to work consistently with a slightly less amount of panel you're power ahead.

    Just to be sure we've looked at all possibilities (or as many as I can think of), this is a 240 VAC system and not a 208 VAC right? And you're not at elevation 6,000 feet or anything like that?

    As for GT inverter brands, people who have SMA http://www.solar-electric.com/suboysb50wag.html or Fronius http://www.solar-electric.com/frigpl5uni50.html or http://www.solar-electric.com/frigpl10uni1.html all seem to be fairly happy with their choices.

    Be advised that if you change inverters you'll have to make sure the arrays are compatible with the new units and you'll probably have to get okay from the utility and/or AHJ for the change.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #10
    Re: Problems with Solectria Inverters

    The other advantage to doing the panel removal as a test is that if it does work and you still decide to use a different inverter you can in good conscience sell the Solectras as operational. If not then you have a good leg to stand on for warranty replacement and you can sell the replacements as new.
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  • new2solar
    new2solar Registered Users Posts: 14 ✭
    #11
    Re: Problems with Solectria Inverters

    Both good points, thanks guys. It is a 240v system, I'm not sure of the elevation, but its southern Ontario, so nothing extreme. I'll let you know the outcome.
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #12
    Re: Problems with Solectria Inverters

    From what you said before I assumed you didn,t live that far North because you said you didn,t have freezing temperatures. I am south of Lake Erie and I usually have a few days with -0 f temperature. I used -22f for planing my system. I think your temps could be even lower in Ontario.In my previous post I picked tennesee as a location and 12 of the panels was listed for thier temp. I will redo it for -25 f and see what the results are. Still says 2 strings of 12 modules @ -40f. and 12 @ highest temp on fronius chart. I don,t have any experience with selectra inverters but they seem to have all the specifications any other inverter has. So probably getting another brand inverter probably isn,t going to make any difference. Yep! I thinks 13 panels is too high of voltage when weather is cold for sure. :Dsolarvic:D
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #13
    Re: Problems with Solectria Inverters

    Just checked selectra string chart and they limit to 12 panels per string. Your installer made a mistake. You would most likely have problems with any brand of inverter if you tryed to use 13 panels in a string. In my fronius it records the highest voltage it ever received. I guess if it ever goes over 600vdc they don,t have to honor warranty. You should read your manual and see if you can find the highest voltage your inverter ever received. One of my inverters was 12 vdc below the limit so I am going to take 1 panel off it before winter. :Dsolarvic:D
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #14
    Re: Problems with Solectria Inverters

    See here's the thing:
    Worst-case scenario your panel Voltage (Voc & Vmp) increases by a factor of 1.3 (the number we use here in the Great White North).
    The OP's panels have a Vmp of 29.6, so that should rise to a max of 38.48 (which will actually lower when the panels are producing current as they will warm up). Multiply by 13 panels and you get a string Vmp of 500.24, which is below the Solectria's claimed 550 Volt Vmp operating maximum. So it should work. (Usually it's the Voc going high from cold temps that stops the inverter from functioning to begin with.)

    But it doesn't. :confused:

    So either the panels are pushing out more Voltage than spec'd or the inverters aren't functioning as per their specs.

    In either case it doesn't work as is, and if dropping one panel per string gets it to work consistently then go for it.
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #15
    Re: Problems with Solectria Inverters

    I just went by what selectra,s string chart said for poletop mounts and max-22f which is for pa 50 miles south of erie pa. Lt might be even a few degrees colder in Southern ontario but I doubt that it would be very much colder. Solarvic II got a voc of 44.17 coldest 13 panels would be 575 voc. I couldn,t find much info on arise panels.
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  • new2solar
    new2solar Registered Users Posts: 14 ✭
    #16
    Re: Problems with Solectria Inverters

    Sorry for the confusion about the temp Solarvic. I meant the current temps are above freezing. It gets much colder during the winter, but, since my installation is a fixed ground mount, the sun is at a pretty steep angle during the winter and the inverters seem to cut out less often. Your correct about the string sizing chart. When the tech dept was contacted about the installation, I believe the tech said something like the PVI5000 has the same voltage window as the PVI5300, so they will work with 13 panels, but will derate more often(if I recall correctly). Its interesting, the Ontario government has changed the rules for future installations. Both the inverter rating and the panel rating can now not exceed 10kw (for future installations) In hindsight, its probably a good idea, as it will avoid problems like I'm having now.
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #17
    Re: Problems with Solectria Inverters

    If you can,t install more than 10,000 watts of solar ,you would never output 10,000 watt ac. That doesn,t make sence if they allow a 10,000watt output. If the inverter doesn,t derate all that much maybe you could live with it. My solar here in pa has been doing real well for april. Had more sunny days then usual and usually getting a breeze to help keep the panels cooler. I wonder if you let the panels get a little dusty if that would hold the voltage low enough for you not to have problems. Solarvic
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #18
    Re: Problems with Solectria Inverters

    Couldn't the OP just cover the last panels in each of the strings to test this theory.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #19
    Re: Problems with Solectria Inverters
    solar_dave wrote: »
    Couldn't the OP just cover the last panels in each of the strings to test this theory.

    Have you seen any of the threads on shaded panel problems? Knocking one out in a series string can be an issue.
    It shouldn't be too hard to disconnect the MC4 connectors and bypass one panel per string. In fact he only has to do it for one inverter and then compare the side-by-side results, so to speak.
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #20
    Re: Problems with Solectria Inverters
    new2solar wrote: »
    Sorry for the confusion about the temp Solarvic. I meant the current temps are above freezing. It gets much colder during the winter, but, since my installation is a fixed ground mount, the sun is at a pretty steep angle during the winter and the inverters seem to cut out less often.
    FWIW, if it is a voltage issue that is giving you the problem the tilt angle of the array has little or nothing to do with it.
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  • trends
    trends Registered Users Posts: 6 ✭
    #21
    Re: Problems with Solectria Inverters

    Problem "the inverters kick out regularly with a DCinjectcurH error message"

    Cause - A grid connected photovoltaic (PV) system is a well-known example. DC power from the solar panels is converted to AC by an inverter before injection into the AC network. Ideally the output current of the inverter should be purely AC. But in practice it will contain a small amount of DC. Excessive DC injection into the AC network can result in problems such as corrosion in
    underground equipment[1], transformer saturation and transformer magnetizing current distortion[2], metering errors and malfunction of protective equipment[3]. For these reasons there are standards that impose limits on DC injection.

    Solution - Return inverter (one at a time) under warranty. If you are upset with the 4900W output vs the 5000W output ask for a upgrade to the PVI5000T (will cost you $$$). Consider running your numbers first to see if the upgrade warrants the investment.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #22
    Re: Problems with Solectria Inverters

    Can DC injection happen with a Transformer (80#) isolated inverter, or only the "transformerless" inverters ?
    Powerfab top of pole PV mount | 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 ,

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #23
    Re: Problems with Solectria Inverters
    mike90045 wrote: »
    Can DC injection happen with a Transformer (80#) isolated inverter, or only the "transformerless" inverters ?

    I would guess not--But I have seen failed rectifiers that create a DC bias current in the AC input current to a load--Which then can cause transformers to overheat. Does any isolated GT inverter have such a circuit on the input--Don't have a clue (but probably not--but something popped the 240 VAC branch circuit breaker on my 3.3 kW GT inverter--had to replace).

    Could you get unbalanced AC output from a non-isolated GT system. Don't know how the work, but it certainly sounds possible--especially if they have an error code for it.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #24
    Re: Problems with Solectria Inverters

    newtosolar. Did you come to any conclusions about the problems with your selectra inverters? :Dsolarvic:D
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  • new2solar
    new2solar Registered Users Posts: 14 ✭
    #25
    Re: Problems with Solectria Inverters

    I guess its hats off to Solectria. They shipped me a repaired inverter to install, while I return mine one at a time for a hardware fix. Currently I'm operating with one original inverter and one replacement. Its been quite cloudy the last couple of days, but the sun came out briefly in full force yesterday for a few minutes. My old inverter shut down once, but the new one kept going. Hopefully, they've nailed the problem, but it will take a few more days of full sun to know for sure. I did offer to pay for an upgrade to the PVI5000t, but they tell me its based on another model, so its not possible... I'd have to buy new ones if I want true 5kw output inverters. Note to self...read the specs for future purchases!
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  • cjsully14
    cjsully14 Registered Users Posts: 1 ✭
    #26
    I am on my third PVI5000 inverter. My original one worked well and last just before the warranty ran out, so they shipped me a refurbished replacement unit that worked for 1 month and then was doing the same thing, derating, display wacked out with crazy characters and started to errors when it said Mode ? Grid/MPP or Mode " Grid/MPP. There are no Error lights or Ground Faults.  I am at the point where I just want to replace it with another manufacturer's inverter but I am not sure which one to go with the will work with my existing panels and wiring. My system was installed in 2007.
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