TS4-A-F on panels connected in parallel

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  • Avatar
    Martin Perez

    Hello!

    This is the Final Report Executive Summary: Tigo MLPEs worked Ok using the combined home run from several strings connected in parallel, but had to use both transmitting cores.

    We used one Q.CELL Q.PLUS L-G4.2 345W panel in series with two Q.CELL Q.PRO G3 250W panels, with one Tigo TS4-A-F and one TS4-A-2F; six of these strings in parallel connected to the six inputs of an Echo Worthy combiner box; so, a 3s6p configuration.

    The combined home run is connected to a Schneider Conext 60-150 MPPT charger controller, an XW Pro (6848) 6.8kW inverter/charger, and a MiniPDP. Inside the MiniPDP an AC breaker was dedicated to the Tigo RSS Dual Core Transmitter power supply (the XW 12V aux output port was not used, as it it's specified as only a 250mA power supply).

    The negative of the combined home run goes through both RSS cores at the same time, and both cores' white side looking toward the charger and, as such, looking toward the inverter (we did not test looking toward the panels; maybe yes, but cannot remember at this moment). If one core is disconnected from the transmitter, but not removed from the home run cable, the production drops significantly, probably indicating that some Tigos are not firing. Disconnecting and connecting back the core to the transmitter was always performed after shutting down the transmitter by opening and closing its AC breaker. We did not test removing the core from the cable.

    The Tigo documentation, training videos, faqs, etc. all talk about passing one of the home runs of the serial string through the RSS core; and when talking about parallel panels connection, they say that one of the home runs of each parallel connection go through the core; it is, then, not clear for us that the combined home run can go through the core. That was confirmed by the Technical Support team upon an inquiry.

    We are really pleased by all your support, and we think we shall share the experience for the benefit of all.

    Best regards,

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    Martin Perez

    Hello Ron!

    I am afraid that I did not understand your question thoroughly.  Please confirm:

    Do you have four strings (or four panels) in parallel?

    If so, are you using a combiner box or Y Branch Parallel Adapter Cables?  Not important actually.

    When you say “or do we have to have to have 4 wires to the inverter”, did you mean running the four wires through the core?  Please clarify.

    If you have four strings in parallel, and you are running the combined home run cable through a single core, maybe not all the Tigos are getting the PLC signal strong enough to activate.  You may use both cores at the same time, if you bought the dual core Tigo RSS Transmitter kit; if you only have one core available, you may try to measure the current of each string, trying to identify which one is not activating, if any.

    We may need some more information of your system configuration, so we may help you out in a better way.  For example: number of strings or panels, if they are all the same brand and model or different, how are you combining them, how are you providing power to the RSS Transmitter, maybe the charge controller and inverter brands and models, if you have a clamp meter to safely and easily measure current, and whatever other information you may deem necessary to share with us.

    Our experience was that by mixing different model panels, the MPPT charge controller may some time get confused while tracking the maximum power point of the strings, “giving up” earlier than when finding the correct MPP.  This happens in the early morning when the panels are just waking up.  After a while, if panels are briefly disconnected from the charge controller and reconnected back (or the MPPT is cycled from operational to standby and back to operational), the MPPT will start tracking from a higher voltage and will find a better maximum power point of the strings, yielding a significantly higher production.

    I want to disclaim that I am not a Tigo employee or representative; I am just a satisfied customer that is sharing my experience with my Certified Installer and the products he suggested me to use, to pay back for the support we have received.

    Best regards,

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  • Avatar
    Greg Smith Community Moderator
    Early Adopter

    Hello Braath,

    Yes, you can use TS4-A-F in parallel as well as series. As long as the strings go through the same Core, then you will adhere to our design criteria. This article explains it in more detail.

    TS4-A-F Design Essentials

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    Martin Perez

    Hello!

    Actually the first part of the question was left unanswered, and I would like to have a response on that regard.

    The question is: Can we connect several strings in parallel and pass the combined single home run trough the RSS transmitter core?

    Let's say we have three panels with their Tigo each and connected in series. Then, we repeat that configuration three more times, to end up with four strings of three panels in series each.

    Those four strings will connect to a four input combiner box. Can we pass the single output of the combiner box through the RSS transmitter core?

    I asked this directly to Customer Service, and the response was that it is Ok to do so, but total length of equivalent wires should not exceed 1,000 ft.

    The OP assumption that it might work, but there would exist a limit due to the signal division between strings (or panels) is interesting, and we would like to make sure we understand is this limit is such as to avoid such arrangement or what.

    Thanks for your support.

    Best regards

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    Greg Smith Community Moderator
    Early Adopter

    Hi Martin, I don't see any unanswered questions except for the very last one you proposed. Yes, you can use TS4-A-F in parallel strings, and it looks like Tigo Service said that combining them into a single output is acceptable as long as the roundtrip homerun distance does not exceed 1000 (300m) feet as stated in the link above.

    This distance requirement ensures a strong PLC signal travels through the module DC conductors to the TS4-F's. This distance can be extended to 500 meters if you double up on the RSS Transmitter Cores.


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    Martin Perez

    Hi Greg!

    Thank you for taking care so quickly, we appreciate it.

    I remember reading on using two cores to enhance the PLC signal. That means to pass the same home run cable trough both cores (as shown in the picture) at the same time, right? (Do both LEDs shall blink when both cores are connected? It is a basic RSS transmitter, it is not a Pure Signal one.)

    Is it important toward where the white side of the core is looking? I mean, if using the positive home run and the white side is looking toward the combiner box, vs using the negative home run.

    Is there any concern if the combiner box has anti-backflow and anti-reverse protection diodes?

    A lot of questions, I know; I will not complaint of not being answered any more :O)

    Best regards

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    Greg Smith Community Moderator
    Early Adopter

    It is no trouble at all, Martin. That is what the Community is for- I guarantee someone else has or will have the same question.

    You are correct, you must run the negative DC homeruns through both Cores so that the RSS Transmitter can really boost that signal.

    Concerning the Cores (commonly called CT's), as with most CT's the direction matters. We have two kinds of Cores- one with a dual color black and white faces, or the previous version, black on both sides. The black Core does not have an arrow indicating flow like most Cores.

    For the dual color Core, the white side should always be oriented to face the PV Inverter. The black Core is a little trickier since there is no visual indicator printed on the Core. It ends up being a trial and error process. After installation, if the open circuit voltage is very low, this indicates the Core is reversed and not sending the keep alive signal to the TS4-F or -2F. Each TS4 will output 0.6VDC when it is off. So, if you have 12 modules on this string, the voltage reading would be 7.2VDC. You could swap the Core leads connecting to the RSS lower terminals to correct this since it is much easier than pulling all the homeruns and then rotating the Core.

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    Ron Robertson

    Hello

    so can we run the combined home run through the core or do we have to have to have 4 wires to the inverter ??  my system is producing 1/2 the wattage. I have been chasing the problem down and that might be it.

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    Ron Robertson

    hello

    Just making sure that I understand your above statement on parallel connections going through the core. I have 8 panels same brand and size in series 405 watts each. I have connected two of these strings in parallel on the roof leaving me with 2 wires positive and negative home run to the inverter. The rss core is located at the inverter so only one positive wire is going through it (100 ft) away. I should be getting 395 volts and 6480 watts but I am only seeing 395 volts and 3240 watts   It looks like you are saying above that I need to unbundle my parallel wires on the roof and run two more home runs wires to the inverter with both positive wires going through the core then parallel at the inverter.

    Thank for all your help and research 

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  • Avatar
    Martin Perez

    Hey Ron!

    This is really good information to figure out what is happening.  You do not need to unbundle your parallel connection on the roof, I was just trying to figure out what your configuration was.  So, it is Ok to keep the bundle on the roof and keep the only one wire through the RSS core.  It seems that only one string is being activated, so it may be necessary to use two cores instead of one, if available.  To verify if only one string is being activated, it will be useful to read the current on each string with a clamp meter.

    May we know if your are using four Tigo TS4-A-2F modules, or eight TS4-A-F modules per string, or what modules are you using?  This is not really important, but might help a little.

    A possible troubleshooting would be to unbundle the parallel connection on the roof and connect only one string at at time to the inverter and through the core, just to make sure that each string can be activated and all modules are working Ok.  If both strings works independently but not together, then the issue would be related to the Tigos not all being activated with the single core.  If only one string is working, you will have an assignment of figuring out what is happening with the non working string (a connection problem, a defective panel, a defective Tigo module, etc.).

    One other important thing to evaluate is how are you powering the RSS Transmitter; Are you using the included power supply, or are you using the 12V output of the inverter, if any?  If using the inverter, please make sure it can provide the specified current requirements of the transmitter, that I guess is 500mA (this is why we are not using the 250mA port of our inverter).  These are just thoughts to take into consideration when tracing the issue.

    Best regards,

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    Ron Robertson

    Using four Tigo TS4-A-2F modules. I did unbundle them when I first discovered that we were only getting half wattage. Each string is producing 1/2 the output. About 1700 watts I have since ordered a rss single detector that just showed up. Need to go back up on the roof and test each TS4-A-2F or disconnect all the TS4s and see what I get. I am running a 12V power supply not off the Sol-ark 15K. Weather in poor in Calif right now. Can't wait to get back on roof and do so some more testing.

    I talked with a local solar guy he was thinking I might need to add a CAA and TAP. but what I see I do not need this for the TA4-A-2F system. 

    Thanks for your help

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    Martin Perez

    Hello Rob!

    I am glad to know that you are definitely on the right track; please share your findings for the benefit of all.  Keep posting if you need any further assistance.

    Best regards,

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    Curtis Community Moderator

    Hello Martin Perez

    Thank you for contributing to the Tigo Community.

    Yes, you may run strings in parallel to a combiner, and then have only the positive (or negative) going through a Tigo Transmitter Core. However, the strings must be in the correct polarity. If they are reversed, then the system may experience a phasing or cancelation of the signal for one or more of the strings on the system. 

     

     

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    Curtis Community Moderator

    Hello Ron Robertson

    If you are only retaining half of the wattage, it could be due to one of these topics: 

    • Reverse polarity issues - If you have paralleled strings in a combiner (pre-transmitter), or if you are using 2 transmitter cores on one string, make sure to have all strings and the cores in the correct polarity. Reverse polarity issues can cancel the signal for one or more strings (within a group of parallel strings), and reverse polarity of dual cores can cancel the signal, altogether. For more information: How to check Dual Core RSS Transmitter Polarity.

    • Signal transfer Issue or damage to TS4 unit - One or more units are either not producing, or not hearing the RSS Transmitter signal. Test for each string voltage separately (in series), to confirm whether the event happening on each string, or if it is only happening on one string. Once it's been narrowed down, you can cut the string in half and test each half to see if the voltage differs. It's a bit of work, but it's the only way to find out what's happening. For more information on testing methods: Voltage Measurement of TS4-F Fire Safety Products

    • Excessive shade or Orientation issue - Strings that are in parallel must be the same in length, shade and orientation to the sun. Otherwise, the shortest string (or string with the most shade), will control or lower the maximum output of all paralleled strings. For more information: Design Considerations for Uneven Parallel Strings.

    • Crosstalk Issues - All wires that are in proximity to each other, have a high probability of Crosstalk. If you have two or more signal sources, and the strings are running through the same cable tray or combiner, this may be contributing to Crosstalk. For more information: Crosstalk and How to Mitigate it

    If you are experiencing any unexpected or abnormal results on your system, please Contact the Support Team.

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    Cesar Borrego

    Hola,

    Tengo una instalación antigua de 12v on dos cadenas de 4 paneles 250w 37A (Voc), cada una conectadas en mixto serie/paralelo, es decir cada cadena tiene 2 placas conectadas en serie y conectadas en paralelo a otros 2 en serie.

    Cada cadena contratada por un regulador de carga Xantrex.
    La pregunta es ¿se pueden utilizar los optimizadores TS4-A-O en este tipo de conexión mixta serie paralelo?
    Si es así ¿Se pueden conectar a el regulador Xantrex XW MPPT 60/150 en vez de a un inversor?
    Gracias por su consideracion.

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    English Translation
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    Hello,

    I have an old 12v installation with two chains of 4 panels 250w 37A (Voc), each one connected in mixed series/parallel, that is, each chain has 2 PV Modules connected in series and connected in parallel to 2 others in series.

    Each chain contracted by a Xantrex charge regulator. The question is, can TS4-A-O optimizers be used in this type of mixed serial-parallel connection? If so, can they be connected to the Xantrex XW MPPT 60/150 regulator instead of an inverter? Thanks for your consideration.

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    Curtis Community Moderator

    Hola Cesar Borrego,

    ¡Gracias por tu pregunta de la comunidad!

    Las series Tigo TS4-A-O (optimizador) y TS4-A-F (seguridad contra incendios) son compatibles con la mayoría de los sistemas. Sin embargo, debe leer la hoja de datos de lo que esté comprando para asegurarse de que su diseño no exceda el voltaje o la corriente máximos del MLPE (electrónica de potencia a nivel de módulo). Para obtener más información, consulte:

    Si desea un servicio más personalizado, nuestro equipo de ingeniería de ventas puede revisar el diseño de su sistema y confirmar si tendrá éxito.

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    English Translation
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    Hello Cesar Borrego

    Thank you for your Community question!

    The Tigo TS4-A-O (optimizer) and TS4-A-F (fire safety) series are compatible with most systems. However, you must read through the datasheet on whatever you are purchasing to make sure that your design does not exceed the maximum voltage or current of the MLPE (module-level power electronics). For more information, please see: 

    If you would like more personalized service, our Sales Engineering Team can review your system design and confirm if it will be successful. 

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