Can anybody help.

I have a new PV grid installation 12x240 sanyo and SB3000. I am having the following issue, sent this to sma for advice via my installer.Attachment not found.Attachment not found.

Just to clarify what is happening, the output for no reason is dropping and will remain low for the rest of the day (see top picture) if the inverter is reset the power comes back to the expected output (see second picture) on this occasion the power dropped from 2kw down to 500w and stayed there, following a reset 30 minutes later the power went back to 1.7kw. The question is why should a reset bring the power back up?

This also has happened in the morning, where a reset brings the power up from 200w to 1.5kw with just the reset.

many thanks
Gary

Comments

  • BB.BB. Posts: 25,058Super Moderators admin
    Re: Can anybody help.

    I am also looking at the beginning of your day too... very flat then jumps up. Do you have some sort of shading issue or array that does not point south?

    What is the Vmp/Imp of the array (series/parallel connections)? Is the Vmp/Voc of the array over the inverter's MPPT tracking / operating limits?

    Otherwise, you appear to have GT Inverter issues.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GazzGazz Posts: 38Solar Expert
    Re: Can anybody help.
    BB. wrote: »
    I am also looking at the beginning of your day too... very flat then jumps up. Do you have some sort of shading issue or array that does not point south?

    What is the Vmp/Imp of the array (series/parallel connections)? Is the Vmp/Voc of the array over the inverter's MPPT tracking / operating limits?

    Otherwise, you appear to have GT Inverter issues.

    It is all in series.

    -Bill

    Bill,

    Yes there is some shading in the morning, 2 off the 12 panels are half covered. The issue I have is why if I reset the system it come back up at a hight power, might be 500W, reset and it comes back up at 1.5Kw.

    Any suggestions, is there a problem or is that the way it is.

    Gary
  • BB.BB. Posts: 25,058Super Moderators admin
    Re: Can anybody help.

    Does not sound right to me. I think it is time to call the vendors.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GazzGazz Posts: 38Solar Expert
    Re: Can anybody help.

    To help can anybody tell me what should be happening to the voltage displayed on the front panel of the inverter. Does the MPP tracking hold it constant or does it fluctuate as the sun changes.

    The reason for asking is that the other morning I had a low output then reset the inverter and the output went up and as the sun remained out all morning I got a good output. In the afternoon it clouded over and the output went all over and would not settle down, its as if the inverter is fixed on the setting that it was reset at or started up on.

    Just wounderd what the voltage should be doing.

    Gary
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Can anybody help.

    variations in the amount of light hitting the pvs will vary the current and thusly the wattage as the sun is the power source and any blockages or diminished collection angles will result in lower readings. is it a case of it won't come back up after a blockage like shading or clouds without hitting reset, for if it is then suspect a problem with the inverter.
  • BB.BB. Posts: 25,058Super Moderators admin
    Re: Can anybody help.

    My Array Voltage (Grid Tied) will vary from 280 to 340 volts (Vmp reading from my GT inverter) or so (usually around 290-310 in full sun)--depending on how hot the array is--and of course, it will be less with little sun--clouds, morning, evening, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Posts: 2,341Solar Expert ✭✭✭✭
    Re: Can anybody help.

    Sounds like a bad inverter! When unshaded, note the MPPV, this voltage number should automatically be close to your high power point and just moving slightly every 2 or 3 seconds.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

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