11 panel string volts and amps question

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  • negatron
    Junior Member
    • May 2017
    • 15

    11 panel string volts and amps question

    I'm just looking for some rough numbers and I can pull specs off the sheets if asked, but I'd like a couple of opinions about the output of a string.

    The string is 11 panels in series of JAP-300 24v 300 watt panels.
    In full sun directly perpendicular to the panels what approximate V and A numbers would be approximate for the string?
    Just curious.

    Thanks

    Negatron
  • Sunking
    Solar Fanatic
    • Feb 2010
    • 23301

    #2
    Easy peasy 5th grade math.

    The current is already printed on the label, just read it, don't ask anyone to do it for you. In a series circuit I1 = I2 = I3.... = I11. Now tell us how much current your Imp spec listing is, and you answered your own question. Should be around 8 to 9 amps.

    Voltage eis almost as easy if you can add or multiply. Again look at your panel specs and look for Vmp and Voc and multiply by the number of panels in series. Example if Vmp = 36 volts, then 11 x 36 volts = 396, just cal it 400 volts. Voc will be higher.

    See, Easy Peasy.

    Series circuit Rules

    Voltage and Power Add
    Current is equal in all nodes. With solar panels, the current is limited by the lowest panel.


    Parallel Rules

    Current and Power Add
    Voltage does not change. However in a parallel arrangement, voltage will be the lowest voltage panel. Thus when using panels in parallel they should be the exact same model with same Vmp and Voc.
    MSEE, PE

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    • negatron
      Junior Member
      • May 2017
      • 15

      #3
      I know the 5th grade math and Ohms Law and the parallel vs series calc.
      Thanks for clarifying the Vmp definition for me.
      It's been a while since I shopped and jotted down the basic meanings of the terms.
      The panels have a spec of 36.4 x 11 = 400 and the last checks I did at the DC disconnects
      a couple of months ago when the sun was hot were right there with a jump up to 425.
      I can deal with that.
      Thanks
      negatron

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