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PV String Voltage Range Calculator

Apply user-entered module temperature coefficients to estimate cold open-circuit and hot operating string voltage, expose both voltage margins and compare them with entered inverter limits.

Inputs

Module data and string

Range: 0.1–250 V

Enter Voc at STC from the exact module datasheet.

Range: -2–2 %/°C

Enter the signed coefficient from the exact module datasheet, commonly stated as %/°C.

Range: 0.1–250 V

Enter Vmp at STC from the exact module datasheet.

Range: -2–2 %/°C

Enter the signed coefficient from the exact module datasheet. If unavailable, do not substitute a generic value.

Range: -60–50 °C

Use a design cell-temperature value supported by the project method and local climate data, not ambient air temperature by default.

Range: 0–100 °C

Use the design hot-cell temperature for the array and mounting conditions.

Range: 1–100

Enter the proposed number of modules wired in series.

Inverter data

Range: 1–2,000 V

Use the exact inverter datasheet maximum DC voltage.

Range: 1–2,000 V

Use the lower MPPT operating limit from the exact inverter datasheet.

Result

Cold Voc margin to inverter maximum (V)
46.63
Hot Vmp margin above MPPT minimum (V)
129.35
Maximum modules for entered cold Voc limit
18.00
Minimum modules for entered hot MPPT limit
15.00
Estimated hot string Vmp (V)
629.35
Estimated cold string Voc (V)
953.37
Estimated module Vmp at maximum temperature (V)
34.96
Estimated module Voc at minimum temperature (V)
52.97
Within the entered voltage bounds

Formula

Calculation logic

Formula definitions and substituted values.

Before relying on the result

  • Check cold-weather string Voc against the inverter maximum
  • Check hot-weather string Vmp against the entered MPPT minimum
  • Compare the proposed string against the module and inverter voltage data supplied by the user.

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Compare the proposed string against the module and inverter voltage data supplied by the user.