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Solar Array Voltage Calculator

Check string voltage across the temperature range against inverter limits.

About Solar Array Voltage Calculator

Panel voltage rises as temperature falls, so the worst case for insulation and inverter rating is a cold sunny morning. String length must be set by that condition rather than by nominal ratings. Exceeding the inverter maximum input voltage destroys it immediately and voids the warranty, making this the single most safety-critical solar calculation.

Formula

Solar Array Voltage

Voc(cold) = Voc × (1 + |coefficient| × (25 − T_min) ÷ 100); string voltage = Voc(cold) × panels

Voc rises in cold
Panel voltage increases as temperature falls, the opposite of power

Worked example

With the default values below, Solar Array Voltage Calculator returns Maximum String Voltage of 650.13. Change any input above and every figure here is recalculated in your browser.

Inputs used

Panels in seriesaccepts 1–40
12
Panel open circuit voltageminimum 0.1 V
49.5 V
Voltage temperature coefficientaccepts -1–0 %/C
-0.27 %/C
Minimum cell temperatureaccepts -50–40 C
-10 C
Inverter maximum input voltageminimum 1 V
1,000 V

Results

Maximum String Voltage
650.13 V
String Voltage at 25 Degrees
594.00 V
Maximum Panels per String
18
Headroom to the Inverter Limit
349.87 V
Verdict
Within the inverter voltage limit

Step by step

  1. 1Values used
  2. 2Solar Array Voltage
  3. 3Maximum String Voltage= 650.13 V
  4. 4String Voltage at 25 Degrees= 594.00 V
  5. 5Maximum Panels per String= 18
  6. 6Headroom to the Inverter Limit= 349.87 V
  7. 7Verdict= Within the inverter voltage limit

Assumptions and limits

  • The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Solar Array Voltage calculated?

Voc(cold) = Voc × (1 + |coefficient| × (25 − T_min) ÷ 100); string voltage = Voc(cold) × panels Panel voltage rises as temperature falls, so the worst case for insulation and inverter rating is a cold sunny morning. String length must be set by that condition rather than by nominal ratings.

Why does Solar Array Voltage matter?

Exceeding the inverter maximum input voltage destroys it immediately and voids the warranty, making this the single most safety-critical solar calculation.

What values do I need to enter?

This calculator takes 5 inputs: Panels in series, Panel open circuit voltage, Voltage temperature coefficient, Minimum cell temperature, Inverter maximum input voltage. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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