What is the ideal DC/AC ratio for a solar inverter?

The optimal DC/AC oversizing ratio is typically 1.1–1.3 (e.g., 13 kWdc array on a 10 kW inverter). Higher ratios improve inverter utilization but cause more clipping losses.

How do I calculate maximum string voltage?

Multiply open-circuit voltage (Voc) of one panel by number of panels in series, then apply temperature correction for the coldest expected temperature. Must stay below inverter's maximum input voltage (typically 600–1000V).

How many panels per string?

Divide the inverter's MPPT voltage range by single panel's Vmp. Most residential strings are 7–15 panels. Commercial strings can be up to 20+ panels depending on voltage limits.

String Inverter Sizing Calculator

Size a string inverter for your solar PV array. Calculate maximum string voltage, minimum string length, and inverter DC/AC ratio for optimal performance.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Size a string inverter for your solar PV array. Calculate maximum string voltage, minimum string length, and inverter DC/AC ratio for optimal performance. Use the inverter sizing result to inform your clinical assessment.

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Frequently Asked Questions

What is the ideal DC/AC ratio for a solar inverter?

How do I calculate maximum string voltage?

How many panels per string?