Engineering Sizing & Compliance Utility

Solar System Sizer & String Calculator

Calculate string electrical constraints, cold-temperature Voc surge (NEC Article 690.7), MPPT voltage operating windows, and DC/AC oversizing ratios.

1. Temperature-Corrected Voc Sizing

Ensures maximum string open-circuit voltage never exceeds inverter Vdcmax (typically 600V, 1000V, or 1500V) during extreme sub-zero winter mornings.

2. Summer MPPT Minimum Voltage

Calculates string Vmp derating at 65°C cell temperature to ensure array voltage stays above the inverter's lowest MPPT tracking threshold.

3. Inverter Loading Ratio (ILR)

Analyzes DC-to-AC power ratio economics (typically 1.15 to 1.35) to balance inverter clipping losses against balance-of-system cost optimization.