Main Formula: Power = System Power × (Irradiance / 1000) × 75% × Temperature Factor
Temperature Factor: Temperature Factor = 1 + Temperature Coefficient × (Cell Temperature - STC Temperature)
Cell Temperature: Cell Temperature = Ambient Temperature + (Irradiance / 1000) × 20°C
Step-by-Step:
- Step 1: Power Ratio = Irradiance (W/m²) ÷ 1000
- Step 2: Cell Temperature = Ambient Temperature + (Irradiance ÷ 1000) × 20°C
- Step 3: Temperature Factor = 1 + Temperature Coefficient × (Cell Temperature - STC Temperature)
- Step 4: Hourly Power = System Power × Power Ratio × 0.75 × Temperature Factor
Advanced Settings: Temperature coefficient and STC temperature can be configured in Advanced Settings to match your specific panel specifications.
Assumptions: Base 75% efficiency includes inverter, cable, and system losses. Temperature factor accounts for panel heating (configurable % per °C above STC temperature). The weather API handles panel orientation, but temperature affects performance differently for different orientations.