1. What is a Solar Panel Output Calculator?

Definition: This calculator estimates the actual power output of a solar panel based on its rated capacity, current solar irradiance, and system derate factor.

Purpose: It helps solar installers and homeowners predict energy production under different conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{Output} \) — Actual power output (Watts)
• \( P_{\text{rated}} \) — Panel's rated power capacity (Watts)
• \( \text{Irradiance} \) — Solar radiation intensity (W/m²)
• \( \text{Derate} \) — System efficiency factor (0-1)

Explanation: The formula adjusts rated power by current sunlight conditions and accounts for system losses.

3. Importance of Solar Output Calculation

Details: Accurate output estimation helps in system sizing, energy production forecasting, and ROI calculations.

4. Using the Calculator

Tips: Enter the panel's rated power (from specs), current irradiance (default 1000 W/m² for standard conditions), and derate factor (default 0.75 for typical systems).

5. Frequently Asked Questions (FAQ)

Q1: What is standard test condition (STC) irradiance?
A: 1000 W/m² is the standard testing irradiance level at which panel ratings are determined.

Q2: What affects the derate factor?
A: Temperature, wiring losses, inverter efficiency, dirt, shading, and age all contribute to derating.

Q3: How do I find current irradiance?
A: Use local solar monitoring systems or irradiance maps (typically 800-1100 W/m² at noon on sunny days).

Q4: Why divide irradiance by 1000?
A: This normalizes the irradiance to the STC reference value used for panel ratings.

Q5: Does this calculate daily energy production?
A: No, this gives instantaneous power. For daily energy, multiply by peak sun hours and account for sun path.