1. What is a Solar Panel Power Output Calculator?

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

Purpose: It helps solar installers and homeowners determine expected power production under specific conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Output — Actual power output (Watts)
• Wattage — Panel's rated wattage (Watts)
• Irradiance — Solar radiation intensity (W/m²)
• Derate — System efficiency factor (0-1)

Explanation: The formula adjusts the panel's rated output based on current sunlight conditions and system losses.

3. Importance of Power Output Calculation

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

4. Using the Calculator

Tips: Enter the panel's rated wattage, current irradiance (default 1000 W/m² for standard test conditions), and derate factor (default 0.75). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is standard test condition irradiance?
A: 1000 W/m² is the standard irradiance used for panel ratings, representing peak sunlight at sea level.

Q2: What factors affect the derate value?
A: Temperature, wiring losses, inverter efficiency, soiling, and other system losses contribute to derating.

Q3: How do I find current irradiance?
A: Use local solar monitoring data or irradiance maps. Typical values range 800-1100 W/m² at noon.

Q4: Why divide by 1000 in the formula?
A: Panel wattage ratings are based on 1000 W/m² irradiance, so this normalizes the calculation.

Q5: Does this account for panel orientation?
A: No, orientation effects should be reflected in the measured irradiance value used.