1. What is a Solar Wattage Calculator for RV?

Definition: This calculator estimates the usable wattage from solar panels for RV applications, accounting for system efficiency losses.

Purpose: It helps RV owners and solar installers determine the actual power available after accounting for typical efficiency losses in solar systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_w \) — Usable wattage (watts)
• \( P_{solar} \) — Solar panel rated output (watts)
• \( \eta_{solar} \) — System efficiency factor (typically 0.15-0.2)

Explanation: The solar panel's rated output is multiplied by the system efficiency factor to account for real-world losses (wiring, charge controller, battery, etc.).

3. Importance of Solar Wattage Calculation

Details: Accurate wattage estimation ensures proper system sizing, prevents power shortages, and helps optimize battery storage capacity.

4. Using the Calculator

Tips: Enter the solar panel's rated output in watts and the system efficiency factor (default 0.17). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is system efficiency so low?
A: The 15-20% range accounts for multiple losses: panel degradation, wiring resistance, charge controller efficiency, battery charging losses, and temperature effects.

Q2: What's a typical efficiency factor for RV systems?
A: Most RV solar systems operate at 15-20% overall efficiency. Newer systems with MPPT controllers may reach up to 22%.

Q3: Should I use panel wattage or system wattage?
A: Use the panel's rated STC (Standard Test Conditions) wattage - this is the number printed on the panel or specification sheet.

Q4: How does this relate to battery capacity?
A: Multiply usable wattage by peak sun hours to estimate daily watt-hours, then divide by battery voltage for amp-hours needed.

Q5: Does this include cloudy day performance?
A: No, this calculates optimal conditions. For cloudy days, multiply the result by 0.3-0.5 for realistic output.