Pv Panel Output Calculator

PV Panel Output Calculator

function calculatePVOutput() { var panelRatedPower = parseFloat(document.getElementById("panelRatedPower").value); var numberOfPanels = parseFloat(document.getElementById("numberOfPanels").value); var peakSunHours = parseFloat(document.getElementById("peakSunHours").value); var systemLossFactor = parseFloat(document.getElementById("systemLossFactor").value); if (isNaN(panelRatedPower) || panelRatedPower <= 0) { alert("Please enter a valid positive number for Single Panel Rated Power."); return; } if (isNaN(numberOfPanels) || numberOfPanels <= 0) { alert("Please enter a valid positive number for Number of Panels."); return; } if (isNaN(peakSunHours) || peakSunHours < 0) { alert("Please enter a valid non-negative number for Average Daily Peak Sun Hours."); return; } if (isNaN(systemLossFactor) || systemLossFactor = 100) { alert("Please enter a valid System Loss Factor between 0 and 99.9."); return; } var actualLossFactor = (100 – systemLossFactor) / 100; // Calculate daily output per panel in Watt-hours (Wh) var dailyOutputPerPanelWh = panelRatedPower * peakSunHours * actualLossFactor; // Calculate total daily output for all panels in Watt-hours (Wh) var totalDailyOutputWh = dailyOutputPerPanelWh * numberOfPanels; // Calculate monthly output in kilowatt-hours (kWh) // Using average days in a month (30.44) var monthlyOutputkWh = (totalDailyOutputWh * 30.44) / 1000; // Calculate annual output in kilowatt-hours (kWh) var annualOutputkWh = (totalDailyOutputWh * 365) / 1000; document.getElementById("dailyOutputWh").innerText = totalDailyOutputWh.toFixed(2) + " Wh"; document.getElementById("monthlyOutputkWh").innerText = monthlyOutputkWh.toFixed(2) + " kWh"; document.getElementById("annualOutputkWh").innerText = annualOutputkWh.toFixed(2) + " kWh"; } // Run calculation on page load with default values window.onload = calculatePVOutput;

Understanding Your PV Panel Output

Estimating the energy output of your solar photovoltaic (PV) panels is a crucial step in planning a solar energy system. This calculator helps you get a realistic idea of how much electricity your panels can generate daily, monthly, and annually, taking into account key factors that influence performance.

How the Calculator Works

Our PV Panel Output Calculator uses a straightforward formula to estimate energy production. It considers the rated power of your panels, the number of panels, the amount of sunlight they receive, and common system inefficiencies.

Key Input Definitions:

• Single Panel Rated Power (Wp): This is the "Watt-peak" rating of a single solar panel, indicating its maximum power output under ideal test conditions (Standard Test Conditions – STC). A typical residential panel might be 300-450 Wp.
• Number of Panels: The total count of solar panels in your system.
• Average Daily Peak Sun Hours: This is a critical factor representing the equivalent number of hours per day when solar irradiance averages 1,000 watts per square meter (W/m²). It accounts for varying sun angles, cloud cover, and seasonal changes. For example, a location might have 4.5 peak sun hours, meaning the total solar energy received throughout the day is equivalent to 4.5 hours of full, direct sunlight. This value varies significantly by geographic location and time of year.
• System Loss Factor (%): No solar system operates at 100% efficiency. This factor accounts for various losses, including:
  • Temperature Losses: Panels perform less efficiently at higher temperatures.
  • Inverter Efficiency: The inverter converts DC power from panels to AC power for your home, with some energy loss.
  • Wiring Losses: Resistance in cables causes minor energy loss.
  • Soiling/Dust: Accumulation of dirt, dust, or snow on panels reduces light absorption.
  • Shading: Partial or full shading from trees, chimneys, or other obstructions.
  • Mismatch Losses: Slight variations in performance between individual panels.
  A typical system loss factor ranges from 10% to 25%.

The Calculation Formula:

The calculator uses the following logic:

Daily Output (Wh) = Single Panel Rated Power (Wp) × Average Daily Peak Sun Hours × (1 - System Loss Factor / 100) × Number of Panels
Monthly Output (kWh) = Daily Output (Wh) × 30.44 / 1000
Annual Output (kWh) = Daily Output (Wh) × 365 / 1000

The daily output is calculated in Watt-hours (Wh) and then converted to kilowatt-hours (kWh) for monthly and annual figures (1 kWh = 1000 Wh).

Realistic Examples:

Let's consider a few scenarios:

• Small Residential System (Default Values):
  • Single Panel Rated Power: 400 Wp
  • Number of Panels: 10
  • Average Daily Peak Sun Hours: 4.5 hours
  • System Loss Factor: 15%
  • Estimated Output: ~1530 Wh/day, ~46.6 kWh/month, ~558.5 kWh/year
• Larger System in a Sunny Location:
  • Single Panel Rated Power: 450 Wp
  • Number of Panels: 20
  • Average Daily Peak Sun Hours: 5.5 hours
  • System Loss Factor: 12%
  • Estimated Output: ~4356 Wh/day, ~132.5 kWh/month, ~1590.9 kWh/year
• System in a Less Sunny Location with Higher Losses:
  • Single Panel Rated Power: 350 Wp
  • Number of Panels: 8
  • Average Daily Peak Sun Hours: 3.0 hours
  • System Loss Factor: 20%
  • Estimated Output: ~672 Wh/day, ~20.5 kWh/month, ~245.3 kWh/year

Factors Affecting Actual Output:

While this calculator provides a good estimate, actual PV panel output can vary due to:

• Weather Variability: Daily and seasonal changes in cloud cover, rain, and snow.
• Panel Orientation and Tilt: Optimal angles maximize sun exposure.
• Degradation: Solar panels slowly lose efficiency over their lifespan (typically 0.5% to 1% per year).
• Maintenance: Regular cleaning can prevent significant soiling losses.
• Grid Conditions: In some cases, grid limitations can affect inverter operation.

Use this calculator as a valuable tool for initial planning and comparison, but always consult with a professional solar installer for a precise assessment tailored to your specific location and needs.