1. What is the Solar Panel and Battery Calculator?

This calculator helps determine the battery capacity needed for a solar panel system based on panel wattage, sunlight hours, and system voltage. It's essential for designing efficient off-grid or backup power systems.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• House Solar Panel W — Solar panel wattage (watts)
• Sun h — Daily sunlight hours (hours)
• V — System voltage (volts)

Explanation: The equation calculates how much battery storage (in amp-hours) you need to store the energy your solar panels produce during sunlight hours.

3. Importance of Battery Capacity Calculation

Details: Proper battery sizing ensures your solar system can meet energy demands during periods without sunlight and prevents over-discharging batteries, which extends their lifespan.

4. Using the Calculator

Tips: Enter solar panel wattage, average daily sunlight hours, and system voltage. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical system voltage for home solar?
A: Common voltages are 12V (small systems), 24V (medium), or 48V (larger systems). Higher voltages reduce current and allow smaller wires.

Q2: How many sunlight hours should I use?
A: Use average peak sun hours for your location, which accounts for weather and seasonal variations (typically 3-6 hours).

Q3: Should I add a safety factor?
A: Yes, multiply the result by 1.2-1.5 to account for inefficiencies and provide reserve capacity.

Q4: What about battery depth of discharge?
A: Lead-acid batteries should only be discharged to 50%, so double the calculated capacity for them.

Q5: Does panel orientation affect this calculation?
A: Yes, panels not facing optimal direction will produce less power, requiring more capacity.