1. What is the Battery Capacity Calculation?

The battery capacity calculation determines the required battery size (in amp-hours) for a solar power system based on your daily energy needs, desired days of autonomy, battery specifications, and system efficiency.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• Daily Energy Consumption — Your total daily energy needs in watt-hours
• Days of Autonomy — Number of days the system should run without sun
• Battery Voltage — Nominal voltage of your battery bank
• Depth of Discharge — Maximum recommended discharge level (typically 0.5 for lead-acid)
• Efficiency — System efficiency factor (typically 0.85-0.95)

Explanation: The equation accounts for all factors that affect battery sizing in solar applications.

3. Importance of Proper Battery Sizing

Details: Correct battery sizing ensures your solar system meets your energy needs while maximizing battery life and system reliability.

4. Using the Calculator

Tips: Enter all values in the specified units. Depth of Discharge and Efficiency should be between 0 and 1. Typical values are pre-filled for common systems.

5. Frequently Asked Questions (FAQ)

Q1: What is Days of Autonomy?
A: The number of consecutive days your system should provide power without solar input (typically 2-5 days).

Q2: What Depth of Discharge should I use?
A: For lead-acid batteries, 0.5 is typical. Lithium batteries can often use 0.8-0.9.

Q3: What affects system efficiency?
A: Inverter efficiency, charge controller efficiency, wiring losses, and temperature effects.

Q4: Should I round up the battery size?
A: Yes, always round up to the next available battery size to ensure sufficient capacity.

Q5: How does temperature affect battery capacity?
A: Cold temperatures reduce battery capacity. In cold climates, you may need to increase capacity by 20-30%.