1. What is Battery Size Calculation?

The battery size calculation determines the required battery capacity (in ampere-hours) needed to power an inverter for a specific duration. It's essential for designing reliable power backup systems.

2. How Does the Calculator Work?

The calculator uses the battery size formula:

Where:

• \( \text{Inverter W} \) — Inverter power rating in watts
• \( \text{Time} \) — Desired runtime in hours
• \( \text{V} \) — Battery bank voltage

Explanation: The formula calculates the total energy needed (watt-hours) and converts it to battery capacity (ampere-hours) based on the system voltage.

3. Importance of Battery Sizing

Details: Proper battery sizing ensures your power system can handle the required load for the desired duration without over-discharging the batteries, which extends battery life and improves system reliability.

4. Using the Calculator

Tips: Enter the inverter's wattage rating, desired runtime in hours, and battery bank voltage. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Should I add a safety margin to the calculated size?
A: Yes, it's recommended to add 20-30% to account for inefficiencies, aging, and unexpected load increases.

Q2: What's the difference between Ah and Wh?
A: Amp-hours (Ah) measure charge capacity, while watt-hours (Wh) measure energy capacity. Wh = Ah × V.

Q3: Does inverter efficiency affect the calculation?
A: Yes, for more accurate results, divide the result by the inverter's efficiency (typically 85-95%).

Q4: How does battery type affect sizing?
A: Different battery chemistries (lead-acid, lithium) have different depth-of-discharge limits that should be considered.

Q5: Can I use this for solar systems?
A: Yes, but solar systems require additional calculations for charging capability and days of autonomy.