1. What is the Battery Capacity Formula?

The battery capacity formula calculates the required ampere-hour (Ah) rating for a battery bank to power an inverter load for a specified duration, accounting for inverter efficiency and battery voltage.

2. How Does the Calculator Work?

The calculator uses the battery capacity equation:

Where:

• Inverter Load — Total wattage of devices to be powered
• Backup Hours — Desired runtime during power outage
• Inverter Efficiency — Typically 0.85-0.95 (85%-95% efficient)
• Battery Voltage — 12V, 24V, or 48V system voltage

Explanation: The formula converts watt-hours to ampere-hours by accounting for system voltage and efficiency losses.

3. Importance of Battery Capacity Calculation

Details: Proper battery sizing ensures sufficient backup power, prevents premature battery failure, and optimizes system cost and performance.

4. Using the Calculator

Tips: Enter total load in watts, desired backup time in hours, inverter efficiency (default 0.85), and battery bank voltage (typically 12V, 24V, or 48V).

5. Frequently Asked Questions (FAQ)

Q1: What's typical inverter efficiency?
A: Most quality inverters are 85-95% efficient. Pure sine wave inverters tend to be more efficient than modified sine wave.

Q2: Should I add a safety margin?
A: Yes, it's recommended to add 20-30% to the calculated capacity to account for battery aging and unexpected load increases.

Q3: How does battery type affect capacity?
A: Lead-acid batteries should only be discharged to 50% capacity for longevity, while lithium batteries can often discharge to 80-90%.

Q4: What if I have multiple batteries?
A: For parallel connections, Ah ratings add up. For series connections, voltage adds up while Ah stays the same.

Q5: How does temperature affect capacity?
A: Battery capacity decreases in cold temperatures - you may need to oversize by 10-20% in cold climates.