1. What is the Battery Size Calculation?

The battery size calculation determines the required battery capacity (in ampere-hours) needed to support a UPS load for a specified duration at a given voltage. This ensures your UPS system can provide adequate backup power during outages.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• UPS Load VA — The volt-amp rating of the UPS load
• Time — Desired backup time in hours
• V — Battery bank voltage

Explanation: The equation calculates the ampere-hour capacity needed by considering the power requirement (VA), desired runtime, and system voltage.

3. Importance of Proper Battery Sizing

Details: Correct battery sizing is crucial for ensuring uninterrupted power supply during outages, preventing premature battery failure, and optimizing system cost and performance.

4. Using the Calculator

Tips: Enter the UPS load in volt-amps (VA), desired backup time in hours, and system voltage in volts. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Should I add a safety margin to the calculated battery size?
A: Yes, it's recommended to add 20-25% to the calculated size to account for battery aging and efficiency losses.

Q2: What's the difference between VA and watts?
A: VA is apparent power (volts × amps), while watts is real power. For sizing, use the VA rating unless you know the power factor.

Q3: How does battery voltage affect the calculation?
A: Higher voltage systems require fewer amp-hours for the same power, as power = voltage × current.

Q4: Can this be used for any battery type?
A: The calculation provides theoretical capacity. Actual battery performance varies by chemistry (lead-acid, lithium-ion, etc.).

Q5: How does temperature affect battery sizing?
A: Cold temperatures reduce battery capacity. In cold environments, size batteries 10-20% larger than calculated.