Fire Alarm Battery Size Calculator For UPS

Battery Size Formula:

\[ \text{Battery Size (Ah)} = \frac{\text{UPS Fire Alarm VA} \times \text{Time (hours)}}{\text{V (volts)}} \]

Battery Size:

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1. What is Fire Alarm Battery Size Calculation?

The Fire Alarm Battery Size calculation determines the required battery capacity (in ampere-hours) needed to power a UPS-based fire alarm system for a specified duration. Proper sizing ensures the system remains operational during power outages.

2. How Does the Calculator Work?

The calculator uses the following formula:

\[ \text{Battery Size (Ah)} = \frac{\text{UPS Fire Alarm VA} \times \text{Time (hours)}}{\text{V (volts)}} \]

Where:

\( \text{UPS Fire Alarm VA} \) — The volt-amp rating of the UPS fire alarm system
\( \text{Time} \) — Required backup time in hours
\( \text{V} \) — System voltage (typically 12V or 24V for fire alarm systems)

Explanation: The formula calculates the ampere-hours needed by considering the power requirement (VA) multiplied by the required duration, then divided by the system voltage to get the battery capacity.

3. Importance of Proper Battery Sizing

Details: Correct battery sizing is critical for fire alarm systems to ensure they remain operational during power outages as required by safety regulations. Undersized batteries may lead to system failure during emergencies.

4. Using the Calculator

Tips:

Enter the VA rating from your UPS fire alarm specifications
Specify the required backup time (typically 24-96 hours depending on regulations)
Enter the system voltage (usually 12V or 24V)
All values must be positive numbers

5. Frequently Asked Questions (FAQ)

Q1: What is the typical backup time required for fire alarm systems?
A: Most jurisdictions require 24 hours of standby plus 5 minutes of alarm, but check local codes as some require up to 96 hours.

Q2: Should I add a safety factor to the calculated battery size?
A: Yes, it's recommended to add 20-25% to the calculated value to account for battery aging and temperature effects.

Q3: What voltage should I use for the calculation?
A: Most fire alarm control panels operate at 24V DC, but always verify with your specific equipment's specifications.

Q4: How does temperature affect battery sizing?
A: Batteries lose capacity in cold temperatures. For installations below 20°C (68°F), you may need to increase battery size by 25-50%.

Q5: Can I use this calculator for other UPS applications?
A: While the formula is similar, fire alarm systems have specific requirements. For other applications, consult the UPS manufacturer's guidelines.