1. What is the Fire Alarm Battery Size Calculator?

The Fire Alarm Battery Size Calculator determines the required battery capacity (in ampere-hours) for fire alarm systems powered by inverters. It ensures your fire alarm system has adequate backup power during outages.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• Inverter Fire Alarm Load W — Total wattage of the fire alarm system
• Time — Required backup time in hours
• V — Battery system voltage (typically 12V or 24V)

Explanation: The formula calculates the battery capacity needed to sustain the fire alarm load for the specified duration at the given voltage.

3. Importance of Proper Battery Sizing

Details: Correct battery sizing is critical for fire alarm systems to ensure uninterrupted operation during power failures, which is essential for life safety and code compliance.

4. Using the Calculator

Tips: Enter the total wattage of your fire alarm system, the required backup time in hours, and the battery system voltage. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical voltage for fire alarm batteries?
A: Most fire alarm systems use either 12V or 24V battery systems. Check your specific equipment specifications.

Q2: How long should fire alarm batteries last?
A: NFPA 72 typically requires 24 hours of standby plus 5 minutes of alarm, but local codes may vary.

Q3: Should I add a safety factor to the calculation?
A: Yes, it's recommended to add 20-30% to the calculated Ah to account for battery aging and temperature effects.

Q4: What about battery type (lead-acid vs. lithium)?
A: This calculator provides the capacity needed. The actual battery size may vary based on battery chemistry and discharge characteristics.

Q5: How often should batteries be replaced?
A: Lead-acid batteries typically need replacement every 3-5 years, while lithium batteries may last 10+ years.