1. What is the Battery Calculation?

The battery calculation determines the required battery capacity (in ampere-hours) for fire alarm systems based on system load, required backup time, and a safety margin from the manufacturer's catalogue.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• \( System\ Load \) — Current draw of the fire alarm system in amps
• \( Required\ Backup \) — Required backup time in hours
• \( Catalogue\ Margin \) — Safety factor from manufacturer's specifications (typically 1.25-1.4)

Explanation: The equation calculates the minimum battery capacity needed to maintain system operation during power outages.

3. Importance of Battery Calculation

Details: Proper battery sizing ensures fire alarm systems remain operational during power failures, meeting code requirements and providing continuous protection.

4. Using the Calculator

Tips: Enter system load in amps, required backup time in hours, and catalogue margin (typically 1.25). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical catalogue margin?
A: Most manufacturers recommend 1.25 to 1.4 to account for battery aging and temperature effects.

Q2: How do I determine system load?
A: System load should be measured or calculated based on all connected devices in alarm condition.

Q3: What backup time is required by code?
A: Most jurisdictions require 24 hours of standby plus 5 minutes in alarm, but check local regulations.

Q4: Should I round up the calculated Ah?
A: Yes, always select the next available standard battery size greater than your calculation.

Q5: Does temperature affect battery capacity?
A: Yes, cold temperatures reduce capacity. Additional margin may be needed in cold environments.