1. What is the Backup Battery Calculation?

The backup battery calculation determines the required battery capacity (in amp-hours) to maintain a fire alarm system during power outages based on the system's current draw and required backup duration.

2. How Does the Calculator Work?

The calculator uses the simple equation:

Where:

• \( Alarm\ System\ Load \) — Current draw of the fire alarm system in amps
• \( Backup\ Requirement \) — Required duration of backup power in hours

Explanation: The equation calculates the total amp-hours needed by multiplying the system's current draw by the required backup time.

3. Importance of Backup Battery Calculation

Details: Proper battery sizing ensures fire alarm systems remain operational during power outages, which is critical for life safety and code compliance.

4. Using the Calculator

Tips: Enter the total current draw of your fire alarm system in amps and the required backup duration in hours. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's typical backup requirement for fire alarms?
A: Most codes require 24 hours of standby plus 5 minutes of alarm, but check local regulations.

Q2: Should I add a safety factor?
A: Yes, it's recommended to add 20-30% to the calculated value to account for battery aging and temperature effects.

Q3: How do I find my system's current draw?
A: Check manufacturer specifications or measure with a clamp meter during normal operation.

Q4: Does this account for alarm mode current?
A: No, you should calculate separately for standby and alarm modes, using the higher result.

Q5: What battery types are used for fire alarms?
A: Sealed lead-acid (SLA) batteries are most common due to their reliability and maintenance-free operation.