1. What is Standby Battery Capacity?

Standby battery capacity refers to the amount of energy storage required to maintain a fire alarm system during power outages. It ensures the system remains operational for the required duration (typically 24 hours) plus a safety margin.

2. How Does the Calculator Work?

The calculator uses the standby capacity formula:

Where:

• Home Standby A — Current drawn by system in standby mode (amps)
• 24 — Required hours of standby power
• Margin — Safety factor (typically 1.25-1.5)

Explanation: The formula calculates the minimum battery capacity needed to power the system for 24 hours with an additional safety margin.

3. Importance of Proper Standby Capacity

Details: Adequate standby capacity is critical for fire safety compliance and ensures the alarm system remains operational during extended power outages.

4. Using the Calculator

Tips: Enter the system's standby current in amps and your desired safety margin (typically 1.25). All values must be valid (current > 0, margin ≥ 1).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical standby current for home systems?
A: Most home fire alarm systems draw between 0.1-0.5A in standby mode, but check your specific system specifications.

Q2: Why include a margin?
A: The margin accounts for battery aging, temperature effects, and unexpected current draws.

Q3: How often should batteries be replaced?
A: Typically every 3-5 years, or when capacity drops below 80% of rated value.

Q4: Can I use this for commercial systems?
A: Commercial systems may have different requirements - consult local fire codes.

Q5: What battery type is best?
A: Sealed lead-acid (SLA) batteries are commonly used for their reliability and maintenance-free operation.