Fire Alarm Battery Calculator
Estimate the standby battery capacity required for a fire detection and alarm system.
Ah = (Iq × standby hours) + (Ia × alarm hours), followed by the selected safety and derating multipliers.
This calculation supports engineering estimates. Verify final battery selection against the relevant standards and manufacturer documentation.
Important notes
- Confirm standby and alarm durations for the system and application.
- Use approved manufacturer data or measured currents.
- Allow for age, temperature, discharge rate and charger condition.
- This estimate does not replace competent design verification.
For supporting terminology and design context, read the wiki guidance on fire alarm power supplies and batteries, emergency power backup systems and BS 5839 fire alarm system guidance.