UK Intruder Alarm Battery Calculator

Calculate the required backup battery capacity based on typical UK standards (PD 6662 / BS EN 50131).

Total Quiescent (Standby) Current (Iq):

Total current draw of panel, detectors, keypads etc. in standby.

Total Alarm Current (Ia):

Total current draw of the *entire system* during alarm (including standby load + sounders, strobes etc.).

Required Standby Time (Ts) in Hours: Typically 12 hours for graded systems.

Required Alarm Sounding Time (Ta) in Hours: Typically 15 minutes (0.25 hours).

Safety / Derating Factor (Fs): Accounts for battery aging/temp. 1.25 = 25% margin.

Disclaimer: This calculator provides an estimate based on the formula. Always consult manufacturer datasheets and adhere to specific system grade requirements (PD 6662 / BS EN 50131). Professional installation and verification are recommended.