StandbyCalc Battery Calculator

StandbyCalc works out the standby battery you need for UK fire and intruder alarm systems in seconds. Enter the quiescent and alarm currents, pick the fire alarm category or the intruder alarm grade, and get the minimum battery capacity in Ah plus the next standard SLA battery size. Add the fitted battery to see whether it's above or below the calculated minimum. Every battery calculation is free. No ads, no tracking, no sign-up and no subscription. FIRE ALARM BATTERY CALCULATION - Based on BS 5839-1 - Categories L, M and P - 24 h standby, or 6 h where a standby generator is fitted - Category P premises left unoccupied: standby periods up to 72 h INTRUDER ALARM STANDBY - Based on BS EN 50131 and BS 9263, Grades 1 to 4 - BS 4737 (legacy systems) for older installations - Standby battery sizing for control panels and remote power supplies PSU AND SLA BATTERY SIZING - Standalone 12 V and 24 V power supplies with your own standby and alarm periods - Minimum Ah with de-rating applied, rounded up to the next standard SLA battery HOW IT WORKS 1. Enter the panel and device currents for standby and alarm 2. Choose the system type, then the category or grade 3. Read off the minimum capacity and the SLA battery to fit 4. Optional: enter the fitted battery to see if it's above or below the calculated minimum The working is shown in full: C = 1.25 x (I1 x T1 + D x I2 x T2) NEW IN 1.0.5 - Fitted battery: enter the fitted Ah and battery date, see whether it's above or below the calculated minimum, and copy a one-line result for your service sheet (free) - Fitted battery line on PDF reports (Pro) - BS 4737 now labelled "BS 4737 (legacy systems)" STANDBYCALC PRO (one-off £9.99) - Redesigned branded PDF reports with your logo - Full formula working on every report - Save calculations against a site and come back to them later - A clear PDF record of each calculation for your job file Built for UK fire and security installers, engineers and maintainers who need a quick standby battery calculation on site. Always check results against the panel and battery manufacturer's data. From D4N LTD. Support: https://d4n.io/projects/standbycalc/ Independent app, not affiliated with or endorsed by BSI.