Switching guide · StandbyCalc
Switching to StandbyCalc
Moving your standby battery sums off a paper worksheet or a spreadsheet. Who it suits, what carries over, and what it costs.
Download on the App StoreWho it’s for
Engineers who size alarm batteries
- Fire alarm engineersSizing standby batteries for systems based on BS 5839-1, Categories L, M and P.
- Intruder alarm installersGrades 1–4, based on BS EN 50131 and BS 9263.
- Anyone with a standalone PSUCustom standby and alarm periods for signalling, access control or CCTV power supplies.
What moves over
From paper, a spreadsheet or another app
- Your inputsThe same figures you write on a worksheet: panel and device quiescent and alarm currents, the system type, and the category or grade. StandbyCalc picks the standby and alarm periods for the category or grade, or you set them for a standalone PSU.
- Your answerMinimum battery capacity with de-rating applied, plus the next standard SLA battery size, with the working shown.
- Your job file (Pro)Save calculations against a site for later, and export a branded PDF report with your name, company, the site and the full formula working.
There is no import from a spreadsheet: you type the currents in once per calculation. Always check results against the panel manufacturer’s data.
What it costs
Free to calculate, £9.99 once for Pro
- FreeEvery calculation, every standard, category and grade. No sign-up.
- Pro: £9.99, one-offBranded PDF reports with full formula working and saved calculations against a site. No subscription.
Good to know
The small print
StandbyCalc works out a minimum battery capacity from the figures you enter. Calculations are based on BS 5839-1 (fire) and BS 9263 (intruder). Check results against the panel manufacturer’s data before you fit a battery.
BS 5839-1 is a British Standard published by BSI. StandbyCalc is an independent app, not affiliated with or endorsed by BSI.