Access-Control Battery-Backup Calculator
When the mains fail, the standby battery has to keep your readers, controllers and monitoring alive for as long as your strategy needs. Enter the total system current, the backup hours you want, the battery chemistry and the system voltage to get the required battery Ah, the next standard size to buy, and the real runtime it delivers. Planning figures; runs in your browser.
Egress must always work. A fail-safe lock on an escape route releases when power — and the battery — run out; that is the correct behaviour for egress. The backup is there to keep readers, controllers and monitoring alive, not to hold a door shut. Never rely on the battery to keep a fail-secure lock locked forever, and never wire a fail-secure lock on an escape door. The building code and fire strategy govern how every egress door must behave.
Planning estimate only — battery capacity falls with age and cold, so a battery that once gave the full runtime will give less after a few years. Replace standby batteries every few years, test the real runtime, and confirm against the battery datasheet. The building code and fire strategy govern egress behaviour.
Related Guides — Deep-dive reading
Access Control Maintenance in India (2026): Readers, Locks and Fail-Safe Egress
How to keep a card, keypad, fingerprint or face access-control system reading reliably and locking securely — and, above everything, how to test that its doors still release on a fire alarm and on power loss, so an access-controlled door never becomes a life-safety trap.
SecurityUPS and Battery Maintenance in India (2026): Keep Security Alive Through a Power Cut
How to look after the UPS units and backup batteries that keep your cameras, NVR, alarm panel and gate controller running when the mains fails — treating batteries as consumables you replace on schedule, and proving it with a regular pull-the-mains backup test.
SecurityUPS and Battery Schedule for India (2026): Keeping the System Alive Through a Cut
A ready-to-adapt schedule that lists each backup unit, what it protects and the autonomy it must deliver, so cameras, panels, controllers and the recorder ride through India's frequent power cuts.
SecurityRelated Tools — You may also find these useful
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Size a UPS/inverter and battery to keep CCTV, NVR, router and alarm running through a power cut — load, Ah, VA and cost.
Backup PowerAccess-Card Quantity Calculator
How many access cards or fobs to order and re-order, from users, spare stock, a visitor pool and annual loss.
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Total current and power an access system draws, to size the power supply — locks, readers and controllers.
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