Back-up Power Supply

Back-up Power Supply

Maintenance-Free Lead-Acid Gel Batteries in sirens serve as a primary source of power for amplifiers and, in case of a power failure from the mains or solar cells, batteries also serve as a back-up power source for both sirens and other devices. Valve-regulated lead-acid (VRLA) gel types, sometimes also called sealed lead-acid (SLA) gel batteries are used for various kinds of Telegrafia’s products.  They are maintenance-free, leak-proof and position insensitive.

As for battery capacity, it is vital to know the requirements of a specific project. The battery capacity is calculated based on the required minimum standby time, configuration and the minimum necessary full-power time of a siren.

For explanation, when the minimum standby time is set for 72 hours, a siren can operate in standby mode for 72 hours after a power cut. Subsequently, when the required full-power time is set for 20 minutes, a siren can produce a warning signal for 20 minutes until the batteries run out (become discharged).



Minimum required standby time: 72 hours
Minimum required full-power time: 20 minutes
Recommended battery capacity: 27 Ah
Calculated battery capacity: 24.06 Ah
Voltage: 24 V

The time calculated is always reduced due to local conditions such as temperature, battery type, battery life, and other parameters.
In the calculations, assumptions are made for the full siren power output (when sounding a continuous alarm tone) and fully charged batteries.


The article was written by

Monika Siserova

Monika is an international business manager for Balkan, Benelux and Scandinavian states. She worked with a diverse range of organisations, including government institutions, IGOs in the field of migration, private sector and non-profits. The mentioned experience laid a sound foundation for a challenging and meaningful job she has in the Telegrafia Company. Therefore, she is very excited about bringing you the latest news from the field of early warning and notification systems.

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