Yuasa closed Battery 12V / 17Ah, rechargeable - Tous les Vragens

Good question, that depends first of all on the battery. How many ampere hours is it (Ah)?
Then it's important to know how many components need to be powered.

The operating time t in hours for a 2.3Ah battery:

t = capacity (Ah) / current (A)

Current consumption - Operating time - Note
100 mA (0.1 A) - 23 hours - Small control panel in standby mode
200 mA (0.2 A) - 11.5 hours - With additional modules
500 mA (0.5 A) - 4.6 hours - Control panel with GSM/IP
1 A - 2.3 hours - During an alarm with a siren

Realistic correction
In practice, batteries often deliver 80–90% of their nominal capacity, especially at higher discharge rates.
Therefore, the practical operating time is usually 10–20% shorter than the table.

Conclusion (summarized):
A 12V/2.3Ah battery keeps an alarm system operational:
Approximately 10–20 hours at low consumption (100–200 mA).
Only 2–5 hours at higher consumption (0.5–1 A).