Approximate backup time - assumptions for calculations

Siedlec, 2017-11-10
Approximate backup time - assumptions for calculations
1) Approximate backup time is based on the assumed power consumption of the
following receivers.
Camera:
Analog HD camera – 5W
PoE IP – 5W
DVR and NVR with hard drive:
4-channel recorder - 20W
8-channel recorder - 25W
16-channel recorder - 30W
2) The calculations assume that cameras are connected to the power supply outputs in
the following way:
- If the PoE IP switch is used, then the cameras are connected to all of its ports.
- If the power supply with voltage distribution strip is used, then the cameras are
connected to all of its ports.
3) The calculations take into account the electricity consumption for own needs.
4) The calculations take into account the energy efficiency of the used voltage
converters (when used in the power supply/switch).
5) The basic formula for calculations.
t =
,

t – Approximate backup time [h]
0.8 – The coefficient taking into account the decrease in battery capacity
due to aging.
C – Battery capacity [Ah]
Iz – Current consumption by PSU systems [A]
I – Current drawn from the power supply [A]
6) The calculations take into account the decrease in battery capacity as a function of
the current drawn:
C20 = 100% of the battery capacity
C10 = 95% of the battery capacity
C5 = 85% of the battery capacity
C1 = 60% of the battery capacity