What Size UPS Do You Need for Security Cameras and an NVR?
Size a UPS for an NVR, PoE switch, router and security cameras using actual watts and target runtime.
A UPS for a surveillance system has two separate jobs: supply enough instantaneous power and store enough battery energy for the runtime you want. The VA rating alone does not tell you runtime.
Add the real load
- NVR or recorder watts.
- PoE switch base consumption.
- PoE camera watts across all ports.
- Router and modem watts if remote access matters.
- Any monitor you truly need during the outage.
For example, an NVR at 20W, PoE switch electronics at 10W, six cameras averaging 7W each and router/modem at 20W creates about 92W before margin.
Leave power headroom
Do not buy a UPS whose maximum watt output is barely above the measured load. Cameras can draw more power when infrared LEDs or heaters activate, and UPS batteries lose capacity as they age.
Runtime is nonlinear
UPS batteries do not deliver their nameplate watt-hours perfectly at every load. Manufacturer runtime charts are the best final authority. A calculator can estimate the energy requirement, then you should confirm the chosen model's runtime curve near your actual load.
Use the UPS runtime calculator to estimate the energy target.