What Size UPS Do You Need for 8 PoE Security Cameras?
Size a UPS for eight PoE cameras, an NVR, switch and router using real watts, headroom and target runtime instead of VA alone.
An eight-camera PoE system is a chain: cameras, PoE switch, NVR and usually router/modem. If any required link loses power, part of the system stops working. UPS sizing therefore starts with the combined real watt load, not the camera count or the VA number printed on the battery backup.
Step 1: total the real watts
Use camera maximum power draw where possible because infrared LEDs, spotlights, heaters and motors can raise consumption at night or in bad weather. Add the switch's own electronics, the recorder and any network gear that must remain online.
Step 2: leave output headroom
APC recommends a UPS output watt capacity around 20–25% above attached equipment load. Using that approach, a 111W surveillance load should not be paired with a UPS that can barely deliver 120W; a unit comfortably above roughly 140W output gives more operating margin.
Step 3: size runtime separately
Output capacity only tells you whether the UPS can run the load. Runtime depends on battery energy and the UPS efficiency curve. Two units with the same 600VA label can have different runtime at 100W because their battery packs differ.
What to keep powered
- PoE switch: without it, the cameras lose power.
- NVR: without it, centralized recording stops.
- Router: needed if cameras and NVR communicate through it or if local app access depends on it.
- Modem/ONT: only needed for internet alerts or remote viewing; local recording may continue without it.
Should the monitor be on the UPS?
Usually no. A display can consume a meaningful share of the battery while adding nothing to recording continuity. Keep the recording chain alive first and add a monitor only if someone must actively operate the system during outages.
Use the Security Camera UPS Runtime Calculator for battery-runtime estimates and the Solar Camera Power Budget Calculator for off-grid camera designs.