UPS Battery Calculator for CCTV & Security Systems

How to Use the UPS Calculator

Add each device in your security system using the quick-add buttons or the custom device row at the bottom of the table. Adjust the quantity and wattage for each item — the watt values are editable directly in the table, so you can match your actual equipment specs from the datasheet. Once your load list is complete, set the desired backup time and your battery bank voltage. The required VA rating and battery capacity update in real time.

UPS Sizing for CCTV and Security Systems

A correctly sized UPS for a security installation needs to account for three things: the total continuous power draw of all connected devices, the target runtime during a mains failure, and the inefficiencies of the battery and inverter stages. Under-sizing the VA rating risks the UPS shutting down under load; under-sizing the battery bank means the system goes offline before the target runtime is reached.

This calculator applies a power factor correction of 0.8 — the standard assumption for switching power supplies used in NVRs, PoE switches, and IP cameras — to convert your watt load to a VA rating. Battery capacity is calculated accounting for inverter efficiency, battery charge/discharge efficiency, and a 50% depth of discharge limit, which is the standard recommendation for lead-acid and AGM batteries to preserve service life.

Typical Power Consumption of Security Devices

Power draw varies significantly between device types and models. The values in the quick-add buttons are representative averages for planning purposes — always verify against your actual equipment datasheets before ordering a UPS. Typical ranges:

• IP cameras (fixed, PoE Class 2–3): 8–15W per camera
• PTZ cameras: 20–30W, higher during pan/tilt movement
• 4ch NVR: 15–25W
• 16ch NVR: 30–60W depending on HDD count
• 32ch NVR: 60–120W with multiple HDDs under load
• 8-port PoE switch: device consumption 8–15W plus full PoE budget if cameras are connected directly
• Access control panels: 10–25W, plus door lock strikes and readers
• Monitors (24"): 20–35W depending on brightness

Note that PoE switches supply power to cameras through the network port. If your cameras are powered by a PoE switch, add the switch's total PoE budget (not just its base consumption) to your load calculation, or list cameras and switch separately as done in this calculator's presets.

Battery Bank Voltage: 12V, 24V, or 48V?

The battery voltage setting determines how the required energy capacity is translated into amp-hours. All three voltages produce the same energy output — the choice affects how many batteries are needed and how they are wired.

A 12V system is common for small installations with a single battery. A 24V system (two 12V batteries in series) is standard for mid-sized CCTV racks and reduces cable losses at the same power level. A 48V system is used in larger installations and telecom-style cabinets where high capacity is needed with lower current draw. Match the voltage setting to your actual battery bank configuration.

Frequently Asked Questions

What VA rating UPS do I need for a CCTV system?

Add up the wattage of all devices — NVR, cameras, PoE switch, monitors — and divide by 0.8 to get the minimum VA rating. A 300W total load requires at least a 375VA UPS. It is good practice to size the UPS at 20–25% above the calculated minimum to allow headroom for startup surges and future load additions.

How long will a UPS run a CCTV system?

Runtime depends on the battery bank capacity, the total load in watts, and the efficiency of the system. A larger battery bank extends runtime proportionally. This calculator sizes the battery bank for a target runtime you specify — set your required backup duration and the tool returns the Ah capacity needed for your battery bank at the chosen voltage.

Should I use a 12V or 24V battery for a security system UPS?

For small systems (one NVR, a few cameras, under 150W), a single 12V battery is usually sufficient. For larger installations, a 24V bank (two 12V batteries in series) gives you more capacity in a manageable form factor and reduces current, which lowers cable and connector losses. The battery bank voltage in this calculator does not change the energy result — only the amp-hour figure changes to reflect the voltage.

Can I use a standard office UPS for CCTV?

Yes, for short runtimes. Standard office UPS units (typically 5–15 minutes at full load) are adequate for graceful shutdown protection. For security applications requiring 2–8 hours of backup, you need a UPS with an external battery connection or a dedicated DC power backup unit sized to the calculations above.