Buying Guides · bijgewerkt 2026-10-16

UPS for Security Cameras: Keep Recording During Power Cuts

A security system is only useful when it is powered. Storms, grid maintenance and winter faults are common across Europe, and a power cut is exactly when you might want your cameras working. An uninterruptible power supply (UPS) is a simple, affordable way to keep recording for a while, and to shut your recorder down safely if the outage lasts longer.

What a UPS does for a camera system

A UPS is a box with a built-in battery that sits between the wall socket and your equipment. If mains power drops, it switches to battery within milliseconds, so your devices never notice. It also smooths out surges and brownouts, which can quietly damage electronics over time.

For CCTV there are two benefits. First, continuity: cameras keep recording for minutes or hours. Second, protection: an NVR that loses power mid-write can corrupt its hard drive or the latest recordings. A UPS gives it time to finish and shut down cleanly.

Which cameras actually need one

Not every setup benefits equally, so start by looking at how each camera is powered.

• PoE cameras with an NVR: the best candidates. One UPS can cover the NVR, the PoE switch (or the NVR’s built-in PoE ports) and every camera attached to it.
• Wi-Fi cameras on mains adapters: each camera has its own plug, so you would need to power the cameras and the router from a UPS, which is less tidy. Often the router and a few key cameras are enough.
• Battery and solar cameras: they carry on regardless, but they still need your Wi-Fi to be up for remote alerts.
• 4G/LTE cameras: they do not depend on your home router, so they are naturally resilient to local power cuts, provided they have their own battery or solar supply.

What to connect to the UPS

Think about the whole chain from camera to your phone. If any link loses power, the chain breaks. Use this checklist:

• The NVR, including its hard drive.
• The PoE switch, if your cameras do not plug straight into the NVR.
• The internet router and modem or ONT, if you want remote viewing and push alerts during an outage.
• Any Wi-Fi access point that your cameras rely on.
• Mains-powered cameras that are not on PoE, if they are worth the extra load.

Keep other items off it. Monitors, TVs, printers and kettles waste precious battery and can overload the unit. If you do want a monitor, use it only briefly for checking footage.

Working out how much power you need

UPS units are rated in VA (volt-amperes) and in watts. The watt figure is the one that matters, and it is usually around 60 to 70 per cent of the VA number. Add up what you want to protect, then leave some headroom.

A rough example for a small PoE system:

• Four PoE cameras at roughly 5 to 10 W each: 20 to 40 W
• NVR with one hard drive: roughly 15 to 25 W
• Router and modem: roughly 10 to 20 W

That gives a total of around 50 to 85 W. Check the actual figures on each device’s label or in its specification sheet, as they vary by model, and cameras with heaters, spotlights or PTZ motors can draw more. As a rule, choose a UPS whose rated watts are at least 30 per cent above your total load.

Estimating runtime honestly

Runtime depends on battery capacity and load. A simple estimate is:

Runtime (hours) ≈ usable battery watt-hours ÷ load in watts

Small consumer UPS units store modest energy, often in the region of 70 to 150 Wh, and not all of it is usable once conversion losses are counted. With a load of 70 W, that may mean well under an hour. This is normally enough to ride out brief outages and to shut down properly, but it will not run a system overnight.

Manufacturers publish runtime charts showing minutes at various loads, and these are more reliable than a calculation. If you want several hours of cover, you need a much larger UPS or one that accepts external battery packs, which costs more and takes up more space.

You can stretch runtime by reducing load: protect only the NVR, switch and router, and leave non-essential cameras off the UPS.

Choosing the right type

You will mainly see three designs:

• Offline (standby): the cheapest. It switches to battery when power fails. Fine for a basic setup in an area with stable mains.
• Line-interactive: adds automatic voltage regulation, correcting small dips and surges without using the battery. A sensible choice for most homes and small businesses.
• Online (double conversion): always runs from the inverter, giving the cleanest power. It suits critical sites but is larger, noisier and costlier.

For a typical home or shop NVR system, line-interactive is usually the sweet spot. Also look for a unit with enough outlets marked as battery-backed, and a socket type that matches your country’s plugs.

Setting it up and looking after it

Plug the UPS into a wall socket, then connect your devices to its battery-backed outlets. Let it charge fully before relying on it, which typically takes several hours. Then test it: with the system running, unplug the UPS from the wall and confirm that cameras keep recording and the alarm beep sounds. Do this at a quiet time of day.

A few habits help it last:

• Place it indoors in a cool, ventilated spot. Heat shortens battery life considerably.
• Do not chain it to a power strip or another UPS.
• Check whether your NVR supports automatic shutdown through a USB or network signal from the UPS. Not all do, so look in the manual.
• Test it every few months and expect to replace the battery after roughly three to five years.

Remember too that a local outage may also take down your internet provider’s street equipment, so remote access can fail even if your router stays on. For that reason, local recording on the NVR is the main benefit of the UPS.

Conclusion

Add up the wattage of your NVR, PoE switch and router, choose a line-interactive UPS rated comfortably above that, and check the manufacturer’s runtime chart. Aim for enough time to ride out short cuts and shut down cleanly, test it before the winter storms arrive, and your cameras will keep watching when the lights go out.