How Much Power Does a CCTV Camera Use? Read It, Don’t Guess

Start With the Label, Then Distrust It Slightly

Two places carry the number. The first is the camera’s own datasheet, which usually quotes a maximum draw in watts. The second, and the more useful one for older equipment, is the power supply that came with it: read the output line, not the input line. An adapter marked 12 V DC 2 A has a 24 W ceiling, and that ceiling is the most the camera is allowed to pull, not what it pulls on average. An allowance read as a draw can even imitate a fault: when the battery stops filling, a camera that is not charging usually has a site cause before a hardware one.

That gap between ceiling and average is the whole reason sizing by nameplate goes wrong. A camera rated at 24 W might draw 6 W in daylight with infrared off, 9 W after dark with it on, and 18 W on the one cold night the internal heater kicks in. Size for 6 W and the site is dark by the second night. Size for the 24 W ceiling and you buy battery you never use. The working number is the realistic continuous draw at the worst moment of a normal night, which is why the label is the starting point rather than the answer. Holding that draw where it started over a few years is a lighter job than it sounds, and the seasonal check list is the whole of it.

One more label detail that catches buyers: a camera sold with a 12 V DC adapter and a camera sold with PoE are different loads even when the model name is nearly the same. The DC version runs directly from a 12 V output. The PoE version needs a PoE injector or switch, and that injector becomes part of the load you have to count.

If the Label Is Vague, Measure Once

Ten minutes with a DC clamp meter or an inline power meter settles the question permanently for a given camera model, and the reading is worth more than any datasheet. Measure with the camera doing its real job: infrared on, recording to whatever it records to, and network connected. Measure twice if the model has a heater, once at room temperature and once with the thermostat likely to have closed, because those two readings can differ by a factor of two.

Two habits make the reading usable. First, note the voltage at the same time as the current, because watts are volts times amps and a sagging supply changes both. Second, write both numbers on a label inside the enclosure or in the site file. The next person to size a point on that route should not have to repeat the measurement, and the same camera model will produce the same number on every copy of that site.

If measuring is impossible before purchase, ask the supplier for the input rating and treat the highest figure you are given as the planning number, then confirm it on the first unit. What you must not do is size the system on an average that assumes infrared is never used, because on a security camera infrared is used every single night.

From Watts to Watt-Hours: The Step Everyone Skips

How much power does a CCTV camera use, then, once the label and the meter have both been consulted? The answer only becomes useful when it is turned into watt-hours. A wattage on its own sizes nothing. A 10 W camera runs for 24 hours and asks for 240 Wh a day; a 20 W camera asks for 480 Wh. Both of those assume the camera works the whole day, and the duty cycle behind a 24/7 recording requirement is what decides whether it does. Those daily watt-hours are compared against usable battery energy. For these systems the figure is quoted at 12 V nominal, with the reserve the system keeps in hand and the conversion loss already taken off, which gives roughly 326 Wh on a 40 Ah battery, 490 Wh on a 60 Ah, and 979 Wh on a 120 Ah.

A worked example makes the comparison concrete. Take a fixed camera at 8 W and a router at 4 W, so 12 W continuous and 288 Wh a day. The router half of that figure is the one most lists leave under-counted, and the router load at a camera point covers it device by device. On the 60 Ah battery that is about 1.7 days of reserve, comfortable for a normal night and thin across two grey days. The 120 Ah battery gives about 3.4 days on the same load, which is the difference between a site that recovers from bad weather and one that needs a visit. Add a heater-equipped PTZ at 20 W and the daily figure climbs past 700 Wh, which pushes the same site onto the largest battery in the range. The panel and battery sizing method behind these numbers is written out step by step if you want to run your own figures through it. If the figures say the reserve reaches zero, the flat-battery walkthrough describes what that day looks like.

Then check the panel side. Recharge has to cover the daily consumption on a short day in the worst month, and that is a different calculation from the battery reserve. The battery decides how long a point survives; the panel decides whether it recovers. How farms size each camera point, where every point is its own site, is set out in this walkthrough. How a system behaves across a stretch of cloudy and cold weather is covered with numbers in that guide.

Four Ways This Number Gets Fudged

Counting daytime only. The camera runs at night, and infrared is on for most of it. A draw measured at noon on a sunny day is the low point of the day, not the average.

Ignoring the accessories. The router, the radio, the NVR and the PoE injector are all on the same output. A 6 W camera with a 5 W router is an 11 W site, and the second number doubles the first one’s importance. Add devices until the list is whole and the count question answers itself; the camera-count arithmetic is that sum worked twice, on watts and on watt-hours.

Treating the adapter rating as consumption. A 12 V 2 A adapter is a 24 W allowance, and most cameras never approach it. Sizing on allowances buys battery nobody needed and hides the real question, which is the measured night-time draw.

Assuming an inverter is needed. Cameras, routers and most NVRs run on low-voltage DC, which is what an off grid camera system outputs, so converting to mains-style AC only adds losses. Whether an inverter is needed for a solar camera system is one of the questions we answer most often, and the short version is that it usually is not.

What the Wiring Looks Like

A single-camera run needs one cable: the DC5521 plug from the system output to the camera. The panel, controller and battery side is pre-wired at the factory, so there is no wiring diagram to follow on site and no mains work anywhere in the installation. Two cameras change one thing — a splitter at the output, sized against the same 5 A ceiling as everything else on the output.

That is the whole wiring task. What deserves the attention instead is upstream of it: the daily watt-hours the camera burns, which is what the earlier sections work through.

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