Best PoE Security Camera System: NVR Kits, Channels and Storage Math

A PoE camera gets power and data from the same Ethernet cable, plugged into a port on the NVR or a PoE switch. Nothing runs on batteries, nothing competes for Wi-Fi, and the cameras keep recording to the NVR even when your internet is down, because they talk to the recorder over its own cables.

The cost is the install. Every camera needs a cable run back to the recorder, which means drilling through an exterior wall or soffit and pulling cable through an attic or crawlspace. If you cannot run cable, a solar or plug-in Wi-Fi camera that records to microSD is the no-subscription alternative.

Channels are how many cameras the NVR can record. A kit with 4 cameras on an 8-channel NVR leaves 4 open ports, and adding a same-brand PoE camera later is one cable and a few taps in the app. Running out of channels means buying a second recorder, so pick more channels than you think you need.

Count the spots first: front door, driveway, back door, each side yard, a detached garage. Most single-family homes land on 4 to 6. Pick 8 channels for that, and 16 for large lots, multiple outbuildings or a small business.

4K is 8 megapixels (3840 x 2160). 12MP packs 50% more pixels into the frame, which helps you read a face or a plate at a longer distance or crop into a wide shot. It also makes bigger files, so the same drive holds fewer days.

For a front door or a driveway under about 40 ft, 4K is plenty. Spend on 12MP or a zoom lens when the thing you need to identify is far from the camera: the end of a long driveway, a gate or a street.

Storage is bitrate times time. A camera recording at 1 Mbps writes 1 megabit a second, which is 10.8 GB a day (1 / 8 x 86,400 seconds / 1,000). So the rule of thumb is: GB per day per camera = Mbps x 10.8.

Example: four 4K cameras at 4 Mbps each write 4 x 4 x 10.8 = 173 GB a day, so a 2 TB drive (about 2,000 GB) holds about 11.5 days of nonstop recording. Push the bitrate to 8 Mbps and the same drive holds about 5.8 days. Eight cameras at 4 Mbps on a 4 TB drive also work out to about 11.5 days.

Your NVR shows the bitrate each camera is set to; plug that into the formula. Recording only on motion or person detection instead of 24/7 stretches a drive much further. When the drive fills, the NVR overwrites the oldest footage, so nothing stops recording.

Buying the recorder and cameras separately lets you mix camera types: turrets at the doors, a zoom bullet at the end of the driveway, a 180 degree camera over the yard. The Reolink RLN8-410 records only Reolink PoE cameras, so keep the cameras in one brand.

If you want cameras on a plain PoE switch with no NVR, each camera records to its own microSD card. That is the lowest-cost wired setup, though a thief who takes the camera takes its card too.

Ethernet tops out at 100 m (328 ft) per run, which is why Reolink rates its PoE cables at up to 330 ft. Measure each run from the camera spot to where the NVR will sit, following the path the cable will actually take through the attic or walls, and add 10 to 15 ft for slack.

Use Cat5e or Cat6, and outdoor or direct-burial rated cable for any run that sits outside or underground. Put the NVR somewhere cool and hidden, near your router so it can reach the app, and on a small UPS if you want it recording through a short power outage.

Fewer, smarter cameras mean fewer runs. A pan-tilt camera that tracks a person across a yard, or a 180 degree dual-lens camera, can replace two fixed cameras and their two cables.