PoE devices — security cameras, wireless access points, VoIP phones — are only as reliable as the power on their Ethernet cable. When the building loses power, the switch or injector feeding them dies, and so does your security footage and Wi-Fi. A PoE battery backup fixes that at the point where it matters.
What is a PoE battery backup?
It is a battery unit with an Ethernet pass-through: LAN in, powered Ethernet out. Data flows through untouched while the unit injects 24V or 48V PoE power from its battery whenever mains power fails. Your camera or access point never notices the outage.
24V or 48V? Get the voltage right
Standards-based (802.3af/at) devices expect 44–57V, so choose 48V. Many wireless ISP radios and some cameras use passive 24V instead. A selectable injector like the one in the Zeatech ZP-64Wh covers both with a hardware switch — but always check your device's spec before powering it.
How long will PoE gear run on battery?
Using a 64Wh battery and the runtime formula (watt-hours ÷ load × 0.9): a 5W camera runs about 11 hours, a 10W access point about 5.5 hours, and a 20W combined PoE load about 3 hours. Estimate your own setup with the runtime calculator.
One box for mixed loads
Most sites are not PoE-only. The ZP-64Wh combines the 24V/48V PoE injector with 9V/12V/24V DC jacks and USB 5V, so one unit backs up the camera, the router it talks to, and the ATA for the phone line — up to 38W total. That is the difference between a camera that records the outage and one that becomes part of it.
