Nobody buys a battery. They buy the end of a specific problem: a camera that stops recording, a router that drops the line, a PLC that faults mid-cycle. Each guide below starts from that failure and works back to a model.
PoE switches, NVRs and cameras that reboot on every flicker. Sized on the switch's budget, not the camera count.
5–8 W per camera · 10 ms transfer 02Fibre survives an outage. The CPE does not, unless something keeps the PPPoE session alive through the gap.
6–12 W typical · 8+ hours 03Unattended cabinets specified by autonomy hours, not by nameplate. Sized from the site load curve.
24 / 48 Vdc · 1–10 kWh per site 04Ride-through for PLCs, HMIs and gateways: seconds to minutes, at a reliability level that has no tolerance.
12–48 Vdc bus · DIN rail 05Loads past the last socket: fence lines, gateways, sensors and cameras on panel and battery alone.
Up to 32 days reserve · no mains 06 · ToolEnter the load in watts and the hours you need covered. It returns a model and a runtime range, with the assumptions printed next to it.
Open the calculatorLoad in watts, runtime in hours, ambient temperature in the enclosure, and whether the load needs a clean sine wave. Everything else — capacity, cell grade, connector, enclosure — follows from those four.
A supplier who cannot name the jobs they decline has not read your specification.