APC Back-UPS systems provide battery backup and surge protection for computers and electronics. They are intended to bridge short outages, keep communications equipment online for a period of time, or provide enough runtime for an orderly shutdown.
The Back-UPS family spans multiple VA and watt ratings and outlet layouts. Depending on model, features can include USB charging, automatic voltage regulation, user-replaceable batteries, communications and a mix of battery-backed and surge-only receptacles.
Select by actual load and runtime rather than VA alone. A 1500 VA model, for example, may support very different runtimes depending on the connected wattage.
Add the wattage of the devices that must remain on battery, then leave reasonable capacity for startup behavior and future additions. Review the runtime curve or APC runtime data at a load close to the planned installation.
For networking equipment, modem/router loads are often small enough to run significantly longer than a desktop workstation on the same UPS, but the result still depends on the exact model and battery condition.
VA is apparent power capacity. The connected equipment must stay within both the UPS VA rating and its watt rating.
High-inrush devices can overload smaller UPS systems. Use APC guidance for the exact UPS and load before placing printers or other high-current devices on battery-backed outlets.
