APC Back‑UPS CS BK500 – 500 VA Standby UPS Battery Backup

Overview

The APC Back‑UPS CS BK500 is a 500 VA uninterruptible power supply (UPS) engineered to provide temporary battery support and surge protection for essential electronics, networking devices, and small systems during utility power irregularities. It is typically deployed by IT technicians, small business support personnel, and home office administrators to maintain uptime long enough for orderly shutdowns or to bridge short outages without loss of data or equipment operation.

This UPS operates on standby (offline) topology with a stepped approximation to a sine wave output. It supports a nominal 120 V AC input/output and delivers up to 500 VA / 300 W of capacity. The internal battery engages automatically when incoming voltage deviates beyond acceptable thresholds, switching within milliseconds to maintain connected loads.

Outlets include a combination of battery‑backup with surge protection and surge‑only protection, enabling segmentation of connected devices by criticality to maximize available runtime for essential loads. Built‑in LED indicators and audible alarms provide real‑time status for line power, battery mode, low battery, overload, and wiring fault conditions. USB and serial communication ports support basic UPS monitoring and controlled shutdown when integrated with host systems.

The internal maintenance‑free sealed lead‑acid battery has typical recharge times in the range of 8 hours, supporting several minutes of runtime depending on load demand (e.g., ~15 min at ~150 W, ~3 min at ~300 W). This battery configuration is user‑replaceable using APC RBC2 cartridge series to sustain ongoing service life.

The compact tower enclosure is not rack‑mountable but fits easily near workstations, network closets, or shelf‑mounted equipment. It provides basic power continuity and is suitable for environments where short bridging time and surge protection are sufficient to protect critical electronics.

Key Features

• 500 VA / 300 W standby UPS with stepped sine wave output
• 6 outlets (3 battery backup + surge, 3 surge only)
• Maintenance‑free sealed lead‑acid battery with ~8 h recharge
• USB and serial communications support basic monitoring
• LED indicators and audible alarms for power event alerts

Specifications