CyberPower Intelligent LCD Series UPS 1500VA Mini-tower BRG1500AVRLCD2 READ

posting Condition: AS-IS - NO Returns or Refunds - the screen is flashing a "replace battery" error. the internal battery does not hold a charge and turns off when unplugged from the outlet. We tried putting a working internal battery for testing, but when we unplugged it from the outlet, it gave us an "E21" error. No original box.  The BRG1500AVRLCD2 Intelligent LCD Series UPS from CyberPower is a mini-tower device with line-interactive topology that provides battery backup and surge protection via sine and simulated sine waveform output for desktop computers, workstations, networking devices, and home entertainment systems. It provides an output capacity of 1500 VA / 900W and features an input voltage of 120 VAC at 57-63 Hz using Automatic Voltage Regulation (AVR) to help correct minor power fluctuations without switching to battery power. This Smart App UPS has an integrated LCD panel that displays immediate, detailed information about its battery and power conditions to a