A mini-tower UPS with line interactive topology, the CyberPower PFC Sinewave CP1500PFCLCD provides battery backup (using sine wave output) and surge protection for desktop computers, workstations, networking devices, and home entertainment systems requiring active PFC power source compatibility...
www.cyberpowersystems.com
It is LF Sine wave inverter, 1500VA/900W, the unit is not made to run full load for a long period of time in battery mode, it is made to run long enough till batteries run down without over heating.
The charger circuit is the yellow transformer (SMPS) to the right of the 3 fuses on the main PCB.
Notes: the company I used to work for have Cyberpower produce custom made UPS for us, common failure are the lytics caps for the charger circuit go bad.