The APSX4048SW PowerVerter® APS X Series 4000W Inverter/Charger with automatic line-to-battery transfer and integrated charging system serves as an extended run UPS, a standalone power source and an automotive inverter. It provides up to 4000 watts of pure sine wave power to connected equipment, helping it perform better and last longer. The unit can be operated in single-phase mode and an extremely efficient 3-phase mode suited for high-capacity industrial and commercial installations. For increased capacity, up to seven total APSX4048SW units can be configured in a parallel connection for increased capacity up to 28 kW.Supplies up to 4000 watts of continuous 220,230 or 240V selectable AC input & output from any 48V DC battery or automotive DC source; 50/60 Hz pure sine wave output(hardwired). When hardwire AC input is energized, commercial power passes through to connected equipment and the battery set is recharged via 3 stage, 1/70 amp charging system. In UPS mode, the APS system responds to blackouts and severe voltage fluctuations with a near instantaneous automatic transfer to battery-derived AC output. Includes a set of high current DC input terminals for simple installation(user supplies batteries and cabling - see owner's manual for recommendations). Passes sine wave utility or generator power during battery charging and UPS line power operation, and sine wave AC output in inverter and UPS backup modes. Built-in Automatic Voltage Regulation(AVR) corrects line power AC brownouts and overvoltages without using battery power during battery charging and UPS standby modes. Reliable large transformer design, with frequency control powers resistive electronic loads or large inductive motors, compressors and other items with high current needs on startup. Optional APSRMSW wired remote power switch with full status LEDs provides remote power inverter on/off switching and continuous status information(part# APSRMSW sold separately). Supports an unlimited amount of runtime with any number of user-supplied batteries connected. Highly adaptable to a variety of applications and site conditions with adjustable charger settings for wet/gel battery types and selectable line to battery power transfer voltages.