Utility/work truck inverter/charger is the quiet alternative to gas generators with no fumes, fuel or noise. It provides equipment with utility or generator supplied AC electricity filtered through premium ISOBAR surge protection. This DC-to-AC inverter with automatic line to battery transfer and integrated charging system serves as an extended run UPS, standalone power source or an automotive inverter suitable for rugged work site applications. It supplies up to 1250W of continuous 120Vac power from any 12Vdc battery or automotive DC source. OverPower inverter output feature temporarily provides up to 150% of the continuous output for 1 to 60 minutes and DoubleBoost inverter output feature delivers up to 200% of continuous output for up to 10s providing the extra power needed to start heavy-duty tools and motorized equipment. When AC cable is connected to live wall socket, commercial power passes through to connected equipment and the battery set is recharged via 3-stage selectable 10/40A charging system. In UPS mode, the APS system responds to blackouts and voltage fluctuations with a near instantaneous automatic transfer to battery derived AC output. A set of high current DC input terminals is included for simple installation. Reliable large transformer design, with frequency control, powers resistive electronic loads or large inductive motors, compressors and other devices with high current needs on start-up. Included is the APSRM4 wired remote power switch with full status LED’s which provides remote power inverter on/off switching and continuous status information. The UT1250UL supports an unlimited amount of runtime with user-supplied batteries. Versatile inverter/charger system with auto-transfer switching serves as an automotive inverter for utility work trucks, conversion vans, fleet service vehicles, standalone power source for off grid, alternative energy or export applications, emergency home power applications such as sump pumps, and as an uninterruptible power supply (UPS) for items compatible with 16.6ms transfer time.