... down automatically when switching to battery for power supply , no output , or inverter failure , output short circuitINV lamp ... lamp onInverter works at city power modeBUZZEROverload , low battery , or inverter failureTechnical Specifications-2 Power (w)3005007501k1.5k2k3K4k5KInput Voltage ... or high as the battery capacity. UPS power inverter --solar power ,low frequency inverter , pure sine wave