Description capacity (va/w) 1000va/800w nominal battery voltage 12vdc line mode input nominal voltage 220vac voltage range 170-280vac (narrow range) 90-280vac (wide range) normal frequency 50hz or 60hz output volatge 220vac frequency/ waveform following the utility transfer time 20ms typical back up mode output voltage 220vac frequency 50hz or 60hz (auto detection) waveform simulated sine wave protection discharge, over-charged, over-loading, overtemperature, short circuit protection battery charger (powered by ac) charging algorithim 3-step charging ac charging mode 10a/20a floating charging voltage 13.75 ±0.25v overcharging voltage 15.30v general physical dimension (d*w*h) 316mm(d)*227mm(w)*92mm(h) operating environment 0-50?C, 0%-90% relative humidity (non-condensing) storage environment 15?C to 55?C noise level less than 50db