well if u r talkin abut apc thn apc 1 kva makes 670 watts if it is in black color and 650 watts if it is in white color .. difference is cux of new and old models ... white ups is very very very very old model ... and 1 kva, 1.5 kva both works with 2 batteries ... u can use 2 numbers of 175 ah battery for maximum backup times ....
and if u r talkin abut any other pak cheen dosti ups like homage etc or local made then its hard to find out its max wattage ....