said by Thane_Bitter:Stepped is expected at this price.
Actually its MUCH worse:
"Waveform Type Stepped approximation to a sinewave"
It also lacks any sort of management feature outside a USB/Serial port; the 1500 they use to sell at least had a smart card slot which added a whole array of expansion communication and control options. The run time is crap as well barely 4mins at full load; it will be half that amount as the batters age.