Why does my inverter have low voltage output?

The voltmeter you�re using might not �True RMS.� The inverter in the PP2.6 has modified sine wave output. Modified sine wave voltage is a type of square wave that has an RMS (Root Mean Square) value of 120 VAC in this inverter. A general-purpose AC voltmeter is calibrated to accurately measure the RMS value of a Pure Sine Wave and NOT of a Modified Sine Wave. If this general-purpose voltmeter is used to measure Modified Sine Wave voltage, it will indicate a lower value (98 VAC to 108 VAC). For accurately measuring the voltage of a Modified Sine Wave, use a voltmeter which is designed to measure �True RMS Values� such as the Fluke 87, Fluke 8060A, Fluke 77 / 99, Beckman 4410 etc. This is demonstrated in the following YouTube video: https://www.youtube.com/watch?v=v3Ozup3HACk