Inverter function is to put DC current from battery, to AC 220V.
It goes through different PCB boards and the transformer. The efficiency will lose during the transfer. And this is why on grid solar system efficiency is higher than off grid solar power system.
Output Voltage(Battery Mode): 110VAC±2% / 120VAC±2% / 220VAC±2% / 230VAC±2% / 240VAC±2%
This means in battery mode, inverter output 220VAC ± 2%. Stable output voltage is good for all home appliances. It will extant home appliances using time compare to output unstable voltage.
Output Frequency(Battery Mode): 50Hz±0.5 or 60Hz±0.5
Output Wave(Battery Mode): Pure Sine Wave
Efficiency(AC Mode) : >99%
This is different from the battery mode. Because in this mode, city grid supply AC power, no need transfer battery DC current to AC. In below data will tell you what is the difference of city mode and battery mode.
Output Voltage(AC Mode): Follow input
Output Frequency(AC Mode): Tracking Automatically
Output waveform distortion (Battery Mode):≤3%(Linear load)