AC Input Voltage Range

There are different acceptable AC input voltage range for different kinds of loads.
For some relatively sensitive electronic devices, a narrow input range of 184-253VAC (100-135V for 120VAC models) is required to protect them.
While for some resistive loads which work in a wide voltage range, the input AC range can be customized to 154-253VAC (90-135V for 120VAC models), this helps to power loads with the most AC input power without frequent switches to the battery bank.
In order to make the inverter accept dirty power from a generator, when the SW2 is switched to position “1”, the inverter will bypass an AC input with a higher voltage(164-264Vac for 230Vac models, 90-135Vac for 120Vac models) and wider frequency (40Hz plus for 50Hz/60Hz). Accordingly, the AC charger will also work in a higher voltage(174-254Vac for 230Vac models, 100-135Vac for 120Vac models) wider frequency range (43Hz plus for 50Hz/60Hz).
This will avoid frequent switches between battery and generator. But some sensitive loads will suffer from the low quality power.
The pros and cons should be clearly realized before you do the setting.