Inverters can be classed according to their power output. The following information is not set in stone, but it gives you an idea of the classifications and general power ranges associated with them. Th.
[pdf] An inverter converts a 110 Volt DC voltage (battery) into an AC voltage (230V-50Hz). The standard output voltage is 230 Volt, 50Hz with a pure sine wave. This means that this inverter supplies the same type of voltage as the wall socket. This allows any electrical device to work on it.
[pdf] Most residential solar panels generate between 16-40 volts DC, with an average of around 30 volts per panel under ideal conditions. However, the actual voltage fluctuates based on temperature, sunlight intensity, shading, panel age and quality.
[pdf] 
