Off-grid inverter
A complete system solution for off-grid inverters using modular components consists of a number of manageable building blocks: inverter/charger,
solar charge controller, automatic generator starter module, and system control board.

As the name suggests, the off-grid inverter is a system that is disconnected from the public grid. The DC power emitted by the solar panel is first stored in the battery, and then the battery is transported to the off-grid inverter for inversion. 
The load can also be returned to the battery for storage. For remote areas without power network coverage, such as deserts, plateaus, and deep forests, it can provide power demand anytime, anywhere.

Grid inverter
Grid-connected inverters are generally divided into photovoltaic power generation grid-connected inverters, wind power generation grid-connected inverters, 
power equipment power generation grid-connected inverters and other power generation equipment power generation grid-connected inverters. 
The biggest feature of the grid-connected inverter is the high power and low cost of the system.
The grid-connected inverter is generally used in the system of large-scale photovoltaic power stations. Many parallel photovoltaic strings are connected to the DC input end of the same centralized inverter. 
Generally, three-phase IGBT power modules are used for high power.The low power uses field effect transistors, while the use of DSP conversion controllers improves the quality of the power produced, making it very close to a sine wave current.

The biggest difference between grid-connected inverters is that they do not do any battery storage. The DC power generated from the solar panels is directly converted into AC power through inverters and directly connected to the public power grid. Safety regulations and policies, otherwise the grid connection cannot be provided.