Choosing an Inverter for Off-grid Pv Systems

The inverter is one of the most important and most complex components in an independent energy system. To choose an inverter you should know some basic functions, capabilities, and limitations.

All types of off-grid PV electric energy systems share a common bond which is the storage battery, the storage battery absorbs and releases energy in the form of direct current (DC) electricity

In contrast, the national grid supplies alternating current (AC) electricity. AC is the standard form of electricity for anything that "plugs in" to mains power. DC flows in a single direction. AC alternates its direction many times per second. AC is used for grid service because it is more practical for long distance transmission.

An inverter converts DC to AC, and also changes the voltage. In other words, it is a power adapter. It allows a battery-based system to run conventional appliances through conventional wiring. There are appliances able to use DC directly but for the majority of modern appliances you will need an inverter.

There is another type of inverter that we are not concerned with in this article called a grid-interactive inverter. These are used to feed solar (or other renewable) energy into a grid-connected home and to feed excess energy back into the national grid.