The inverter is the heart of all but the smallest power systems.
It is an electronic device that converts direct current DC power
from batteries or solar modules into alternating current AC
power to operate lights, appliances or anything that normally
operates on power supplied by the utility grid. Inverters come
in many varieties, sizes and qualities and offer various features
that specialize them for particular applications.
Off-grid, or standalone, inverters convert DC power stored in batteries
to AC power that can be used as needed. Select an inverter for
your power system based on the maximum load you will be powering,
the maximum surge required, AC output voltage required,
input battery voltage and optional features needed.
Grid-tie, or utility intertie, inverters convert DC power from PV
modules into AC power to be fed into the utility grid. There are
two major types of grid-tie inverters; string inverters and low
voltage input inverters.
Using a dual-function inverter allows you to sell excess power to
the utility, and also maintain a battery bank for standby power in
the event of a utility power failure. The Xantrex XW series, and the
OutBack GFX series inverters are primarily standalone inverters
that can function as an intertie inverter at the same time, but with
a lower efficiency than an inverter designed for grid-tie only.