Batteries are cheap and easy to replace, if they ever do go bad. In the last 2 years a revolution in inverters has been happening, mainly at Trace Engineering. This firm has responded to changing customer needs very rapidly. Most households run on AC because AC wiring is cheaper and somewhat safer than DC wiring. The AC output of inverters is either a modified sine wave or true sine wave.
Most residential systems use modified sine wave inverters, which are somewhat less expensive.
Wiring Since solar electric systems are basically DC, they have wiring requirements different form AC systems. A large switch with fuses is required between the inverter and batteries to protect the inverter. Batteries are capable of putting out thousands of amps.