Grid Tie Solar Power System w/ Battery Backup Drawing
As you can see compared to the simple grid tie system, the battery backup system is a little more complex. It includes a battery system, which is typically a group of lead acid batteries, a charge controller to keep the system from cooking the batteries from an overcharge and a critical load sub-panel. The point of a battery backup system is not to power you entire house through a blackout but to provide backup power to your most important electrical loads in your home or business. The downsides of a battery backup system are the increased cost of the overall system, the maintenance of the batteries and the installation time of the system with batteries jumps up 40% compared to a system without batteries.
So it really depends on where you live, how reliable your utility company is and if you have loads in your house that need to be redundant. What do you think? Is adding batteries to your system worthwhile?