A grid-tie battery backup system serves two purposes. The first, as a source of energy when the grid is down for homes and organizations that can find themselves unable to power critical load appliances such as medical devices, computer systems, sump pumps, or refrigeration units. The second purpose, while the grid runs normally, is to enhance power management performance, such as storing energy during low rate hours and scheduling its usage during peak rate hours hence offsetting your energy costs when electricity rates are at their highest.