Off-grid electrical systems provide continuous electrical power to thousands of consumers who live and work far beyond the reach of power lines. The very core of these systems is the battery bank. Electricity stored in batteries is used by the inverter to produce household AC power when it is needed. Batteries play the same role in an off-grid system as a water reservoir does in a utility scale hydro electric system – they both store energy for use on demand.
In many ways batteries can be best described as “buckets of electricity”, they may be emptied and refilled and they have a measurable capacity. The capacity of batteries is usually expressed in Amp Hours. In a typical off-grid electrical system the inverter/charger is capable of both emptying and refilling the batteries.
Off-grid systems are generally employed in remote locations without utility grids. It’s a good solution in an area where running a line to the local utility grid is prohibitively expensive, or an area where blackouts and brownouts are relatively common. With an off-grid system, your solar energy system would supply all of the power a cabin, home or business would need.
Off-grid systems completely relieve you from dependency on electrical grids. Off-grid systems typically require a larger up-front investment than grid-tie systems. This is, in large part, due to the greater demands on the system. A grid-tie usually supplements a home’s energy demands, reducing the amount of energy required from the utility grid. An off-grid system is responsible for providing all power-appliances, lighting, and the electricity required for other utilities.
When designing a off-grid system, try to think of the entire picture, down to each light bulb. Standard incandescent lighting is notoriously energy inefficient. You may want to consider fluorescent or LED lighting instead.
Off-grid systems are generally larger than grid-tie systems. To be fully independent, a system must have a greater array of energy-producing panels, which in turn requires more batteries to store the charge and more equipment to regulate the charge. While requiring more parts will require a large initial investment, in the long-run an off-grid system may save you thousands.