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.