Basics Applications Stand-Alone
What is a Stand-Alone Solar System?
Stand-alone systems use a battery to store energy. When the sun is not shining or it is cloudy, the battery supplies the loads, either DC or AC or both. Some stand-alone systems use the power directly without using batteries. An example is a directly connected water pumping system. Charge controllers are used to control the battery charging. Inverters are used to convert the DC if AC loads are used. Battery system are more expensive than grid-connected systems, but still lower cost than running a generator constantly. A standby generator or wind turbine can lower the overall cost of the total system because the solar system doesn't have to be as large and the generator is not running constantly.
More information about stand-alone systems is in the Solar Basics book. Design examples for stand-alone systems are in the Solar Design book.