Solar Battery systems are used to store energy from Photovoltaic (PV) systems that are not tied to the utility grid.  Less than 1% of PV systems use batteries today.  These systems are usually used for remote cabins in the woods and for RV's or dedicated loads like security systems or medical devices.  The batteries can store energy for use at night or on cloudy days.  There are a variety of batteries that are especially manufactured for use with renewable energy. Most systems will require a group of batteries that are connected in a series and can be held in a bank or rack. 
The most common are deep cycle, sealed, lead-acid because they are the least expensive, require no maintenance and are easy to find.  Avoid shallow cycle batteries such as car batteries because they are designed to provide a large amount of power for a short time.  They are not designed to be deeply discharged and their life will be very short.  Consult a professional solar dealer to match the batteries for your off grid system. 

Always use a charge controller when using batteries for a photovoltaic system.  Charge monitors manage the charge current of the batteries and ensure they are not over charged. 

Batteries must be stored and handled with care.  They can be very dangerous if misused. Avoid allowing lead-acid batteries to sit uncharged for several days.  This will ruin the battery. 

Life-cycle costing for remote solar vs. Remote fossil fuel generators

Solar Energy                                    Fossil Fuel
High Front End Cost                          Low front end cost
Long Life of product                          Shorter Life (Replacement costs)
Low maintenance                             Higher Maintenance
No Fuel costs!                                 Consumes fuel