Battery storage systems generally consist of three main components:
A battery which contains individual battery cells wired together capable of discharging and being charged with DC voltage. There are a range of different battery technologies, for example Lead Acid and Lithium Ion.
Inverter-Charger unit which is capable of converting DC electricity from the battery to AC electricity and converting AC to DC for charging the battery from mains power.
Balance of system components such as wiring, battery management systems and other measurement and control components such as meters and switches. For battery systems capable of running standalone from the grid, extra components such as change-over switches will be required.
Battery manufacturers and suppliers offer a range of different products that may require different levels of system integration and installation work. Examples include:
Battery only: Some manufacturers of battery systems only provide the battery and you will need to have a battery installer integrate the battery with a compatible inverter, control system and potentially a new or existing solar system.
Battery storage system with inverter: Some manufacturers provide a fully integrated battery storage system with battery, inverter-charger and control system that can be installed at your home on its own and is a separate system to your solar system which still has its own inverter.
Solar and battery storage system: Some manufacturers provide an integrated solar and battery storage system, where there is a single unit that contains the inverter-charger and battery, and the DC side of the solar system is connected to this all-in-one system.