Choose a battery based on your evening electricity use, solar generation and whether you want backup during blackouts, rather than simply buying the largest capacity. Ask an accredited installer about usable capacity, round-trip efficiency, warranty terms, outdoor placement, ventilation and protection from extreme temperatures. Compare your retailer’s tariffs and feed-in rates, as shifting solar energy to evening use may affect the value of a battery. Check current rebates and eligibility through energy.gov.au, and have the system installed and maintained by appropriately licensed professionals.