A solar battery can store surplus daytime generation for evening use, helping some households reduce grid electricity purchases and use more of their solar power. Whether it is worthwhile depends on your electricity rates, daily consumption, solar system size, battery capacity, export payments, upfront cost and how long you expect to stay in the home. Ask an accredited installer for a tailored comparison that includes usable capacity, warranty terms, estimated payback and backup capability, rather than relying only on advertised storage capacity. Check current rebates and eligibility on the relevant official government website, and use a licensed installer.