A battery can help use more of your solar electricity after dark, but whether it is worthwhile depends on your energy use, export rate, tariff, battery price and expected lifespan. Check the usable capacity, round-trip efficiency, warranty terms, installation costs and whether the system can provide backup power during an outage. Ask an accredited installer for an estimate based on your household’s usage rather than relying on advertised savings. Rebates and incentives can change and may depend on your circumstances, so check current information through energy.gov.au and your state or territory program.