A solar battery may be worth considering if you regularly use electricity after sunset, export substantial solar during the day, or want greater backup during outages. Compare its upfront cost with potential savings from using stored energy instead of buying electricity, taking into account your feed-in tariff, battery capacity, energy usage and expected lifespan. A qualified solar installer can model different sizes using your interval-meter data, but savings and payback periods are not guaranteed. Check the warranty, usable capacity, installation requirements and retailer terms before making a decision.