The average cost per watt for energy storage cabinets can range broadly from $200 to $800. Factors such as technology type, brand reputation, system capacity, and regional pricing dynamics contribute to this variance. Why such a wide range? The biggest factor is size, measured by how many kilowatt-hours (kWh) of electricity the battery can store. Battery systems can range. Solar battery costs vary by brand and capacity, and there are several other expenses associated with home energy storage. Several key factors influence the overall price: Battery capacity (kWh): Larger batteries store more energy and cost more overall, but often have a lower cost per kilowatt-hour. The Tesla Powerwall 2 starts at $8,400 for 13. High-capacity systems with advanced features may command prices on the higher end.