Adding an energy storage battery to a residential solar panel system typically costs $7,000 to $18,000. The final price depends on what you buy and who installs it. 5 kWh capacity, top-tier software. com team also considers pricing, the bankability of the manufacturer, and the controlling software, as the best battery hardware is useless without operating control software to tell it what to do. What Impacts Solar Battery Cost?The cost of a solar battery varies significantly based on capacity, battery chemistry, brand, features, and installation expenses.