The cost of a 50kW lithium-ion battery storage system using LiFePO4 technology can range from $30,000 to $60,000 or more, depending on the quality and brand of the batteries. The Battery Box is Blue Diamond Machinery's proprietary standalone Battery Energy Storage System (BESS) designed to deliver clean, silent and reliable off-grid power. Why. How Much Does a 50kW Solar System Cost in Australia? The cost of a 50kW solar system depends on several factors, including: Every commercial site is different, which is why ADS Solar provides customised proposals based on your energy usage and business requirements. Get a quick quote! I agree that. On an energy basis, batteries are 50% cheaper since the first battery was installed. Yet, capex per kilowatt of installed power capacity has remained relatively flat.