The most important factor here is the capacity. While it might result in higher upfront costs, it’s vital to ensure your solar battery has enough capacity to store the excess energy your solar panels produce, to minimise the amount that is lost. Low capacity solar batteries might be cheaper but may not store all the extra energy produced by your solar panels, and hence can result in your home not being powered effectively. According to our research, a 5kW system will typically require a 10kW battery.