Energy storage requirements are calculated by multiplying daily energy consumption by backup duration. Then, divide by battery depth of discharge (DoD). Choosing the wrong battery size can lead to power shortages, wasted investment, or system instability. This guide breaks down key cost drivers, industry benchmarks, and optimization strategies – helping you make informed decisions whet. The Enphase System Estimator is a tool to get a preliminary estimate of the size, cost and savings of your solar and battery system. All calculations are an estimate based on the power the solar panels are expected to generate, battery capacity, and your average electricity usage last year.