Add the loads that will run at the same time during an outage. For example, a 2kW average load needed for 4 hours requires 8kWh before losses. At 90% system efficiency and 80% usable depth of discharge, the estimated nominal capacity is 8 ÷ 0.9 ÷ 0.8 ≈ 11.1kWh. Then check startup peaks from equipment such as air conditioners and pumps. This is an initial estimate; final sizing must use the actual load profile.




