How long can a LiFePO4 battery run your appliances? Enter the battery’s nominal voltage and Ah rating, your total AC load, and your inverter assumptions to estimate runtime. The calculator also compares estimated nominal-voltage DC current with the BMS rating you enter.
Formula and assumptions: nominal Wh = voltage × Ah. Usable AC Wh = nominal Wh × usable fraction × inverter efficiency. Runtime hours = usable AC Wh ÷ (AC appliance watts + idle watts). The enhanced v3 model treats idle draw as AC-equivalent demand; it does not silently reinterpret a manufacturer’s DC-side idle specification. Batteries start at 100% charge. Current = effective watts ÷ efficiency ÷ nominal voltage, so actual current can rise as voltage drops.
Household example: a 25.6V 100Ah battery contains 2,560 nominal DC Wh. At 90% usable capacity and 90% inverter efficiency, usable AC energy is 2,073.6Wh. A steady 300W load plus 20W AC-equivalent idle draw gives 6.48 hours, displayed as about 6h 29m. Estimated current is 13.89A at nominal voltage. These illustrative values do not promise an appliance can start or that a specific battery supports the load.