Wastewater/ CALCULATOR
Sump pump battery runtime
Estimate outage runtime from usable battery energy, pump duty cycle and standby load.
Use watt-hours from the battery specification.
Reserve capacity for battery life and low-voltage cutoff.
Include inverter and wiring losses.
Use measured running input; starting power is checked separately.
Use a wet-weather observation or conservative scenario.
Include inverter idle draw, controls and alarms.
Usable delivered energy
844.80 Wh
Pump duty cycle
16.67 %
Average pump demand
83.33 W
Average total demand
91.33 W
Estimated outage runtime
9.25 h
Energy used each hour
91.33 Wh/h
Interpretation:The energy-only estimate is 9.25 hours at an average load of 91.33 W. Confirm motor starting surge and test the complete backup system.
The observed duty cycle remains constant and the power source can supply motor starting surge. Capacity falls with age, temperature and high discharge rate. This energy estimate does not verify inverter surge, transfer controls, alarms or safe battery installation.