HTHOMETALLYTHE PRACTICAL HOME GUIDE

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.

FROM ESTIMATE TO ACTION

Use the result, not just the number.

01

Verify the inputs

Measure or document each input. If a value is only an estimate, record its source and test a conservative alternative.

02

Keep the calculation traceable

Save the input link or copied result together with the date, units and assumptions. A number without its inputs cannot be checked later.

03

Confirm the decision

Compare the estimate with the related guide, current product data and requirements that apply at your location before buying or building.

Inputs to verify

Nominal battery energy (Wh)
Use watt-hours from the battery specification.
Usable battery fraction (%)
Reserve capacity for battery life and low-voltage cutoff.
Conversion efficiency (%)
Include inverter and wiring losses.
Pump electrical input (W)
Use measured running input; starting power is checked separately.
Pump run time per hour (min/h)
Use a wet-weather observation or conservative scenario.
Continuous standby load (W)
Include inverter idle draw, controls and alarms.

Continue your calculation

Wastewater

Sump pit storage and pump cycling

Estimate active pit volume, fill time, drain time and starts per hour from measured levels and flows.