How long will a sump pump run on a 100Ah 12V LiFePO4 battery?

A sump pump drawing about 800 W will run roughly 1.1 hours on a 100Ah 12V LiFePO4 battery (using ~80% usable capacity and typical inverter loss). Lead-acid of the same rating gives less, because only about 50% is usable.

How many watts does a sump pump use?

A typical sump pump draws around 800 W, though actual draw varies by model and, for motor-driven appliances, cycles on and off.

Battery run-time

How long will a sump pump run on a battery?

A sump pump draws about 800 W. How long it runs depends on your battery's capacity, voltage and chemistry. Adjust the values below for your exact setup — the estimate updates live.

Battery capacity (Ah)

Battery voltage (V)

sump pump load (W)

Chemistry

What changes the run-time

Three things move the number: your battery's usable capacity (chemistry sets how much you can safely draw — about 80% for LiFePO4, 50% for lead-acid), the sump pump's actual power draw (rated watts can differ from running watts, and motors cycle on and off), and inverter losses if you run it on AC. This estimate accounts for usable depth of discharge and typical inverter loss.

To size a complete system around a sump pump and other loads, use the full system calculator.

Battery run-time calculator

Usable capacity calculator

All run-time guides

Estimates for planning only. Verify with a meter; see the methodology.

How long will a sump pump run on a battery?

What changes the run-time

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