Can a Power Station Run a Sump Pump?

Learn how to match a portable power station to a sump pump: starting watts, realistic runtime, float switch tips and a layered backup plan.

Storms that knock out power often bring heavy rain, and that is exactly when a sump pump matters most. If the pump stops, groundwater can rise in the pit and spill into a basement within hours. A portable power station can keep a standard plug-in pump running, but only if you size it properly and set it up in a way that works while you are asleep or away.

This guide covers the numbers to check, how to estimate runtime, and what else belongs in a basement flood plan.

Step one: read the pump label

Find the nameplate on your pump or in the manual. You want the running watts (or amps and volts, which you can multiply to get watts) and the horsepower rating. Many household pumps are around 1/3 to 1/2 horsepower, and they draw a few hundred watts while running. The label is the only reliable source for your pump, so check it rather than guessing.

Motors need a short burst of extra power to start. That starting surge can be two or three times the running figure. A power station must handle that surge, so compare it with the unit's surge rating, not just its continuous output. If the pump is hardwired into the wall instead of plugged in, a licensed electrician must make any change to connect it to backup power.

Estimating how long it will run

A sump pump does not run constantly. It switches on when the water reaches the float, empties the pit, and shuts off. How often that happens depends on the weather, soil and water table. During a heavy storm it may cycle every few minutes. In a dry spell it may not run for hours.

Here is a simple example. Say your pump draws 800 W while running and runs about three minutes out of every hour. That is roughly 40 Wh per hour. A power station with 1,000 Wh of capacity could then cover more than a day of light cycling, minus some conversion loss. In a downpour with the pump running much more often, the same battery could drain in a few hours. Use your own pump label and your own observations to adjust the numbers, and see what size power station do I need for the general method.

• Runtime in hours is roughly usable watt-hours divided by average watts drawn.
• Plan for the worst case, which is a long storm with the pump running often.
• Leave a reserve. Do not count on the last 10 to 15 percent of the battery.

Plug it in the right way

Most sump pumps use a tethered or piggyback float switch with its own plug. The pump's plug goes into the switch plug, and the switch plug goes into the outlet. Keep that arrangement. If you run the pump directly into a power station and bypass the switch, it will run constantly and burn out, or run dry.

• Plug the float switch plug into the power station, then the pump into the switch.
• Use a short, heavy-duty extension cord only if you must, and keep the connection off the wet floor.
• Set the power station on a shelf or platform above any water, never on the basement floor.
• Make sure the station's outlet is on and that it will not shut itself off after a period of low load. Some units have an auto-off setting you may need to disable. Check the manual.

Build a layered backup plan

One battery is a start, not a full plan. Pumps fail for reasons other than outages, including stuck floats and clogged intakes, and a long outage can outlast any single battery.

1. Test the pump every season by pouring water into the pit until the float lifts and the pump kicks on.
2. Consider a separate battery-backup pump on its own float and its own battery. These sit in the pit beside the main pump and take over if it fails. Ask a plumber what suits your pit.
3. Where the local rules allow it, some homes use a water-powered backup pump, which runs on municipal water pressure. It does not work with well water and may be restricted in some areas, so check first.
4. Add a high-water alarm so you hear about a problem before the basement floods.
5. Lift stored items off the floor and keep valuables and electronics up high.

Charging it back up

If the outage drags on, you will need to recharge. Solar panels can help in daylight (see how to charge a power station with solar panels), and a generator can top up a battery while you run it safely outdoors. Rotate your pump onto the recharged battery and keep the second source ready if you can.

For a bigger picture of what else to power, see how to prepare for a power outage and compare options at our power stations hub.

Quick answers

Keep reading

Some links are affiliate links. We may earn a commission at no cost to you. How we make money. General information only, not professional advice.