Can a portable power station run a sump pump, and for how long?

A sump pump is one of the most useful things to keep running in a storm, and one of the trickiest for a battery. It's a motor, so it needs a burst of power to start. And it can run a lot when the rain is heavy.

Can a power station start a sump pump?

Check two numbers on the station's spec sheet against Champion's wattage chart:

Pump size	Running watts	Starting watts
1/3 HP	500–800 W	1,000–1,600 W
1/2 HP	800–1,050 W	1,300–2,150 W

• Continuous watts must be above the pump's running watts.
• Surge watts must be above its starting watts.

Here's how some stations stack up, from the makers' specs:

Power station	Continuous	Surge	1/2 HP pump?
EcoFlow RIVER 2 Max 500	500 W	1,000 W	No: below the running watts
Jackery Explorer 1000 v2	1,500 W	3,000 W	On paper, yes
Anker SOLIX C1000	1,800 W	2,400 W	On paper, yes
BLUETTI Elite 100 V2	1,800 W	2,700 W	On paper, yes
EcoFlow DELTA 3 Max Plus	3,000 W	6,000 W	Yes, with room to spare

"On paper" matters. A surge rating only lasts a moment, and some pumps start harder than the chart. Test your pump on the station at home, on a dry day, before you rely on it. If the station shuts off as the pump kicks on, see power station shuts off under load.

How long will a power station run a sump pump?

A sump pump doesn't run all the time. It kicks on when the water rises, empties the pit, and shuts off. So what matters is the share of time it runs.

Average watts = pump running watts × share of time running

Hours = station Wh × 0.85 ÷ average watts

The 0.85 allows for the energy lost turning battery power into 120 V AC.

Worked example: a 1/2 HP pump at 1,000 W

How busy the pump is	Share of time	Average draw	1,000 Wh station	2,000 Wh station
Light rain (6 min an hour)	10%	100 W	about 8.5 hours	about 17 hours
Steady rain (15 min an hour)	25%	250 W	about 3.4 hours	about 7 hours
Heavy storm (30 min an hour)	50%	500 W	about 1.7 hours	about 3.4 hours

These are estimates, not measurements. Your pit, your water table and the storm decide the real numbers. The calculator above starts at a 100 W average on a 1,070 Wh station; change the load to match your pump.

A smaller pump: 1/3 HP

Champion lists a 1/3 HP pump at 500 to 800 running watts. Take the middle, 650 W, running 25% of the time on a 1,024 Wh station:

• Average draw: 650 × 0.25 = about 160 W
• Run time: 1,024 × 0.85 ÷ 160 = about 5.4 hours

That's about 55% longer than a 1,000 W pump at the same pace (about 3.5 hours). If you're replacing a pump anyway, its running watts are worth checking on the label.

Find your own share of time: in the next rain, time how long each pump cycle runs and how many cycles there are in an hour. Five 1-minute cycles an hour is about 8%.

When a power station isn't enough

• Heavy, long storms. A pump running half the time drains a 1 kWh station in under two hours.
• Two pumps, or a pump plus a fridge. Add up the Wh for everything.
• Multi-day outages. Unless you can recharge, the station runs out.

For those, a fuel generator does better. See what size generator for a sump pump. A dedicated battery backup sump pump is another option many homes use.

How to hook it up safely

• Plug the pump straight into the station with its normal cord. Most sump pumps plug into an outlet near the pit.
• Keep the station dry and off the floor. Set it on a shelf or sturdy table, away from the pit and any water.
• Don't use a long, thin extension cord. It can drop the voltage and make starting harder. If you need one, use a heavy-duty cord rated for the pump's amps.
• Never backfeed the house through a wall outlet to reach the pump's circuit. If you want to power a hard-wired pump, have a licensed electrician install a transfer switch or interlock.

Tips to stretch the battery

• Charge to 100% when heavy rain is forecast.
• Unplug everything else from the station while the pump depends on it.
• Recharge between storms from the wall, solar, a car or a generator. See how long it takes to charge a power station.

If you recharge from a gas generator, run it outdoors only, 20+ feet from the house, away from windows and doors. Read our carbon monoxide guide.