Can a power station run a sump pump?
Short answer
Yes, if it has enough surge. A typical 1/2 HP sump pump draws about 1,050 W running and around 2,150 W for a second when it starts, so you need a power station rated for at least 2,200 W surge. A 1,000 Wh unit then lasts about 20 hours in light rain, 3 to 7 hours in steady to heavy rain, and under an hour if the pump runs nonstop.
Surge is what decides it
Sump pumps use induction motors that pull two to three times their running watts to start. A 1/3 HP pump needs around 1,300 W to start and 800 W to run. A 1/2 HP pump needs about 2,150 W to start and 1,050 W to run. If the power station's surge rating is lower, the pump will try to start and the power station will shut off.
Check the pump's label for horsepower and amps. Amps multiplied by 120 gives running watts; multiply that by about 2 for a safe starting estimate.
How much energy one pump cycle uses
A typical cycle lasts 10 to 60 seconds, depending on pit size and inflow. A 20-second cycle on a 1,050 W pump uses about 6 Wh. Even 100 cycles a day adds up to only around 600 Wh. The table below covers heavier use, where the pump is running for hours in total.
Runtime by power station size
Runtime depends on how often the pump kicks on. The columns assume a 1/2 HP pump at 1,050 W running for a total of 1, 3 or 6 hours per day, and 85% usable battery energy.
| Power station | Light rain (1 h/day) | Steady rain (3 h/day) | Heavy storm (6 h/day) | Can it run it? |
|---|---|---|---|---|
| 256 Wh 300 W output | 5 hours | 1.7 hours | 50 minutes | No, output too low |
| 512 Wh 600 W output | 9.9 hours | 3.3 hours | 1.7 hours | No, output too low |
| 1,024 Wh 1,800 W output | 19.9 hours | 6.6 hours | 3.3 hours | Yes |
| 2,048 Wh 2,400 W output | 39.8 hours | 13.3 hours | 6.6 hours | Yes |
| 3,600 Wh 3,600 W output | 2.9 days | 23.3 hours | 11.7 hours | Yes |
For your exact appliance and power station, use the runtime calculator.
Setup tips
- Keep the power station off the basement floor and away from the pit. Water and batteries don't mix.
- Plug the pump directly into the power station, or use a short 12 gauge extension cord. Thin cords cause voltage drop that makes starting harder.
- Test it before storm season: unplug the pump from the wall, plug it into the power station and pour a bucket of water into the pit.
- Charge the power station fully whenever a storm is forecast, and keep it topped up with solar or a car charger during long outages.
Consider a dedicated backup pump
If your basement floods regularly, a battery backup sump pump system (a 12 V pump with its own marine battery and charger) is often the better answer. It switches on automatically when the main pump fails, with no need for anyone at home. A power station works well as a flexible backup that also runs your fridge and lights, but it needs you to plug things in.
Frequently asked questions
What size power station do I need for a sump pump?
For a 1/2 HP pump, choose a unit with at least 2,200 W surge and 1,500 W continuous output. For a 1/3 HP pump, 1,500 W surge is usually enough. Capacity of 1,000 Wh or more gives useful runtime.
How long will a power station run a sump pump?
A 1,000 Wh unit keeps a 1/2 HP pump going for about 20 hours if the pump runs about an hour a day in total, but for under an hour if the pump runs nonstop.
Can I run a sump pump on a car inverter?
Usually not. Most plug-in car inverters are rated for 150 to 400 W, far below what a sump pump needs to start.
Sources and method
Runtime figures assume 85% of battery capacity reaches AC appliances and typical US appliance ratings. See exactly how we calculate. Found a mistake? Tell us and we will fix it.