You need about 533 Wh — and 24 units fit. The smallest sufficient is the Goal Zero Yeti 700; we never push more capacity than your load can use. Surge to clear: 1,500 W.
The math
Running watts (everything on at once) = 800 W
Surge watts (worst single startup + the rest running) = 1,500 W
Average draw (cyclic loads counted by their duty cycle) = 160 W
Watt-hours = 160 W × 3.0 h ÷ 90% usable reserve = 533 Wh
1
Goal Zero Yeti 700smallest that fits
677 Wh1,000 W cont · 1,500 W surge~3.8 h on this load$$
Goal Zero’s LiFePO4 value unit — a 1,000 W inverter for fridge and essentials.
🔗 The "Check price" buttons are brand-direct affiliate links. Once our brand affiliate programs are approved these will earn a commission — at no extra cost to you, and it never changes which unit we recommend. Disclosure.
⚡ Duty cycle matters here. A sump pump runs only when the pit fills — minutes per hour in heavy rain — so its energy is far below 800 W × hours. We size watt-hours on the duty-weighted average (160 W), not the peak — so we don't oversell you capacity.
Can a specific unit run a sump pump (1/3 hp)?
24 of the units we track deliver enough watts to run a sump pump (1/3 hp). Check a specific one for the runtime and the full verdict:
What size power station do I need to run a sump pump (1/3 hp)?
A sump pump (1/3 hp) draws about 800 W running, with a startup surge near 1,500 W. So you want a unit with at least 800 W continuous output and 1,500 W+ surge. For 3.0 h of runtime that's roughly 533 Wh of capacity — the Goal Zero Yeti 700 is the smallest unit that clears all of it.
How many watts does a sump pump (1/3 hp) use?
About 800 W while running, spiking to roughly 1,500 W on startup. It only draws power about 20% of the time, so over an outage its energy use is well below 800 W × the hours — which is why a modest battery lasts longer than you'd expect. A sump pump runs only when the pit fills — minutes per hour in heavy rain — so its energy is far below 800 W × hours.
Sources: Sump Pump (1/3 HP) wattage — Standard appliance-wattage / generator-sizing charts (representative values; verify your nameplate); station specs — manufacturer published specifications (compiled 2026-06-15; approximate). Informational only — a computed sizing estimate from published appliance-wattage charts and manufacturer station specs. It is not an electrical guarantee. For hardwired or whole-home backup, transfer switches, or any permanent install, consult a licensed electrician.