Sump pump 1/2 HP: how much battery you need
Sump pump 1/2 HP draws about 920 W (800–1050 W range), runs 100% of the time and uses 1840 Wh per day. Start-up surge: 2150 W.
A sump pump runs only when the pit fills, but a storm can keep it cycling for hours. Champion lists 800–1050 W running; we use the middle for energy and the top starting figure (2150 W) for the peak.
Battery needed
| Hours | Wh | Battery (Wh) | Inverter (W) |
|---|---|---|---|
| For 8 hours | 613 | 930 | 1013 / 2150 |
| For 24 hours | 1840 | 2788 | 1013 / 2150 |
| For 72 hours | 5520 | 8364 | 1013 / 2150 |
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Stations that fit (24 h)
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FAQ
How many watts does a Sump pump 1/2 HP use?
Typically 920 W while running, with a range of 800–1050 W depending on model and age. Start-up surge can reach 2150 W.
How long will a 1000 Wh power station run a Sump pump 1/2 HP?
About 0.7 hours on the clock, allowing for the 100% duty cycle, inverter losses and a 20% reserve.
What size power station do I need for a Sump pump 1/2 HP overnight (8 h)?
About 930 Wh of battery and an inverter rated at least 1013 W continuous with 2150 W surge.
Can I run a Sump pump 1/2 HP on solar during an outage?
You need roughly 1227 W of panels in winter to replace a day's use (1840 Wh), charging through a station with a big enough MPPT input.
Other sizes
Other appliances
1 Approximate values: estimated from motor or heater power and typical figures published online, not from a manufacturer chart. Check your appliance label.
Inverter efficiency 88%, usable depth of discharge 90%, reserve 20%. Full method: How we calculate. source