Well pump 1/2 HP: how much battery you need
Well pump 1/2 HP draws about 880 W (750–1000 W range), runs 100% of the time and uses 880 Wh per day. Start-up surge: 2000 W.
A submersible pump starts with a spike several times its running draw; size the inverter for the start, and check whether the pump is 120 V or 240 V. Champion lists 750–1000 W running; we use the middle for energy and the top starting figure (2000 W) for the peak.
Battery needed
| Hours | Wh | Battery (Wh) | Inverter (W) |
|---|---|---|---|
| For 8 hours | 293 | 445 | 969 / 2000 |
| For 24 hours | 880 | 1334 | 969 / 2000 |
| For 72 hours | 2640 | 4000 | 969 / 2000 |
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Stations that fit (24 h)
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FAQ
How many watts does a Well pump 1/2 HP use?
Typically 880 W while running, with a range of 750–1000 W depending on model and age. Start-up surge can reach 2000 W.
How long will a 1000 Wh power station run a Well pump 1/2 HP?
About 0.8 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 Well pump 1/2 HP overnight (8 h)?
About 445 Wh of battery and an inverter rated at least 969 W continuous with 2000 W surge.
Can I run a Well pump 1/2 HP on solar during an outage?
You need roughly 587 W of panels in winter to replace a day's use (880 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