What size generator to run a well pump?
Check, uncheck or adjust the typical device list below — watts, startup surge and battery size update instantly. Numbers come from U.S. DOE, ENERGY STAR and manufacturer spec sheets, not marketing copy.
1. Check what you need to power
Refrigeration & Freezers
Kitchen
Heating, Cooling & Fans
Water & Pumps
- 1
Laundry & Cleaning
Electronics & Office
Medical Devices
Power Tools & Outdoor
Lighting
2. Your sizing
3. Best cross-brand matches
- Anker SOLIX F3800
- surge 9,000W covers your 7,400W start peak
- 6.7 days of your typical daily use (3,840Wh / 575Wh)
- EcoFlow DELTA Pro 3~$2,799
- surge 8,000W covers your 7,400W start peak
- 7.1 days of your typical daily use (4,096Wh / 575Wh)
Static answer (crawlable summary)
Typical device list: Submersible Well Pump (1/2 HP, 240V)×1.
| Continuous load | 1,150 W |
|---|---|
| Startup peak | 7,400 W (driven by 1× Submersible Well Pump (1/2 HP, 240V)) |
| Daily energy use | 575 Wh |
| Recommended capacity | 720 Wh (25% margin included) |
| Minimum inverter | 1,270 W continuous |
Frequently asked questions
What size generator to run a well pump?
For a typical setup (submersible well pump (1/2 hp, 240v)), you need at least 1,150W of continuous power. The single biggest moment is startup: when 1× submersible well pump (1/2 hp, 240v) kicks on, the momentary draw peaks at 7,400W. For overnight runtime we recommend at least 720Wh of battery capacity (your devices use about 575Wh per day, plus a 25% margin).
Which power stations can handle this?
Based on published specs, Anker SOLIX F3800, EcoFlow DELTA Pro 3 all cover the 7,400W startup peak and give you 6.7 days / 7.1 days of typical daily use. Check the comparison cards above for the full numbers.
Why is the startup surge higher than the running watts?
Motor-driven devices (fridge compressors, well pumps, air conditioners) draw 2-5× their running power for a split second at startup — measured as locked-rotor amps (LRA). A generator that only meets the running load will trip or stall when the biggest motor starts. Our data sources: U.S. DOE Energy Saver, ENERGY STAR certified product database, and manufacturer spec sheets (Franklin Electric, Goodman, Zoeller).