Runtime by power station size: Well pump, 1/2 HP
| Power station size | Typical runtime | Realistic range |
|---|---|---|
| 300 Wh | 1 h 42 min | 0.8–4.3 h |
| 500 Wh | 2 h 50 min | 1.4–7.1 h |
| 1,000 Wh | 5 h 40 min | 2.8–14.2 h |
| 1,500 Wh | 8 h 30 min | 4.3–21.3 h |
| 2,000 Wh | 11 h 20 min | 5.7–28.3 h |
| 3,000 Wh | 17 h | 8.5–42.5 h |
Check these three things first
- Voltage. Look at the pump's nameplate or the breaker in your panel. A double breaker (two switches joined) means 240 V. Submersible pumps in deep wells are very often 240 V; shallow-well jet pumps are often 120 V or switchable. A 240 V pump needs a station with 240 V output, such as the Anker SOLIX F3800 or Jackery Explorer 5000 Plus, or two linked units. Check the spec sheet: not every large station has it.
- Startup surge. An induction motor starting against water pressure draws two to three times its running watts or more. For a 1/2 HP pump, plan on a station with at least 2,000 W of continuous output and a surge rating of 3,000 W or more. Bigger pumps (3/4 HP, 1 HP) need proportionally more.
- Wiring. Well pumps are hard-wired. Connecting one to a power station needs a transfer switch or a power inlet installed by a licensed electrician. Never "backfeed" your house by plugging a station into a wall outlet: it can electrocute line workers and damage the station.
How long it runs
A well pump only runs when the pressure tank needs refilling: when someone showers, flushes or fills a sink. A household being careful in an outage might run the pump 2–6 hours a day in total. That's why the average draw (around 60–300 W) is far below the running watts, and why runtime varies so much with how you use water. The table above uses a 150 W average.
Ways to make it work
- Soft starter. A soft-start kit for the pump motor can cut the startup surge sharply, sometimes letting a smaller station start it. Have an electrician or well technician fit it.
- Fill containers instead. Run the pump for a few minutes to fill buckets, jugs and the bathtub, then switch it off. You use the battery only when you choose.
- Don't start it alongside other motors. Let the pump start before switching on the fridge or freezer, so their surges don't stack.
Check your setup with the inverter size calculator, which totals running watts and the biggest startup surge.