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Well pump backup

Running it is easy. Starting it is the test.

Your pump's nameplate tells you both numbers. Put them in and see which power stations can actually start it.
Check my pumpThe soft-start fix

Updated

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What we checked

We have not tested any power station on a well pump.Everything below comes from the makers' own manuals, support articles and store pages, and from safety agencies, read on the dates shown.

Your pump: running and starting watts

Read the label on the pump control box or the motor paperwork for volts and horsepower. Most deep-well pumps are 230 V. If the label gives maximum amps, add them for a closer running figure.

1. Volts on the pump's nameplate
2. 2-wire or 3-wire

A 3-wire pump has a separate control box on the wall, usually near the pressure tank. A 2-wire pump has none.

3. Horsepower
Running
960 W
Franklin's maximum load for 1/2 HP, 230 V
Starting, for an instant
5,290 W
230 V × 23 locked rotor amps

In-stock power stations

  • Bluetti Apex 300Runs it once started; its specs don't cover the start3,840 W output, 3,840 W for motor starts; about 2.5 hours of pumping on a full charge

21 other in-stock stations have no 240 V output, so they can't run this pump.

Hours are time the pump is actually running, not hours of outage: a pump runs only while water is drawn or the pressure tank refills.

How we work it out

  1. Running watts = volts × amps.That is the US Department of Energy's rule for a label that lists amps. With no amps, we use the maximum load watts in Franklin Electric's motor table for your horsepower and voltage.
  2. Starting watts = volts × locked rotor amps.Franklin's manual says a motor's current goes from zero to locked rotor amps, then drops to running amps once it is at full speed. We treat that figure as watts against the station's surge rating, the worst case.
  3. The fit check is the one our outage calculator uses: running watts under the continuous output, and the full start under the surge the maker gives for motors. Bluetti's higher "Power Lifting" figures are for heaters and kettles only, so for those models we count the continuous output.

Every common pump size against the in-stock stations

Running and starting watts for Franklin Electric 4-inch single-phase motors, and which in-stock stations start them
MotorRunningStartingStations whose specs cover the start
1/2 HP, 115 V, 2-wire960 W7,410 WNoneRuns on 21 in-stock stations once started
1/2 HP, 230 V, 2-wire960 W7,410 WNoneRuns on Bluetti Apex 300 once started
3/4 HP, 230 V, 2-wire1,310 W9,360 WNoneRuns on Bluetti Apex 300 once started
1 HP, 230 V, 2-wire1,600 W11.2 kWNoneRuns on Bluetti Apex 300 once started
1.5 HP, 230 V, 2-wire2,280 W15.2 kWNoneRuns on Bluetti Apex 300 once started
1/2 HP, 115 V, 3-wire960 W5,810 WEcoFlow DELTA 3 Max Plus, Anker SOLIX F3000, ALLPOWERS R3500
1/2 HP, 230 V, 3-wire960 W5,290 WNoneRuns on Bluetti Apex 300 once started
3/4 HP, 230 V, 3-wire1,310 W7,870 WNoneRuns on Bluetti Apex 300 once started
1 HP, 230 V, 3-wire1,600 W9,610 WNoneRuns on Bluetti Apex 300 once started
1.5 HP, 230 V, 3-wire2,080 W11.8 kWNoneRuns on Bluetti Apex 300 once started
2 HP, 230 V, 3-wire2,560 W12.2 kWNoneRuns on Bluetti Apex 300 once started
3 HP, 230 V, 3-wire3,400 W19.2 kWNoneRuns on Bluetti Apex 300 once started

Motor figures: Franklin Electric AIM manual, 2026 edition, 4-inch single-phase table (3-wire rows use the standard control box). Other pump brands are close but not identical; your own nameplate wins. Runs and starts itmeans the maker's motor surge figure is at least the full start; it is still the maker's rating, not a test.

The soft-start option

When no station covers the start, the usual fix is to lower the start rather than buy a bigger battery. A soft starter, or a constant-pressure drive in place of the standard control box, ramps the motor up over a second or more, so the inrush is a fraction of the locked rotor current.

Two cautions from Franklin Electric's manual: its single-phase submersible motors may only be used with Franklin's own constant-pressure controllers when a drive is used, and some soft starters are not compatible with its SubMonitor protection. So ask the pump's maker or your well installer which device suits your motor, and have them or a licensed electrician fit it. We don't quote a percentage cut: the makers' claims vary and we haven't measured one.

Connecting it safely

A well pump is wired into your panel, so it never plugs into a power station directly.A licensed electrician installs a transfer switch or an inlet with an interlock, with a permit, so the pump circuit is cut off from the grid before the battery feeds it. Franklin Electric's manual says the same for generators: a transfer switch must be used any time one backs up a pump on the power lines.

Don't open the pump control box yourself; it carries 240 V.

Anything that connects to your breaker panel is a job for a licensed electrician, with a permit and inspection. That covers inlet boxes, interlock kits, transfer switches and the makers' smart panels.

Never power house wiring by plugging a battery or generator into a wall, dryer or range outlet with a double-ended ("suicide") cord. That is called backfeeding: it is illegal, it can electrocute utility lineworkers and neighbors on the same transformer, and it bypasses your home's circuit protection (CPSC, OSHA).

The four ways to connect a battery to a house, and which need an electrician, are on our home backup guide.

The best fit in stock for a 240 V pump

Runs the most 240 V pump sizes

Bluetti Apex 300

Of the in-stock stations from makers we work with, it runs the most of Franklin's 230 V motor sizes, up to 3,840 W continuously. Its specs don't cover the full start of a 1/2 HP pump (5,290 W), so ask its maker and your pump installer about a soft starter before you rely on it. About 2.5 hours of pumping on a full charge.

  • 120/240V output
  • 2.8 kWh
$1,499when we checked*Check price (opens in a new tab) We earn a commission if you buy through this link.

*Price on the maker's US site when we checked on November 14, 2026 ($1,499); prices change often.

Frequently asked questions

Can a portable power station run a 240 V well pump?

Only one with 240 V output. Of the stations we list that were in stock when we checked, that is Bluetti Apex 300. Running the pump is the easy part: a 1/2 HP, 230 V pump draws up to 960 W. Starting it is the hard part: for an instant it pulls about 5,290 W (230 V × 23 locked rotor amps, Franklin Electric). None of the in-stock 240 V stations lists a motor surge that covers that, so a start is not guaranteed. The pump is wired in, so a licensed electrician has to connect the station through a transfer switch.

How do I work out a well pump's starting watts?

Multiply the motor's volts by its locked rotor amps: that is the current it draws for the split second it starts. Franklin Electric's AIM manual lists locked rotor amps for every standard submersible motor; some nameplates show it too. Running watts are volts × the nameplate's maximum amps (the US Department of Energy's method), or the maximum load watts in Franklin's table.

What about a 120 V well pump?

Smaller and shallower pumps are often 115 V, which any station can supply. A 1/2 HP, 115 V 3-wire pump runs at up to 960 W but starts at about 5,810 W. In stock, EcoFlow DELTA 3 Max Plus, Anker SOLIX F3000, ALLPOWERS R3500 list a motor surge that covers it.

Will a soft starter help?

Usually it is the fix. A soft starter or a constant-pressure drive brings the motor up to speed gradually instead of hitting it with the full locked rotor current, so a smaller inverter can start it. Fitting one is a job for a licensed electrician or pump installer, and it must suit your motor: Franklin Electric says its single-phase submersible motors can only be used with its own constant-pressure controllers when a drive is used.

How long will a power station run a well pump?

Count hours of pumping, not hours of outage: a pump runs only while water is drawn or the pressure tank refills. At 960 W, the Bluetti Apex 300 gives about 2.5 hours of pumping from a full charge. Short showers, full loads only in the washer, and no watering stretch it.

Estimates only. Your actual costs depend on your utility's rate plan, how and when you charge or use power, and local prices. This is general information, not electrical, financial, tax or legal advice. Safety first: follow each maker's instructions and your local codes, use certified equipment, and have a licensed professional do any wiring. See our safety notes and disclaimer.

Sources

  1. Franklin Electric, AIM Manual: 60 Hz Submersible Systems, 2026 edition (M1311 06-26), copy hosted by the Nebraska Department of Water, Energy and Environment — 4-inch single-phase motor table (page 39): maximum service-factor amps and watts and locked rotor amps for each horsepower and voltage
  2. US DOE Energy Saver, Estimating appliance and home electronic energy use (archived copy) — watts × hours a day ÷ 1,000 = kWh a day
  3. Eugene Water & Electric Board, Generator sizing considerations — running and starting watts: well pump 1/3 HP 1,000 W (+2,000 W to start), furnace fan blower 1/3 HP 700 W (+1,400), refrigerator/freezer 700 W (+2,200), microwave 1,000 W, laptop 60 W, phone charger 20 W
  4. BLUETTI Apex 300 user manual (section 5.3, Power Lifting Mode)

Keep the house running in an outage

The four ways to connect a big battery to your home, what each costs, and which jobs need an electrician. Start with the home backup guide.

Keep going

Photo: Devon MacKay on Unsplash (Unsplash License).