3/4 HP Cast-Iron Sump Pump: Running Watts, 3600W LRA Surge, Generator Size & LiFePO4 Battery Runtime
A 3/4 HP Cast-Iron Sump Pump requires 1,350 running watts (11.25A at 120V via a NEMA 5-15P plug) and spikes to 3,600 starting surge watts (2.7× LRA inrush). At a realistic 25% duty cycle (~338 Wh/hr net burn), you need a minimum 3,600W inverter or generator and at least 5,302 Wh (~415 Ah @ 12.8V) of LiFePO4 battery capacity for a 12-hour blackout. Our top-matched plug-and-play solar generator for a 3/4 HP Cast-Iron Sump Pump is the EcoFlow DELTA Pro (3.6kWh Wheeled Station).
| Running / LRA Surge | Min Inverter / Gen | 4h / 8h Battery Wh | 12h / 24h Battery Wh (Ah) | Best Solar Generator Match |
|---|---|---|---|---|
| 1,350W run / 3,600W pk | 1,620W cont / 3,600W peak | 1,768 Wh (4h) • 3,535 Wh (8h) | 5,302 Wh / 10,604 Wh (415Ah @12V) | EcoFlow DELTA Pro (3.6kWh Wheeled Station) |
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Interactive Outage Load & Backup Runtime Simulator
Find the exact plug-and-play battery backup or generator to keep your fridge, Wi-Fi, sump pump, and family essentials running during a blackout—no electrical math required.
How Long Do You Need Backup Power?
To safely run this 1 item for 12 hours, you need a plug-and-play power station with at least 5,302 Wh capacity and 1,620 W output (clearing 3,600 W startup surge).
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Rec. Inverter: 1,620W (+20% NEC)
Draws ~11.3A @ 120V • Highest Plug: NEMA 5-15P
Spike Leader: 3/4 HP Cast-Iron Sump Pump
+2,250W inductive LRA spike (staggered)
338 Wh/hr × 12h = 4,056 Wh net
Formula: 4,056 / (0.85 inv × 0.90 DoD)
Protects 3/4 HP Cast-Iron Sump Pump from waveform damage.
Charge Battery from Wall or Solar
Plug into any normal wall outlet to fast-charge to 100% in ~60 minutes before a storm, or top off outdoors with folding solar panels.
Plug Fridge, Wi-Fi, or Sump Pump Into Front 120V Outlet
Plug your appliance's normal 3-prong cord straight into the power station's front 120V AC outlets—just like a wall socket.
Instant Silent Backup Power Indoors with Zero Fumes
Safe for kitchens, nurseries, bedrooms, and apartments with automatic <20ms UPS blackout switchover and zero gasoline or exhaust.
Best Matched LiFePO4 Power Station
Zero fumes, <20ms UPS auto-switchover, safe for bedrooms, apartments & basements.
EcoFlow DELTA Pro (3.6kWh Wheeled Station)
3,600Wh / 7,200W Surge Flagship 120V Home & 30A RV Transfer
Runs your exact load for ~8.1 hrs — Expandable with solar/extra battery
Covers ~8.1h per charge; add solar panels or ~1 expansion pack(s) for full 12h autonomy.
- 3,600W continuous / 7,200W surge handles entire 120V 30A transfer panels
- 3,600Wh LFP base capacity expands to 10.8kWh with Smart Extra Batteries
EcoFlow DELTA 3 Plus
1/2 HP Sump Pumps, Kitchen Fridges & Whisper-Quiet 30 dB UPS
Runs your exact load for ~2.3 hrs — Expandable with solar/extra battery
Covers ~2.3h per charge; add solar panels or ~5 expansion pack(s) for full 12h autonomy.
- 3,600W pure sine surge easily clears 1/2 HP submersible sump pump LRA
- Whisper-quiet 30 dB under 600W load + <10ms server-grade UPS switchover
Best Matched Dual-Fuel Inverter Generator
Unlimited runtime via stored propane or gasoline (operate 20+ ft outdoors only).
Champion 4500W Electric-Start Dual-Fuel Inverter
30A RV Rooftop AC, Mobile Detailing Vans & Jobsite Compressors
Est. 12h Fuel Burn: ~1.4 gal gas OR ~7.3 lbs propane (~0.4 × 20-lb BBQ tanks)
Modeled at ~10% average throttle (~0.12 gal/hr) based on your 338 Wh/hr duty-adjusted load.
- 4,500W starting surge handles factory 13,500 BTU RV ACs & 6-gal compressors
- Built-in NEMA TT-30R 30A RV outlet + push-button electric start
Westinghouse iGen4500DFc Remote-Start Dual-Fuel Inverter
Ultra-Quiet 52 dB RV Boondocking, Detailing & Heavy 120V Home Loads
Est. 12h Fuel Burn: ~1.6 gal gas OR ~8.3 lbs propane (~0.5 × 20-lb BBQ tanks)
Modeled at ~9% average throttle (~0.13 gal/hr) based on your 338 Wh/hr duty-adjusted load.
- Wireless key-fob remote start + electric choke for effortless winter cranking
- Oversized 3.4-gallon tank delivers up to 18 hours between refuels
Essential Hookup & Protection Kit (Auto-Matched to Your Load)
AC Compressor & Well Motor Soft-Start Capacitor Kit
Cuts your 3/4 HP Cast-Iron Sump Pump startup spike (3,600W) by up to 65% so smaller inverters won't trip.
10-Gauge SJTW Heavy-Duty Lighted Generator Cord (25 ft)
Required for your 1,350W continuous / 3,600W surge stack to stop voltage sag on startup.
Heavy-Duty Storm-Proof Outdoor Generator Running Cover
Keeps outdoor dual-fuel generators running safely 20+ ft away from your house in driving storm rain or blizzard snow.
Best Solar Generator & LiFePO4 Battery Runtime for 3/4 HP Cast-Iron Sump Pump (4h, 8h, 12h & 24h)
Calculated at 25% duty cycle (338 Wh/hr) with 85% inverter efficiency & 90% LiFePO4 usable DoD.
| Battery Size | Usable AC Wh | Est. Runtime | Inverter Verdict |
|---|---|---|---|
| 500 Wh | 383 Wh | Overload | Inverter too small for surge/V |
| 1,024 Wh | 783 Wh | ~2.3 hrs | Starts 3600W surge |
| 2,048 Wh | 1,567 Wh | ~4.6 hrs | Starts 3600W surge |
| 3,600 Wh | 2,754 Wh | ~8.1 hrs | Starts 3600W surge |
Minimum Inverter & Generator Size Needed for 3/4 HP Cast-Iron Sump Pump
Evaluates 1350W continuous draw (+20% NEC margin), 3600W peak LRA spike, and 120V output.
| Generator Tier | Rated / Surge | Status | Engineering Note |
|---|---|---|---|
| 2200W Quiet Inverter | 1800W / 2200W | TRIPS | Trips overload — 3,600W LRA surge exceeds 2,200W peak |
| 3500W RV Inverter | 3000W / 3500W | TRIPS | Trips overload — 3,600W LRA surge exceeds 3,500W peak |
| 4500W+ Dual-Fuel / 240V | 4000W / 5500W | PASS | Compatible with comfortable NEC headroom |
Running Watts, LRA Surge & Field Sizing Guidance
High-head 3/4 HP pumps pushing vertical lifts above 15 feet draw 11.25A continuous and up to 30A LRA at rotor lock. Use a dedicated 12-AWG or 10-AWG cord directly into a 20A receptacle on a 2,400W+ LiFePO4 station or 4,000W+ dual-fuel inverter generator.
Waveform Verdict: Pure Sine Wave Mandatory (<3% THD)
High-head 3/4 HP submersible windings experience severe harmonic heating and premature capacitor failure on stepped-wave inverters.
Receptacle Spec: 120V • NEMA 5-15P • 11.25 Amps Continuous
Frequently Asked Sizing Questions: 3/4 HP Cast-Iron Sump Pump
How many watts does a 3/4 HP Cast-Iron Sump Pump use to start and run?
A typical 3/4 HP Cast-Iron Sump Pump draws 1,350 continuous running watts (11.25A at 120V via a NEMA 5-15P plug) and spikes up to 3,600 peak startup surge watts (2.7x running load). With a realistic 25% hourly duty cycle, it consumes approximately 338 Wh per hour.
What size solar generator or battery backup will run a 3/4 HP Cast-Iron Sump Pump overnight?
Accounting for 85% AC inverter conversion efficiency and 90% LiFePO4 usable depth-of-discharge (0.765 total factor), running a 3/4 HP Cast-Iron Sump Pump requires 1,768 Wh for 4 hours, 3,535 Wh for 8 hours, 5,302 Wh (~415 Ah @ 12.8V / ~104 Ah @ 51.2V) for 12 hours, and 10,604 Wh for 24 hours. Our top-matched solar generator for this load is the EcoFlow DELTA Pro (3.6kWh Wheeled Station).
Can a 1500W inverter start a 3/4 HP Cast-Iron Sump Pump?
No — a 1,500W inverter will trip into overload protection because a 3/4 HP Cast-Iron Sump Pump requires 1,350W continuous (1,620W with NEC 20% headroom) and a 3,600W Locked Rotor Amp (LRA) startup surge.
What size generator or inverter do I need for a 3/4 HP Cast-Iron Sump Pump?
Applying the NEC 20% continuous load safety headroom (1,620W continuous) and clearing the 3,600W startup surge requires a generator or battery inverter rated for at least 3,600 peak watts.
Does a 3/4 HP Cast-Iron Sump Pump require a pure sine wave inverter?
Yes — a pure sine wave inverter (<3% THD) is strictly recommended for a 3/4 HP Cast-Iron Sump Pump. High-head 3/4 HP submersible windings experience severe harmonic heating and premature capacitor failure on stepped-wave inverters.
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