- Well Pumps Are Different From Other Appliances
- What Makes Your Pump Use More Power?
- Find Your Pump's Real Power Needs
- How Much Water Do You Actually Need?
- Size Your Battery: The Step-by-Step Math
- Your Inverter Must Handle the Startup Surge
- EcoFlow DELTA 2 Max: Built for Well Pumps
- Set Up Your System Right
- Mistakes That Cost You Money
- Simple Formula You Can Use
- Ensure Your Home Has Water Through Any Power Outage.
What Size Battery Do You Need to Run a Well Pump During a Blackout?
- Well Pumps Are Different From Other Appliances
- What Makes Your Pump Use More Power?
- Find Your Pump's Real Power Needs
- How Much Water Do You Actually Need?
- Size Your Battery: The Step-by-Step Math
- Your Inverter Must Handle the Startup Surge
- EcoFlow DELTA 2 Max: Built for Well Pumps
- Set Up Your System Right
- Mistakes That Cost You Money
- Simple Formula You Can Use
- Ensure Your Home Has Water Through Any Power Outage.
The storm hits. Power goes out across your neighborhood. Most people worry about their lights or TV. But if you have well water, you face a bigger problem—no electricity means no water.
Your well pump needs power to work. When the grid goes down, your faucets run dry. You can't flush toilets. You can't wash your hands. That's not just annoying; it puts your family at risk.
But here's the good news: you can keep water flowing even when the power is out. You just need the right battery backup. Let me show you how to figure out exactly what size you need.
Well Pumps Are Different From Other Appliances
Well pumps work like motors. Motors need two different amounts of power:
Running power: The steady electricity they use once they're working
Starting power: The big burst they need to get going
That starting burst is huge. Most pumps need 2 to 3 times their running power just to start up. Some need even more. A pump that uses 700 watts when running might need 2,100 watts for those first few seconds.
This trips up most people. They buy a battery that handles the running power but can't deliver that startup jolt. When the pump tries to start, nothing happens. You're still without water.
What Makes Your Pump Use More Power?
Several things affect how much electricity your well pump needs:
How deep your well is: Deeper wells need stronger pumps. Lifting water from 200 feet down takes way more power than pumping from 50 feet.
What type of pump do you have:
- Submersible pumps sit down in the water. They usually need 750 to 1,500 watts.
- Jet pumps stay above ground. They typically use 500 to 1,000 watts.
How old is your motor: Newer motors work more efficiently. They do the same job with less electricity. Old pumps can be real power hogs.
How often it runs: Pumps don't run all the time. They turn on when pressure drops, fill your tank, then shut off. A small pressure tank means more starts, which uses more total power.
Here's what typical home pumps use:
| Pump Size | Running Watts | Starting Watts |
| 1/2 HP | 500-960W | 1,000-2,900W |
| 3/4 HP | 750-1,300W | 1,500-4,000W |
| 1 HP | 750-1,900W | 1,500-5,800W |
| 1.5 HP | 1,500-2,500W | 3,000-7,500W |
Remember, these are just estimates. Your pump might be different.
Find Your Pump's Real Power Needs
Don't guess your pump's power requirements. Look at the metal nameplate on your pump motor. This label tells you exactly what you're working with.
You want to find two numbers:
- Volts (probably 115V or 230V)
- Amps (how much current it draws)
If you see volts and amps but no watts, here's the simple math: Watts = Volts × Amps
Example: A pump running on 240 volts that draws 10 amps uses 2,400 watts.
That's your running power. For starting power, multiply by 2 or 3. So your 2,400-watt pump might need 4,800 to 7,200 watts to start.
How Much Water Do You Actually Need?
During a blackout, you're not living normally. You're in emergency mode. Skip the long showers, dishwasher, and lawn sprinklers.
Focus on what matters:
- Drinking water
- Washing hands
- Flushing toilets
- Basic cooking
The CDC says you need 1 gallon per person per day for drinking and basic hygiene. A family of four needs about 4 gallons daily. That's way less than the 80+ gallons Americans normally use.
This matters because it affects how much your pump runs. Less water use means less pump time, which means you need less battery power.
Size Your Battery: The Step-by-Step Math
Here's how to figure out what size battery you need:
Step 1: Calculate Daily Energy Use
Figure out how much power your pump uses each day. During emergencies, most pumps run about 1 to 2 hours total per day.
Let's say your pump uses 1,000 watts and runs 1 hour daily: Daily energy = 1,000 watts × 1 hour = 1,000 watt-hours
Step 2: Account for Energy Loss
Your battery makes DC power. Your pump needs AC power. Converting between them wastes some energy. Good converters (called inverters) are about 85% efficient.
Real battery energy needed = 1,000 ÷ 0.85 = 1,176 watt-hours
Step 3: Pick How Many Days
How long do blackouts usually last where you live? Most people plan for 3 to 7 days. Let's use 3 days:
Total energy for 3 days = 1,176 × 3 = 3,528 watt-hours
Step 4: Protect Your Battery
You shouldn't drain batteries completely. It shortens their life. How much you can safely use depends on the type:
- Lead-acid batteries: Only use 50% safely
- LiFePO4 batteries (the modern type): Can safely use 80% to 90%
LiFePO4 batteries are much better. They last longer, and you can use more of their power. Using 80% of capacity:
Required battery size = 3,528 ÷ 0.80 = 4,410 watt-hours
Step 5: Add Extra for Safety
Always add 20% to 30% more for unexpected needs or cold weather: Final battery size = 4,410 × 1.2 = 5,292 watt-hours
So you need about 5,300 watt-hours of battery capacity.
Your Inverter Must Handle the Startup Surge
Your battery needs an inverter that can deliver that big startup burst. If your pump needs 2,100 watts to start, your inverter must handle at least that much power.
Many people mess this up. They buy enough battery capacity, but the inverter can't handle the surge. The pump won't start, no matter how much energy you have stored.
EcoFlow DELTA 2 Max: Built for Well Pumps
The EcoFlow DELTA 2 Max works great for most home well pumps. Here's why:
Strong Power Output:
Delivers 2,400 watts continuously
X-Boost feature pushes it to 3,400 watts for startup surges
Handles almost all home well pumps
Grows With Your Needs:
Starts with 2,048 watt-hours
Add up to two extra batteries for 6,144 total watt-hours
Scale up when you need more backup time
Modern Battery Technology:
Uses LiFePO4 batteries that last 3,000+ charge cycles
That's about 10 years of daily use
You can safely use 80% to 90% of the capacity
Much better than old lead-acid batteries
Charges Multiple Ways:
Plugs into regular wall outlets
Solar panels can charge it up to 1,000 watts
Car charging for remote locations
Fast charging gets you back to full power quickly
Safe for Indoor Use:
No exhaust fumes
Runs quietly
No carbon monoxide risk
Control everything from your phone
Let's check our earlier example:
We calculated needing 5,292 watt-hours
DELTA 2 Max base: 2,048 watt-hours
Add two extra batteries: 6,144 watt-hours total
Perfect fit with room to spare
Set Up Your System Right
Use thick enough wires: Thin cables waste power and can get hot. For 240-volt pumps or complex setups, hire an electrician.
Keep everything cool: Heat kills batteries fast. Put your power station somewhere cool and dry. Avoid direct sunlight or heat sources.
Test monthly: Run your pump on battery power once a month. Check everything works. The worst time to find problems is during a real outage.
Consider solar panels: Solar can recharge your battery during long outages. Even a small solar setup can keep you going forever.
Mistakes That Cost You Money
Ignoring startup power: Your pump might run on 1,000 watts, but it needs 3,000 watts to start. Plan for both numbers.
Buying too small: Better to have extra capacity than run out of water. Batteries work worse in cold weather. You might use more water than expected.
Forgetting about conversion losses: Converting DC to AC power costs you about 15% of your battery's energy. Don't ignore this.
Running too many things: During an outage, run your pump. Don't also try to power your TV, coffee maker, and charge everyone's phones at the same time.
Simple Formula You Can Use
Here's the basic formula:
Battery Size Needed = (Pump Watts × Daily Hours) ÷ Inverter Efficiency ÷ Usable Battery % × Days of Backup × 1.2 safety factor
Using our example: (1,000W × 1 hour) ÷ 0.85 ÷ 0.80 × 3 days × 1.2 = 5,294 watt-hours
Ensure Your Home Has Water Through Any Power Outage.
You don't have to lose water when you lose power. The right battery backup keeps your well pump running through any blackout.
The key steps are:
1. Find your pump's real power numbers (running and starting watts)
2. Calculate realistic emergency water needs
3. Size your battery for several days of operation
4. Make sure your inverter can handle the startup surge
The EcoFlow DELTA 2 Max handles most home well pumps perfectly. It has the power output for tough startups and enough battery capacity to last for days. You can expand it when you need more backup time.
Don't wait for the next storm to think about your water. Get your backup system sized right now. Turn a potential disaster into just a minor inconvenience.
Ready to keep your water flowing no matter what happens? Check out EcoFlow and see how smart battery technology protects your family's most important resource.