The Simple Math for Keeping the Fridge Cold and the Phones Charged
By Larry Betz | Prepared Not Paranoid https://www.preparednotparanoid.com/
The number on the box isn't how long a power station will last in your kitchen. A big unit that "runs a refrigerator" may only keep it running for a day or two, and some won't start it at all. Before you spend a couple thousand dollars, it pays to do the math. It's simpler than it sounds, and it's the only way to answer the real question: what size power station do I need?
In Part 1, we started small: phones, Wi-Fi, a laptop, and the morning coffee. Now we'll size a system for the kitchen, because the refrigerator and freezer are where most families have the most to lose.
Two Kinds of Watts
Anything with a motor, like a refrigerator, freezer, or well pump, needs a burst of extra power for a few seconds when it starts. That gives you two numbers for every device:
Starting watts (surge) is the short burst it needs to get going.
Running watts is what it uses once it's up and running.
A refrigerator might need about 1,200 watts to start, then settle down to about 200. Your power station has to handle that startup burst, or the fridge simply won't come on. And you don't have to add up everyone's surge. Design around the single biggest one, because your appliances almost never start at the exact same second.
How to Size Your System in 5 Steps
Step 1: Add Up a Real Outage Day
List what you'd actually run, how many watts each uses, and how many hours a day. Multiply watts by hours to get watt-hours. A refrigerator only runs about 8 hours out of 24, because the compressor cycles on and off. Here's what a real outage day looks like in my example.
That comes to about 2,410 watt-hours a day. Notice that the fridge alone is two-thirds of it.
Tip: You'll find the watts on each device's label or power brick. For anything with a motor, a plug-in watt meter (about $20 to $30) shows exactly what it uses. Plug the fridge into one for 24 hours and you'll know your real number, not a guess.
Step 2: Add 15 to 20 Percent
No power station delivers 100 percent of its rated capacity. Converting battery power to wall-outlet power loses some along the way, so most deliver about 85 to 90 percent. Add a cushion:
2,410 x 1.2 = about 2,900 watt-hours for one day.
Step 3: Check the Biggest Surge
Find your biggest starting number. In this example, it's the fridge at about 1,200 watts. Your power station's output needs to be comfortably above that, especially if other things are running at the same time.
Step 4: Decide How Many Days
One day? Three? Multiply your daily number by the days you want to cover. Two days at 2,900 is about 5,800 watt-hours. That's where expansion batteries, solar, or a generator come in.
Step 5: Decide How You'll Recharge
Every battery runs out. Solar panels (Part 4) or a generator (Part 6) can refill it during a long outage. Your plan for recharging matters as much as the battery's size.
How Long Will a Big Power Station Last?
Here's how four current models handle that 2,410 watt-hour day.
Be wary of anyone who says a power station will run your whole house "24/7." Even the big ones buy you a day or two on a normal day's use. That's still a big deal. It may be all you need to save a freezer full of food or get through a storm until the power comes back.
Large Power Station Options
Jackery Explorer 2000 v2
Capacity: 2,042 Wh
Output: 2,200 W (4,400 W surge)
Weight: about 40 lbs
Battery: LiFePO4
Good for: keeping the fridge and phones going for about a day. The lightest of the four, so one person can carry it.
Bluetti Apex 300
Capacity: 2,765 Wh, expandable to about 19 kWh with add-on batteries
Output: 3,840 W, with 120 V and 240 V outlets
Weight: about 84 lbs
Battery: LiFePO4
Good for: a full day on the kitchen essentials, with room to grow.
Anker SOLIX F3800 Plus
Capacity: 3,840 Wh, expandable to 26.9 kWh with add-on batteries
Output: 6,000 W, with 120 V and 240 V outlets
Weight: about 137 lbs, on wheels
Battery: LiFePO4
Good for: about 2 days on the fridge alone, plus enough output to run bigger appliances.
EcoFlow DELTA Pro 3
Capacity: 4,096 Wh, expandable to 12 kWh with add-on batteries
Output: 4,000 W (8,000 W surge), with 120 V and 240 V outlets
Weight: about 114 lbs, on wheels
Battery: LiFePO4
Good for: the longest runtime of the four, about a day and a half on the full outage day.
You'll find these and the other gear I recommend in my Backup Power Amazon store, linked at the bottom of this post.
A note on 240 volts: Most household outlets are 120 volts. Some things in your home, like a well pump, central air conditioning, or an electric range, need 240 volts and usually connect straight to your electrical panel. The bigger power stations above can supply 240 volts, but connecting one to your home's wiring is a job for a licensed electrician and a transfer switch. Part 3 covers that.
Stretch Your Runtime
You can make any power station last longer by cutting back on what you run:
Keep the fridge and freezer doors closed. Every opening lets the cold out and makes the compressor work harder.
Fill empty freezer space with frozen water bottles. A full freezer holds its temperature longer.
Skip the electric coffee maker. It uses a lot of power for a short time.
Run the Wi-Fi router only when you need it, instead of all day and night.
Charge phones and laptops during the day, in one batch.
Trim my example day this way (no coffee maker, Wi-Fi for 12 hours, the laptop for 2) and it drops from about 2,410 to about 1,930 watt-hours. That stretches a DELTA Pro 3 from about a day and a half to almost two days, without buying a thing.
What to Look for in a Large Power Station
Watt-hours (capacity) to cover your daily number with a cushion.
Running and surge watts (output) above your biggest startup surge.
Weight. Many large units weigh 80 to 140 pounds. Wheels and handles matter.
The right outlets, including 240 V if you'll ever need it.
Solar input and expansion batteries, so the system can grow.
UPS or pass-through charging, so it can stay plugged in and take over when the power drops.
A LiFePO4 battery, which lasts thousands of charge cycles.
Coming Up Next
In Part 3, we'll keep the fridge and freezer running: automatic backup, transfer switches, why you never plug into a wall outlet, and how long food stays safe.
Ask Yourself
What would my family's real outage day add up to in watt-hours?
What's the biggest startup surge in my house, and can my power station handle it?
How many days do I want to cover, and how would I recharge?
Remember
Size your system around a real outage day, not the number on the box. Add up your watt-hours, add 15 to 20 percent, and make sure your power station can handle the biggest startup surge. Even big units buy you a day or two, so plan how you'll stretch it and how you'll recharge.
Get Started Today
FREE GUIDE: Lights Out, The Prepared Not Paranoid Blackout Plan. What to do in the first 30 minutes, the first 24 hours, and beyond when the power goes out, plus what to power first, how long food stays safe, and a blackout supply checklist. [CTA: Comment or DM "KEYWORD" / or download it here: LINK]
Go Deeper
The Family Safety Toolkit. This post helps you size your backup power. The Toolkit gives you 20 checklists covering every area of family safety and preparedness, from your go bag and your vehicle to first aid and home safety, all for $19.99. [Get it here: https://www.preparednotparanoid.com/family-safety-toolkit]
The Family Emergency Preparedness Manual is coming soon.
Tools I recommend: The power stations, expansion batteries, plug-in watt meters, and solar panels I recommend are in my Backup Power Amazon store. https://link.amazon/B0aqcCOsk
Related reading:
Backup Power, Part 1: Start Small https://www.preparednotparanoid.com/pnp-library/alternative-power-lesson1
Backup Power, Introduction: Staying Powered Up When It Goes Dark https://www.preparednotparanoid.com/pnp-library/alternative-power
Backup Power, Part 3: Keep the Fridge and Freezer Running https://www.preparednotparanoid.com/pnp-library/alternative-power-lesson3
References
Jackery. Explorer 2000 v2 specifications.
BLUETTI. Apex 300 specifications.
Anker SOLIX. F3800 Plus specifications.
EcoFlow. DELTA Pro 3 specifications.
FEMA / Ready.gov. Power Outages.
U.S. Department of Energy. Estimating Appliance and Home Electronic Energy Use.
Disclaimer
These suggestions are intended to help you and your family build awareness, confidence, and safer decision-making habits. No safety plan, checklist, or training can guarantee 100% protection. This article is for general informational purposes only. Specifications are from the manufacturers as of October 2026 and can change. Runtimes are estimates and will vary with your appliances, temperature, and use. Always follow the manufacturer's instructions, and use a licensed electrician for any connection to your home's wiring. Affiliate disclosure: I've linked to products from my Amazon store that I personally recommend. As an Amazon Associate, I earn from qualifying purchases, at no extra cost to you. Thank you for supporting my work.
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