FREE TOOLS · NO SIGNUP · NO FLUFF

Will your backup power actually work when the lights go out?

Most people find out their battery backup can't handle the job during the blackout. Our calculators do the math before the storm — so you buy the right thing the first time.

4FREE CALCULATORS
$800–2,500AVG. PRODUCT RANGE
10 secTO GET YOUR ANSWER

CALCULATORS

Pick your scenario

Each tool matches your specific equipment to real battery and generator specs. No guessing.

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Sump Pump Battery Checker

Will your portable power station handle the startup surge when your pump kicks on? Pick your pump size and battery — get a clear yes or no.

“Can an EcoFlow Delta 2 run a 1/3 HP sump pump?”

● Live→
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CPAP Backup Runtime

How many hours will your battery keep your CPAP running overnight? Enter your machine, pressure, and humidifier setting — get real runtime numbers.

“How long will a Jackery 1000 run my ResMed AirSense 11?”

Coming soon→
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Fridge & Freezer Runtime

Power's out — how long before your food goes bad? Enter your fridge type and battery size. We'll tell you how many hours you've got and whether cycling helps.

“How long will a power station run my refrigerator?”

Coming soon→
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Whole-House Generator Sizing

Check the boxes for what you need running — sump pump, fridge, lights, HVAC — and we'll tell you the minimum generator wattage with specific model picks.

“What size generator do I need for my house?”

Coming soon→

WHY THIS MATTERS

The expensive mistake most people make

1

They buy on capacity alone

“1,000 watt-hours should be plenty.” But capacity isn't the whole story. A sump pump needs 3–6× its running wattage just to start. If the battery can't surge, it shuts off to protect itself.

2

Brand blogs are biased

EcoFlow's blog says buy an EcoFlow. Jackery's says buy a Jackery. Nobody neutral is matching your specific equipment to real specs. That's what we do.

3

The real test is the blackout

Most people discover their setup doesn't work when the power actually goes out. A $1,200 battery sitting next to a flooded basement. Our calculators catch this before you buy.

GUIDES

Backup power, explained simply

All guides →
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Sump pumps

What size generator do you actually need for a sump pump?

The honest answer — with exact wattage numbers for every pump size.

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Comparison

Battery backup vs. generator for your basement: which wins?

It depends on how long you're without power. Here's how to decide.

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CPAP

CPAP battery backup: how many hours will you actually get?

Realistic runtimes for the most popular machines and batteries.

Backup power info for homeowners.
Not engineers.

Evercells exists because we couldn't find a single resource that answered the question plainly: will this battery actually run my sump pump? Every article we found was either too vague, written for electricians, or published by someone selling the product. We built the tools we wish existed.

We're completely independent. No brand deals, no sponsored content, no affiliate relationships that change what we recommend. When we link to a product, it's because the specs matched — not because someone paid us to say so.