Size your system
Add up watts and watt-hours, then pick a battery bracket that fits.
Start →⚡ Home backup power, explained
Keep the lights on when the grid goes down.
Plain-English sizing math and honest buyer guides for home backup power.
Start here
Three questions every backup plan starts with.
Solar panel math
Series vs parallel, cold-weather voltage, and how many panels your station can take.
Start →Outage runtimes
How long a fridge, sump pump, CPAP, or furnace will really run on battery.
Start →How much backup do I need?
Tick what you want to keep running and for how many hours. All wattages are typical estimates, not measurements of your home.
Latest guides
Every spec has a source and a check date.
Best Portable Power Stations for Home Backup (2026): Specs Compared
Five home-backup power stations compared on capacity, 240V output, surge, solar input and expansion, from official specs. Who each one is for.
Read guide →EcoFlow DELTA Pro Ultra vs Tesla Powerwall 3: Which Should You Buy?
DELTA Pro Ultra vs Powerwall 3: capacity (DC vs AC), power, surge, solar input, install and warranty, compared from official spec sheets.
Read guide →How Many kWh of Battery Do You Need for Whole-Home Backup? (Worked Examples)
Size a home battery from your real loads: daily kWh, days of backup, inverter loss and surge. Three worked house examples, step by step.
Read guide →Power Station for a 240V Well Pump: Surge Sizing and Which Models Can Do It
Most deep-well pumps run on 240V and need a big startup surge. Here's how to size a power station for one, and which models have 240V output.
Read guide →How Long Will a Power Station Run a Refrigerator? Outage Runtime Math
Turn your fridge's EnergyGuide kWh/year into hours of backup. Step-by-step runtime math for popular power stations, with margins for real life.
Read guide →CPAP Runtime on a Power Station: DC vs AC, and How Many Nights You Get
How many nights will a power station run a CPAP? Step-by-step math using ResMed's published power figures, plus why DC can beat AC.
Read guide →We bought one
The site's owner bought an EcoFlow DELTA Pro Ultra X with 4 batteries and is setting it up now; we'll add real measurements once it's running.
We show our math
Every sizing claim comes with the formula and the numbers behind it, so you can redo it for your house.
Dated spec checks
We list the date we checked every spec, and link to the manufacturer source.
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