What size power station do I need?
Updated November 14, 2026
Portable power stations are rated two ways: capacity in watt-hours (Wh), which is how much energy is stored, and output in watts (W), which is how much they can deliver at once. Get both right and the station runs what you need for as long as you need it. Here's a simple way to work it out.
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Step 1: add up the watts you'll run at the same time
Find the wattage on each device's label or manual, then add up everything you'll run together. The station's continuous output rating (W) must be higher than that total.
Fridges, pumps and power tools draw a short surge when they start, often two to three times their running watts. Check the station's surge or peak rating covers it.
Step 2: work out the watt-hours you need
Multiply each device's watts by the hours you'll run it, then add them up. Example: a 60 W CPAP for 8 hours is 480 Wh; a 100 W fridge running about a third of the time for 24 hours is roughly 800 Wh.
Add about 20% for conversion losses. Real-world output from AC outlets is lower than the battery's rated capacity.
Rough sizes that fit common needs
Phones, laptops, lights and a router for an evening: around 300 to 600 Wh.
CPAP overnight, or a fridge through a short outage: around 1,000 Wh.
Several essentials through a longer outage: 2,000 Wh and up, ideally with a battery that can be expanded or recharged by solar panels.
Recharging during long outages
If the power may be out for days, check how fast the station recharges from solar panels and how many watts of solar input it accepts. Pairing a station with panels can keep essentials running when the grid is down.
Battery chemistry matters for lifespan: LiFePO4 (LFP) batteries are rated for far more charge cycles than older lithium-ion types.
Quick checklist
- Continuous output (W) higher than everything you'll run at once
- Surge rating that covers fridges, pumps and tools starting up
- Capacity (Wh) for your hours of use, plus about 20%
- Solar input and recharge time if outages can last days
- LiFePO4 battery for a longer life
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Questions
Can a power station run a refrigerator?
Usually yes if its continuous output covers the fridge's running watts and its surge rating covers the start-up. Capacity decides how long: check the fridge's daily energy use (kWh per year divided by 365 gives a rough daily figure).
Is a power station safe to use indoors?
Battery power stations make no fumes, so they can be used indoors, unlike gas generators, which must run outdoors away from windows and doors.
How long will a 1,000 Wh power station last?
Divide usable capacity (about 80 to 90% of the rating) by the watts you draw. At 100 W, a 1,000 Wh station lasts roughly 8 to 9 hours.
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