What size power station do I need to run a mini fridge?

A mini fridge draws roughly 60-100 running watts but can spike to 200-300W on startup, so almost any power station with a 300W+ continuous rating can run one. Runtime is the real question: a 288Wh unit (like the Jackery 300 Plus) gives a compact fridge around 3-4 hours, while a 1,000Wh+ unit stretches that to 10-14 hours on a single charge.

How many watt-hours does a power station need for a CPAP machine?

Most CPAP machines (with humidifier) draw 30-60 continuous watts, so a 200-300Wh power station typically covers 4-6 nights of use. If you want a week or more without recharging, size up to a 500-1,000Wh unit — the extra capacity matters more than the wattage rating for a low-draw device like a CPAP.

Is a bigger watt-hour rating always better?

No — bigger capacity means more weight, more cost, and more wasted potential if you never use it. A 300Wh unit that covers your actual devices for a weekend is a better buy than a 1,500Wh unit you only drain to 20%. Size to your real watt-hour math (device watts x hours needed), then round up for a safety margin, not the other way around.

What Size Power Station Do I Need? A No-Guesswork Sizing Guide (2026)

Quick answer

Add up the running watts of everything you’ll plug in at once, multiply by the hours you need to run them, and that’s your minimum watt-hour (Wh) capacity — then check the continuous watt (W) rating separately, since a big battery with a small inverter still can’t run power-hungry devices. As a rough starting point: 200-300Wh covers a phone, some lights, and a CPAP for a weekend; 500-1,000Wh adds a mini fridge or laptop into the mix for multi-day trips; 1,500Wh and up is the home-backup and heavy-appliance range. Get both numbers right and the size question answers itself.

Power station shopping gets confusing fast because listings lead with watt-hours (Wh) as if that’s the whole story, when the continuous watt (W) rating is just as important — and surge watts matter for anything with a motor or compressor. Below is the math to size a unit to what you’ll actually run, not just the biggest number on the box.

The two numbers that actually matter

Watt-hours (Wh) = how long it runs. This is the battery’s total stored energy. A 1,000Wh power station can run a 100W device for roughly 10 hours (accounting for ~10-15% inverter loss). This matches the standard 0.85 efficiency factor most third-party power-station runtime calculators use internally — battery capacity times 0.85, divided by device wattage.
Watts (W) = what it can run at once. This is the inverter’s continuous output ceiling. A power station with a 2,048Wh battery but only a 500W continuous rating still can’t run a 1,200W space heater — capacity and output are two separate specs, and both are printed on every listing.
Surge/peak watts matter for motors and compressors. Mini fridges, sump pumps, and power tools draw 2-3x their running wattage for a split second on startup. A unit’s surge rating (usually listed separately from continuous watts) needs headroom for that spike or the device will trip the inverter’s overload protection. See our power station inverter guide for exactly why that overload protection exists and how continuous and surge watts differ.

Device wattage cheat sheet

Device	Running watts	Surge watts	Hours on a 500Wh unit
Smartphone charging	5-10W	10W	40-70 charges
Laptop	30-65W	65W	7-13
CPAP machine (w/ humidifier)	30-60W	60W	7-13
LED camp light / lantern	5-15W	15W	25-70
Mini fridge / cooler	60-100W	200-300W	4-7
Full-size refrigerator	150-400W	800-1,200W	1-2.5
Microwave (700W)	700-1,000W	1,000W	0.4-0.6
Window AC (small)	500-1,200W	1,800-2,400W	0.3-0.8

According to EcoFlow’s published device-runtime charts, this is the same math its own sizing calculator uses internally — running watts times hours needed, checked against the inverter’s continuous rating, with surge headroom added for anything that cycles a compressor or motor. Treat the table above as a starting estimate; always check the wattage sticker on your specific device, since models vary.

Sizing by use case

Weekend camping (phone, lantern, maybe a CPAP): 200-300Wh, 300W+ continuous. The Jackery 300 Plus and EcoFlow River 3 Plus class covers this with room to spare and stays under 10 lbs. Need to shave off both cost and weight? Our EcoFlow River 3 review covers the smaller, cheaper 245Wh base model.
Extended van life / multi-day trips (laptop, mini fridge, lights): 1,000-1,100Wh, 1,500W+ continuous. This is the sweet spot covered in our best portable power station picks — enough to run a compressor fridge continuously while still charging devices.
Home backup (fridge, WiFi, a few circuits during an outage): 2,000Wh+ with expansion-battery capability, 2,400W+ continuous. See our best power station for home backup picks for expandable units built for this. Just protecting a router or a PC from short blips? Our power station vs. UPS comparison covers when a cheaper desk UPS is enough instead. Only need to cover the fridge itself rather than the whole panel? Our best power station for a refrigerator picks size specifically to that surge and duty-cycle math.
Heavy hardwired loads (well pump, window AC, power tools): 3,600Wh+, 3,000-6,000W continuous — the largest units on the market, usually paired with a transfer switch.
Garage (tools, a fridge, WiFi during an outage): 1,000-2,000Wh, 1,800W+ continuous covers most two-car garages. See our best power station for a garage picks — and check your garage door opener’s age first, since anything installed since 2019 already has its own battery backup built in.

A simple sizing formula

List every device you’ll run at the same time, not everything you own.
Add up their running watts. This is your minimum continuous-watt requirement — check it against surge watts too if anything has a motor or compressor.
Multiply total watts by the hours you need coverage. That’s your minimum watt-hour requirement.
Add 20-30% headroom for inverter loss and battery degradation over time, then round up to the nearest common capacity tier (300Wh, 500Wh, 1,000Wh, 2,000Wh, 3,600Wh+).

Buyers who size to the exact minimum often end up shopping again within a year because their needs grew slightly — a small amount of headroom is cheaper than a second purchase.

Once you’ve landed on a target capacity, it’s worth checking whether a battery unit is even the right technology for your situation — see our power station vs. generator comparison if you’re still weighing that against a traditional gas generator. Only need that capacity once, for a single trip or event? Our power station rental vs. buying breakdown covers when a daily rental actually beats a purchase. Warranty length and cycle life vary a lot at the same capacity tier, too — our Renogy Phoenix 1000 review breaks down why a cheap 1,000Wh-class unit isn’t always the better buy once you factor those in. If you’re planning to recharge off-grid rather than off a wall outlet, size your solar input alongside your battery capacity — our best foldable solar panel picks cover which wattage class matches which power station size.

The bottom line

Size a power station in two steps, not one: watt-hours for runtime, continuous watts for what it can power at once, with surge headroom for anything that has a motor. Most weekend users land in the 200-300Wh tier, multi-day campers and van-lifers want 1,000Wh+, and home-backup buyers should look at 2,000Wh and up with expansion capability.