What Size Portable Power Station Do You Need? (2026 Sizing Guide)

How to Size a Portable Power Station the Right Way

The most common mistake buyers make is guessing. Buy too small and your power station dies mid-outage; buy too big and you've overspent by hundreds. Sizing a portable power station comes down to two numbers: the watts your devices draw (can the station run them at all?) and the watt-hours of capacity (how long will it last?). Here's how to get both right.

Step 1: Add Up Your Running Watts

List every device you need to power at the same time and add up their wattage. Rough draws: LED lights 10W each, phone 10W, laptop 60W, Wi-Fi router 15W, full-size refrigerator 150W running (but 1200W+ at startup surge), CPAP 40W, space heater 1500W, microwave 1000W. Your power station's continuous output rating must exceed this total, and its surge rating must cover the momentary spike when motors (fridges, pumps) kick on.

Step 2: Calculate Watt-Hours for Runtime

Runtime (hours) ≈ capacity (Wh) ÷ device draw (W), with about 15% lost to inefficiency. A 1024Wh unit running a 150W fridge lasts roughly 1024 ÷ 150 × 0.85 ≈ 5.8 hours. Need it to run overnight? You'll want 2000Wh+ or solar recharging.

Matching EcoFlow Models to Real Use Cases

• Phones, laptops, camping (under 300Wh): EcoFlow RIVER 3 / RIVER 2 — light, under $300, perfect for devices and short trips.
• CPAP, small fridge, work site (300–1000Wh): EcoFlow RIVER 3 Max Plus or DELTA 3 1000 Air — covers essential devices through a night.
• Home essentials backup (1–2kWh): EcoFlow DELTA 3 Plus (1024Wh) or DELTA 3 Max Plus (2048Wh) — fridge, lights, Wi-Fi, and electronics through a multi-hour outage.
• Whole-home / high-draw appliances (3kWh+, 240V): EcoFlow DELTA Pro 3 (4096Wh) — runs HVAC, dryers, and well pumps; expandable for multi-day coverage.

Compare all EcoFlow power stations by capacity →

Don't Forget Recharge Speed and Solar

Capacity only tells half the story. During an extended outage, a unit you can recharge from solar (or fast AC when grid returns) effectively has unlimited runtime. EcoFlow's DELTA 3 series recharges to 80% in under an hour on AC and accepts solar input, which matters more than raw capacity for true emergency preparedness.

Frequently Asked Questions

What size power station do I need to run a refrigerator?

A refrigerator draws about 150W running but surges to 1200W+ at startup. You need a power station rated for at least 1500W surge and, for meaningful runtime, 1000Wh+ of capacity. A 2000Wh unit like the EcoFlow DELTA 3 Max Plus runs a typical fridge 10+ hours.

How many watt-hours do I need for camping?

For phones, lights, and a fan over a weekend, 250–500Wh is plenty. Add a portable fridge or CPAP and you'll want 1000Wh, or 500Wh paired with a solar panel for unlimited daytime recharging.

What's the difference between watts and watt-hours?

Watts measure power draw at a moment (whether a device can run at all); watt-hours measure energy capacity over time (how long it runs). You need enough watts to start a device and enough watt-hours to keep it running.

Is it better to buy a bigger power station than I need?

Buy roughly 25% more capacity than your calculated need to cover startup surges, battery aging, and unexpected loads — but going far larger wastes money and adds weight. Expandable models like the DELTA 3 series let you add capacity later instead of overbuying upfront.