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Portable Power Station Sizing
What Size Portable Power Station Do I Need?
The two numbers that matter are watt-hours (how long it runs) and watts (what it can power at once). Get both wrong and you'll either overpay for capacity you never use, or find out mid-trip that you're out of battery.
The formula
Add up the running watts of everything you want powered, multiplied by the hours you'll run each one; this is your daily watt-hour need. Multiply that by your days of autonomy (days without charging) and a safety buffer, and you've got your target capacity.
Capacity (Wh) = (Σ device watts × hours/day) × 1.2–1.8 buffer × days of autonomy
Continuous output (W) = Σ watts of everything running at once
Surge output (W) = continuous output + highest single surge load
Example: A Starlink dish (50W, 6 hrs), a laptop (65W, 3 hrs), and LED lighting (15W, 5 hrs) works out to roughly 570 Wh/day. With a 1.2x buffer and 1 day of autonomy, that's a ~685 Wh minimum — comfortably covered by a 700–1000Wh class power station.
Frequently asked questions
What size portable power station do I need for camping?
For a weekend of phones, lights, and a fan, 300–600Wh usually covers it. Add a camp fridge or travel cooktop and you're closer to 1000Wh+.
Can a portable power station run a fridge?
Yes, if the continuous output rating clears the fridge's running watts and the surge rating clears its compressor startup spike, which is often 2-3x the running wattage.
How much bigger should I buy than my calculated number?
Add 15-20% on top of your raw watt-hour total. Inverter losses, cold-weather derating, and forgetting to unplug something all eat into your real-world runtime.
What's the difference between watts and watt-hours?
Watts is how much power something draws right now. Watt-hours is how much total energy is stored. You need enough watts for your heaviest device to start, and enough watt-hours for everything to run as long as you need it to.