What Size Power Station Do I Need? A Simple Sizing Guide
Buying a power station without sizing it first is the most common mistake — too small and it won't run what you need, too big and you overpay. The good news: sizing comes down to two numbers you can work out in a few minutes. Here's how.
Step 1: Add up your watts (what it must power at once)
List everything you'd run at the same time and add their wattages. You'll find watts on the device label or in its manual. Rough examples:
- Phone / laptop charging: 10–100W
- Wi-Fi router + a few lights: 50–150W
- Refrigerator (running): ~100–200W (but 2–3× that at start-up)
- Microwave / coffee maker / power tools: 800–1,500W
- Well pump or 240V appliances: 2,000W+
Your power station's continuous output (W) must be higher than this total — and watch start-up surge: motors (fridges, pumps) briefly pull far more than their running watts, so leave headroom.
Step 2: Estimate your watt-hours (how long it must run)
Multiply a device's watts by the hours you need it: watts × hours = watt-hours (Wh). Example: a 100W fridge for 10 hours = 1,000Wh. Add up your devices' watt-hours to find the capacity you need. (Build in ~20% buffer for real-world efficiency.)
Quick picks by need
- Phones, laptops, lights, CPAP overnight — ~1,000Wh is plenty. The lightweight BLUETTI Premium 100 V2 (1,024Wh, 2,000W, ~25 lbs) or the fast-charging AC180P (1,440Wh).
- Fridge + essentials through a long outage — 2,000–2,700Wh. The Premium 200 V2 (2,073.6Wh, 2,700W).
- Whole-home, well pumps, 240V, multi-day — the expandable Apex 300 (2,764.8Wh, 3,840W, up to 58kWh).
- Just the refrigerator — the dedicated FridgePower UPS.
Tip: buy expandable if you're unsure
If your needs might grow, choose a model you can add expansion batteries to later (like the Apex 300). You start with what you need now and scale up without buying a whole new system.
Still not sure? We'll size it for you
Robo Mechanix is an authorized BLUETTI dealer with a US-based team that sizes systems every day. Tell us your devices and runtime goal and we'll recommend the right unit — no over-buying. Request a quote or browse the Power Solutions collection. For model picks, see our best power stations buying guide.
FAQ
How do I calculate watt-hours?
Multiply a device's watts by the hours you'll run it (watts × hours = Wh), then add your devices together and add ~20% buffer.
Why does my fridge need more than its running watts?
Motors draw a brief start-up surge 2–3× their running wattage. Your station's output must cover that spike, not just the running load.
Is it better to buy bigger than I need?
A little headroom is smart, but a far-oversized unit costs more and weighs more. Buying an expandable model is the better way to leave room to grow.
