How we recommend power stations

Where the numbers come from

Specs come from each maker's US product page or user manual, and each model lists its sources and the date we checked them. When a maker contradicts itself, we use the lower figure. When a spec isn't published, we leave it blank and mark it; models whose core specs we haven't confirmed are kept out of the quiz and charts. Appliance energy use comes from ENERGY STAR data, manufacturer manuals and utility wattage tables.

We don't run a test lab and don't claim hands-on testing. When we mention an independent measurement, we name who made it.

Step 1: rule out what can't work

• Continuous output must be at least 10% above everything you might run at once. Boost modes (X-Boost, Power Lifting, SurgePad) don't count, because they only work for heating appliances.
• Surge rating must cover the start-up spike of your biggest motor, such as a fridge compressor or sump pump. If a maker publishes no surge figure, we only use the continuous rating.
• Capacity must cover the time you asked for. Extra batteries count for a day or longer, and only when the unit can stay put or roll.
• Weight, budget band, 240 V, UPS and solar needs you told us about are hard limits too. Models that are discontinued or not yet shipping are out.

Step 2: the runtime math

Runtime = rated Wh × 0.9 ÷ (AC watts ÷ 0.85 + inverter standby + DC watts ÷ 0.9)

The 0.9 is the share of capacity the battery management system lets you use. AC devices lose about 15% in the inverter, which also draws standby power while its outlets are on: 10–12 W for small and mid units, about 18 W for 2 kWh units and about 30 W for home-backup units unless the maker publishes its own figure. Fridges and freezers use typical daily energy, not running watts × 24. Cold weather cuts usable capacity by about 15% around 14°F and 35% near −4°F. We show a range from 15% below to 5% above the estimate.

Step 3: score what's left

• Capacity fit (25%): best when the station covers 1.2 to 2 times what you asked for. Much bigger means paying for and carrying capacity you won't use.
• Power headroom (15%): running at 80% of rated output or less is easier on the inverter during long runs.
• Recharging (15%): wall charge time, solar input relative to your daily use, and car charging, depending on your answers.
• Portability (15%): lighter is better within the carry limit you chose.
• Ports (10%): enough AC outlets for your devices, high-wattage USB-C for laptops, and an RV outlet for RV use.
• UPS (10%): when you're powering a CPAP or working online, faster switchover scores higher.
• Longevity (5%): warranty length and rated cycle life.

Unconfirmed core specs and older models lose a few points. We show no more than two models from one brand, so you see real alternatives.

What we leave out

We don't show prices, because Amazon prices change by the hour; the budget question uses broad price bands that we recheck regularly. We don't show star ratings. And nothing about which store or program pays us is part of the score. See the affiliate disclosure.