A power station has two ratings that matter most and that are easy to mix up. Watts (W) are how much power it can deliver at once: they decide what you can run. Watt-hours (Wh) are how much energy the battery holds: they decide how long you can run it. A 2,000 W station with a 500 Wh battery can start a kettle but will be empty in about 15 minutes; a 300 W station with a 1,000 Wh battery can run a laptop all week but won’t run the kettle at all.
Step 1: what do you need to run at once?
Add up the running watts of everything you’ll plug in at the same time, then pick a station whose continuous AC output comfortably exceeds it. Look at the device’s label or manual for its input power, or better, measure it with a plug-in watt meter. Typical loads:
| Device | Typical draw |
|---|---|
| Phone charging | 5-25 W |
| Laptop | 30-100 W |
| CPAP (no humidifier) | 30-60 W |
| LED string lights | 5-20 W |
| Fridge, full-size (average while cycling) | 100-200 W |
| Chest freezer (average) | 50-100 W |
| Coffee maker or kettle | 800-1,500 W |
| Microwave | 1,000-1,500 W |
| Window air conditioner | 500-1,200 W |
| Circular saw | 1,200-1,800 W |
Motors and compressors (fridges, pumps, power tools) draw two to three times their running watts for a moment at start-up. The station’s surge rating has to cover that. Some stations advertise a “boost” or “power lifting” mode that runs heating appliances like kettles above the inverter’s rating by lowering the voltage; it works for resistive loads but not for motors or electronics.
Step 2: how long does it need to run?
Use this estimate:
runtime in hours ≈ battery Wh × 0.85 ÷ average watts
The 0.85 accounts for inverter losses: independent tests of AC output typically find stations deliver 80-90% of their rated capacity, and the tested capacity figure on each product page shows the real number for that model. A 1,000 Wh station running a 60 W fridge average delivers about 850 Wh, or around 14 hours.
Running devices from the 12 V car outlet or USB-C ports skips the inverter and gets more out of the battery, so DC is worth using where a device supports it.
Cold weather, battery age and the station’s own standby draw (often 10-20 W with the inverter on) all reduce runtime. Turn the AC inverter off when you only need USB.
Step 3: pick a battery chemistry
- LiFePO4 (LFP) is now standard on most new stations. It’s rated for 3,000-4,000 cycles to 80% capacity, is more tolerant of heat, and is much less prone to thermal runaway. The trade-off is weight.
- NMC lithium-ion is lighter for its capacity but typically rated for 500-1,000 cycles. Fine for occasional camping, a poor fit for daily solar cycling.
- Sodium-ion is new to the market: better cold-weather performance and cheaper materials, but heavier than LFP for now.
Step 4: charging and solar
Fast AC charging is the single biggest quality-of-life difference between models. The best stations go from empty to full in about an hour from a wall outlet, which matters when you only get a short window to top up before a storm or a trip.
For solar, check the maximum input watts and the voltage range. Panels wired in series raise voltage; a station accepting 60 V can take more panels in series than one limited to 30 V. As a rough guide, a panel delivers 60-75% of its rated watts in good sun.
Home backup features
- UPS / pass-through: the station powers devices from the wall and switches to battery when the power drops. A switchover under 20 ms (10 ms or less is better) keeps most computers, routers and CPAP machines running without a restart. Check whether the maker calls it a true UPS or just “EPS”.
- Expansion batteries add capacity later without buying a second inverter.
- Transfer switch or smart panel connections let a large station back up home circuits directly. Those installations need an electrician.
- 240 V output is required for well pumps, central air and some ranges; most stations only output 120 V unless two are linked.
Air travel
In the US, the FAA allows lithium batteries up to 100 Wh in carry-on bags, and 101-160 Wh with airline approval. Every power station is far over that limit, so none can fly; a USB power bank is the only portable battery you can take on a plane. See the current FAA battery guidance.
Checklist
- Continuous AC output above the total load, with surge to cover any motor start-up
- Enough watt-hours, after roughly 15% losses, for the runtime you need
- LiFePO4 chemistry if it will be cycled often or left in a hot vehicle
- A fast wall charge, and enough solar input for your panels
- UPS switchover of 20 ms or less if it will protect computers or medical devices
- A warranty of at least 5 years on a large or home-backup unit
Frequently asked questions
Can I leave a power station plugged in all the time? Most modern stations are designed for it, and many let you cap the charge level at 80-90% to slow battery wear. Check the manual; stations sold with UPS features are built for continuous connection.
Can a power station run a CPAP all night? Yes, for nearly any size. A CPAP without a heated humidifier averages 30-60 W, so even a 300 Wh station covers a night. Running it from the DC outlet with the maker’s DC adapter extends runtime considerably.
Is a power station the same as a generator? No. It’s a battery: silent, fume-free and safe indoors, but it only holds what you charge into it. A fuel generator runs as long as there’s fuel. Many people pair a station with solar panels to recharge without fuel.