How Big a Portable Power Station Do You Need?
Choosing the right size comes down to two numbers: the watts your devices draw at the same time, and the watt-hours (Wh) you need to keep them running. This guide shows how to work both out in a few minutes.
Step 1: List what you want to run
Write down each device and its power draw in watts. The label on the charger or appliance usually shows it. Typical ranges, which vary by model:
- Phone charging: about 10 to 20 W
- Laptop: about 45 to 100 W
- LED lights: about 5 to 15 W each
- TV: about 50 to 150 W
- CPAP machine: about 30 to 60 W (heated humidifier adds more)
- Refrigerator: about 100 to 200 W while running, with a higher start-up surge
- Microwave, kettle, coffee maker, space heater: roughly 600 to 1,800 W
Step 2: Check the output rating (W)
Add up the watts of everything you will run at the same moment. The power station's continuous output must be higher than that total. Devices with motors or compressors, such as refrigerators and pumps, can draw two to three times their running power for a second or two when they start, so check the surge rating as well.
Step 3: Calculate the capacity you need (Wh)
Multiply each device's watts by the hours you want to use it, then add the results. A simple estimate for runtime is: capacity in Wh multiplied by 0.85 (conversion losses), divided by the watts you are drawing.
Example: a 500 Wh station running a 60 W laptop and 10 W of lights draws about 70 W. Runtime is roughly 500 x 0.85 / 70, or about 6 hours.
Rough size guide
- Up to 300 Wh: phones, tablets, lights and a laptop for a weekend trip.
- 500 to 1,000 Wh: camping with a small fridge or CPAP, remote work, short outages.
- 1,000 to 2,000 Wh: van life, a refrigerator during an outage, small power tools.
- 2,000 Wh and above: home backup for essentials, higher-power appliances, extended off-grid use.
Other things worth checking
- Battery chemistry: LiFePO4 batteries typically last for several times more charge cycles than other lithium types.
- Recharging: look at wall, car and solar input. Faster input means less waiting, and solar input matters for long trips.
- Ports: make sure the AC outlets, USB-C power delivery and DC ports match your devices.
- Weight: bigger capacity means a heavier unit; check you can carry it where you need it.
Specifications and prices change often, so always confirm details on the store page before ordering.