What Size Portable Power Station Do I Need? A Simple Sizing Guide

This guide is based on manufacturer specifications, published information and buyer feedback. We do not claim hands-on testing. Always follow the instructions that come with your own equipment.

The right size depends on two numbers: how much power your devices draw at once (watts) and how long you need them to run (hours). Multiply them and you get the energy you need in watt-hours (Wh). This guide walks through the steps with simple maths.

Step 1: List what you want to power

Write down each device and its power use in watts. The label on the device or its power adapter usually shows the number. For devices that only list amps and volts, multiply them (volts x amps = watts).

Device	Typical running watts
Phone charging	5-20 W
Wi-Fi router and modem	10-25 W
LED light	5-15 W
Laptop	45-100 W
TV (flat screen)	50-150 W
Mini fridge	50-100 W while running
Full-size fridge	100-200 W while running, higher surge at start
Coffee maker, microwave, space heater	800-1,800 W

These are typical ranges, not exact values. Check the labels on your own equipment.

Step 2: Add up watts and hours

Multiply each device’s watts by the hours you want it to run, then add them. For example, a router (15 W) for 8 hours is 120 Wh, a laptop (60 W) for 4 hours is 240 Wh and three LED lights (30 W total) for 5 hours is 150 Wh. That is 510 Wh.

Step 3: Add a safety margin

Power stations lose some energy converting battery power to AC, so you never get 100% of the rated capacity. A common rule is to assume around 80-85% is usable and then add a little extra for cold weather and battery aging. In the example above, 510 Wh needs roughly a 700-800 Wh unit.

Step 4: Check the output rating

Capacity tells you how long. Output tells you what you can run at the same time. Add the running watts of everything you will use together and make sure the power station’s continuous output is higher. Devices with motors, such as refrigerators and pumps, need extra power for a moment at start-up, so check the surge (peak) rating as well.

Rough size guide

Capacity	Good for
Under 300 Wh	Phones, lights, a router, a laptop for a short time
500-800 Wh	Weekend camping, small appliances, a mini fridge
1,000-1,500 Wh	Home essentials for a short outage: router, lights, devices, a fridge for some hours
2,000-3,000 Wh	Longer outages, RVs, vans, job sites
3,000 Wh and up	Expandable home backup for several essentials

Other things to check

• Ports: enough AC outlets, USB-C power delivery and a car (12V) port for your devices.
• Recharge options: wall, car and solar input. See our guide on how many solar panels you need.
• Weight and size: larger units are heavy and are usually moved on wheels.

Use our runtime calculator to turn watts and capacity into hours.

Worked examples

Example 1: Weekend camping

A small family wants to charge four phones, run LED lights for five hours and a mini fridge for a weekend. Phones: 4 x 15 Wh = 60 Wh per day. Lights: 20 W x 5 h = 100 Wh per day. A mini fridge cycling at about 70 W for roughly half the day uses around 400 Wh per day. That is about 560 Wh per day, or roughly 1,100 Wh for two days. With losses, a 1,000-1,500 Wh unit, or a 500 Wh unit plus a solar panel, would suit.

Example 2: Short home outage

For a router (15 W), a laptop (60 W), two lamps (20 W) and phone charging (30 W) over eight evening hours, the load is about 125 W. Eight hours gives 1,000 Wh before losses. A 1,000-1,500 Wh unit covers it with margin. Adding a full-size refrigerator raises the energy need a lot, so you would look at 2,000 Wh or more.

Example 3: Work from home

A laptop (60 W), monitor (30 W) and router (15 W) draw about 105 W. A 500 Wh unit gives roughly four hours; a 1,000 Wh unit gives eight or more.

Common sizing mistakes

• Ignoring surge power. A compressor or pump can need several times its running watts for a moment.
• Forgetting efficiency. Not all of the rated watt-hours reach your devices.
• Planning to run heating or cooling. Space heaters, ovens and central air conditioners use far more than a portable unit can supply for long.
• Buying only on capacity. Check output watts, port types and recharge options too.

Frequently asked questions

Is a bigger power station always better?

Not always. Larger units cost more, weigh more and are slower to recharge from solar. Pick the size that covers your actual needs plus a margin.

What is the difference between watts and watt-hours?

Watts measure how much power a device uses at a moment. Watt-hours measure energy over time, like the size of a fuel tank. A 1,000 Wh battery can supply 100 W for about 10 hours before losses.

Can I run a refrigerator?

Often yes, if the output and surge rating are high enough. See can a power station run a refrigerator.

About the author