Power Station Watts vs Wh Explained – Choose the Right Size

When you choose a power station, two numbers tend to get mixed up: watts (W) and watt-hours (Wh). Watts determine whether a device will run; watt-hours determine how long. Once you understand the difference, you can pick the right size first time and avoid buying a unit that is too small or needlessly expensive. Below we explain it with worked examples.

What is a power station and when do you need one?

A power station, also called a portable power station or solar generator, is a portable battery with AC outlets, USB ports and often a 12 V output. You use it during a power cut, at the campsite, in a camper van or at a work site without mains power. It gives you quiet, clean electricity without petrol or cables to the grid.

The strength of a power station is its flexibility: charge it from a wall socket, your car or a solar panel, and take it wherever you need it. You'll find the full range in our Bluetti collection and the wider off-grid power category.

Watts (W) vs watt-hours (Wh): the difference

These two numbers tell you very different things. Don't confuse them, because that is where buying decisions often go wrong.

• Watts (W) is the power output: the maximum load you can connect at the same time. A 1,000 W power station can run devices totalling up to 1,000 W. Connect more and it shuts down.
• Watt-hours (Wh) is the capacity: the total energy it can store. A 1,000 Wh power station delivers roughly 1,000 W for one hour, or 100 W for ten hours.

In short: watts determine whether a device switches on, watt-hours determine how long it keeps running. You need both to make the right choice.

Choosing the right size: worked examples

Work it out in two steps. First add up the power (W) of everything you want to use at the same time; that total must stay below your power station's maximum output. Then work out how many Wh you need for the runtime you want.

A few examples of typical consumption:

• Charging a phone: around 10 to 20 W. A 500 Wh power station can charge your phone dozens of times.
• Laptop: 30 to 65 W. With 500 Wh you can work for a full day.
• Fridge: 100 to 150 W while running, with a peak when the compressor starts. Allow 1,000 to 1,500 Wh per 24 hours.
• Kettle or hair dryer: 1,500 to 2,200 W. For these you need a high-output model, not just a lot of capacity.

Example: if you want to keep your fridge, Wi-Fi and phones running for a day during a power cut, look for a model with generous capacity (around 2,000 Wh, for example) and enough output to handle the fridge's start-up current.

Outputs and charging options

Besides W and Wh, look at the connections. Check the number of 230 V outlets, USB-A and USB-C (Power Delivery) ports, and whether there is a 12 V output for use in a car or camper van. As for charging: mains power is the fastest, but with a solar panel you turn it into a true solar generator that recharges itself outdoors. That's handy during a longer power cut or for off-grid use. Do check the maximum input power so your panel is a good match.

Safety and lifespan

Look at the battery cell type. A portable power station with LiFePO4 cells (lithium iron phosphate) typically lasts 3,000 charge cycles or more and is safer and more stable than older lithium-ion cells. For frequent use, LiFePO4 is the better choice. Use the unit within its specified temperature range and don't charge it in an enclosed, hot space.

Recommended models and advice

For phones, lighting and a laptop at the campsite, a compact model with modest Wh is enough. For emergency power at home with a fridge and internet, choose a larger model with high output and plenty of capacity. If you want to bridge a short mains outage in your meter cupboard or server corner, also take a look at a UPS battery. Not sure which size you need? Send us your list of devices via WhatsApp or get in touch, and we'll work it out together.

Frequently asked questions

How long can a power station run a device?

Divide the capacity (Wh) by the consumption (W) of your device. A 100 W device on a 500 Wh power station runs for roughly five hours, slightly less in practice due to conversion losses. So for a fridge that uses 1,200 Wh per 24 hours, you'll need a model of roughly 1,500 Wh or more.

Can I charge a power station with solar panels?

Yes, most models have a solar input, which turns them into a solar generator. You connect a portable or fixed solar panel and charge without a wall socket. Check your power station's maximum input power so your panel's output matches it and you get the best charging performance.

What exactly do W and Wh mean?

W (watts) is the power output: the maximum you can connect at the same time. Wh (watt-hours) is the capacity: the total amount of energy stored. Watts determine whether a device works, watt-hours determine for how long. To choose the right size, always look at both numbers.

Can a power station run a kettle or hair dryer?

Only if its output (W) is high enough. A kettle or hair dryer draws 1,500 to 2,200 W, so choose a model that delivers that much power, otherwise the unit will shut down. The capacity (Wh) then determines how often or how long you can use such a device.

Is a power station an alternative to a home battery?

For flexible, temporary power, often yes. A power station is portable and ready to use straight away. It is less suitable as a replacement for a fixed home battery that buffers your whole house, because it doesn't connect automatically to your meter cupboard. For emergency power and individual devices, a power station is actually the more practical option.

How much power and capacity do I need?

First add up the power (W) of all devices you'll use at the same time; that total must stay below the power station's maximum. Then decide on the runtime you want in hours to calculate the Wh you need. Still not sure? Send your list of devices via WhatsApp and we'll recommend a suitable model.