Portable Power Stations Explained: What Can They Power During a Power Cut?

A portable power station is essentially a large rechargeable battery with built-in electrical sockets and charging ports.

Unlike traditional petrol or diesel generators, power stations store electricity rather than generating it by burning fuel. They operate quietly, produce no exhaust fumes during use and can be used indoors.

Most power stations can be charged from a normal household socket. Many can also be recharged using compatible solar panels, which could be particularly useful during an extended power cut.

Depending on their size, power stations can operate everything from mobile phones and laptops to fridges and some high-powered household appliances.

However, there are two important figures you need to understand before purchasing one.

Watt-hours tell you how much electricity a power station can store.

For example, a 500Wh power station stores 500 watt-hours of energy, while a 2,000Wh model stores four times as much.

To understand what this means, imagine you have an appliance that continuously consumes 50 watts.

In theory, a 500Wh power station could operate it for 10 hours:

500Wh ÷ 50W = 10 hours

However, some electricity is lost when converting the energy stored in the battery into electricity suitable for household appliances.

For the calculations in this article, I will assume approximately 85% of the battery capacity is usable.

This means a 500Wh power station would provide approximately 425Wh of usable electricity, allowing our 50W appliance to operate for around 8.5 hours.

Actual efficiency varies between models.

While watt-hours tell you how much electricity a power station stores, watts tell you how much power an appliance consumes and how much a power station can deliver at once.

For example, imagine two power stations that both have a 1,000Wh battery.

One has a maximum output of 500W, while the other has an output of 1,800W.

Although both store the same amount of electricity, the second can operate much more powerful appliances.

A 1,500W appliance would exceed the output limit of the first power station but could potentially operate using the second.

This is particularly important for appliances such as kettles, microwaves and electric heaters, which can consume considerable amounts of electricity.

Some appliances, including fridges, also briefly require additional power when starting. This is known as surge power.

When choosing a power station, you need to consider both its battery capacity (Wh) and its maximum output (W).

Many modern portable power stations use lithium iron phosphate (LiFePO4) batteries, which offer several advantages over the lithium-ion battery types commonly found in smaller USB power banks.

The main advantages are longer lifespan and improved safety. Many LiFePO4 batteries can withstand around 3,000 charging cycles before their capacity falls to approximately 80%. They are also more thermally stable, reducing the risk of overheating.

The main disadvantage is that LiFePO4 batteries can be heavier than other lithium-ion batteries with the same capacity. However, for a power station primarily intended for home emergency use, I believe their durability and improved thermal stability make them the better choice.

The following table demonstrates approximately how long different appliances could operate using power stations ranging from 300Wh to 2,000Wh.

These calculations assume 85% usable battery capacity and that only one appliance is being powered at a time.

Important: These are illustrative estimates, not guaranteed running times. Actual electricity consumption varies between appliances, and power stations differ in efficiency.

The fridge calculations assume an average consumption of 40W over time. Fridges cycle on and off, so actual running times depend on the model and operating conditions. The power station must also be capable of handling the fridge's initial power surge.

The phone charging figures represent continuous charging at 15W, not the number of full phone charges.

You should also remember that connecting several appliances simultaneously will reduce the available running time.

Portable power stations are particularly useful for low-energy equipment such as lighting, phones, laptops and internet routers.

However, appliances that produce heat often consume considerably more electricity.

For example, a typical UK kettle might use 2,000–3,000W, while an electric heater could consume 1,000–2,000W.

One alternative worth considering is a lower-powered travel kettle. Some travel kettles consume approximately 1,200W, making them suitable for power stations with a continuous output of at least 1,200W. Although they generally take longer to boil water than a standard kettle, they could provide a practical option during a power cut.

Even a large 2,000Wh power station would only operate a 2,000W heater for approximately 51 minutes, assuming it had sufficient output capacity.

For this reason, I would generally prioritise using stored electricity for essential equipment rather than heating or cooking.

You can read about alternative cooking arrangements in my article How to Cook in an Emergency Situation.

Most portable power stations offer several charging options:

• Household socket: Usually the simplest and quickest option, although this will not be available during a power cut.
• Solar panels: Many models support solar charging, allowing you to replenish the battery using sunlight. However, charging performance depends heavily on weather conditions, particularly during UK winters.
• Vehicle charging: Some power stations can be charged from a vehicle's 12V socket, although this is often relatively slow.

Solar charging is particularly interesting for emergency preparedness because it could allow you to generate additional electricity during a prolonged power cut.

I will explore solar panels for power stations in a future article.

I believe a portable power station can be a valuable addition to a household emergency kit, particularly if you want to keep essential electrical equipment operating during a power cut.

However, they are not necessarily a priority for everyone.

If you simply want to keep your phone charged, a much cheaper USB power bank may be sufficient.

For households wanting to operate lighting, communications equipment, laptops or refrigeration, a larger power station could be worth considering.

Before buying one, I would recommend identifying which appliances you want to power, checking their electricity consumption and deciding how long you would need them to operate.

Remember the two most important figures:

Watt-hours (Wh) determine approximately how long your appliances can operate.

Watts (W) determine which appliances the power station is capable of running.

In my next article, I will compare recommended portable power stations for emergency preparedness, looking at different battery capacities and price ranges to help you choose a suitable model for your household.