What can a portable power station run in a power cut?
A portable power station can keep the essentials going through a short power cut: lights, a phone, the broadband router and perhaps a TV or a fridge. It won't run your whole house, and it won't run a lot of heating. The trick is to decide the short list first, then work out the battery that covers it.
Start with the short list
Think about what you would actually miss in the first few hours.
- Lights, so you are not relying on torches.
- Phones, so you can check the outage and stay in touch.
- The router, so the internet stays up if the connection itself still works.
- A fridge or freezer, if the cut will be long enough to worry about food.
- A TV or a laptop, for comfort or work.
A worked example: a four-hour evening cut
| Item | Watts | Hours | Watt-hours |
|---|---|---|---|
| Broadband router | 10 W | 4 | 40 Wh |
| Two LED lamps (10 W each) | 20 W | 4 | 80 Wh |
| TV | 80 W | 3 | 240 Wh |
| Two phones charging (10 W each) | 20 W | 2 | 40 Wh |
| Total | 400 Wh |
Divide by about 0.77 for conversion losses and the part of the battery you can't use, and you get roughly 520 Wh of battery. Add a fridge-freezer averaging about 45 W while it is running (and running roughly a third of the time) and you add around 60 Wh, which takes the total to about 600 Wh. The same method is in the camping guide.
The output needed here is small: the whole list adds up to a few hundred watts, so even a modest unit has enough. Capacity, not output, is what you are buying.
What to leave off
- Kettles, toasters, heaters and hair dryers. They draw 1,000 W or more. Use a gas hob or a flask instead.
- Anything left on standby. Small loads add up over several hours.
A few things to check
- Gas central heating still needs electricity for its pump and controls. The boiler is usually wired in, so don't try to power it from a plug-in unit without advice from a qualified heating engineer or electrician.
- Don't connect a power station to your house wiring or plug it into a socket to feed the house. Plug your devices into the unit directly, using extension leads if needed. Any fixed backup system should be fitted by a qualified electrician.
- Automatic switchover. Some units advertise a UPS or pass-through mode that takes over within milliseconds, useful for a desktop computer or router. The claim varies between models, so check the maker's description.
- Charge it before you need it. A power station sitting at 20% isn't much use. Many makers suggest topping it up every few months.
Longer cuts
For a cut that lasts a day or more, the battery needs to grow with the hours, and a fridge becomes the biggest single load. Solar panels can top the battery up in daylight, but the UK winter gives little. Run your own list through the power sizer with a power cut loaded and change the days to match.
Not sure whether you want a battery or a petrol generator? See power station vs petrol generator.