How to Charge Your Phone During a UK Power Cut — Full Guide

Your Phone Is Your Lifeline

During a power cut, your phone becomes the single most important device in your home. It's your communication, your news source, your torch, your entertainment, and your connection to emergency services.

The problem? Most phone batteries barely last a full day under normal use. During a power cut — when you're using it more than usual — it can die in hours.

Here's how to keep it charged and make the charge last.

Power Banks: The Essential Investment

If you take one thing from this article, let it be this: buy a power bank.

What to Look For

• Capacity: Measured in mAh (milliamp hours). A 10,000mAh bank charges most phones 2–3 times. A 20,000mAh bank gives you 4–5 full charges
• Output: Look for at least 18W output for reasonably fast charging. USB-C PD (Power Delivery) is fastest
• Size: Bigger capacity = bigger and heavier. A 10,000mAh bank is pocket-sized. A 20,000mAh is bag-sized
• Quality: Stick to reputable brands. Cheap unbranded power banks can be poorly made and in rare cases a fire risk

How Many Do You Need?

One per person is ideal. At minimum, one per household. Keep them charged — set a monthly reminder to top them up.

Keeping Your Power Bank Ready

The biggest mistake people make with power banks is letting them sit uncharged in a drawer. A power bank slowly loses charge over time, even when not in use.

• Charge to 80% and store (better for long-term battery health)
• Top up every 1–2 months
• Keep the charging cable with the power bank
• Store at room temperature

Car Charging

If you have a car, you have a backup power source that most people forget about.

What You Need

• A car phone charger (USB-C or USB-A, depending on your car's ports)
• Most modern cars have USB ports that charge slowly — a dedicated 12V socket charger is faster
• A good car charger with Quick Charge or USB-C PD costs about £10–£15

How to Use It

• Start your car engine (don't just use the ignition — the battery will drain)
• Plug in your phone
• Run the engine for 20–30 minutes to get a decent charge
• You can charge multiple devices if your charger has multiple ports

Important Notes

• Never run your car engine in a closed garage — carbon monoxide risk
• Keep fuel in mind — if you're charging regularly, you're using fuel
• This works even if your house has no power at all

Solar Chargers

Solar chargers are useful for extended outages, but let's be realistic about British weather.

What to Expect

• In summer, a good solar panel can charge a phone in 3–5 hours of direct sunlight
• In winter, you're looking at much longer — possibly all day for a partial charge
• Cloudy days significantly reduce output
• They work, but they're a supplement, not a primary solution in the UK

What to Look For

• At least 20W output for phone charging
• Foldable panels are more practical for storage
• Some combine a solar panel with a built-in power bank — useful but slower to charge
• Waterproof/weather-resistant is important

Best Approach

Use solar to keep your power bank topped up during the day, then charge your phone from the power bank as needed. This is more efficient than charging your phone directly from a solar panel.

For a deeper dive into portable solar charging — including panel wattage, real-world UK output, and camping setups — see our sister site INeedSolar.

Battery-Saving Tips During a Power Cut

Preserving your phone's battery is just as important as having a way to charge it.

Immediate Steps

1. Turn on Low Power Mode — Both iPhone and Android have this. It reduces background activity and extends battery significantly
2. Reduce screen brightness — Turn it down as low as you can comfortably read
3. Turn off Wi-Fi — There's no internet anyway if your router has no power
4. Turn off Bluetooth — Unless you're using it for something specific
5. Turn off location services — A significant battery drain
6. Close background apps — Especially anything that refreshes constantly (social media, email)

If You Need to Conserve Heavily

• Aeroplane mode — Turns off all wireless connections. You can still use the phone as a torch, alarm, or to read offline content. Turn it off briefly to check for messages
• Turn off the phone entirely — If you don't need it for several hours, switch it off. A phone that's off uses almost no battery
• Limit screen time — Every minute the screen is on drains battery. Read a book instead

What Drains Battery Fastest

Knowing what kills your battery helps you avoid it:

• Screen brightness (biggest drain)
• Video streaming or gaming
• GPS and navigation
• Searching for signal in low-coverage areas
• Camera use (especially video)
• Keeping the screen on

Portable Power Stations

If you want to go beyond phone charging, portable power stations can run small appliances:

• They're essentially large rechargeable batteries (200Wh to 2000Wh+)
• Can power phones, laptops, LED lights, small fans, CPAP machines, and more
• Range from about £100 for a basic unit to £1,000+ for larger ones
• Charge from mains, car, or solar panels
• Heavier and more expensive than power banks but far more versatile

These are worth considering if anyone in your household depends on powered medical equipment, or if you live somewhere with frequent long outages.

Your Phone Charging Emergency Kit

Total essential kit: about £35–£55. That's your phone sorted for any power cut.

The Monthly Routine

1. Check your power bank charge level — top it up if below 50%
2. Make sure the cable is still stored with it
3. Check your car charger is still in the car
4. Keep your phone battery above 50% as a general habit (you never know when a power cut will hit)

Your phone is too important to let it die during an emergency. A power bank and a car charger — that's all it takes.