Power outage at home: charge your phone and save battery¶

When the lights go out, your phone becomes your lamp, your news source, your clock and your link to family and your utility company. It is also a device that will run out of power in a day or less if you use it as you normally do. A short outage is an inconvenience. A long outage after a storm, a heatwave or a grid failure can last days, and your phone battery is a resource that you have to manage.

This guide explains how to keep your phone alive when the power is off at home. It covers what to do in the first hour, how to stretch a single charge for days, how to charge safely from a car, a power bank, a solar panel or a generator, where to find community charging points, and which mistakes to avoid. It also explains the safety rules that matter most, including carbon monoxide. For general outage safety, read power outage, and for the larger picture, see regional grid collapse and blackout.

Do this now¶

1. Switch your phone to low power mode and dim the screen. Do it before the battery drops, not after. Save the charge for calls, texts and alerts.
2. Check that the outage is not just your home. Look at the breaker panel and at neighbours' windows. Report the outage to your electricity company by their website, text service or phone, if you have signal.
3. Charge every device you can while there is still some power or backup. If the outage is only starting, plug in phones, power banks, torches and radios now.
4. Use a torch, not your phone, for light. A phone flashlight uses a lot of battery. Use a battery torch or a lantern, and keep the phone for communication.
5. Plan how you will charge. The main options are a power bank, a car charger, a solar charger and a community charging point. Pick one and begin.
6. Never run a generator, a grill or a camping stove indoors, in a garage or near a window. These produce carbon monoxide, which cannot be seen or smelled. See the safety section below.

What happens to your phone in a long outage¶

Understanding the limits helps you plan. Your phone does not only need power at home. It also needs the mobile network to work.

• Your battery is finite. A typical phone lasts about a day with normal use. With careful settings it can last two to four days, and longer if you use it only a few minutes a day.
• Mobile towers have backup power, but not forever. Many have batteries or generators that last hours, and some last longer. In a long outage, towers may stop working, so coverage can fade even if your phone is charged.
• Wi-Fi stops. Your home router needs power. Without it, calls over Wi-Fi and home internet will not work, and your phone will rely on mobile data.
• Cordless landline phones stop working. The base station needs mains power. A corded phone often works during an outage, because the line supplies its own power.
• Networks get busy. Many people use their phones at once, so calls may fail while texts get through.
• Cold and heat change battery life. Batteries lose capacity in the cold, and heat can make a phone slow or shut down.

Stretching a single charge for days¶

If you cannot charge your phone, you can still make it last. The key is to treat your battery as a ration.

Set your phone to the lowest useful mode¶

1. Turn on low power or battery saver mode. This limits background activity.
2. Lower the screen brightness to the minimum you can read, and set a short screen timeout of 15 or 30 seconds.
3. Switch off Wi-Fi if your router is off. Searching for a network wastes power.
4. Switch off Bluetooth, hotspot, and NFC unless you need them.
5. Turn off background app refresh, automatic downloads and automatic updates.
6. Switch off location services for apps that do not need it.
7. Turn off push notifications for apps that are not important.
8. Use dark mode if your phone has an OLED display.
9. Close apps that run in the background, especially video, maps and games.
10. Turn off vibration and haptic feedback.
11. Put the phone in airplane mode between checks if you have strong reasons to save power. Turn it off at set times, such as the top of each hour, to receive messages.

Use the phone in short windows¶

Choose set times to check in, for example, 8 in the morning, noon and 6 in the evening. Keep the phone in airplane mode or powered off between them. During each window, send texts, check alerts and your utility's updates, then switch it off again. A phone that is turned off uses almost no power.

Prefer text to calls, and calls to video¶

A text message uses far less energy than a call, and a call uses far less than video. Texts also get through more often when networks are crowded. Keep messages short and clear. Avoid sending photos, videos and large files.

Keep the phone at a good temperature¶

In the cold, keep the phone inside a coat or next to your body. In heat, keep it in the shade and away from direct sun. Do not put a phone in the freezer or near a heater to warm or cool it.

Use other devices for jobs the phone does¶

• Torch or lantern instead of the phone flashlight.
• A battery or hand crank radio for news. See off grid emergency communications.
• A wind up or battery clock instead of the screen.
• A paper notebook for lists and numbers.
• A paper map instead of navigation.
• A corded landline for calls, if you have one.

What long battery life looks like¶

With these steps, a phone that would normally last one day can often be made to last two to four days if you check it only a few times a day. The exact figures depend on the phone, its age and the temperature. Treat these as estimates, and test your own phone before an emergency.

Charging options at home¶

Power banks¶

A power bank is the best home backup. It stores several charges and works anywhere.

• Charge it before the outage. Keep one or two banks full and top them up every few months, since they slowly lose charge.
• Pick the right size. A 10,000 mAh bank gives roughly two phone charges, and 20,000 mAh roughly four. A household may want a larger one, or several.
• Use it wisely. Charge the phone to about 80 percent and stop. Do not leave the phone plugged in at 100 percent for long.
• Share it. In a family, agree who charges first and what the priority is, for example the phone with the best battery life or the one of the person who has a medical need.
• Keep the bank warm. Cold reduces output.
• Do not use a damaged or swollen bank. Stop using it and take it to a recycling point.
• Keep it away from flammable material while charging.

Car charging¶

A car is a convenient power source, but it needs care.

1. Move the car outside. Park it outdoors, in the open, with the exhaust pipe clear of snow, mud and obstructions. Never run the engine inside a garage, even with the door open.
2. Use a 12 volt socket adapter or the car's USB ports. Bring your own cable.
3. Run the engine only while charging. A short run of 20 to 30 minutes is often enough to charge phones. Fuel is precious in an outage, so do not idle for hours.
4. Keep a window slightly open if you sit in the car. Check that the exhaust pipe is not blocked.
5. Check your fuel. Keep your tank at least half full during storm seasons, since petrol stations may be without power.
6. Do not drain the car battery. Charging with the engine off can drain it, and the car may not start. If you need to charge with the engine off, do it for short periods.
7. Be careful in the cold. If you stay in the car for warmth, you risk carbon monoxide poisoning. Read carbon monoxide.
8. Hybrid and electric cars may charge a phone through a socket or USB port, but check the manual. Using an electric car to charge a phone uses a small amount of its range.

Solar chargers¶

A small solar panel can give a trickle charge in daylight.

• Choose a foldable panel designed for phones, rated at about 10 watts or more.
• Place it in direct sun, and angle it toward the sun.
• Charge a power bank with it, rather than charging the phone directly, because the bank smooths out the cloud and shade.
• Expect a slow charge, and do not rely on it in heavy cloud or winter.
• Keep it clean and dry.

Hand crank chargers and radios¶

A hand crank radio with a USB port can give a small emergency charge. A minute of cranking gives only a few minutes of phone use, so treat it as a last resort for a short call or a text. Its main value is the radio, which can give news and alerts when the network is down.

Generators and portable power stations¶

A portable generator can charge many devices, but it carries serious risks.

• Place the generator outdoors, at least 6 meters (20 feet) from the house, doors, windows and vents, with the exhaust pointing away. Do not run it in a garage, a basement, a shed or on a porch.
• Install battery operated or plug in carbon monoxide alarms with battery backup in the home.
• Refuel only when the generator is cool and switched off. Store fuel outside, away from living areas.
• Never connect a generator to a house outlet or wiring without a proper transfer switch installed by a qualified electrician. Back feeding can kill utility workers and neighbours.
• Use heavy duty outdoor extension cords rated for the load.
• Keep it dry. Use a canopy or cover, not a closed box.

A portable power station, which is a large battery with sockets and USB ports, is a safer indoor alternative, since it has no exhaust. Charge it before storm season and top it up every few months. Read generator safety and carbon monoxide and generator safety before you use a generator.

Laptops and other batteries¶

A laptop battery can charge a phone through a USB port, but it drains the laptop quickly. Use it only when the phone is nearly flat and the laptop is charged. Camping lamps and some battery packs also have USB sockets.

Table: charging options compared¶

Community charging points¶

When the outage lasts many hours or days, local authorities and community groups often set up places to charge phones. These may be open for a few hours a day.

Where to look¶

• Emergency shelters and relief centres. Many have charging stations, power strips and information desks.
• Libraries and community centres. They may have a backup generator, or they may be in an area with power.
• Town halls and civic buildings.
• Fire stations and police stations, in some areas. Check your local policy before you go, as staff are busy with emergencies.
• Schools, churches and other places of worship that open to the community.
• Shops, malls and cafes in areas where the power is on. Politely ask, and consider buying something small.
• Hospitals, only for medical needs, not for charging.
• Mobile charging trucks or trailers set up by utilities, charities or local government after major storms.
• Neighbours with a generator, solar or power in the next street. Ask kindly, and offer to bring your own cable and a thank you.
• Your workplace, if power is on there.

How to find them¶

• Check your local government or utility website and social media accounts, when you have signal. Many publish lists after a major event.
• Listen to a battery radio for announcements.
• Look for signs and volunteers, and ask a neighbour.
• Call your local non emergency information line, if available, not the emergency number.
• Dial the local information service, for example 211 in parts of the United States and Canada, where it exists. Check that it applies in your area.

Using a community point safely¶

1. Bring your own cable, wall adapter and power bank. Do not use shared or unknown cables.
2. Do not use unknown public USB ports without protection. See public charging kiosks and data blockers.
3. Label your cable and charger, so they do not get mixed up.
4. Stay with your device, or use a locker if provided.
5. Be patient and share. Charge to about 50 to 80 percent, and let others have a turn.
6. Go with a buddy, and follow the instructions of staff and volunteers.
7. Check road and travel conditions first. Do not drive through floodwater or past downed power lines. See downed power lines and vehicle electrocution.
8. Take a power bank to charge while you wait, then charge at home.

Decision guide¶

flowchart TD
    A["Power goes out at home"] --> B["Switch phone to low power mode and dim screen"]
    B --> C["Report the outage and check alerts"]
    C --> D{"Do you have a charged power bank?"}
    D -- "Yes" --> E["Charge the phone to about 80 percent and save the bank"]
    D -- "No" --> F{"Is a car with fuel available?"}
    F -- "Yes" --> G["Park outdoors and charge for 20 to 30 minutes with the engine on"]
    F -- "No" --> H["Go to a community charging point or ask a neighbour"]
    E --> I["Use the phone in short check in windows"]
    G --> I
    H --> I
    I --> J{"Is anyone in danger or in need of medical power?"}
    J -- "Yes" --> K["Call your local emergency number"]
    J -- "No" --> L["Keep conserving and wait for restoration"]

Staying informed without wasting battery¶

In an outage, information is as important as light. You want to know when power will return, what hazards exist and where to find help.

• Use a battery or hand crank radio. It uses very little energy and does not need the network. Tune to local news, or to national weather radio where it exists, such as NOAA Weather Radio in the United States.
• Use emergency alerts. Wireless emergency alerts are sent to phones in the area without a subscription, and they use little power.
• Check the utility's website or text service in your check in windows, not all day.
• Ask neighbours. Many neighbourhood groups share news door to door.
• Do not scroll social media. It drains battery and spreads rumours.
• Download news and maps ahead of time if you know a storm is coming.

Staying safe in an outage¶

Carbon monoxide¶

Carbon monoxide is the main danger of the improvised power and heat that people use in outages. It is colourless and odourless, and it can kill in minutes at high levels.

• Never run a generator, car, grill, camping stove or heater in a garage, a basement, a shed or any enclosed space.
• Do not use a gas oven or stove to heat a home.
• Place a generator at least 6 meters (20 feet) from the house.
• Install carbon monoxide alarms with battery backup, and test them.
• Know the signs: headache, dizziness, nausea, confusion, and tiredness. If anyone shows signs, get into fresh air and call your local emergency number. See carbon monoxide and smoke inhalation first aid.

Fire from candles¶

Candles are a leading cause of home fires in outages. Use battery torches and lanterns instead where you can. If you must use candles, keep them in sturdy holders on a flat surface, away from curtains and children and pets, and never leave them burning when you sleep.

Food and medicine¶

A closed refrigerator keeps food cold for about 4 hours, and a full freezer for about 48 hours, or 24 hours if half full, according to US food safety guidance. Keep doors shut. If you have refrigerated medicine, such as insulin, ask your pharmacist or doctor how to keep it safe.

Medical devices¶

If someone relies on an oxygen concentrator, a ventilator, a CPAP or other powered equipment, plan ahead. Contact your electricity company about priority restoration, keep backup batteries, and know when to go to a hospital or shelter. Read power outage for oxygen concentrators, ventilators and CPAP.

Heat and cold¶

In a heatwave, a power cut means no fans or cooling. Go to a cooler public place if possible, drink water, and read extreme heat. In winter, dress in layers, close off a room, and read winter storms.

Downed power lines¶

Treat every fallen line as live. Stay at least 10 meters (33 feet) away, and warn others. Report it to the utility and call your local emergency number.

Prepare before the outage¶

Preparation is cheap. If you do these things in calm weather, an outage becomes a manageable nuisance.

1. Buy at least one power bank, preferably two, and keep them full. Check them every three months.
2. Keep a car charger and a cable in each vehicle, and keep the fuel tank at least half full in storm season.
3. Keep a battery or hand crank radio and spare batteries.
4. Store battery torches or lanterns where you can find them in the dark.
5. Consider a solar charger or a portable power station.
6. Keep a corded landline phone if you rely on a landline.
7. Keep a paper list of key phone numbers and a notebook. See emergency contact card generator.
8. Install carbon monoxide alarms and smoke alarms with battery backup.
9. Save your electricity company's outage number and website on paper as well as in your phone.
10. Know where community charging points and shelters are in your area.
11. Agree a family plan. Decide who will be contacted, how to check in and where to meet. See phone dead during a disaster or evacuation.
12. Charge everything when a storm warning is issued.
13. Download maps, news and entertainment for offline use.
14. Set up a low power routine and practise it once.
15. Put together an emergency kit. Read emergency kit.

A day by day plan for a long outage¶

A simple plan keeps everyone calm and the battery alive. Adjust it to your household and your devices.

Day one¶

Switch every phone to low power mode, and charge power banks and radios while you still have some power. Report the outage, then check on neighbours who may need help, particularly older people and anyone who uses powered medical equipment. Use text for contact, and agree on set check in times. Keep the car tank above half full, and park the car where you can reach it safely.

Day two¶

Review your battery levels, and decide who needs power first. Use the car for a short charging run outside, or go to a community charging point. Keep the phone off between check in windows. Listen to the radio for restoration estimates and news about shelters.

Day three and beyond¶

If the outage continues, plan around the long term. Think about whether it is safer to stay or move to a shelter, a relative or a hotel with power. Keep food and water safe, and keep warm or cool as the weather requires. Charge a power bank each time you have access to power, and keep one full for emergencies.

What to do when power returns¶

Restoration can be sudden, and it can come with surges. Take a few minutes to protect your equipment and reset your plan.

1. Switch off or unplug sensitive electronics before the power returns, if you can. Leave one light on to know when it is back.
2. Wait a few minutes after the power returns before you plug equipment back in, as surges are common.
3. Charge every phone, power bank and radio first. You may lose power again.
4. Check food in the fridge and freezer, and throw away items that were above safe temperatures for too long.
5. Reset clocks, routers and smoke alarms.
6. Replace used batteries and refill your fuel.
7. Note what worked and what did not, and improve your plan.
8. Thank the people who helped, and share any spare supplies.

Common mistakes to avoid¶

• Using the phone flashlight for hours. Use a proper torch.
• Leaving the phone on full brightness and Wi-Fi searching.
• Waiting until the battery is at 10 percent to save power.
• Idling the car for hours. It wastes fuel and risks carbon monoxide.
• Charging in a closed garage.
• Running a generator near a window or door.
• Back feeding a generator into the house.
• Calling when a text would do.
• Using the emergency number for non emergencies, such as asking when power will return.
• Sharing unverified rumours.
• Using damaged cables and power banks.
• Leaving candles burning unattended.

Key points to remember¶

• Switch to low power mode early, and use a torch instead of the phone flashlight.
• Texts use less power than calls, and calls use less than video.
• A power bank is the best home backup, so keep one or two full.
• Charge in a car only outdoors, with the engine on for short runs.
• Place generators at least 6 meters (20 feet) from the house, and never indoors.
• Community charging points open after long outages, so bring your own cable.
• Check your phone at set times, and keep it off or in airplane mode between them.
• Look after neighbours who may need help, and keep medical equipment powered first.

Sources checked¶

• Ready.gov and the Federal Emergency Management Agency (FEMA, United States): power outage guidance, including keeping phones and power banks charged and using text messages.
• Centers for Disease Control and Prevention (CDC, United States): carbon monoxide poisoning prevention during power outages, including generator placement.
• US Department of Agriculture Food Safety and Inspection Service: refrigerator and freezer times during a power outage.
• Federal Communications Commission (FCC, United States) and Ofcom (United Kingdom): information on phone networks, emergency calls and backup power for cell sites.
• Red Cross: power outage safety and preparing a family communication plan.

Always follow the advice of your own national and local authorities.

Frequently asked questions¶

How long can I make my phone battery last in a power outage?¶

With low power mode, a dim screen, Wi-Fi and background activity off, and checking the phone only a few times a day, many phones can last two to four days. Turning the phone off or using airplane mode between check in windows stretches it more. Results depend on the phone, its age and the temperature.

Is it safe to charge my phone in the car during a blackout?¶

Yes, if the car is outdoors in the open, with the exhaust pipe clear. Never run the engine in a garage or enclosed space, because of carbon monoxide. Charge for short periods of 20 to 30 minutes with the engine on, and watch your fuel level.

Where can I charge my phone if the whole area has no power?¶

Look for community charging points at emergency shelters, libraries, community centres and relief trucks set up after major events. You can also ask a neighbour or a business in an area with power. Bring your own cable and adapter, and keep the use short so that others can charge too.

Should I use my phone as a flashlight during an outage?¶

Only briefly. A phone flashlight uses a lot of battery, and you need that power for calls, texts and alerts. Use a battery torch or a lantern for light, and keep a few spare batteries.

Related guides¶

• Power outage
• Generator safety and carbon monoxide
• Phone dead during a disaster or evacuation
• Regional grid collapse and blackout
• Emergency kit