The short answer
Charge phones and compatible portable batteries before an expected outage, keep each battery with the cable it needs, and choose at least one phone to remain powered on for alerts and essential communication. During the outage, lower screen brightness, use low-power settings, limit streaming and large downloads, and preserve the selected alert phone's cellular connection when service is available.
Start here
- Charge the phones and portable batteries the household already uses.
- Pair every battery with a compatible cable and charger.
- Choose one phone to remain available for alerts and essential communication.
- Save essential contacts and instructions where they can be opened offline.
Before an expected outage
- List the phones, portable batteries, radios, accessibility devices, cables, and adapters the household depends on.
- Stop using any battery that is swollen, cracked, leaking, unusually hot, discolored, producing an odor, or making unusual noises.
- Charge with the manufacturer-provided or manufacturer-approved equipment. A connector that fits does not establish compatibility.
- Turn on appropriate low-power settings and learn how to reduce screen brightness and background activity.
- Choose the alert phone and confirm that emergency alerts are enabled.
Preserve the alert path
Keep the selected alert phone powered on and connected to cellular service when it is available. Airplane mode saves power by turning off radios, which also prevents cellular calls, texts, and Wireless Emergency Alerts until it is switched off.
A spare phone that is not carrying the household's alert role may use airplane mode during a known service failure, with planned times to reconnect. Do not apply that tactic to every device by default.
- Lower screen brightness and use low-power mode.
- Close or restrict nonessential background activity.
- Avoid streaming, large downloads, games, and prolonged flashlight use.
- Use brief text messages for non-emergency check-ins when networks are congested.
- Use portable batteries in a planned order and preserve power for alerts and accessibility communication.
If you charge from a vehicle
Wait until the immediate outdoor hazard has passed. Move the vehicle completely outside before running its engine. Never idle it in a garage, carport, or other enclosed or partly enclosed space, even with a door open.
Keep the vehicle stationary while connecting and using the phone unless a passenger can manage it safely. Do not enter floodwater, fire conditions, debris, or another unsafe area merely to reach the vehicle.
Know when a battery is no longer safe to use
- Do not charge a wet or damaged device.
- Keep rechargeable devices out of direct sunlight and hot vehicles.
- Stop using a battery that changes shape or color, leaks, smells unusual, makes unusual noises, or becomes unusually hot.
- If a battery emits smoke, gas, sparks, or flame, move away, call 911, and follow the dispatcher's instructions.
- Follow local instructions for battery recycling or disposal. Do not place lithium-ion batteries in household trash or curbside recycling.
What changes this answer
General guidance becomes a personal decision through these details.
Alerts, calls, accessibility communication, home access, and caregiving should be ranked before optional use.
Battery age, condition, compatibility, capacity, and cables determine what charging is actually available.
A charged phone is not proof that cellular or internet service is working.
Heat and cold affect battery performance and safe charging. Follow the device's allowed range.
Where this guidance stops
- A portable phone battery is not a backup-power plan for medical equipment.
- Phone settings, satellite features, and emergency-alert behavior vary by device, carrier, and software version.
- No marketing capacity can promise a fixed number of charges under every condition.
Sources
Consequential guidance is checked against the linked source material.
- Federal Emergency Management Agency. Ready.gov. Alternative phone-charging guidance. Checked September 13, 2026.
- Federal Communications Commission and Federal Emergency Management Agency. Tips for Communicating During an Emergency. Battery conservation, texts, network use, and vehicle charging. Checked September 13, 2026.
- U.S. Fire Administration. Battery Fire Safety. Charging, damage, heat, and disposal guidance. Checked September 13, 2026.
- U.S. Consumer Product Safety Commission. Batteries, Fire (High-Energy Density). High-energy battery safety. Checked September 13, 2026.
General information, not advice tailored to you or a guarantee of safety. You are responsible for decisions about your safety. Follow current directions from local authorities. Read the safety disclaimer.