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When the power fails, switch on your phone’s battery-saving mode, dim and time out the display, shut down radios and background activity you do not need, and reserve the remaining charge for essential texts and calls. Keep a charged USB power bank ready; use a car charger only in safe, well-ventilated conditions.
1. Turn on Battery Saver or Low Power Mode
This is the fastest platform-specific change because it applies several restrictions at once. The exact menu depends on your operating-system version and, for Android, the phone manufacturer.
iPhone
- On iPhone 14 and earlier, open Settings > Battery > Low Power Mode.
- On iPhone 15 and later, open Settings > Battery > Power Mode > Low Power Mode.
Apple’s Low Power Mode reduces background activity, lowers display brightness, limits refresh rate on supported ProMotion devices, and pauses some automatic downloads and mail fetching. It switches off when the phone reaches 80% charge. On supported iPhones with Adaptive Power enabled, Low Power Mode can turn on automatically at 20%.
Android
Open Settings > Battery > Battery Saver. Google says Battery Saver limits or turns off background activity and can delay selected visual effects, features, network connections, and apps. Manufacturer menus and labels can differ, so use the Settings search box if you cannot find the control.
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2. Dim the display and shorten the screen timeout
The screen is a constant, visible source of routine drain. FCC and FEMA guidance specifically recommends reducing brightness, and Android documentation also recommends making the screen turn off sooner.
- Lower brightness to the least level that still lets you read emergency information.
- Set the shortest practical screen timeout or auto-lock period.
- Stop leaving the display on while waiting for messages; wake it only when needed.
These settings work on both iPhone and Android, although the exact control may be under Display, Display & Brightness, or Auto-Lock.
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3. Disable radios and background drains you do not need
Connectivity features can keep searching, syncing, or sharing data even when you are not actively using them. Turn off only the services that are genuinely unnecessary, because emergency calls and alerts may require a network connection.
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1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minute- Airplane mode: Use it when mobile connectivity is not needed. Turn it off before placing an emergency call or when you must receive network-based alerts.
- Wi-Fi and Bluetooth: Disable unused connections so the phone is not repeatedly looking for networks or accessories.
- Hotspot or tethering: Turn it off. Google identifies tethering as a significant battery drain.
- Location and GPS: Avoid prolonged navigation or location-heavy apps unless they are necessary for safety.
- Push notifications and background access: Restrict nonessential apps, particularly social, shopping, video, and cloud-sync services.
Google also warns that streaming, long GPS use, and prolonged navigation consume battery. NYC Health advises turning off unused Wi-Fi or Bluetooth, disabling push notifications and background app access, and using the phone for emergency information.
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4. Reserve the remaining charge for essential communication
Use the phone as an emergency communicator rather than an entertainment device. FCC guidance recommends limiting non-emergency calls, keeping necessary calls brief, and trying text messages. FEMA explains that texts require less bandwidth and may transmit more reliably when networks are crowded. NYC Health’s concise advice is: “Text. Don’t call.”
- Send short texts for status checks and coordination.
- Make calls only when information cannot wait for a text or when someone faces immediate danger.
- Avoid video streaming, gaming, large downloads, social feeds, and media uploads.
- Close apps that are actively using power, unless you need them for emergency information.
FCC and FEMA summarize the approach as reducing screen brightness, using airplane mode, and closing power-hungry apps unless the phone is needed.
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Keep a safe charging backup
FEMA recommends having an emergency charging option for phones and other mobile devices. The U.S. Department of Energy recommends keeping spare batteries and a car charger. For most households, a charged USB power bank is the most broadly useful single backup; a 12V USB car charger is a secondary option if you have access to a vehicle.
What to check when choosing a power bank
- Capacity: A larger capacity generally provides more potential recharges, but adds size and weight.
- Compatibility: Check whether its ports match your phone’s USB-C or USB-A cable.
- Recharge method: Confirm how the bank itself is replenished and keep it charged before an outage.
- Safety certifications: Prefer products with recognized safety certification and protection against overcharge and overheating.
- Practical portability: A smaller bank may be easier to keep with an emergency kit, while a larger one can support more devices.
Official guidance does not establish a universal number of extra hours or a guaranteed percentage improvement for any tweak or power bank. Actual runtime depends on signal strength, temperature, battery health, screen use, and the phone model.
Using a vehicle to charge
If you charge from a running vehicle, FCC, FEMA, and Department of Energy guidance requires outdoor or otherwise well-ventilated conditions. Never run a vehicle in a garage or another enclosed space because exhaust can cause carbon-monoxide poisoning. Move the vehicle outside before charging, once immediate danger has passed.
Quick Recap
A simple outage sequence
- Check for immediate hazards and follow local emergency instructions.
- Enable Low Power Mode or Battery Saver.
- Dim the screen and shorten its timeout.
- Turn off unused Wi-Fi, Bluetooth, hotspot, location services, notifications, and background access.
- Use airplane mode only while you do not need network connectivity.
- Send essential updates by text and keep calls brief.
- Connect a charged USB power bank before the phone reaches a critically low level.
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