Car phone charger and power bank: keep your phone alive long enough to call for help
Pick a tested power bank, store it safely and stretch your battery while you wait
Safety Behind the Wheel Foundation built this guide from National Highway Traffic Safety Administration (NHTSA) kit guidance and data, Occupational Safety and Health Administration (OSHA) battery safety guidance, the Centers for Disease Control and Prevention (CDC), federal motor carrier rules and national emergency calling guidance. Every source is listed at the end.
Why a charged phone matters when you are stuck
A breakdown, a collision or a closed highway can turn a short drive into a long wait. Your phone is usually how you reach help, tell family where you are and learn when the road will open. NHTSA ranks the phone first on its roadside kit list because it lets you call for help wherever you are [1].
The weak point is power. Maps, music and calls drain a phone fast on a long drive. That is why NHTSA lists a charger right next to the phone [1, 2]. The CDC’s winter car kit also adds a portable charger and extra batteries [3].
Help can also be far away. In 2024, 41 percent of traffic deaths in the United States happened in rural areas [7]. That year, 67 percent of drivers killed in rural crashes died at the scene, compared with 50 percent in urban areas [7]. On a quiet road, your phone may be the fastest way anyone learns you need help.
This guide covers the power side of staying connected, for drivers, families, fleets and remote travelers. For what to do at the roadside itself, see our guide to roadside breakdown safety.
What goes in a phone charging kit
Plan for things to fail. If one way of charging breaks, you need another, plus a backup plan if both fail.
A power bank is a portable battery pack. You charge it at home, then use it to charge your phone anywhere, engine on or off. A car charger is an adapter for the car’s 12 volt power outlet, or a cable for a built in USB port.
Comparison compiled by Safety Behind the Wheel Foundation
What goes in a phone charging kit
| Item | What it does | Tip |
|---|---|---|
| Car charger | Charges the phone while the car runs | Some outlets shut off with the ignition |
| Two charging cables | One to use and one spare | Match the plug to each family phone |
| Charged power bank | Charges the phone when the car is off or disabled | Pick one that can fully charge your phone at least twice |
| Wall charger at home | Refills the power bank between trips | Recharge right after each use |
| Written phone list | Lets you call from any phone | Include family and your roadside service |
| Battery powered radio | Brings weather news without using the phone [3] | Pack spare batteries for it [3] |
Keep the kit in one small pouch so it moves easily between cars. Some jump starters have a USB port too, and a separate Drive With Care guide covers them. They help, but they should not be your only phone charger.
How to choose and buy a power bank
Start with your phone. Look up its battery size in the manual or on the maker’s support page. Battery size is usually listed in milliamp hours (mAh), a measure of how much charge a battery holds.
Then pick a power bank rated at two to three times your phone’s mAh number. Some energy is lost as the bank moves power to the phone, so you will get fewer charges than the simple math suggests. Test it at home to learn the real number.
Also check these features:
- Ports. Make sure the bank’s ports fit your cables and your phone’s plug.
- Charge indicator. Lights or a display that show remaining charge help you spot a bank that needs a refill.
- Size. A bank that fits in a console or seat pocket is more likely to stay in the car.
- Safety testing. OSHA advises using lithium batteries and chargers tested to a proper safety standard, such as UL 2054, and certified by a Nationally Recognized Testing Laboratory (NRTL) where that applies [4]. An NRTL is a private lab that OSHA recognizes. Its mark means the lab tested the product and found it meets one or more safety standards [5].
- Temperature range. Find the safe range for use, charging and storage in the instructions.
You can find chargers and power banks at auto parts stores, outdoor and camping stores, electronics stores, phone carrier stores, and safety and medical supply stores. For a replacement charger or battery, OSHA advises choosing one designed and approved for your device and buying it from the device maker or an authorized reseller [4]. A low price does not prove a product is unsafe. But a charger with no testing mark, no maker’s name and no instructions is a poor choice for a safety kit.
Fleets and families can buy one model for every vehicle to keep checks simple. If someone in your family uses a powered medical device, ask the device maker or care team about travel backup power. Do not assume a phone power bank can run it.
Heat, cold and where to store it in the car
A parked car bakes in summer and freezes in winter. Lithium ion batteries, the kind in phones and power banks, do not handle either extreme well.
NHTSA warns that even on a 60 degree day with the windows cracked, a car’s interior can quickly reach deadly heat [1]. OSHA says lithium batteries can be damaged when temperatures get too high, giving above 130°F as an example [4]. Charging one when it, or the air around it, is below freezing can also damage it [4].
That damage matters because of thermal runaway. This is a chain reaction in which one failing battery cell heats the cells next to it. It can end in smoke, fire or an explosion [4].
Follow the temperature limits in your power bank’s instructions, and build these habits:
- Never leave a power bank or phone on the dashboard or a seat in direct sun.
- Store the kit in a shaded, closed spot, such as a console or under a seat, away from heater vents.
- In heat waves or deep cold, bring the bank inside when you park for hours. Keep it with your keys so it goes back in the car.
- On cold trips, carry the bank in an inside coat pocket, and let it warm up before you recharge it.
- Keep the kit dry. OSHA advises keeping lithium batteries somewhere cool and dry [4]. Safety Behind the Wheel Foundation gives drivers the same advice.
Charging on the road without adding distraction
A charging cable can pull your eyes and hands off the road. Drivers fumble for plugs, pick up the phone to check the battery or chase a cable that slid under the seat. In 2024, 3,208 people were killed and 315,167 were injured in crashes involving distracted drivers [6].
Set up charging before you shift out of park:
- Plug in the phone and put it in a mount or a fixed spot before you move.
- Route the cable away from the steering wheel, pedals and gear selector.
- If the cable or phone falls, leave it until you can stop in a safe place.
- Check the battery level at stops, not while driving.
Federal rules for truck and bus drivers show how seriously regulators take reaching. FMCSA counts reaching for a phone in a way that moves the driver out of a seated, belted position as using a hand held phone [8]. These drivers may not use a hand held phone while driving, except when they need to reach police or emergency services [9].
Every driver can use the same rule: set up the phone and cable so you never reach for them while moving. Our guide to phone setup before driving covers driving modes and mount placement.
Make the battery last while you wait
Once you are safely stopped, treat your battery like your water supply. Spend it on what matters most.
- Call for help first, while the battery is strongest. Dial 911 for a car accident, an injury or any danger. Call your roadside service for a simple breakdown.
- Give your location right away: the road, your direction, the nearest exit or mile marker and landmarks. If the call drops, the dispatcher already knows where you are.
- Text one family member your location and plan, and ask them to update others.
- Turn on battery saver mode, dim the screen and close maps, video and games.
- Plug into the power bank before the phone runs very low. Unplug when it is nearly full, and save the rest for later.
- Keep the phone and power bank warm and dry, such as in an inner pocket.
- Use a battery powered radio for weather and traffic news, and save the phone for calls [3].
You can also charge from the car, but only when running the engine is safe. If you are stuck in snow, NHTSA advises clearing the exhaust pipe first [2]. Run it only in short bursts to keep warm, and avoid long runs with the windows up [2]. Common signs of carbon monoxide poisoning include headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion [10]. If anyone has them, turn off the engine, get fresh air if it is safe and call 911.
The CDC also advises keeping your gas tank near full in winter [3]. A fuller tank leaves more fuel for heat and charging if you get stuck.
If the phone dies or has no signal
Plan for the phone to fail anyway. Batteries run out, phones break in collisions, and many roads have dead zones.
- A spare phone. Any wireless phone can call 911, even one without a service plan [11]. But a 911 call from a phone without active service does not send the caller’s location [11]. If you keep an old phone as a backup, keep it charged and be ready to say where you are.
- A written phone list. It lets you call family from another person’s phone.
- Know where you are. Notice mile markers, exits and towns as you drive, so you can describe your location without a map app.
- Text if you cannot talk. The National 911 Program’s advice is to call if you can and text if you cannot [11].
- Plan for dead zones. On remote routes, tell someone your route and arrival time. Our guide to journey management for work drivers explains check ins and satellite options.
Care, checks and warning signs
A power bank only helps if it holds a charge when you need it. Like any rechargeable battery, it holds less as it ages. Set a phone reminder to check the kit each season.
If a power bank shows any of those warning signs, OSHA advises taking it out of use right away and placing it away from anything that can burn [4]. If one gets hot, hisses or smokes while you drive, pull over when it is safe. Get everyone out, and call 911 if there is fire. Do not toss an old power bank in the household trash. Ask your local recycling or household waste program how to drop off lithium batteries.
Tips for families and fleets
For families:
- Give every driver a kit, including teens. Teach new drivers to charge before they leave, not while they drive.
- Save the power bank for phones. Tablets and games can drain it before an emergency.
- Before a road trip, bring the bank inside the night before and charge it fully.
From 2011 to 2022, more than 21,000 U.S. workers died in work related motor vehicle crashes [12]. For fleets:
- Assign a car charger, two cables and a power bank to each vehicle, and add them to the pre trip inspection.
- Choose mounts and cable routes that support hands free rules. Commercial drivers may hold a phone while driving only to reach police or emergency services [9].
- Test power banks on a schedule, and pull any that show damage.
Frequently asked questions
How big a power bank do I need for my car?
Look up your phone’s battery size in milliamp hours (mAh). Then choose a power bank rated at about two to three times that number. That usually allows one or two full charges, because some energy is lost along the way. Go larger if you carry passengers with phones or drive remote roads. Charge your phone from the bank once at home to see what you really get.
Can I leave a power bank in my car all year?
You can keep it in the car most of the time, but extreme heat and cold are hard on it. OSHA says high heat, such as above 130°F, can damage lithium batteries, and recharging below freezing can too [4]. Store it shaded and out of the sun. Bring it inside during heat waves and deep cold, and follow the temperature range in its instructions.
Is it safe to charge my phone from the car with the engine off?
A short top up is usually fine, but the power comes from the car’s battery. A long session with the engine off can leave the car unable to start. That is one reason to carry a power bank. If you run the engine to charge, make sure the exhaust pipe is clear and the car is not in an enclosed space [2].
What should I do if my power bank swells or gets hot?
Stop using it. OSHA advises taking a damaged lithium battery out of service right away and moving it away from anything that can burn [4]. Warning signs include bulging, cracking, hissing, leaking, rising heat and smoke [4]. If it smokes or catches fire in the car, pull over when safe, get everyone out and call 911. Ask your local waste program how to dispose of it.
Do I still need a power bank if my car has USB ports?
Yes. Built in ports only help while the car has power. After a wreck, a dead car battery or a long wait with the engine off, they may not work. A charged power bank keeps working when the car cannot. Think of the car ports as your everyday charger and the power bank as your emergency reserve.
The bottom line
Recommendation from Safety Behind the Wheel Foundation
Safety Behind the Wheel Foundation urges every driver to keep a charged power bank in the car and to call for help before the battery runs low. A phone that dies at the roadside cannot call for help. Carry two ways to charge it: a car charger with good cables, and a power bank you keep charged, tested and out of extreme heat and cold. Choose products tested to a safety standard, and retire any that show damage.
Set up charging before you drive, not while you are moving. If you get stuck, call for help first, give your location early and then save every bit of power you can. A few minutes of care each season keeps that lifeline ready.
Related articles
- Roadside breakdown safety: what to do when your car breaks down
- Phone setup before driving: set it once, then drive distraction free
- Journey management for work drivers: weather, breakdowns and check ins
- Rural road safety: why country roads are deadlier and how to drive them
- Post crash care: what to do in the first minutes after a crash
Sources and further reading
- 1National Highway Traffic Safety Administration. Summer Driving and Road Trip Tips. Accessed October 2026. nhtsa.gov/summer-driving-tips
- 2National Highway Traffic Safety Administration. Winter Weather Driving Tips: Prepare Your Vehicle. Accessed October 2026. nhtsa.gov/winter-driving-tips
- 3Centers for Disease Control and Prevention. Preparing for a Winter Storm. Updated December 2, 2025. cdc.gov/winter-weather/safety/index.html
- 4Occupational Safety and Health Administration. Preventing Fire and/or Explosion Injury from Small and Wearable Lithium Battery Powered Devices (Safety and Health Information Bulletin). Published June 20, 2019. osha.gov/…/shib011819.pdf
- 5Occupational Safety and Health Administration. OSHA’s Nationally Recognized Testing Laboratory (NRTL) Program. Accessed October 2026. osha.gov/…/nationally-recognized-testing-laborato…
- 6National Highway Traffic Safety Administration. Distracted Driving Dangers and Statistics. Accessed October 2026. Data year: 2024. nhtsa.gov/risky-driving/distracted-driving
- 7National Highway Traffic Safety Administration, National Center for Statistics and Analysis. Rural/Urban Traffic Fatalities: 2024 Data (Traffic Safety Facts). Published July 2026. Data year: 2024. crashstats.nhtsa.dot.gov/…/813828
- 8Electronic Code of Federal Regulations. 49 CFR 390.5, Definitions (Federal Motor Carrier Safety Regulations). Up to date as of October 2, 2026. ecfr.gov/…/section-390.5
- 9Electronic Code of Federal Regulations. 49 CFR 392.82, Using a hand-held mobile telephone. Up to date as of October 1, 2026. ecfr.gov/…/section-392.82
- 10Centers for Disease Control and Prevention. Carbon Monoxide Poisoning Basics. Updated January 12, 2026. cdc.gov/carbon-monoxide/about/index.html
- 11National 911 Program (NHTSA Office of EMS). FAQ About Calling 911. Updated March 8, 2023. 911.gov/calling-911/frequently-asked-questions
- 12CDC National Institute for Occupational Safety and Health (NIOSH). Motor Vehicle Safety at Work. Updated May 16, 2024. Data year: 2011 to 2022. cdc.gov/niosh/motor-vehicle/about
This article reflects the safety priorities of roadside emergency readiness and staying able to call for help. It is general safety education, not legal, medical or insurance advice, and it does not endorse any product or seller. Rules change, so verify details with official sources. For your own situation, follow your phone's and power bank's instructions. Ask the maker about product safety, your employer about work rules, and your care team about backup power for any medical device. Reviewed October 2026.
Cite this article: Safety Behind the Wheel Foundation. “Car phone charger and power bank: keep your phone alive long enough to call for help.” drivewithcare.org, https://drivewithcare.org/car-phone-charger-power-bank/. Reviewed October 2026.
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