The FAA’s lithium battery rules for air travel come down to a few firm principles: spare batteries and power banks must travel in your carry-on, never in checked baggage; batteries installed in a device can be checked only if the device is completely off and protected against activation; and each battery has to stay under a size limit that depends on its chemistry. Consumer lithium-ion batteries up to 100 watt-hours and lithium-metal batteries up to 2 grams of lithium content fly without special permission. Larger sizes need airline approval, and some are prohibited outright.
Where Batteries Can Go: Carry-On vs. Checked
Every spare lithium battery has to be in your carry-on. That includes loose batteries, power banks, portable chargers, and external battery packs. There are no exceptions. The reason is practical: if a battery starts smoking in the cabin, a flight attendant can reach it and douse it, while a fire in an inaccessible cargo compartment is one of the most dangerous scenarios in commercial aviation.1Federal Aviation Administration. PackSafe – Lithium Batteries
Batteries installed inside a device can travel in checked baggage, but the device has to be fully powered off. Sleep mode and hibernation do not count. The device also needs some protection against accidental activation, such as a hard-sided case or padding that keeps switches from being triggered by shifting luggage.2eCFR. 49 CFR 175.10 – Exceptions for Passengers, Crewmembers, and Air Operators
If your carry-on gets gate-checked at the last minute, pull out every spare battery and power bank before you hand the bag over. Those items have to stay with you in the cabin.1Federal Aviation Administration. PackSafe – Lithium Batteries
Size Limits That Apply to Passengers
Federal rules recognize two chemistries with separate limits. Lithium-ion is the rechargeable type in phones, laptops, tablets, cameras, and power banks. Lithium-metal is generally non-rechargeable and appears in watches, some cameras, and certain medical devices.3eCFR. 49 CFR 173.185 – Lithium Cells and Batteries
For lithium-ion, the number to remember is 100 watt-hours. A rechargeable battery rated at 100 Wh or below can fly with you without special permission. Smartphones, standard laptops, tablets, and most cameras sit well below that ceiling. Batteries rated between 101 and 160 Wh need airline approval before you board, and you are limited to two spares in that range, which must go in your carry-on. These larger cells typically power professional video gear, extended-life laptop batteries, and some medical devices. Anything above 160 Wh is prohibited on passenger aircraft.4Federal Aviation Administration. Airline Passengers and Batteries
For lithium-metal batteries, the limit is measured differently: no more than 2 grams of lithium content per battery. Medical devices such as automated external defibrillators and nebulizers may carry lithium-metal batteries up to 8 grams with airline approval, and you can bring up to two spares in the 2-to-8-gram range for the device they power.2eCFR. 49 CFR 175.10 – Exceptions for Passengers, Crewmembers, and Air Operators
How to Calculate Watt-Hours
Most batteries print the watt-hour rating on the label. When they don’t, you can calculate it. If the label shows amp-hours, multiply voltage by amp-hours: a 14.8V battery rated at 6.6 Ah equals 97.7 Wh. If the label shows milliamp-hours, common on phone batteries, multiply voltage by milliamp-hours and divide by 1,000. A 3.7V phone battery rated at 4,000 mAh works out to 14.8 Wh.1Federal Aviation Administration. PackSafe – Lithium Batteries
Protecting Terminals on Spare Batteries
Every spare battery has to have its terminals protected against a short circuit. A short happens when the positive and negative terminals touch metal at the same time, and it can generate enough heat inside your bag to start a fire. The FAA accepts several methods: keep the battery in its original retail packaging, tape over the exposed terminals, slide it into a battery case or sleeve, or put it in its own plastic bag or protective pouch.1Federal Aviation Administration. PackSafe – Lithium Batteries
Products Travelers Frequently Get Wrong
A few product categories trip people up because they aren’t obviously “batteries.”
Power Banks and Portable Chargers
Power banks and external chargers are treated as spare lithium-ion batteries. Carry-on only, terminals protected, and the same 100 Wh limit without airline approval. High-capacity models sold for charging laptops can push past 100 Wh, so read the label before packing. Batteries carried for resale or distribution are prohibited entirely.1Federal Aviation Administration. PackSafe – Lithium Batteries
E-Cigarettes and Vaping Devices
E-cigarettes and vapes must travel in your carry-on or on your person. Checked baggage is prohibited because the heating element can activate accidentally and ignite the liquid inside. The FAA recommends removing the battery, separating the battery from the heating coil, or using a case that covers the activation button.5Federal Aviation Administration. PackSafe – Electronic Cigarettes, Vaping Devices
Smart Luggage
Suitcases with built-in lithium batteries for USB ports, GPS tracking, or motorized wheels can fly as carry-on only, unless you remove the battery. Once removed, that battery follows the standard spare-battery rules: cabin only, terminals covered. Smart bags with very small batteries below 2.7 Wh, such as some Bluetooth luggage trackers, are exempt from the removal requirement and can go in the hold as-is.6Federal Aviation Administration. PackSafe – Baggage Equipped with Lithium Batteries
Hoverboards and Personal Electric Vehicles
Self-balancing boards, electric scooters, and similar personal electric vehicles almost always contain lithium-ion batteries above 160 Wh, which puts them past the hard passenger-aircraft limit. Even models with smaller batteries are banned by most major airlines. Don’t plan on bringing one aboard.
Mobility Aids, Oxygen Concentrators, and Other Medical Devices
Batteries for wheelchairs and mobility scooters get more generous limits than consumer electronics. Lithium-ion batteries for these devices can go up to 300 Wh. For spares, you can carry either one at up to 300 Wh or two of up to 160 Wh each, and the spares must stay in the cabin.7Federal Aviation Administration. PackSafe – Wheelchairs and Mobility Devices
If the chair’s design doesn’t adequately protect the battery, it has to come out, travel in your carry-on with terminals covered, and the airline needs to know where it is stored so the pilot can be notified. When the battery is securely enclosed within the chair’s frame and shielded from baggage shifting, it can remain installed during transport in the cargo hold.7Federal Aviation Administration. PackSafe – Wheelchairs and Mobility Devices
Portable oxygen concentrators have their own rule. Airlines can require you to bring enough fully charged batteries to power the device for at least 150% of the scheduled flight time. A four-hour flight means six hours of battery. Each battery has to be clearly marked with its rating.8U.S. Department of Transportation. Portable Oxygen Concentrator
Damaged, Defective, or Recalled Batteries
A damaged, defective, or recalled lithium battery cannot be carried on, checked, or shipped through normal channels. The FAA’s position is blunt: never ship, load, or transport a damaged package containing lithium batteries.9Federal Aviation Administration. Lithium Battery Resources
Signs of trouble include swelling, leaking, unusual odor, or excessive heat during charging. A compromised cell is far more likely to go into thermal runaway, where the reactions inside generate escalating heat, toxic gas, and flames that can overwhelm an aircraft’s fire suppression system. If a device with a damaged battery has to be returned to the manufacturer, the battery must come out first, or the shipment must meet specialized DOT packaging and notification requirements that go beyond what a consumer can do at home.
If a Battery Overheats in Flight
Tell a crew member immediately if a device starts hissing, smoking, or getting unusually hot. Don’t try to handle it yourself. Flight crews are trained to respond to thermal runaway, and the FAA updated its guidance for airlines on this in 2025.10Federal Aviation Administration. SAFO 25002 – Managing the Risks of Lithium Batteries Carried by Passengers and Crewmembers
The Halon extinguishers on aircraft can knock down open flames, but they don’t stop the chemical reaction inside the battery. The primary response is large amounts of water to cool the cell and prevent the reaction from spreading. That process continues until every cell has discharged its energy. This is exactly why spares belong in the cabin: crew have to see the problem, reach it, and douse it before it grows.10Federal Aviation Administration. SAFO 25002 – Managing the Risks of Lithium Batteries Carried by Passengers and Crewmembers
Penalties for Getting It Wrong
For most travelers, the practical consequence of a violation is having a battery confiscated at the security checkpoint or the gate. The formal penalties are heavier. Civil fines for violating federal hazardous materials transportation rules can reach $102,348 per violation, rising to $238,809 if the violation causes death, serious injury, or major property destruction. Each day of an ongoing violation counts as a separate offense.11eCFR. 49 CFR 107.329 – Maximum Penalties
Willful or reckless violations of federal hazardous materials law carry criminal penalties of up to five years in prison, doubling to ten years if the violation leads to death or bodily injury.12Office of the Law Revision Counsel. 49 USC 5124 – Criminal Penalty Those figures generally target shippers and businesses that package or label incorrectly, but deliberately hiding prohibited batteries in checked luggage or misrepresenting what’s in a package can put an individual in the same territory.