Travel gadgets such as phones, tablets, laptops, cameras and portable power banks make journeys more comfortable and connected, but they all share one thing: lithium batteries. When you fly, those batteries are subject to strict safety rules that are designed to prevent fires in the air. Understanding the regulations before you pack can save you from having items confiscated at the checkpoint or, worse, creating a hazard onboard.
Why Lithium Battery Rules Matter for Travel Gadgets
Lithium ion and lithium metal batteries power nearly every portable electronic device people carry. According to the Federal Aviation Administration’s PackSafe guidance, all lithium ion batteries are capable of overheating and entering a process called thermal runaway. This can happen without warning if a battery is damaged, overheated, exposed to water, overcharged, or improperly packed. Manufacturing defects can also trigger it. Because of this risk, aviation authorities worldwide have created detailed rules for how passengers may transport devices and spare batteries.
The FAA notes that flight crews are trained to recognize and respond to lithium battery fires in the cabin. Passengers should notify a crew member immediately if their lithium battery or device is overheating, expanding, smoking or burning. Knowing the rules helps you avoid becoming the cause of an in-flight emergency.
Spare Batteries and Power Banks: Carry-On Only
One of the most important rules to remember is that spare (uninstalled) lithium ion and lithium metal batteries, including power banks and cell phone battery charging cases, must be carried in carry-on baggage only. The FAA states this clearly, and the Transportation Security Administration echoes the same instruction on its website. When a carry-on bag is checked at the gate or at planeside, all spare lithium batteries and power banks must be removed from the bag and kept with the passenger in the aircraft cabin.
This rule applies to spare batteries for personal electronics such as cameras, cell phones, laptops, tablets, watches and calculators. It also covers external battery chargers, often called portable rechargers or power banks. If the battery is already installed inside a device like a laptop or a camera, different rules may apply, and those devices can sometimes travel in checked baggage, but the TSA advises checking the FAA regulations for portable electronic devices containing batteries. For more on selecting a power bank that meets travel requirements, see our guide to choosing a power bank.
Watt-Hour Limits and Airline Approval
Not all lithium batteries are treated equally. The FAA sets size limits based on the battery’s chemistry and energy rating. Lithium metal (non-rechargeable) batteries are limited to 2 grams of lithium content per battery. Lithium ion (rechargeable) batteries are limited to a rating of 100 watt hours (Wh) per battery. The FAA says these limits allow for nearly all types of lithium batteries used by the average person in their electronic devices.
If you need to travel with a larger lithium ion battery, the FAA permits passengers to carry up to two spare larger lithium ion batteries with a rating exceeding 100 Wh but not more than 160 Wh, provided the airline approves. This size covers some after-market extended-life laptop batteries and certain professional audio/visual equipment batteries. For lithium metal batteries, the higher limit is 2 to 8 grams of lithium content, also with airline approval and a limit of two spare batteries per person.
The TSA’s page on lithium batteries with 100 watt hours or less in a device confirms these same limits. It also notes that the final decision on whether an item is allowed through the checkpoint rests with the TSA officer. Many airlines, both domestic and international, may have stricter quantity and watt-hour limits, including how many power banks each passenger may carry, regardless of capacity. The FAA advises checking with your air carrier for its specific restrictions before traveling.
Newer lithium ion batteries often have the watt-hour rating marked on them. If yours does not, the FAA explains how to calculate it: multiply the battery voltage by the amp hours (Ah). This simple math can help you confirm whether a spare battery falls within the allowed range.
Protecting Battery Terminals from Short Circuits
Even a battery that meets the size limits can become dangerous if its terminals are not protected. The FAA requires that battery terminals be protected from short circuit, meaning they must not come into contact with other metal objects such as keys, coins, or other batteries. A short circuit can generate heat and potentially start a fire.
The FAA lists several acceptable methods for protecting terminals: leaving batteries in their original retail packaging, covering the terminals with tape, using a battery case, using a battery sleeve in a camera bag, or placing them snugly in a plastic bag or protective pouch. Taking a moment to insulate the terminals before you pack is a simple step that makes a real difference.
Damaged or recalled batteries and battery-powered devices that are likely to create sparks or generate a dangerous evolution of heat must not be carried aboard an aircraft at all, unless the damaged or recalled battery has been removed or otherwise made safe. The FAA suggests visiting the Consumer Product Safety Commission, manufacturer, or vendor website for recall information.
Charging Your Travel Gadgets with USB Power Delivery
Once you have the battery rules sorted, the next practical concern is keeping your gadgets charged. Many modern travel gadgets rely on USB for power, and the USB Power Delivery (USB PD) specification has become a common standard. According to the USB Implementers Forum (USB-IF), USB has evolved from a data interface capable of supplying limited power to a primary provider of power with a data interface. Today, many devices charge or get their power from USB.
The USB PD Revision 3.1 specification, announced in 2021, enables delivering up to 240W of power over a full-featured USB Type-C cable and connector. Before this update, USB PD was limited to 100W. The newer specification introduces fixed voltages of 28V, 36V, and 48V, which enable power levels up to 140W, 180W, and 240W respectively. An adjustable voltage supply mode allows the device being powered to request intermediate voltages between 15V and the maximum available fixed voltage of the charger.
USB-IF highlights that power direction is no longer fixed, so the product with the power, whether host or peripheral, can provide the power. This flexibility allows, for example, a monitor connected to wall power to charge a laptop while still displaying. It also means a single USB charger can power multiple devices, each negotiating only the power it needs. For more on safe charging practices, see our phone charger safety basics article.
Confirm with Your Airline Before You Fly
While the FAA and TSA provide the baseline rules, individual airlines can impose stricter policies. The FAA explicitly states that many airlines, both domestic and international, may have tighter quantity and watt-hour limits. Before you pack your travel gadgets, visit your airline’s website or contact them to confirm their current restrictions. This is especially important if you plan to carry multiple power banks or larger batteries that require airline approval.
Staying informed also means checking the condition of your batteries. If a battery looks swollen, dented, or otherwise damaged, leave it at home. The same goes for any device subject to a safety recall. A few minutes of preparation can help you avoid delays at the airport and keep everyone on board safer. For broader guidance on handling portable electronics safely, read our portable electronics safety overview.
Frequently asked questions
Can I put a power bank in my checked luggage?
No. Both the FAA and the TSA require spare lithium batteries and power banks to be carried in carry-on baggage only. If your carry-on bag is gate-checked, you must remove the power bank and keep it with you in the cabin.
What happens if my battery has no watt-hour label?
If the watt-hour rating is not marked on the battery, the FAA advises calculating it by multiplying the battery’s voltage by its amp hours (Ah). This will give you the watt-hour figure to check against the 100 Wh limit for lithium ion batteries.
Do I need airline approval for a 100 Wh battery?
For lithium ion batteries rated at 100 Wh or less, no airline approval is needed under FAA rules. However, if you wish to carry a larger battery (101 to 160 Wh), you must get airline approval and are limited to two spare batteries per person. Always verify with your airline, as some may have stricter policies even for batteries under 100 Wh.
For more practical advice on choosing and using gadgets on the go, visit our travel gadgets category page.
