TSA, FAA, and IATA rules permit a battery pack in carry-on bags when its watt-hour rating stays under 100 Wh for unlimited use, between 100 and 160 Wh with airline sign-off capped at two per passenger, and never inside checked luggage regardless of size. Spare lithium-ion cells must travel in your cabin, never the cargo hold, because a thermal runaway event at altitude has no quick fix once the aircraft is sealed.
Carry-on only is the rule that protects every flight.
Below, the watt-hour tiers, per-device exceptions, airline-specific quirks, and a packing checklist keep your battery pack in hand luggage from being pulled at the bin.
Why Lithium Batteries Get Special Treatment on Planes
A single 18650 cell holds roughly the same energy as a grenade of black powder, and once it goes into thermal runaway, it generates its own oxygen. Halon fire bottles in the cargo hold cannot smother that reaction. Two cargo-deck fires on widebodies in 2010, one a UPS 747 at Dubai and one an Asiana 747 over the South China Sea, traced back to bulk lithium shipments, not passenger phones.
That history is what forced ICAO’s 2016 Dangerous Goods panel rules: every spare lithium-ion cell on a passenger flight must now ride in the cabin where a flight attendant can see it and drop it into a thermal bag within seconds.
TSA, FAA, IATA, and the Airlines Rarely Agree on Paper
TSA enforces the cabin ban on checked spares. The FAA writes the underlying 49 CFR 175.20 regulations. IATA publishes the Lithium Battery Guidance that most non-US carriers copy. Each US airline then layers its own maximum count, gate-check rules, and in-seat charging policy on top of that federal baseline. When TSA says under 100 Wh is fine and Delta says two packs max in first class, Delta wins on Delta metal.
Knowing which layer applies to your specific ticket saves a confiscated battery at the bin.
Watt-Hours, Not Milliamp-Hours, Became the Universal Yardstick
Milliamp-hours measure charge, not energy. A 5,000 mAh phone bank at 3.7 V delivers 18.5 Wh, while the same 5,000 mAh at 7.4 V in a laptop-style two-cell pack delivers 37 Wh. Watt-hours collapse both voltage and capacity into one number that scales to risk.
Every regulation from IATA Section II to IATA Section IB keys off Wh, and once you internalize the conversion, you can read any battery label in any country and know where it lands.
The Watt-Hour Tiers That Decide Everything
Three watt-hour bands exist, and the band your battery falls into decides packing position, paperwork, and whether airline approval is required.
Under 100 Wh, The Unrestricted Zone
Anything rated under 100 watt-hours moves through TSA and almost every airline worldwide without paperwork. The Apple MagSafe Battery Pack at 11.1 Wh, a 20,000 mAh Anker PowerCore at 74 Wh, and the Samsung 25 W power bank around 91 Wh all qualify. Roughly 95% of phone, earbud, watch, and laptop banks sold in 2024 land here, which is why the under-100-Wh default rarely trips anyone up.
100 to 160 Wh, Airline Approval Required
A DJI Mavic 3 Intelligent Flight Battery sits at 77 Wh, and a Sony NP-FZ100 camera battery clocks 16.4 Wh, both still safe under the threshold. Step up to a portable laptop charger in the 100 to 160 Wh range and the rule changes. Each carrier requires you to call or check a box at booking, and most cap you at two such batteries per passenger.
Failure to get that pre-approval is the single most common confiscation cause in this band.
Above 160 Wh, Banned as Carry-On
Anything over 160 Wh cannot ride in the cabin on passenger aircraft. Two narrow exceptions exist: wheelchair and mobility-aid lithium batteries installed in the device, and medical equipment batteries supporting life-sustaining gear, both handled through the airline’s special-request desk and never as a spare in your backpack. If your power bank is over 160 Wh, ship it ahead or leave it home.
Converting mAh and Voltage When the Label Is Missing
Divide milliamp-hours by 1,000 to get amp-hours, multiply by voltage, and you have watt-hours. The formula is Wh = (mAh ÷ 1000) × V. A 26,800 mAh bank at 3.7 V works out to 99.16 Wh, sitting one notch under the unrestricted cap. A 30,000 mAh pack at the same voltage hits 111 Wh and crosses into airline-approval territory.
Print that line on a wallet card if you fly with off-brand banks whose labels vanish in the wash.
Knowing your watt-hour tier only matters once you apply it to what actually goes in each bag.
Heads up: damage, recall, or swelling pushes any battery, no matter the watt-hour, into a no-fly zone. A puffy, dented, or recalled cell must not ride in either cabin or hold.
| Wh Tier | Carry-On? | Checked? | Approval Needed? |
|---|---|---|---|
| Under 100 Wh | Yes | Spares: no. Installed: usually yes | No |
| 100 to 160 Wh | Yes, max 2 | Spares: no. Installed: airline-dependent | Yes, airline sign-off |
| Above 160 Wh | No (rare medical exception) | No, unless installed in a mobility device | Not applicable |
| Damaged or recalled | No | No | Not applicable |
Carry-On vs Checked Baggage by Battery Type
Not every battery follows the watt-hour tier the same way. A laptop battery bolted into the chassis behaves differently from a loose 18650 rattling in a camera bag, and vapes, hearing aids, and AirTags each carry their own micro-rule.
Power Banks Always Travel in the Cabin
A power bank is treated as a spare lithium-ion cell no matter the brand or marketing claims. TSA agents repeat the same line at every checkpoint: power banks go in the carry-on, never the hold. The reason is operational: if a power bank vents or ignites in the overhead bin, a flight attendant can see it and move it.
In the cargo hold, the same failure mode goes unnoticed until smoke penetrates the cabin ceiling, by which point options are limited.
Installed Laptop, Phone, and Camera Batteries
Built-in batteries riding inside the device they power can generally travel in checked baggage as long as the device is fully powered off, not in sleep or hibernate mode, and packed so it cannot shift and the activation switch cannot be bumped. TSA still encourages cabin travel for laptops with large batteries, but a properly protected MacBook Pro in a padded sleeve is legal in the hold. Loose spare camera batteries, by contrast, must travel in the cabin.
Lithium-Metal Cells, The Framework Most Guides Skip
Non-rechargeable lithium-metal batteries, the CR123A in a trail camera and the coin cells in a key fob, follow a separate framework based on grams of lithium, not watt-hours. The FAA limits each cell to 2 grams of lithium content, with aggregate limits by battery type. These cells are allowed in both carry-on and checked bags when installed in equipment, but spares must go in the cabin just like lithium-ion spares.
Most guides collapse this into “lithium batteries” and leave you guessing whether your door sensor spares are legal.
Loose 18650s, Vapes, E-Cigs, AirTags, and Hearing Aid Batteries
Loose 18650 cells follow the same spare-battery rule: cabin only, terminals taped or cased, never in the hold. Vapes and e-cigarettes must be carried in the cabin, and the FAA explicitly bans using or charging them on board. Spare lithium-ion cells for vapes follow the standard watt-hour tier. Apple AirTags use a single CR2032 coin cell, which is permitted in both cabin and hold because it falls under the small lithium-metal exemption.
Hearing aid batteries in their retail packs are likewise fine in either bag, but rechargeable hearing aid charging cases count as spares and must ride with you.
Even with the federal rules locked in, each airline still redraws the lines in its own operations manual.
Where US Carriers Diverge From the Federal Baseline
FAA minimums set the floor, but each US carrier builds its own policy on top. Two carriers can both comply with federal law and still disagree about whether a 27,000 mAh bank can charge in seat.
United, Delta, American, and Southwest Side by Side
| Carrier | Max Wh (Spares) | Spare Limit | In-Seat Charging | Notes |
|---|---|---|---|---|
| United | 160 Wh with approval | 2 over 100 Wh | Allowed under 100 Wh only | Larger packs must be off and visible |
| Delta | 160 Wh with approval | 2 over 100 Wh | Allowed, including in-seat outlets | Gate-checks may pull loose power banks |
| American | 160 Wh with approval | 2 over 100 Wh | Allowed | Same TSA baseline |
| Southwest | 160 Wh with approval | 2 over 100 Wh | Allowed | No in-seat power on most 737s |
All four carriers accept the same federal watt-hour floor. The operational drift appears in gate-check behavior and seat-outlet policy, not the number itself.
2024 and 2025 Enforcement Quirks at JFK, LAX, and ATL
JFK terminals have confiscated loose 18650 cells that arrive in contact with each other inside a zip bag. ATL screeners have flagged large-capacity banks in checked luggage at a higher rate than other hubs. LAX tends to follow the printed rule literally: if the Wh is under 100, it goes through without comment. The variation is agent-driven, not policy-driven, which is why printing a label and keeping the battery visible short-circuits most arguments.
Why 20,000 mAh Banks Now Routinely Hit 74 Wh
Cell density has climbed faster than regulators expected. A 20,000 mAh bank rated at 3.7 V is 74 Wh, still under the cap, but the same 20,000 mAh at 7.4 V in dual-cell laptop stacks pushes to 148 Wh. Marketing 20,000 mAh without the voltage number is exactly the ambiguity that gets a battery pulled at the checkpoint. Read the Wh line on the back, not the headline number on the front.
The Gate-Check Problem
When overhead bins fill, gate agents sometimes tag your carry-on for the hold. If that bag contains a power bank, the bag will be offloaded at the jetbridge before it ever leaves the gate. Strip every spare battery out of any bag that could plausibly be gate-checked, including the bag under the seat in front of you.
International Legs and the Rules That Catch Travelers Off Guard
Most US travelers connect through or fly into markets where the watt-hour ceiling is identical but the spare count, paperwork, and gate-check behavior are not. Connecting flights double the exposure because every layover is a fresh screening checkpoint.
EU and UK CAA Rules That Mirror IATA
The European Union Aviation Safety Agency and the UK Civil Aviation Authority both adopt the IATA Lithium Battery Guidance almost word for word, including the 100 Wh default, the 100 to 160 Wh airline-approval band, and the cargo hold ban on spares. Some EU carriers cap you at four spares total under 100 Wh, tighter than the US two-pack rule in the higher tier.
Canada, Australia, and Japan, Where the Caps Shift
Canada matches the US framework but requires Canadian Air Transport Security agents to verify airline approval for the 100 to 160 Wh band. Australia’s Civil Aviation Safety Authority caps you at 15 power banks under 100 Wh with no airline approval. Japan’s JCAB allows up to two spares under 100 Wh and two more between 100 and 160 Wh with carrier sign-off, the most generous count in the major Asia-Pacific markets.
Connecting Flights and Which Screen Counts
On a JFK-FRA-Frankfurt itinerary, the FRA outbound screen applies German rules, but the connecting flight from JFK to FRA is screened under TSA. The strictest rule wins. If your final destination caps you at four power banks and your home carrier allows six, pack four. The transit screen at the connecting airport is the one that confiscates.
Medical-Device Exemptions With Documentation
CPAP machines and lithium backups supporting mobility aids fall under IATA Section II with a special provision. The device battery can exceed 160 Wh when installed in the equipment, and a spare can travel as checked baggage if the airline accepts it. You need a physician’s letter on letterhead, the device’s Wh rating printed on it, and ideally advance notice to the airline’s special-assistance desk. Without that documentation, even a clearly medical device will be pulled at the screen.
Documentation gets devices through the screen, but packing strategy is what keeps your spares from being singled out at the bin.
Packing Spares So Nothing Gets Pulled at the Bin
The cleanest way through any checkpoint is to make every spare battery unambiguous. Visible, labeled, and protected are the three things screeners check first.
Tape the Terminals and Bag Each Cell
Two bare terminals touching a key, coin, or foil wrapper can spark a short that ignites the cell wrapper in seconds. A strip of electrical tape across each terminal, or a separate small plastic case per cell, eliminates the most common cause of battery fires in cabin baggage. Most camera brands ship battery cases for this reason. Loose cells rattling together are a flag, and flags get secondary screening.
Label Each Pack So the Agent Can Verify in Seconds
A printed sticker or permanent-marker line showing manufacturer, voltage, and Wh rating solves most arguments at the bin. Most battery banks already print the Wh on the back. If yours does not, write it there. Agents who can read the rating at a glance wave you through. Agents who cannot will hand-screen it.
Tip: photograph the Wh label of every battery bank before you pack. If a label rubs off mid-flight, you can pull up the photo at the next checkpoint.
What to Do in the Moment of Confiscation
Ask for the airline’s written policy on the spot. If you are in compliance and the agent is wrong, escalate to a TSA supervisor immediately, not after the bag moves on. If the bag is genuinely non-compliant, you generally cannot recover the battery, but you can ask the airline to ship it home via its lost-and-found channel. Most confiscated lithium batteries are destroyed, not returned.
The cost is the battery, not the flight, and TSA does not rebook you for a confiscated power bank.
Pre-Flight Packing Checklist
- Read every Wh label. Anything under 100 Wh goes in the cabin unrestricted. Anything between 100 and 160 Wh needs airline approval on file. Anything above stays home.
- Strip spares from any checked bag. Power banks, loose cells, and vape batteries belong in your personal item or carry-on, full stop.
- Tape terminals or bag each cell. Short-circuit protection is required by 49 CFR 175.20, not optional.
- Power off devices packed in the hold. A sleeping laptop is technically still on; a powered-off laptop in a padded sleeve is legal.
- Carry damaged cells to a battery recycler, not the airport. Puffy, dented, hot, or recalled batteries cannot fly in any bag.
- Photograph labels and approvals. One screenshot per battery is faster than retyping the Wh at every connecting screen.
The Big Picture
One number, watt-hours, decides whether a battery pack sails through, needs a phone call to the airline, or stays home. Memorize the 100 Wh and 160 Wh lines, keep your terminals taped, and your bag passes the screen in seconds.
FAQ
Can a battery pack go in hand luggage?
Yes. Spare lithium-ion battery packs under 100 Wh are allowed in carry-on bags without airline approval. Packs between 100 and 160 Wh require airline sign-off and are capped at two per passenger. Anything over 160 Wh is banned as a carry-on item.
Are power banks allowed in carry-on bags?
Power banks are treated as spare lithium-ion batteries, so the same watt-hour tier applies. TSA, FAA, and IATA all require spare power banks in the cabin, never the hold, regardless of size, brand, or marketing claims.
What size battery pack can you bring on a plane?
Any battery pack under 100 Wh is unrestricted in cabin. Most 20,000 mAh phone banks qualify, but a few 27,000 mAh and larger packs cross into the 100 to 160 Wh band. Always read the watt-hour line, not just the mAh, since voltage changes the math.
Do battery packs have to be in your carry-on, or can they go in checked luggage?
Spares must go in your carry-on. Installed device batteries inside a laptop or camera can ride in checked bags when the device is fully powered off and protected. Loose power banks, 18650s, and vape batteries are cabin-only, no exceptions.
Why are power banks not allowed in checked baggage?
A thermal runaway event in the cargo hold is invisible until smoke penetrates the cabin ceiling, by which point fire suppression is harder. The cabin allows crew to spot a venting battery, isolate it, and use a thermal containment bag within seconds. That visibility is the entire reason for the rule.
How many watt-hours can a power bank have for flights?
Under 100 Wh for unlimited carry-on with no paperwork. Between 100 and 160 Wh with airline approval, capped at two per passenger. Above 160 Wh is banned on passenger aircraft except for installed mobility-aid batteries handled through the airline’s special-request desk.
