Taking a power bank on a plane: the rules that actually apply

Why the rules changed for power banks

For years, airline rules treated a power bank like any spare battery. That has changed. ICAO, the UN aviation agency, added an addendum to its Technical Instructions that separates power banks from spare batteries, and IATA has published guidance for airlines on applying it. IATA's explanation is blunt: power banks are a growing concern because of the risk of thermal runaway and fire on board, manufacturing is cheap and poorly overseen, and cheap units may never have passed the standard UN 38.3 tests.

IATA singles out wireless power banks, the kind that charge a phone by induction, saying several passengers have reported them overheating and destroying themselves. The European aviation safety agency, EASA, issued its own safety bulletin on lithium batteries after a steady rise in incidents, and its advice points the same way: power banks belong in the cabin, where they can be monitored, and are best not used during the flight.

Hand luggage only, and close to you

The one rule that has not changed is the most important: power banks are forbidden in checked baggage. IATA's table for passengers marks them as allowed in carry-on and not allowed in checked bags, and EASA repeats it. If a cabin bag is taken from you at the gate to go in the hold, take the power bank out first.

EASA asks for power banks to be carried where they can be monitored, which in practice means on you or in the bag at your feet. Each one must be protected against short circuits when not in use, for example in its original packaging or with the terminals taped, so that keys or coins in the same pocket cannot touch the contacts. EASA also notes that a lower state of charge is preferable on board and suggests fully recharging after arrival.

Finding the Wh figure on your power bank

The limit is set in watt-hours, not in the milliamp-hours printed in big letters on the box. Many power banks print the Wh rating on the label; if yours only shows mAh, multiply the mAh by the voltage printed next to it and divide by 1,000. A 20,000 mAh power bank at 3.7 V comes to 74 Wh, comfortably under the limit. At 3.7 V, the 100 Wh line falls at about 27,000 mAh.

If the label is worn off or missing, you have no way to show the staff at security what it is, and that is a bad position to argue from. The same goes for a unit with a swollen or damaged case. IATA asks airlines whose crews use power banks to inspect them for damage before use, and the same common sense applies to yours: a battery that is not in good shape is not one to fly with.

Above 100 Wh: ask first, and expect a no

Up to 100 Wh, no approval is needed. Between 100 and 160 Wh, the ICAO addendum allows passengers to carry a power bank with the airline's approval, but IATA has said this allowance is not being carried into its Dangerous Goods Regulations, and its own table for passengers marks power banks above 100 Wh as forbidden. Above 160 Wh, a power bank can only travel as cargo under the dangerous goods rules, not with you.

In practice, a large laptop-style power bank is the one most likely to be refused. If yours is above 100 Wh, check with the airline well before the flight, in writing, rather than at the gate.

Two per person, no charging on board

• No more than two power banks per person.
• The power bank must not be recharged during the flight.
• It should not be used to charge a phone, tablet or other device during the flight.
• Each one protected against short circuits when not in use.

The first two are new requirements in the ICAO addendum and the third is a new recommendation, as IATA lists them. Airlines can be stricter. The Lufthansa Group, for example, says power banks may neither be used nor charged on board its airlines, may only be stored in the seat pocket, on your person or in hand luggage under the seat, and are not allowed in the overhead bins. Check your airline's page before you pack, because the overhead-bin rule catches people out at boarding.

Planning the phone's battery around it

If you cannot charge from a power bank on board, the plan changes slightly. Charge the phone to full before you leave for the airport, top it up at the gate, and use the power bank before boarding or after landing rather than in the air. Download films, music and maps on Wi-Fi beforehand, as in downloading for a flight, so the phone is not searching for a network for hours. Airplane mode does the rest.

The battery matters most in the first hour after landing, when you need the boarding pass, a map and a ride. A data eSIM installed at home connects as soon as you turn on data roaming for it, and our guide on eSIMs and airplane mode explains what to switch when.