A beach trip tends to involve more battery-powered gear than people realise: a phone, a power bank, an action camera, a waterproof speaker, an e-reader and sometimes a drone. Airlines and aviation regulators treat these items differently from ordinary luggage, and getting it wrong can mean a confiscated item at the security line or a bag pulled off the aircraft. This guide explains the main rules in plain language, how to check whether your power bank is within the limits and what to do about drones before you fly.

The basic rule: spare batteries go in the cabin

The US Federal Aviation Administration publishes its guidance for passengers on its PackSafe pages. The central point is that spare, uninstalled lithium batteries must be carried in the cabin and not in checked baggage. This covers power banks, spare camera batteries, spare drone batteries and loose rechargeable cells. The reason is fire risk: if a damaged battery overheats in the cabin, the crew can see it and respond, while in a cargo hold nobody can.

Devices with the battery installed, such as a phone, laptop or camera, may be allowed in checked baggage under the same guidance, but carrying them in the cabin is the safer choice. If a device must go in a checked bag, switch it fully off, not into sleep mode, and pad it so that it cannot be switched on by pressure. Other regulators, including those in Canada, Mexico and Europe, follow similar principles, although the details can differ, so check the rules for your departure and arrival countries as well as your airline’s own policy.

How to work out your power bank’s size

Limits are set in watt-hours, not in the milliamp-hours printed on most power banks. The calculation is simple: multiply the capacity in milliamp-hours by the battery voltage, then divide by 1,000. Most power banks use cells of around 3.7 volts. For example, a 10,000 mAh power bank is about 37 watt-hours, and a 20,000 mAh bank is about 74 watt-hours. Many manufacturers print the watt-hour rating on the case. If yours does not, the calculation will give you a working figure.

• Up to 100 watt-hours: generally allowed in the cabin without special approval.
• Between 100 and 160 watt-hours: typically needs approval from the airline, and the number of spares is usually limited.
• Above 160 watt-hours: not permitted for passengers on commercial flights.

Most travellers will fall in the first group. Large banks sold for camping or laptops can exceed it, so check before packing.

Protect the terminals

Loose batteries should be protected against short circuits. Keep them in their original retail packaging, in individual plastic bags or in a battery case, or tape over exposed contacts. Do not toss several loose batteries together in a pocket with coins or keys. Damaged, swollen or recalled batteries should not be flown at all. If a power bank is warm in your bag, dented or leaking, leave it at home.

Using power banks in flight

Allowed in the cabin is not the same as allowed in use. Some airlines have introduced their own limits on charging power banks during flight, or require them to be visible and not stowed in a seat pocket or overhead bin while in use. These policies are set by the airline and can change, so read your airline’s page for baggage and electronics before you travel. If a power bank gets hot or starts to smoke, tell the crew immediately and do not try to move or cover it.

Drones and other beach-trip gadgets

Drones raise two separate questions. The first is the battery: drone batteries are often larger than phone power banks and are usually subject to the same watt-hour limits, so check the rating printed on the pack and carry spares in the cabin. The second is the legal side at your destination. Many countries require registration, a permit or a ban on flying near airports, resorts, crowds, beaches or protected areas, and rules change. Do not assume that a drone flown freely at home is permitted at a resort. Ask the property whether it allows drones, and check the national aviation authority’s current rules before you pack one.

Action cameras, waterproof speakers and e-readers are usually simple cases, because their batteries are small. Keep them in your cabin bag, and treat a spare action camera battery like any other spare lithium battery. Rechargeable batteries inside waterproof housings are no different.

Security screening tips

Place power banks and cameras where they can be taken out quickly if the officer asks to look at them. Carry charging cables in the same pouch so that you can show that a bank works if asked. Keeping everything in one organised pouch also shortens the time at the checkpoint. For the wider list of what to carry on the plane, see our guide to what to pack in your carry-on, and for adapters and voltage at your destination read our power adapters guide.

If something is taken or damaged

If a security officer or gate agent tells you an item is not allowed, you will usually have to leave it behind or surrender it, because it cannot be moved into the hold. Photograph the item and the paperwork if there is any dispute, and ask whether the airline will hold it. A travel insurance policy may cover some losses, and our notes on what to check before you buy explain how to read the exclusions.

Before you pack

Rules are set by regulators and airlines, and both can change. Check the FAA PackSafe page at faa.gov, the Transportation Security Administration’s website and your airline’s own baggage page before you pack, particularly for larger power banks and drone batteries.