Power banks for travel in NZ: airline rules and what to buy

Airlines treat power banks as dangerous goods because lithium batteries can overheat. Each airline sets its own conditions within international rules, and they can differ by aircraft and route and change at short notice. The safest habit is simple: check with your airline before every trip, including the airline for each leg of a connecting journey.

Useful official starting points are your airline's dangerous goods page, the Aviation Security Service, which runs airport screening in New Zealand, and the Civil Aviation Authority of New Zealand.

When we checked Air New Zealand's batteries and power banks page on 2 October 2026, it said:

• Power banks go in your carry-on bag, never your checked bag, with the terminals protected.
• You can carry up to two power banks, each no more than 100 Wh.
• Keep them under the seat in front, in the seat pocket or on you, not in the overhead locker.
• Do not use a power bank to charge another device during taxi, take-off or landing.
• Do not recharge a power bank from the in-seat power on board.
• Rechargeable earbud and hearing aid charging cases count as power banks.

Treat this as a summary of one airline on one day, not a promise for your flight. Other airlines can be stricter, and Air New Zealand's restricted items page is the place to confirm the current wording.

Airlines use watt-hours (Wh), not milliamp-hours (mAh), because watt-hours measure the energy stored. Many power banks print the Wh figure on the label. If yours only shows mAh, Air New Zealand gives this method: divide the mAh figure by 1,000 to get amp-hours, then multiply by the nominal voltage printed on the battery.

• A power bank labelled 10,000 mAh at 3.7 V: 10,000 ÷ 1,000 × 3.7 = 37 Wh.
• A power bank labelled 20,000 mAh at 3.7 V: 20,000 ÷ 1,000 × 3.7 = 74 Wh.

Use the voltage on your own label rather than assuming. Buying a power bank with the Wh rating printed clearly on it saves a conversation at check-in.

Bigger is not always better for travel. More capacity means more weight in a bag that airlines may weigh, and a large unit can sit closer to the limits above. Think about how long you will be away from a socket: a day of sightseeing or a long-haul flight is a different job from a week of tramping.

Some energy is lost as heat while a power bank charges your phone, so expect fewer full charges than the simple maths on the box suggests. For quick top-ups, choose a power bank with a USB-C output that supports USB Power Delivery; our charger and cable guide explains what wattage your phone can use. A USB-C input also means one cable and one wall charger can look after both your phone and the power bank.

• Pack it where you can reach it, so it can come out at screening if asked and stay with you in the cabin.
• Protect the terminals: keep it in its pouch or a small bag, away from keys and coins.
• Count your earbuds case if your airline treats it as a power bank, as Air New Zealand does.
• Charge it fully at home or at the airport, because you may not be able to recharge it on board.

Pack a short USB-C cable with it. For road trips around New Zealand, a car charger keeps phones going between stops without draining the power bank.

Stop using any power bank that is swollen, cracked, rattles or gets hot while charging, and do not put it in the rubbish: take it to a battery recycling drop-off. Store it somewhere cool and dry, and avoid leaving it in a hot car. If you are buying new earbuds for the trip, see our earbuds and headphones guide.