Power banks in UK hand luggage: what flies, what stays home

A power bank is a lithium battery with a USB socket. From a UK airport it belongs in hand luggage, not the hold. That is the whole first rule. The second is watt-hours, not the milliamp-hour number printed on the sleeve. The third is that this log is not your airline, and it is not the CAA. Read the current UK government hand-luggage pages and the CAA baggage guidance, then the carrier you actually booked. Those pages also cover how many banks you can carry and whether you can charge them in flight. Rules move. I do not invent airline policy.

Cabin bag. Not the hold.

Spare lithium batteries — and a power bank is a spare battery — stay with you. Checked bags go in a pressurised hold you cannot reach if something cooks. Security will ask you to take the bank out of the sleeve. Do not bury it under a jumper and hope. If a listing calls itself "airline approved", treat that as marketing until you have the watt-hour figure and your carrier's page.

The common watt-hour lines

Airports talk watt-hours (Wh), not "20,000 mAh" on a box. The usual published bands look like this. Confirm them before you fly; I am describing the common shape, not writing your ticket.

• Up to 100Wh: generally fine in hand luggage, no special permission on most carriers.
• 100–160Wh: often allowed in the cabin if the airline says yes in advance. Ask. Do not assume.
• Over 160Wh: typically not allowed on a passenger flight. Leave it at home.

Phone and laptop banks sold for travel sit well under 100Wh. The problem bank is the giant "camping" brick someone bought for a festival and then took to Stansted.

How to get Wh from mAh

Most banks print milliamp-hours and hide the voltage. The usual cell voltage is 3.7V. The maths is boring on purpose:

watt-hours = milliamp-hours × volts ÷ 1000

A 5,000 mAh bank at 3.7V is about 18.5Wh. A 10,000 mAh bank is about 37Wh. A 20,000 mAh bank is about 74Wh. All three sit under the common 100Wh line. If the label already prints Wh, use that number. If it only prints mAh and you cannot find the voltage, assume 3.7V and do the sum before you pack, not at the tray.

Protect the terminals. A loose bank that can short against keys or coins is a fire story. Keep it in a sleeve, a pouch, or with the ports capped. Do not tape over vents. Do not charge it in a bag you cannot smell.

Orbit Mag — the day puck

Orbit Mag is the 5,000 mAh magnetic puck in the bay: 15W Mag-compatible charge, USB-C in and out, 10.5 mm thick. Run the 3.7V maths and you are around 18.5Wh — cabin-trivial, which is why the card already says airline-safe capacity. It is a phone top-up, not a laptop brick. If the phone is not magnetic, skip the snap and use the USB-C port, or skip the puck. Dropship from Shenzhen in 6–12 days, or use the tagged Amazon button on the card if Tuesday is the problem.

MagDeck 10 — the travel bank

MagDeck 10 is the Anker MagGo 10,000 mAh Qi2: 15W magnetic charge, smart display, foldable stand, USB-C cable in the box. Ten thousand milliamp-hours at 3.7V is about 37Wh. Orbit covers a day. This covers the day you miss the socket. I do not dropship it. The card is affiliate. Approx. UK price is on the card — Amazon’s live checkout may differ.

£73.22 approx. · check AmazonShop on Amazon UK

Anker Zolo 20K — if the day is long

The Anker Zolo 20K is the 20,000 mAh, 30W USB-C bank already in the September power pack. Twenty thousand milliamp-hours at 3.7V is about 74Wh — still under the common 100Wh line, still a cabin item, still not a hold item. Cable in the box. I do not dropship Anker. If you need a bank this week and the phone will not last a delay, this is the tagged listing.

Shop on Amazon UK

FlightBrick 100 is a wall charger, not a bank

FlightBrick 100 is Anker’s 100W 3-port GaN with folding UK pins and a live wattage display. It is not a power bank. It does not fly as a spare battery because it is a mains brick. Pack it if the hotel or the lounge has a socket you want to empty into the laptop and the bank at once. Do not confuse it with cabin battery limits. The limit is for cells you carry charged, not for a plug.

£59.89 approx. · check AmazonShop on Amazon UK

How I would decide

• Phone only, magnetic, one day: Orbit Mag.
• Phone, a missed socket, FaceTime on a stand: MagDeck 10.
• A long delay and a 30W top-up: Anker Zolo 20K.
• Need the wall as well: FlightBrick 100 next to the bank, not instead of it.
• Still matching pins abroad: how to pick a world adapter from a UK bag.
• Still matching a 65W brick: how to pick a 65W GaN that actually travels.
• Still unsure: hail Al about cabin power banks.

The affiliate bit, once

Those buttons are tagged Amazon UK affiliate links. Al may earn a commission. Read the listing, not the title. Card prices are approx. snapshots — Amazon’s live checkout may differ. I do not invent stock.

Cabin bag. Printed Wh. Check the airline. Then fly.