Keep Your Phone Charged Travelling: Power Bank Rules and Plugs

To keep your phone charged while travelling, you need three things: a power bank in your carry-on, the right plug adapter for your destination, and a few battery settings that stop your phone draining while you navigate and take photos all day. Get those right and a dead phone at the end of a long day, just when you need a map back to the hotel, stops being a risk.

This guide covers the airline rules for power banks (with the mAh to Wh maths), which plugs you need in popular destinations, and the settings that make the biggest difference to battery life abroad.

Power bank rules for flights

Lithium batteries can overheat, and a fire in the cabin can be put out where one in the hold cannot. That is why every airline follows the same basic rules, set out internationally by IATA and in Canada by Transport Canada and CATSA. CATSA’s guidance on batteries and power banks is the place to check before a flight from Canada.

Power bank size	Carry-on	Checked bag
Up to 100 Wh	Allowed	Not allowed
100 to 160 Wh	Only with airline approval, usually up to two	Not allowed
Over 160 Wh	Not allowed	Not allowed

Two more rules catch people out. Spare batteries and power banks must be protected from short circuits, so keep them in their own pouch or with the ports covered. And if a gate agent asks to check your carry-on, take the power bank out first.

How to convert mAh to Wh

Power banks are sold by mAh, but airlines set limits in Wh. If the Wh figure is not printed on the case, work it out: mAh × voltage ÷ 1,000. Most power banks use cells rated at 3.6 or 3.7 V.

Power bank	Approximate Wh	Allowed in carry-on?
5,000 mAh	19 Wh	Yes
10,000 mAh	37 Wh	Yes
20,000 mAh	74 Wh	Yes
27,000 mAh	100 Wh	Yes, at the limit
40,000 mAh	148 Wh	Only with airline approval

A 10,000 mAh power bank charges most phones about one and a half to two times, which is plenty for a day out. A 20,000 mAh one is worth it if you also charge a tablet, or share with a travel companion.

Can you use a power bank on the plane?

Not always. Since 2025, a growing list of airlines, including Emirates, have banned using or charging power banks during the flight, and some require them to stay out of the overhead bins. Others still allow it. The rule is set by each airline, so check its dangerous goods or baggage page before you fly, and charge your phone at the gate instead.

Which plug adapter do you need?

Canada uses Type A and B plugs at 120 V. Most of the world does not, so you need an adapter that changes the plug shape. Check the label on your phone and laptop chargers: if it says INPUT 100-240V, as nearly all modern chargers do, the voltage abroad is not a problem and you do not need a converter.

Destination	Plug types	Voltage
United States, Mexico	A, B (same as Canada)	120 V (127 V in Mexico)
Most of Europe (France, Germany, Spain, Italy, Portugal)	C, F (Italy also L)	230 V
United Kingdom, Ireland	G	230 V
Japan	A, B	100 V
Australia	I	230 V
Thailand	A, B, C, O	230 V

For a multi-country trip, a universal adapter with USB-C ports saves space. A compact GaN charger with two or three USB-C ports lets you charge a phone, a power bank and a watch from one socket, which helps in hotel rooms with a single free outlet.

Why your battery drains faster when travelling

On a travel day your phone works much harder than at home. The biggest drains are:

• Navigation. GPS plus a bright screen for an hour of walking directions uses a lot of power.
• The camera. Photos, videos and the screen on full brightness in the sun.
• Searching for a signal. A phone on a weak signal raises its radio power to stay connected. In the countryside or underground, that adds up.
• Two SIMs at once. With your Canadian line and a travel eSIM both on, the phone keeps two connections alive.
• Hotspot. Sharing your connection with a laptop keeps the radio busy; our hotspot guide has tips.
• Cold weather. Apple says iPhone works best between 0 and 35 °C. In the cold, the battery level can drop quickly and recover once the phone warms up.

Settings that make your battery last all day

1. Turn on Low Power Mode (iPhone) or Battery Saver (Android) in the morning, not when you reach 20%. It reduces background activity and screen refresh.
2. Download offline maps on Wi-Fi before you set out. Navigation still needs GPS, but the phone downloads far less.
3. Lower the screen brightness or keep auto-brightness on, and shorten the auto-lock time.
4. Turn off your second line when you do not need it. If you use a travel eSIM for data and only want your Canadian number for occasional texts, our guide to keeping your Canadian number with Dual SIM explains the trade-offs.
5. Limit background refresh for apps you do not need on the trip, and pause photo backups until you are on Wi-Fi.
6. Use airplane mode on the plane. Searching for a network at 10,000 metres drains the battery for nothing.

Avoid public USB charging ports

Airports, trains and cafés often have free USB ports. They are convenient, but they are not under your control: a USB port carries data as well as power, and security agencies have warned about “juice jacking”, where a tampered port tries to access a phone. The risk is low, and the fix is simple: plug your own charger into a wall socket, or charge from your own power bank.

A simple travel charging kit

• A 10,000 or 20,000 mAh power bank, in your carry-on
• A compact charger with at least two USB-C ports
• One plug adapter per country type on your route (or a universal one)
• Two cables: one that lives in your day bag, one in the hotel room

Pack it the night before, together with the rest of our phone checklist before you fly. And if your phone is charged but the internet still feels slow, our free internet speed test tells you in 20 seconds whether the problem is the connection.