Your pre-travel checklist
- Photograph the capacity label and check the permitted number and capacity with your airline.
- If your cabin suitcase is checked at the gate, remove power banks and spare batteries.
A capacity in mAh without the battery voltage is not the same as Wh. If the label is missing or unreadable, contact your airline before travelling. Check onboard use and charging separately: permission to carry a device does not automatically mean permission to use it during the flight.
Read the rating first
Look for Wh on the power bank itself. If the manufacturer gives only mAh and the cells’ nominal voltage, the approximate calculation is Wh = mAh × V / 1000. For example, 10,000 mAh at 3.7 V is 37 Wh; 20,000 mAh at that voltage is 74 Wh. Do not automatically use the USB output voltage. A calculation replaces neither a readable label nor airline approval.
Make three separate checks
Check capacity, permitted quantity and onboard use separately. Prague Airport currently states a maximum of two spare lithium batteries or power banks up to 100 Wh; discuss higher capacities with the airline. Do not assume the same conditions apply to every flight in a multi-airline booking.
Pack so you can reach it
Give the power bank an accessible pocket. Protect terminals from keys or coins and prevent accidental activation. Check the condition and label before travelling; do not bring a damaged or swollen unit. Photograph the rating the night before departure. A photo helps when asking the airline, but does not replace the device’s own label.
If your cabin bag is checked at the gate
Even a correctly packed cabin suitcase needs reorganising if it is sent to the hold. Remove the power bank and spare batteries before handing over the bag. Leave room in your small personal bag for items that must stay with you in the cabin.
Carriage is not permission to charge
Permission to carry a device does not establish whether you may charge a phone or recharge the power bank during the flight. Read the airline’s onboard-use rules and follow crew instructions. If you need your phone for the return shuttle, keep the contact somewhere else too; do not wait until the battery is almost empty.
Frequently asked questions
Is every 20,000 mAh model acceptable? mAh alone is not enough: voltage, labelling and flight rules matter. An unreadable label? Ask the airline before travelling. Can it go in a checked suitcase? No. Two airlines on the itinerary? Check both, including the connecting and return flights.
IATA’s 2026 update prohibits recharging the power bank onboard and recommends not using it to charge other devices. Airlines may be stricter. Check your carrier’s current instructions before flying.
IATA — Power Banks 2026 (PDF) · IATA — Lithium Batteries (PDF)
Official sources
Prague Airport: Power banks on a flight: check before packing
Prague Airport: security screening
More travel preparation
- Liquids from Prague: Terminal 1 and Terminal 2
- Cabin or checked baggage: what to check
- Prague Airport with a pushchair: car to arrivals
Common questions
May a power bank go in checked baggage?
No. Keep power banks and spare lithium batteries with you in the cabin. Remove them if staff take a cabin suitcase for the hold at the gate.
Is a 20,000 mAh rating enough?
Not on its own. Check the readable manufacturer label, Wh and airline rules. Conversion also depends on cell voltage, not automatically the USB output voltage.
May I charge my phone with an allowed power bank in flight?
Carriage and use are separate. Check your airline’s storage and charging rules and follow the crew. Permission to bring a device aboard is not permission to use it.