Buy in watt-hours, not milliamp-hours, and buy under 100Wh unless you have a reason not to. Product specifications below come from each manufacturer’s own page and the airline rules from the UK Civil Aviation Authority, all read on July 20, 2026.

How to choose

First, understand why Wh is the only number that means anything. Watt-hours are amp-hours multiplied by volts. A bank sold as 10,000mAh could be 37Wh or 39Wh depending on cell voltage, and two banks with the same mAh label can hold different amounts of energy. Nitecore prints the NB10000 Gen4 as 5,000mAh at 7.8V, 39Wh, and adds that this is equivalent to 10,000mAh at 3.9V. Same energy, two labels. Every aviation rule in the world is written in Wh for exactly this reason, and a manufacturer that publishes only mAh is leaving out the figure you will be asked for.

Second, the airline limit, because it caps the whole category. The UK CAA states that power banks up to 100Wh are allowed without operator approval, that 100Wh to 160Wh requires approval from the operator, and that anything over 160Wh is prohibited in passenger baggage. It also caps you at two power banks per person, requires them in carry-on baggage, and says they should never be recharged on board. Spare batteries and power banks must not go in checked luggage at all, and if your cabin bag is gate-checked into the hold you have to take them out first.

Read what that does to your shopping. It puts a hard ceiling on the useful size of a travel power bank at just under 100Wh. It also explains why so many premium banks land at 96Wh, 97Wh or 99.5Wh: that is the largest product a passenger can carry without asking anyone’s permission. The Zendure SuperTank Pro at 96.48Wh is that design decision made visible.

The CAA is the UK regulator, and the figures above are the ones we verified against its published guidance. We have not checked every other national authority, so treat the 100Wh and 160Wh thresholds as verified for the UK and as a strong indication elsewhere rather than as a rule we have confirmed for your country. Individual airlines also set their own stricter limits on quantity and carriage. Check your operator before you fly rather than after you have packed.

Third, size it against what you will charge. A phone battery is roughly 15Wh to 20Wh, so after conversion losses a 39Wh bank is about two phone charges and a 74Wh bank about four. That is the entire calculation for most people camping for a week with a phone, a headlamp and a camera.

Fourth, and this is where people get it wrong, check the output wattage separately. Capacity says how much energy is stored. Output says how fast it comes out, and a laptop cares far more about the second. BioLite publishes 18W total on the Charge 80 PD despite its 74Wh capacity, which is fine for phones and useless for a laptop. Zendure publishes 100W on two of its four USB-C ports and 138W total. If a laptop is on your list, that number is not optional, and no amount of stored energy substitutes for it.

Input wattage matters for the same reason in reverse. An 18W input on a 74Wh bank is a long recharge. A 100W input means you fill it while you eat lunch somewhere with a socket, which in practice is how you keep a bank useful across a long trip.

Last, weight. 143 g, 465 g and 565 g for 39Wh, 74Wh and 96.48Wh. On foot that spread decides it. In a van it does not matter at all.

The short version

On foot, phone and headlamp only: Nitecore NB10000 Gen4, 39Wh at 143 g, IPX7, and nowhere near any airline threshold.

Two people, several days, phones and camera batteries: BioLite Charge 80 PD, 74Wh at 465 g, three ports, 18W total output so laptops are out.

A laptop, and you fly: Zendure SuperTank Pro, 96.48Wh at 565 g with 100W USB-C, sized to sit just under the limit that would otherwise require your airline’s approval.

If you are driving rather than flying, the airline rule stops mattering and the tradeoffs change completely. Where you can park and sleep is the harder question: see free camping in Europe and wild camping, free camping and aires.

More gear pages are in gear.

Sources

  1. UK Civil Aviation Authority, changes to rules on the carriage of lithium cells, batteries and power banks
  2. UK Civil Aviation Authority, Pack right. Safe flight.
  3. Nitecore NB10000 Gen4 power bank, manufacturer product page
  4. BioLite Charge 80 PD portable power bank, manufacturer product page
  5. Zendure SuperTank Pro 26800mAh 100W PD portable power bank, manufacturer product page

Where the original is not in English, the summary above is ours and the linked text is the authority.