Power bank rules for flights

Every lithium battery rule in aviation is written in watt-hours, not milliamp-hours, and this is the whole framework:

Almost every consumer power bank sold for travel sits comfortably in the first band. A 10,000 mAh pack is roughly 37 Wh and a 20,000 mAh pack roughly 74 Wh - both well inside 100 Wh with no approval required. The 101-160 Wh band is where large laptop-charging and camera-crew batteries live, and that is the band where you need to call the airline in advance.

Power banks are marketed in milliamp-hours and regulated in watt-hours, which is the source of most of the confusion. The conversion is simple arithmetic:

Wh = (mAh ÷ 1000) × nominal voltage. Lithium-ion cells are nominally 3.7 V, which is the figure manufacturers use. So a 20,000 mAh bank is (20 ÷ 1) × 3.7 = 74 Wh.

• 5,000 mAh is about 18.5 Wh - fine anywhere.
• 10,000 mAh is about 37 Wh - fine anywhere, and the size most people actually carry.
• 20,000 mAh is about 74 Wh - still under 100 Wh, no approval needed.
• 27,000 mAh is about 100 Wh - right at the threshold, so check the printed figure rather than assuming.
• Over about 27,000 mAh crosses into the approval band. Read the case.

You should not have to do this arithmetic at a checkpoint. Reputable manufacturers print the Wh rating on the case, usually in small type next to the capacity and the certification marks. A power bank with no printed rating is the one most likely to be questioned, and some carriers refuse unmarked batteries outright.

TSA is unambiguous: "Spare lithium batteries, which include both power banks and phone chargers, are prohibited in checked luggage." The FAA requires spare lithium-ion and lithium-metal batteries, including power banks and battery charging cases, to be carried in carry-on baggage only.

The logic is containment, not probability. Lithium cell failures are rare, but a cell that enters thermal runaway in the cabin is visible and reachable - crews are trained for it and aircraft carry equipment for it. The same event in a cargo hold is neither. That is why the rule is absolute rather than risk-weighted, and why it applies equally to a 5,000 mAh pocket charger and a 20,000 mAh brick.

It is also why a bag gate-checked at the aircraft door still needs the battery out of it. If your carry-on is taken at the gate, pull the power bank, your laptop and any spare camera batteries and keep them with you. This is the single most common way people breach the rule without meaning to - see what not to pack in checked luggage for the rest of that list.

• Protect the terminals. Keep the bank in its own pouch or with tape over exposed contacts so loose keys and coins cannot bridge them. A short circuit against a set of keys is a real and documented failure mode.
• Keep it where you can see it. Several carriers now require power banks to stay within reach rather than in an overhead bin, specifically so a problem is noticed early.
• Expect in-flight charging restrictions. A growing number of airlines prohibit charging a power bank from an in-seat outlet, and some restrict using one at all during the flight.
• Do not use a damaged pack. Swelling, a soft or split case, or a bank that gets noticeably hot in normal use should not be flown at all - and should not be in a bag.
• Declare the big ones in advance. Anything in the 101-160 Wh band needs the airline's approval before the day of travel, not a conversation at the gate.
• Keep it reachable at your feet, not in the overhead. Long-haul flight essentials covers what else belongs in the personal item, and best personal item bags covers the bag it goes in.

Three things decide whether a power bank is a good travel battery, and capacity is only one of them.

1. A printed Wh rating on the case. This is the single most useful feature at a checkpoint, and it is also a decent proxy for whether the manufacturer takes certification seriously.
2. Capacity matched to what you actually charge. A phone is roughly 3,000-5,000 mAh, so a 10,000 mAh bank is two or three full charges. A laptop needs USB-C Power Delivery and a much larger bank - and that is the one that approaches the threshold.
3. The right output standard. USB-C PD for a laptop or a fast-charging phone; anything will do for earbuds. A huge battery with a slow output is a heavy way to charge a phone overnight.

The picks below are the three sizes that cover almost every trip, and all three sit well inside the 100 Wh no-approval band. Best power banks for travel is the full shortlist, best electronics organizers for travel is where the bank and its cable should live so you can pull them out at a gate check, and best luggage trackers covers the other lithium device most travelers carry.