The Best Portable Charger for Laptops

Watts and watt-hours are different things

Conflating them is why people buy a large bank that will not charge a laptop, or a fast one they cannot fly with.

• Watts (W) is a rate — how fast the bank can deliver power. A laptop wants 45 W at minimum and is happy at 65 W. Below that it charges glacially or merely slows the rate of discharge.
• Watt-hours (Wh) is a quantity — how much energy the bank holds. This is the figure airlines cap, at 100 Wh without approval and 160 Wh with it.

The compact 10,000 mAh class fails on the first: our other bank publishes an output up to 15 V PD, which is a phone charger. It is excellent at being a phone charger. The compact class, compared.

The 100 Wh ceiling, and where 24,000 mAh sits

Airlines write the rule in watt-hours and every product on the shelf advertises milliamp-hours. The conversion is not printed on most boxes, including this one.

So 24,000 mAh is not an arbitrary size. It is close to the largest capacity that reliably clears the threshold with margin, from a manufacturer whose figures you can check. Anything sold as 30,000 mAh or more is over the line and needs the airline’s prior approval. The three thresholds in full.

One honest gap: Anker publishes 24,000 mAh and does not publish a watt-hour figure on the product page. The ~87 Wh above is our arithmetic, not their number. A bank that prints Wh on the case is easier to defend at a gate, and this one leaves you doing the conversion yourself.

1.39 pounds is the real price

The Anker 737 publishes 22.22 oz — 1.39 lb — against 6.8 oz for the compact bank. That is 3.3 times the weight for 2.4 times the capacity, plus the output that makes it useful.

In context: 1.39 lb is a quarter of the empty weight of the lightest carry-on in our ledger, and 5.6% of Hawaiian’s published 25 lb cabin cap. It is the heaviest single item most people would put in a cable pouch, by a distance.

Which makes this a genuine decision rather than an upgrade. If the laptop never leaves a desk with a socket beside it, the compact bank is the right buy and this one is dead weight for the whole trip.

What 87 watt-hours actually does

Note the last column carefully: a bank never delivers its full rated capacity. Voltage conversion loses energy as heat, so the useful output is meaningfully below the rating. Nobody publishes that loss, so we are not going to put a number on it — but a bank rated at one laptop charge delivers slightly less than one.

It flies in the cabin, and only in the cabin

• Under 100 Wh, no approval needed — but it is a spare battery, and spares are prohibited in checked baggage entirely.
• Gate-checking is the trap. If the bins fill and your bag is taken at the door, the bank must come out first. Nothing screens a gate-checked bag. The full gate-check guide.
• Some carriers ask for individual protection against short circuit — original packaging, a case, or terminals taped. Good practice regardless.
• It reads dense on an X-ray and is a common cause of a secondary bag search. Keep it in one pouch and the search takes seconds.

The recommendation

• You need to charge a laptop away from a socket → Anker 737. 140 W published output, roughly 87 Wh, and a published $109.99 to judge value against.
• Phone and headphones only → the compact 10,000 mAh class, at a third of the weight. It is the right answer for most travelers.
• You want a warranty term → neither. Anker publishes 18 months on the compact bank and no term at all on the 737, which is a real gap on a product whose cell degrades over time.
• You are tempted by 30,000 mAh → do not. That is roughly 109 Wh and needs the airline’s prior approval, which is a conversation at a gate you do not want.