INIU P51L power bank (20,000 mAh, 45 W): compact battery with built-in USB-C cable

The INIU P51L is a 20,000 mAh power bank that brings its own USB-C cable: it is built into the housing, so there's no separate cable to pack. Through that cable or the additional USB-C port it delivers up to 45 watts according to INIU – enough to fast-charge current iPhones and Samsung phones, as well as tablets. A third output, in USB-A format, provides up to 22.5 watts.

It measures 11.5 × 7.3 × 2.9 cm and weighs around 326 g, so it fits a jacket pocket or backpack compartment. INIU states that an iPhone 16 reaches 63 percent in 25 minutes. The rated capacity works out to roughly 74 Wh, below the usual 100 Wh limit for power banks in carry-on luggage.

The power bank itself recharges via USB-C at up to 27 watts. You can connect up to three devices at once, such as a phone, earbuds and a smartwatch charger. INIU offers a three-year warranty.

Worth knowing: with three devices connected, total output drops to 15 watts according to the spec sheet – so plug in just one device for fast charging. For laptops, 45 W may be too little or only good for slow top-ups, depending on the model. Due to voltage conversion, your devices receive less than the rated capacity. Power banks belong in your carry-on, not checked baggage, and airline rules take precedence. INIU lists the model on its own site as P51L-E2.