Xiaomi Power Bank 20,000mAh 22.5W (Integrated Cable)

A big pack with the cable attached

Twenty thousand on the label, a USB-C cable moulded into the body, and three outputs: the built-in cable, a USB-C port and a USB-A port. That means a phone, a pair of earbuds and a friend's handset can all draw at the same time, and nobody has to hunt for a spare wire when the lights go. At 342 g it lives in a backpack, not a trouser pocket. For daily carry, the smaller Baseus Bipow 10000 mAh is half the weight and half the energy.

What the capacity really means

The figure on the cells is measured inside the pack, at the low voltage the cells themselves run at. To charge a phone, that energy is stepped up to 5V, and some of it turns into heat on the way. Xiaomi does something most brands avoid and prints the result: a rated capacity of 13000mAh at 5V. In practice that is roughly two and a half full charges of a typical 5000 mAh phone, not the four that dividing the headline number suggests. Our power bank buying guide explains why every honest pack loses about a third this way.

22.5W, and what your phone will take

22.5W is the ceiling, and a phone only draws what it and the pack agree on. Galaxy phones start Super Fast Charging at 25W, above this ceiling, so they fill at a steadier rate. USB-C iPhones fast-charge over USB Power Delivery and are happy here. OPPO, vivo and Xiaomi's own phones usually need the brand's charger for their headline speeds and fall back to a shared standard on any third-party pack. The fast charging guide sets out which standard each brand uses.

Flights, and spotting a copy

The cells are rated at 74Wh, under the 100Wh that the US Federal Aviation Administration allows in hand luggage without airline approval, and power banks are banned from checked bags altogether. Airlines add their own rules, so check before flying. Capacity is the one thing a buyer cannot judge by eye, which is why big packs are copied so often: look for crisp printing, a model number on the body that matches the box and a full input, output and Wh table. Our fake charger checklist covers the rest, and the other packs we sell are in the power banks section. Bijli jaye to jaye, phone chalta rahe.