Anker 737 Power Bank (PowerCore 24K).

On a spec sheet, the 737 is close to the best power bank you can buy for a laptop-plus-phone travel kit: 24,000mAh, a real-time wattage display instead of a four-dot battery icon, and 140W of output split intelligently across its ports. In two months of daily carry across Southeast Asia, all of that held up exactly as advertised — one overnight charge got a laptop from empty to seventy percent and both phones topped off, every time.

The catch is weight. At just over a pound, it's the single heaviest thing in a daypack that also has to carry a camera, and after the third week I found myself leaving it in the daily bag only on days I knew I'd need the laptop charge, swapping to a smaller 10,000mAh bank the rest of the time.

It's also worth checking your airline's carry-on watt-hour limit before this one goes in a checked bag by mistake — most budget Southeast Asian carriers cap around 100Wh, and this sits right at the edge depending on the exact model. Excellent bank. Just not an everyday-carry one for me.