A good power bank solves that problem but most of them either charge too slowly, run out of juice after one phone charge, or force you to carry a bunch of cables. Anker just dropped the price on their 20,000mAh power bank with a built-in USB-C cable down to $44 from the usual $69 on Amazon. This thing pushes 87W across three devices at once and can charge a MacBook Pro to 50% in under 40 minutes.
It features a pair of USB-C ports that can each output up to 140W of power simultaneously so you can charge two laptops, even if they happen to be a pair of power-hungry 16-inch MacBook Pros. And with a total power output of 300W you can also add a smartphone to the mix and charge it at 20W using an additional USB-A port while your laptops are powering up.