How powerful of a power bank do you need to safely charge a laptop?

A power bank is more than its capacity. You also need to know how fast it can deliver power so your laptop doesn't drain while it's connected.

A power bank is more than its capacity. You also need to know how fast it can deliver power so your laptop doesn&#39;t drain while it&#39;s connected.<p><img src="https://www.engadget.com/img/gallery/how-powerful-of-a-power-bank-do-you-need-to-safely-charge-a-laptop/intro-1790180023.jpg" /></p>