This is a follow-up to this thread: https://arstechnica.com/civis/threa...-polarity-of-this-laptop-barrel-jack.1491071/tl;dr I have a laptop but no charger, and I'm ...

There are very few things as annoying as your phone battery draining in the middle of a drive, especially when you need it to find your way around. You reach across for your power bank, only to ...