Reverse wireless charging is a neat trick, seen on a few high-end phones that have both Qi-powered wireless charging and a big enough battery to occasionally share. But Google’s latest Pixel goes one step further: if you plug it into power the old-fashioned way, it automatically becomes a conventional wireless charging pad.
The “Battery Share” feature on the Pixel 5 can be activated with your phone alone—it’s designed primarily for Google’s own Pixel Buds—but it has to be activated via the settings menu, to avoid accidentally draining the battery. But if you plug in a powered USB cable, flip the phone over, and it detects another Qi device on top of it, it will charge the secondary device all on its own.
This should work with almost any Qi-enabled device, including headphones and other smartphones. It’s a neat little trick, and might come in handy if you have multiple phones that need charging and only one cable, or your iPhone-owning buddy doesn’t have a Lightning plug around.
Source: Google Support via 9to5Google