I've bought this motor driver, which features a 5v output pin. I connected this and the ground pins to a micro-USB adapter, so that I could use a 2-cell LiPo battery to power the driver and the driver to power the RPi3, without needing extra power sources.
However, after trying it out, the RPi loses wi-fi connection and seems to have random CPU throttles. We believe it is because the driver just doesn't output a stable 5v and 2.5A.
Are we doing something wrong or is this the expected behavior of such (cheap) motor drivers?