I’m a new user and love this software 
I have one problem, my old phones battery doesn’t last long 
can you cut +/- on the USB so the printer doesn’t use any power from the phone, or would I break the host connection?
I’m not sure about this solution exactly - but could you get a two-pronged USB-OTG cable and use one of the prongs for charging, the other for controlling the printer?
other users tried Y-cables to charge and print. But it did not work in most cases. As far as I remember, a kernel patch was needed to charge and use OTG at the same time.