I have issues withAdam Beans post, I used mine outside starting around 7. Yes it was still bright out but you can still see and make things out....while it's not ideal, it still functions as it should. I also never had the app disconnect in the half dozen times I used it, nor did I experience any lag whatsoever. I chalk that up to whatever phone he was using and not a fault of the projector or app.
As for charging via a USB pack, that would be great. I'll can imagine there is a adapter that would work and allow it to be charged while on the go.