
I've been messing around with the powerbank recommended by DannyJK. And it occurs to me: its charge circuit has a power booster to give me 5V; it does pass-through charging so I can play while it's plugged in; it's got dual outputs so I can directly power both my screen and my Pi... and it's free! It is bigger than a powerboost, but that's not an issue for my usage. Powering on/off will be tricker - I can't do a simple on/off switch for the whole system, but I should be able to get around that with a discrete power switch for the screen + shutdown script.
So is there any reason why I can't just use this board, rather than a powerboost?