Power analysis

A quick test reveals the Pi+display+WiFi pulls an average ~1.4A, a hefty load on the battery. You might want to use a good quality beefy battery pack to meet the demand.

Also, if you plan to move this display a lot or use it disconnected from power, you might want to change the default ~200mA charging current of the MightyBoost to 500mA by cutting/resoldering this solder jumper: