I tested the battery life just now and would like to share my results.
Firmware is latest .25. Energy Saving mode. Projected onto a 10-inch wall (which I don’t think matters). Sound volume is zero (because I was secretly testing in my office). Playing 1080p MP4 movie files loaded on Sandisk Ultra 128GB microSD card using internal VLC app.
PPMax suddenly shutdown after playing for about 3h50m.
I would say that’s pretty good considering that published specifications only stated 3 hours.
I also posted the same above reply here.