I have the 3rd version and use the lapbook all day allowing the lapbook to go to sleep mode after 15 minutes with the screen on 100% and I’m still at 27% battery power remaining.
Just did a test with v3 Chuwi 14.1 Lapbook and the Lapbook lasted 4 hours with screen 100% the whole time with sleep mode off and playing Link to the Past on a SNES emulator for around 45 minutes. I have the version without the m.2 slot. CPU dynamically adjust as needed and maxes out around 2Ghz.