Manjaro KDE plasma unexpectedly shut down on battery

While I’ve been surfing the web without plugging(battery capacities <= 70%), the OS unexpectedly shut down without any notification. Here is my last previous boot log: Jul 29 15:22:21 8570w kscreen_backend_launcher[1026]: kscreen.xcb.helper: -

I’ve tried to experience it three times on below 70% battery and using another OS without anything like this, so I don’t think It happed because of my hardware.