Brand New Windows 10 Laptop Suddenly Powers Off - Desperate, Have Tried Everything I Could Think Of

Apr 18, 2018
Brand new laptop (Jumper EZBook 3L Pro, Windows 10 Home Build 16299.371) suddenly powered off after a couple hours of use on battery (when battery level was about 30%) without warning and just a short static sound when the screen goes off, like cutting off the power supply on a desktop, not like hibernating. It could not be powered up unless plugged in. Battery percentage when turned on was 0%, and was increasing very fast (reached 100% in 40 minutes). Although at 100%, it keeps showing "plugged in, charging". After leaving it plugged in for about 3 hours at 100%, I disconnected the power cord/charger, laptop immediately went off in the same way (including the static sound). Again couldn't turn it on unless connecting the charger again, indicated level at 0% again, same situation with charging. This happened all the times that I've disconnected the charger. However, booting into safe mode immediately after the 0% was indicated, and disconnecting the power, the laptop ran for more than 3 hours (remember, the battery indicator showed 0% and charging just a few seconds before that!). There have been no sudden shutdowns while in safe mode, only the normal hibernation when the battery was completely exhausted. The battery level of course cannot be monitored in safe mode. I did the safe mode test three times so far, and there have been no sudden shutdowns, with the battery lasting a good few hours each time, although normal mode indicated 0% every time! I tried uninstalling the Microsoft AC Adapter and Microsoft ACPI-Compliant Method Control Battery drivers and reinstalling them to no avail. I have updated all my devices' drivers to the latest version, including the chipset's (Intel Dynamic Platform and Thermal Framework etc.) The event viewer only logs the sudden shutdown but no other errors or critical events. Given the safe mode situation, the battery obviously is in good shape, but I have tried using an identical charger from my brother's laptop (they're exactly the same, he of course has no problems), nothing changed. I've also compared my laptop's devices' drivers with his, and everything seems to be the same.
Problems could have started after latest Windows 10 Update, but can't be sure as I had barely used laptop before that and mostly plugged in.

Any idea of what I should do?