How to change the AeroBook battery

You were right. This is not a bios problem. I had to, again, do a clean install with the image file provided by Chuwi as stated here - [Aerobook] [Tutorial]To Reinstall Windows 10 for CHUWI Aerobook.

Battery life now on full charge is only about 1 hour. This is painful!

Now, the function keys like backlight, brightness, volume, etc. only work if I press Fn and then the corresponding key. How can I get it back to the way it was? I have tried reinstalling HID and keyboard drivers, but they didn’t work.
Thanks