I've done a clean install of Windows 7 x64 on an ASUS X501A laptop. The battery is detected and shows in the system tray as "plugged in, charging". However the charge level stays at 76% and if the AC cord is plugged out the laptop turns off. The laptop does not turn on without being plugged in either. Everything worked perfectly prior to reinstall.
- Downloading and installing all the ASUS drivers, including the ATK ACPI driver
- Checking the BIOS - there do not seem to be any battery-related settings
- Flashing the BIOS to the latest version
- Uninstalling Microsoft ACPI-Compliant Control Method Battery in device manager as suggested on the internet
- Full power discharge/ATX reset as suggested by ASUS support: remove mains power charger, remove battery, press and hold power button for 10 seconds, reconnect battery and mains and turn on
I have a feeling all this may have something to do with the EFI BIOS that comes on the laptop. During the reinstall I had to delete all partitions and start anew, because the Windows installer complained about the improper order of GPT partitions. The EFI System Partition was recreated by the installer, and I am guessing that it may be missing the particular ACPI driver needed to make the battery work.
I've tried researching this, but could not come up with any useful info. I am hoping someone here may know a bit more about this and maybe help me understand what's going on and how to fix it. Barring that, I'll have to re-image the drive off an identical ASUS laptop with stock install and hope it fixes things.