I have a Dell Vostro 3650 running Windows 8.1 The battery was giving me about 30 minutes battery life so I bought a new, 9 cell, OEM battery.The "Problem" with the 9 cell battery is that it seems that Windows 8 is not really detecting the battery? I'm not sure. It will only tell me "unknown time remaining". It will not give me a notification of when the battery is going to die (Except the physical red button lighting on the front of the computer).In terms of battery life, the battery works fine. I get hours and hours of battery life so I know the battery is functioning properly. In the BIOS, it is detected as battery performing regularly. I don't know why it is not showing the time. I tried uninstalling the Microsoft ACPI drivers in device manager and rebooting but nothing changed. I was a able to SHORTLY borrow a similar laptop to mine, but running windows 7. The time remaining was being detected. My Bios version is on the latest version. Why is this happening? 
My Computer
At a glance
Windows 8.1 PRO3rd Generation Intel Core i7‐3612QM CPU @ 2.1...8GB DDR3NVIDIA GeForce GT 525M (128 bit), 1GB Grpahics
- Computer type
- PC/Desktop
- Computer Manufacturer/Model Number
- DELL VOSTRO 3650
- OS
- Windows 8.1 PRO
- CPU
- 3rd Generation Intel Core i7‐3612QM CPU @ 2.10GHZ
- Memory
- 8GB DDR3
- Graphics Card(s)
- NVIDIA GeForce GT 525M (128 bit), 1GB Grpahics
- Screen Resolution
- 1920X1080
- Hard Drives
- 750GB 5400RPM