M11x r3 not charging when on

I have had this laptop for over 4 years now and for last few months the computer only charges when turned off. When I turn the computer on it usually charges for around 15-45 minutes then stops until the battery runs flat and computer turns off. When restarting with half full battery the computer won't charge. Charger is original.
Has anyone had similar problems? How do you fix this?
Any help is appreciated!

 

Have you already tried doing a power drain/hard reset? If not, disconnect the AC adapter, remove the battery, disconnect the CMOS battery. Hold down the power button 30 seconds. Put the CMOS battery back in. Connect the AC adapter and boot from that. Set everything in the BIOS the way it needs to be set, (date, time, RAID/AHCI and anything else as far as customized settings,) then install the main system battery while the system is running.

If that does not help, try running the Dell PSA test at boot and see if it identifies any issues with the battery or AC adapter.

 

Everything was going great but right around the 45min mark stopped charging after I removed cmos battery.
Dell PSA didn't recognize power adapter and the only error was that battery is reaching its end. Might this be the cause of my problem?

Edit: Managed to get Ac adapter recognized in Dell PSA. Came up as an 90w adapter and no errors were found.

 

Download Hwinfo. It should tell you the wear level on your battery.

http://www.hwinfo.com/