Thank you for posting the video. For how long this problem has been occurring? Try the below mentioned steps and see if these steps help:
1. Disconnect all peripherals and confirm if system is working fine with AC Adapter only.
2. Remove AC adapter, Battery and drain flea power by pressing and holding the power button for 10-15 seconds. Re-connect the AC Adapter and battery and check if the percentage of charge increases.
3. Check the AC Adapter status in the BIOS. Ensure it is not Unknown/Not Detected.
4. Try charging the battery with the notebook powered off.
5. If any of these steps do not work, please update the latest BIOS from our support site
Note: Plug your computer to a good, working UPS before you update the BIOS. If you experience a loss of AC power or a significant voltage sag/spike during the BIOS flash, you will either have to buy a new BIOS chip or buy a new motherboard.
6. Try swapping with a known good battery (if available). If known good battery stops the light from blinking, the battery is faulty.
7. Try running "Primary Battery test" using Dell Diagnostics. Click here
to find steps on how to run Dell 32-Diagnostics.
8. Run the "MS-Fix it" for "Fix power consumption problems and extend the laptop battery life". Click here
to access this "MS-Fix it".
Do reply with results.
To know more about Dell's products, services and drivers & downloads, please go to http://dell.to/YBlak6