Latitude E7240 unable to perform BIOS update

Hi,

I have a Latitude E7240 Ultrabook, 
Intel Core i7-4600U CPU @ 2.10GHz + 2.70 GHz
Windows 10 Pro 64 bit

A few weeks back I noticed that my laptop stopped charging my battery. I managed to charge multiple batteries plus a new one on a colluege's laptp which is exactly the same. When I plug it into my laptop which is then plugged in, it will drain the battery until 60% and just keep it there so it does not lose power nor charges it back up.

The solutions that I have tried so far:

• Changed power adapter
• Replaced 2 other batteries
• Tried a docking station
• Reinstalled a fresh copy of Windows 10
• Replaced power jack with new one, did not make any difference

So far no fix. When I boot it comes up with a message:

"The battery currently attached to the system will not supply enough power to dock for it to function.
Please attach AC power to the dock for it to function normally."

I have run the onboard diagnostics plus the thorough POST mode but it does not detect any problems.

When I press F1 to continue it loads Windows but the performance is very reduced (CPU max 0.78 GHz).

Dell Assistant does not pickup any problem.

I tried to update BIOS from downloading the latest version directly from Dell website, but it says "The AC adapter and battery must be plugged in before the system BIOS can be flashed." and keeps looping this error message.

Anyone has any advice or idea how to possible solve this?

Thank you in advance
Jason