It seems that Dell Power Adapters now have a memory chip inside them that identifies that the adapter is an official Dell device - The Chip is a DS2501 or similar.
If the computer fails to see the right adapter the battery will not be permitted to charge.
The solution is to fit an approved adapter - you might ask for your money back for the one you bought.
http://www.laptop-junction.com/toast/content/inside-dell-ac-power-adapter-mystery-revealed
Good luck..., January 2015
