I have been using my riva ego same batteries and charger since September 2010, I had some issues with the batteries getting super hot while charging, however the solution is since I am a dripper, clean the inside of the battery with a q tip dipped in alcohol, clean the charger's battery contact, make sure they are completely dry from both the alcohol and any ejuice. They charge fine and have not given me any problems.
HTH,
Charlie