have you tried cleaning the threads on the battery and the charger? It may just not be making a good connection due to residue.
One of my Volt standard 78mm batteries is taking longer and longer to charge each time I charge it. The last time it took about 3 1/2 hours to charge. Today it has been on the charger for 4 1/2 hours and the LED light is still on. I'm using the USB/Wall charger configuration.
Does this mean that my battery is about shot?