There is one more thing you may want to try before investing in a new battery. As I mentioned in post #6, try charging the battery offline. That is, in a standalone charger, out of your phone. Most people don't have a standalone charger for BL-5J batteries, but you can use virtually any digital camera charger, provided the batteries have the same nominal voltage (~3.7V) and you have two short pieces of wire and the necessary skills to connect it with the right polarity. Don't leave it unattended and on or near flammable surfaces though. Not recommended to people who don't have a clue about electronics. Risk of fire or explosion.