I think it goes without saying that anyone with the tbolt knows the battery sucks! Ive only had mine since july and by the time i reached last week, the battery got so bad it would only hold a charge for about 3 1/2 hours. After reading the suggestion about using the Rezound battery i went out and bought one yesterday. I fully charged it and it has been 26 hours of being unplugged with HEAAAVVVY use of internet, wi-fi and GPS, and i STILL have 10% left! Im so happy i saw the suggestion to use this battery, it beats the hell out of buying the extended one!