So I bought a 3rd party extended battery for my Fascinate and it is not supported by Samsung. Found out that the only approved accessories for any Samsung device are listed on their website. If you try to use a 3rd party battery in your phone, the device will not charge it. A message pops up saying "non supported battery - battery will not charge" and the battery indicator just flashes red and empty. The battery will have to be charged by pulling it out and charging in a stand alone battery charger. I talked with a support person at Samsung via chat because their call center is closed on weekends, but they will chat with you 24/7. I swear that customer support person must have only typed maybe 5 words per minute. Most of the words were 3 to 5 letters long except the long words that are 9 and 8 letters long, you can see what they typed in the next sentence. Using any third party accessory will void the warranty.