Now that the Thunderbolt has extended batteries that have been out and tried for a good while now...let's see what everyone's rankings are based on user experience as the best extended batteries for the Thunderbolt...if you've tried both kinds (ones that fit in the standard cover, and ones that have to have a bigger back door) let's separate those into two separate rankings...let the voting begin! This should be very helpful for new owners, so let's keep discussions down and just list simply the battery, and a few word description... Your top rated extended batteries that fit in existing back cover: 1. 2. 3. Your top rated batteries that require a bigger back cover: 1. 2. 3.