I just joined this forum and did this myself on my 2nd gen iPod touch and it is my believe that one of the three battery connection or solder points, specifically the middle one, does not have a solder plate or line underneath it like the other two, which were very easy to solder back on, but the middle one gave me the impression I overheated and removed it, but there are no traces of a plate in the middle, not even at the old battery's middle connection point.