Battery at least 3 years old was pretty much beyond its useful life, you could say I was walking around with a car battery under my arm as I had to constantly plug the phone in. not really very wireless now is it?
Well, I screwed up, my eyes are not great and I really should have purchased some jeweler's loupes, you know the kind you wear?, I lost one of the microscopic screws, no big deal but working without proper light on something this small is just not smart. Anyway I got to the point of replacing the battery and re installing the motherboard, only to find that the SIM card would not go in, because I didn't see when I put the battery in I actually stepped on one of the ribbon cables and of course the battery was not set right in the backing, frustrated I stopped work and set everything aside for the next morning when the sunlight made all the difference in the world, took everything apart and re- assembled successfully. This battery totally rocks, the ifixit kit is complete and awesome, including all tools needed to install, I am very happy and very highly recommend this. Now I have a phone for another 3 years, though tell the truth I'm just waiting for the iPhone 5 :)
Light Light Light, work in a very well lit place and if your vision is not that great, by all means a loupe, things are too small in this devise to work without one and you do need both hands free.