20 - 30 minuten
About two weeks ago, my iPhone 3GS started experiencing rapid battery drain and it would just shut off in the middle of a phone call if it wasn't plugged in to power, regardless of how much charge was on the battery. I Googled the problem and it looked like others had experienced the same symptoms and recommended the iFixIt kit to replace the battery.
This repair was not for the faint of heart. If you are comfortable working on the insides of computers, then you can probably handle this repair. Everything is very tiny inside the iPhone, so it was like performing surgery. Thank goodness for the tools that came with the kit, and the Spudger which I ordered separately from iFixIt. It took me about an hour, but I was able to remove the old battery, install the new battery and have the phone work on the first attempt. It was tricky, since the ribbon cables, connectors, etc. were so darn tiny.
Just take your time with this repair. Read all of the instructions in the guide very carefully. I definitely recommend the hair dryer tip to help loosen the adhesive on the back of the battery. I don't think I could have removed the battery otherwise, at least not without breaking a few things in the process.