20 - 30 minutos
Phone was randomly shutting off around 30%
Faily easy. Once you figure out how much force is required to undo the ribbon cables went without a hitch. Be careful with Cale 3
Definitely buy the extra spudger. The one that came with the battery is crap and broke both ends inside the phone. May want to buy two of them as appeared like it was going to break when I was prying out the battery. The guide could really use a reverse guide especially for cable three. My advice is find a YouTube video that goes for just that one cable to see how it goes back together.
iPhone 3GS Replacement Battery
Phillips #00 Screwdriver