30 minuten - 1 uur
My iPhone 5S battery was slowly dying, as a result it could barley hold a full days worth of charge.
The screen was easy enough to remove. I needed to be careful with the home button ribbon since there was only 1 inch slack. Once I removed all of that, the screen cables and shields, I pulled on the adhesive battery strips to remove them, but they broke. It was very difficult to remove the battery and after it did not budge, I got a hairdryer to heat the base and used the spudger underneath the battery to slowly force it out. The original battery was destroyed in the removal but once it came out then it was easy to remove what was left of the adhesive strips. Putting the replacement battery back in was easy, but it required a small adhesive foam pad on the battery connector. I used a cut piece of a 3M strip and had to take care connecting the screen and the home button ribbon (that bit was really fiddly). everything clicked back into place easily, turned it on and viola! The whole job took approx. 1 hour, most of that time was carefully removing the old battery.
The guide says to slowly pull the adhesive strip when removing the battery, this does not work. you will need to force the battery out by getting a spudger underneath it while taking care not to damage any connectors. I would also recommend a bright light to work under and a good organisation system (you may want to put the individual screws on separate sticky notes so you know where they came from and what step they are from.