I bought a used phone, immediate problem with battery. I checked all the functionality with the phone on the charger. Everything seemed solid so I decided to replace the battery, not the phone. My family was VERY sceptical since I had never tried anything like this before except putting display, game and comm boards into pc’s in the bad old days.
Successful but not easy, problem putting tape on new battery. I read all the comments about removing cover from tape, started looking for a problem (none) and then confused my self with the directions. I stretched the tape at the end, I trimmed about 10-15% at the end because it bunched up.
Removing the old battery I broke the the first glue strip, the second came off easily, then lots fussing to get the broken piece out, just be patient.
I put down a piece of packing tape, sticky side up to track all the small screws.
The only other real problem was the tiny connectors, hard to know if they were secure but they all connected successfully. I used the phone for about half a day until the battery discharged to 5% then full charge in a little less than 3 hours.
Easy does it all the way.