Three issues. 1) My phone battery would last 12-16 hours without phone use. 2) Signal strength would drop to 1 bar from 5. 3) Phone would get hot during charging and use.
I followed the installation instructions for disassembly and noticed that the foam insulator on the battery terminal had shifted and could have been providing a high impedance short (the back of my phone would get warm and the charge would last 12 hours). I tried to reposition the foam but it would not stay put so I cut two ¼” X ¼ ” pieces of electrical tape to replace the foam. I also reformed the antenna spring to ensure it made positive contact. Following this I used some isopropyl alcohol to clean the entire rear cover and the mating surfaces on the phone then reassembled per the video and instructions and performed a battery calibration.
It has been two days and I have recorded 40 minutes of talk time and some minor web surfing and I have 75% charge left.
Check the battery terminal insulator, clean all mating surfaces with alcohol.